Seismic fluctuation stress measuring and calculating method, device, medium and product

Abstract

The invention discloses a seismic fluctuation stress measuring and calculating method and device, a medium and a product, and relates to the technical field of seismic dynamics research, and the method comprises the steps: constructing an observation region earth crust model according to the earth crust structure parameters of an observation region; according to the earth crust model of the observation area and a seismic source mechanism corresponding to the actually measured seismic wave, determining an excellent seismic phase which contributes to the energy of the actually measured seismic wave at the observation point and an optimal seismic phase combination thereof; respectively determining a fluctuation stress component time history generated by each excellent seismic phase by using a seismic fluctuation stress formula; and superposing the time histories of the fluctuation stress components generated by all the excellent seismic phases according to the time sequence of reaching the observation point to obtain the time history of the seismic fluctuation stress generated at the observation point in the seismic process. According to the method, the optimal seismic phase combination of the actually measured seismic waves at the observation points is determined by constructing the earth crust model of the observation area, and then seismic fluctuation stress measurement and calculation are completed.

Description

Technical Field

[0001] The present application relates to the technical field of seismic dynamics research, and particularly to a method, device, medium and product for calculating seismic wave stress. Background Art

[0002] Earthquake disasters are difficult to predict, have great destructiveness and wide influence. Once they occur, they often bring serious consequences. There are many factors affecting the degree of earthquake disasters. Research shows that 75% of the deaths in earthquakes come from the damage and collapse of buildings. Earthquakes are also the main inducement for landslides. The research on the dynamic stability of slopes is one of the hot issues in geotechnical engineering. Whether it is the damage of buildings by earthquakes or the instability of slopes caused by earthquakes, it is caused by the dynamic load transmitted by seismic waves through rock and soil masses. The direct cause of the seismic damage of rock and soil masses is that the seismic wave stress exceeds the dynamic strength of rock and soil masses. At present, the core index widely used in seismic dynamics research is ground motion acceleration, but ground motion acceleration cannot directly reflect the magnitude of the seismic wave stress generated by seismic waves inside rock and soil masses. Therefore, the calculation of seismic wave stress has important engineering application value.

[0003] The existing technology cannot directly measure seismic wave stress. The material composition and structural configuration of the earth's medium are very complex. It is almost impossible to calculate the wave stress field in a certain area by theoretical methods. Even for methods such as semi-analytical, high-frequency approximation or numerical solution, the current application scope is mostly limited to the calculation of the source stress field, and there is no literature report on the calculation of the seismic wave stress field at observation points far from the earthquake source. Summary of the Invention

[0004] The purpose of the present application is to provide a method, device, medium and product for calculating seismic wave stress, which can calculate seismic wave stress based on measured seismic waves.

[0005] To achieve the above purpose, the present application provides the following solutions:

[0006] In the first aspect, the present application provides a method for calculating seismic wave stress, including:

[0007] Constructing a crust model of the observation area according to the crustal structure parameters of the observation area; the observation area is the area between the earthquake source and the observation point;

[0008] Obtaining the measured seismic wave and the seismic source mechanism parameters corresponding to the measured seismic wave at the observation point;

[0009] Determining the prominent seismic phases that significantly contribute to the energy of the measured seismic wave and their optimal seismic phase combinations at the observation point according to the crust model of the observation area and the seismic source mechanism parameters corresponding to the measured seismic wave; the optimal seismic phase combination includes multiple prominent seismic phases;

[0010] Using the seismic wave stress formula, determine the time history of the wave stress component generated by each dominant seismic phase respectively;

[0011] Superpose the time histories of the wave stress components generated by all dominant seismic phases according to the arrival time sequence at the observation point to obtain the time history of the seismic wave stress generated at the observation point during the earthquake process.

[0012] Optionally, the crust model of the observation area is used to simulate multiple crustal layers in the observation area; the crustal layers include: sedimentary cover layer, upper crust layer and lower crust layer.

[0013] Optionally, based on the crust model of the observation area and the seismic source mechanism parameters corresponding to the measured seismic waves, determine the dominant seismic phases that contribute significantly to the energy of the measured seismic waves at the observation point and their optimal seismic phase combinations; the optimal seismic phase combinations include multiple dominant seismic phases, including:

[0014] Optimize the seismic source parameters and the crust model parameters of the observation area by using sensitivity analysis and seismic phase fitting orthogonal experiment;

[0015] Based on the optimized crust model of the observation area, determine all seismic phases that satisfy Snell's law;

[0016] Screen out the dominant seismic phases that contribute significantly to the energy of the measured seismic waves at the observation point from all seismic phases that satisfy Snell's law to form the optimal seismic phase combination of the measured seismic waves at the observation point.

[0017] Optionally, the wave energy amplitude ratio of the dominant seismic phase is greater than the amplitude ratio threshold of the dominant seismic phase; the amplitude ratio threshold of the dominant seismic phase is 1% of the amplitude ratio of the maximum value of the wave vector modulus of the seismic phase to the maximum value of the vector modulus of the direct SV wave.

[0018] Optionally, the time history of the wave stress component generated by the dominant seismic phase is determined by substituting the time history of the particle vibration velocity of the basic seismic phase vibration of the last wave path of the dominant seismic phase arriving at the observation point into the seismic wave stress formula; the wave path is a section of the seismic wave ray corresponding to the seismic phase, which is used to describe the process of a basic seismic phase propagating from the seismic source to the observation point direction along the seismic phase wave propagation path (i.e., along the ray) in a crustal layer; the basic seismic phases include: P wave, SV wave and SH wave.

[0019] Optionally, the seismic wave stress formula includes: P wave stress tensor formula, SV wave stress tensor formula and SH wave stress tensor formula;

[0020] The P wave stress tensor formula includes: the wave stress component formula generated by the compressional wave P + and the wave stress component formula generated by the tensile wave P - generated;

[0021] The SV wave stress tensor formula includes: the lower shear wave SV + and the formula for the generated wave stress component, and the upper shear wave SV - and the formula for the generated wave stress component;

[0022] The SH wave stress tensor formula includes: the right shear wave SH + and the formula for the generated wave stress component, and the left shear wave SH - and the formula for the generated wave stress component.

[0023] Optionally, the formula for the wave stress component generated by the compressive wave P + is:

[0024]

[0025] where, is the normal stress component generated by the compressive wave P + on the horizontal plane with the coordinate axis z as the normal at the observation point; is the shear stress component generated by the compressive wave P + shearing along the x-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point; is the shear stress component generated by the compressive wave P + shearing along the y-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point; V P is the modulus of the time history of the particle vibration velocity generated by the P wave; λ and μ are collectively called Lame constants; c P is the longitudinal wave velocity; θ m is the incident angle of the seismic wave; α m is the incident direction angle of the seismic wave;

[0026] The formula for the wave stress component generated by the tensile wave P - is:

[0027]

[0028] where, is the normal stress component generated by the tensile wave P - on the horizontal plane with the coordinate axis z as the normal at the observation point; is the shear stress component generated by the tensile wave P - shearing along the x-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point; is the shear stress component generated by the tensile wave P - shearing along the y-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point;

[0029] The formula for the wave stress component generated by the lower shear wave SV + is:

[0030]

[0031] Among them, is the normal stress component generated on the horizontal plane with the coordinate axis z as the normal at the observation point for the down shear wave SV; + The shear stress component that shears along the x-axis direction generated in the horizontal plane with the coordinate axis z as the normal at the observation point; is the down shear wave SV + The shear stress component that shears along the x-axis direction generated in the horizontal plane with the coordinate axis z as the normal at the observation point; is the down shear wave SV + The shear stress component that shears along the y-axis direction generated in the horizontal plane with the coordinate axis z as the normal at the observation point; V V is the modulus of the time history of the particle vibration velocity generated by the SV wave; c S is the shear wave velocity;

[0032] The formula for the wave stress component generated by the up shear wave SV is: - The formula for the wave stress component generated by the up shear wave SV is:

[0033]

[0034] Among them, is the normal stress component generated on the horizontal plane with the coordinate axis z as the normal at the observation point for the up shear wave SV; - The shear stress component that shears along the x-axis direction generated in the horizontal plane with the coordinate axis z as the normal at the observation point; is the up shear wave SV - The shear stress component that shears along the x-axis direction generated in the horizontal plane with the coordinate axis z as the normal at the observation point; is the up shear wave SV - The shear stress component that shears along the y-axis direction generated in the horizontal plane with the coordinate axis z as the normal at the observation point;

[0035] The formula for the wave stress component generated by the right shear wave SH is: + The formula for the wave stress component generated by the right shear wave SH is:

[0036]

[0037] Among them, is the normal stress component generated on the horizontal plane with the coordinate axis z as the normal at the observation point for the right shear wave SH; + The shear stress component that shears along the x-axis direction generated in the horizontal plane with the coordinate axis z as the normal at the observation point; is the right shear wave SH + The shear stress component that shears along the x-axis direction generated in the horizontal plane with the coordinate axis z as the normal at the observation point; is the right shear wave SH + The shear stress component that shears along the y-axis direction generated in the horizontal plane with the coordinate axis z as the normal at the observation point; V H is the modulus of the time history of the particle vibration velocity generated by the SH wave;

[0038] The left shear wave SH - The formula for the generated wave stress component is as follows:

[0039]

[0040] Wherein, is the normal stress component generated by the left shear wave SH - on the horizontal plane with the coordinate axis z as the normal at the observation point; is the shear stress component generated by the left shear wave SH - shearing along the x-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point; is the shear stress component generated by the left shear wave SH - shearing along the y-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point.

[0041] In a second aspect, the present application provides a computer device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to implement the above-mentioned seismic wave stress measurement method.

[0042] In a third aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the above-mentioned seismic wave stress measurement method is implemented.

[0043] In a fourth aspect, the present application provides a computer program product, including a computer program, and when the computer program is executed by a processor, the above-mentioned seismic wave stress measurement method is implemented.

[0044] According to the specific embodiments provided by the present application, the following technical effects are disclosed in the present application:

[0045] The present application provides a method, device, medium and product for calculating seismic wave stress. First, according to the elastic wave theory, a calculation formula for seismic wave stress generated by the basic seismic phases (P wave, SV wave, SH wave) corresponding to the last wave path of the seismic wave reaching the observation point from the seismic source radiation is derived; then, the GRT technology based on ray tracing is used to perform seismic phase fitting on the measured seismic wave, and the seismic phases (dominant seismic phases) that contribute significantly to the measured seismic wave at the observation point are selected according to the magnitude of the seismic phase wave energy, the optimal seismic phase combination of the seismic wave at the observation point is determined, and a fitting seismic wave that is relatively consistent with the measured seismic wave is obtained; at the same time, the wave time history of the dominant seismic phase is also stripped from the measured seismic wave; furthermore, the time history of the wave stress component generated by the dominant seismic phase is calculated by applying the seismic wave stress formula of different basic seismic phases, and the time histories of the wave stress components of all dominant seismic phases in the optimal seismic phase combination are superimposed according to the time sequence of the seismic phases reaching the observation point, so as to obtain the time history of the seismic wave stress generated at the observation point during the earthquake process. The present application proposes a method for performing seismic phase fitting on the measured seismic wave, stripping the dominant seismic phases that contribute significantly to the measured seismic wave energy at the observation point, and determining the optimal seismic phase combination of the seismic wave at the observation point, thereby laying a foundation for calculating the seismic wave stress within a certain depth range at the observation point by using the measured seismic wave at the observation point. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments and technical solutions of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only one embodiment of the present application, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0047] Figure 1 It is a flowchart of a method for calculating seismic wave stress in an embodiment of the present application;

[0048] Figure 2 It is a stereographic projection diagram of the focal mechanism of the 7.0-magnitude earthquake in Jiuzhaigou in an embodiment of the present application;

[0049] Figure 3 It is a vertical displacement time history diagram of the direct P wave (P2 - P1) in an embodiment of the present application;

[0050] Figure 4 It is a vertical displacement time history diagram of the dominant seismic phase with the basic seismic phase of the P wave in the last wave path in an embodiment of the present application;

[0051] Figure 5 It is a vertical displacement time history diagram of the direct SV wave (SV2 - SV1) in an embodiment of the present application;

[0052] Figure 6In an embodiment of the present application, it is the vertical displacement time history diagram of the dominant seismic phase with the basic seismic phase of SV wave in the last wave path;

[0053] Figure 7 In an embodiment of the present application, it is the tangential displacement time history diagram of the direct SH wave (SH2 - SH1);

[0054] Figure 8 In an embodiment of the present application, it is the tangential displacement time history diagram of the dominant seismic phase with the basic seismic phase of SH wave in the last wave path;

[0055] Figure 9 In an embodiment of the present application, it is the time history diagram of the fluctuating stress component of the dominant seismic phase with the basic seismic phase of P wave in the last wave path;

[0056] Figure 10 In an embodiment of the present application, it is the time history diagram of the fluctuating stress component of the dominant seismic phase with the basic seismic phase of SV wave in the last wave path;

[0057] Figure 11 In an embodiment of the present application, it is the time history diagram of the fluctuating stress component of the dominant seismic phase with the basic seismic phase of SH wave in the last wave path;

[0058] Figure 12 In an embodiment of the present application, it is the time history diagram of the seismic fluctuating stress generated within a certain depth range of the ground surface at the Wenxian Seismic Station observation point during the 7.0 - magnitude Jiuzhaigou earthquake; Figure 12 (a) is the σ z time history diagram generated within a certain depth range of the ground surface at the Wenxian Seismic Station observation point during the 7.0 - magnitude Jiuzhaigou earthquake in an embodiment of the present application; Figure 12 (b) is the τ zx time history diagram generated within a certain depth range of the ground surface at the Wenxian Seismic Station observation point during the 7.0 - magnitude Jiuzhaigou earthquake in an embodiment of the present application; Figure 12 (c) is the τ zy time history diagram generated within a certain depth range of the ground surface at the Wenxian Seismic Station observation point during the 7.0 - magnitude Jiuzhaigou earthquake in an embodiment of the present application. Detailed implementation manners

[0059] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only one embodiment of the present application, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0060] To make the above - mentioned objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below in conjunction with the drawings and specific implementation manners.

[0061] In an exemplary embodiment, as Figure 1 shown, a method for calculating seismic wave stress is provided, including:

[0062] Step 101: Construct a crust model of the observation area according to the crust structure parameters of the observation area. The observation area is the area between the seismic source and the observation point. The crust model of the observation area is used to simulate multiple crustal layers of the observation area. The crustal layers include: sedimentary cover layer, upper crust layer, and lower crust layer.

[0063] Step 102: Obtain the measured seismic wave and the seismic source mechanism parameters corresponding to the measured seismic wave at the observation point.

[0064] Step 103: Determine the dominant seismic phases and their optimal phase combinations that significantly contribute to the energy of the measured seismic wave at the observation point based on the crust model of the observation area and the seismic source mechanism parameters corresponding to the measured seismic wave; the optimal phase combination includes multiple dominant seismic phases.

[0065] Step 103 includes: optimizing the seismic source parameters and the crust model parameters of the observation area by using sensitivity analysis and seismic phase fitting orthogonal experiment. Based on the crust model of the observation area with optimized parameters, determine all seismic phases that satisfy Snell's law. Screen out the dominant seismic phases that significantly contribute to the energy of the measured seismic wave at the observation point from all seismic phases that satisfy Snell's law to form the optimal phase combination of the measured seismic wave at the observation point. The amplitude ratio of the dominant seismic phase wave energy is greater than the amplitude ratio threshold of the dominant seismic phase. The amplitude ratio threshold of the dominant seismic phase is 1% of the amplitude ratio of the maximum value of the seismic phase wave vector modulus to the maximum value of the direct SV wave vector modulus.

[0066] By performing seismic phase fitting on the measured seismic wave, stripping out the dominant seismic phases that significantly contribute to the energy of the measured seismic wave at the observation point from the measured seismic wave, and determining the optimal phase combination of the seismic wave at the observation point, this step includes: 1) Establishing a crust model according to the crust structure of the area between the seismic source and the observation point; 2) Generating all seismic phases that satisfy Snell's law according to the layered structure of the crust model between the seismic source and the observation point; 3) Screening out the dominant seismic phases that significantly contribute to the seismic wave at the observation point according to the magnitude of the seismic phase wave energy, and determining the optimal phase combination participating in the seismic phase fitting; 4) Using the optimal phase combination participating in the seismic phase fitting to superimpose to obtain a synthetic seismic wave, and adjusting the seismic source and crust model parameters with the best waveform fitting similarity between the synthetic seismic wave and the measured seismic wave as the standard, and finally confirming the optimal parameter combination of the seismic source and the crust model and realizing the stripping of the dominant seismic phases of the measured seismic wave.

[0067] 1) Establishing a crust model according to the crust structure of the area between the seismic source and the observation point specifically includes:

[0068] Based on the research results of the crustal structure, the crustal model between the earthquake hypocenter and the seismograph in this application is set to three layers - the sedimentary cover (n1), the upper crust (n2), and the lower crust (n3). Below the crust is the upper mantle. The interface between the lower crust and the upper mantle is the Moho discontinuity. The thickness of the sedimentary cover is set to 2 km, the thickness of the upper crust is set to 26 km, and the thickness of the lower crust is set to 15 km. The elastic wave velocity of each layer is calculated by weighted average according to the thickness. The medium density of each layer of the crustal model is set. The generalized crustal model and its initial parameters used for phase fitting in this application are determined as shown in Table 1 according to the above method.

[0069] 2) Generate all seismic phases that satisfy Snell's law according to the layered structure of the crustal model between the hypocenter and the observation point, specifically including:

[0070] There are three basic seismic phase types of seismic waves (body waves) radiated from the hypocenter: P waves, SV waves, and SH waves. These body waves reach the observation point through different crustal layers along different paths in the crust, and each passing through a stratum is a wave path segment. Referring to the crustal layer model given in Table 1, the basic seismic phase wave paths (ray segments) passing through each crustal layer are represented by adding the corresponding layer sequence numbers to the basic seismic phase type symbols (P1, SV1, SH1; P2, SV2, SH2; P3, SV3, SH3). The different seismic phase fluctuations reaching the observation point are expressed by segmental combination of each segment of the basic seismic phase wave path. For example, the propagation path (ray segment) of the direct P wave from the hypocenter to the observation point is that the hypocenter radiates a P wave → P wave in the second layer → P wave in the first layer → direct P wave at the observation point, which can be expressed as P2 - P1.

[0071] Table 1 Initial parameter table of the horizontally homogeneous layered generalized crustal model used for phase fitting

[0072]

[0073] 3) Screen out the dominant seismic phases that contribute significantly to the seismic waves at the observation point according to the magnitude of the seismic phase wave energy, and determine the optimal seismic phase combination for phase fitting, specifically including:

[0074] Screen reasonable seismic phase combinations for seismic phase fitting from the seismic phases that conform to Snell's law according to the energy magnitude criterion. Use the CPS330 software to perform energy analysis on the seismic phase fluctuations corresponding to the three basic seismic phases, namely P-wave, SV-wave, and SH-wave, radiated by the seismic source at the observation point, and screen out the dominant seismic phases corresponding to the three seismic source radiation fluctuations at the observation point, and then determine the optimal seismic phase combination of the seismic fluctuations at the observation point: 1) Analyze the energy of all seismic phase fluctuations of the three basic seismic phases, namely P-wave, SV-wave, and SH-wave, radiated by the seismic source and reaching the observation point after passing through each layer of the crust, and obtain the maximum value of the acceleration vector modulus of each seismic phase fluctuation and its amplitude ratio to the maximum value of the acceleration vector modulus of the direct SV-wave; 2) Select the seismic phases with an amplitude ratio to the maximum value of the direct SV-wave vector modulus reaching or exceeding 1% as the dominant seismic phases, and form the optimal seismic phase combination participating in the seismic phase fitting for the seismic phase fitting of the measured seismic waves.

[0075] 4) Use the optimal seismic phase combination participating in the seismic phase fitting to superimpose to obtain the synthetic seismic wave, and adjust the seismic source and crust model parameters with the criterion of the optimal waveform fitting similarity between the synthetic seismic wave and the measured seismic wave. Finally, confirm the optimal parameter combination of the seismic source and crust model and realize the stripping of the dominant seismic phases of the measured seismic wave, specifically including:

[0076] After determining the optimal seismic phase combination participating in the seismic phase fitting, it is still necessary to repeatedly adjust the parameters of the seismic source and crust model so that the fitting similarity between the synthetic seismic wave obtained by superimposing the optimal seismic phases generated by the seismic source and crust model determined by parameter adjustment and the measured seismic wave reaches the optimum. First, perform a sensitivity analysis on all seismic source and crust model parameters, and then select the parameters with higher sensitivity as the objects for parameter adjustment for the orthogonal test of seismic phase fitting, so as to quickly search for the relatively optimal parameter combination of the seismic source and crust model.

[0077] Use the fitting similarity C to control and evaluate the similarity (fitting effect) between the synthetic seismic wave superimposed by the optimal seismic phase combination participating in the seismic phase fitting and the measured seismic wave. The calculation formula of the fitting similarity C is as follows:

[0078]

[0079] In the formula: X represents the amplitude sequence of the measured seismic wave, Y represents the amplitude sequence of the synthetic seismic wave, the time intervals (Δt) of the amplitude sequences of the measured seismic wave and the synthetic seismic wave are the same, and the quantities (n) are the same; x i and y i respectively represent the i-th sampling value of the amplitude sequence of the measured seismic wave and the amplitude sequence of the synthetic seismic wave; and respectively represent the average values of the amplitude sequences of the measured seismic wave and the synthetic seismic wave.

[0080] System parameter sensitivity analysis: The optimal waveform fitting similarity C that can be achieved by adjusting only this parameter while keeping the initial values of other parameters unchanged max The absolute difference ΔC relative to the initial waveform similarity value C0 (ΔC = |C max - C0|) is the sensitivity of this parameter. The larger the absolute difference ΔC, the greater the sensitivity of the parameter to the fitting similarity C. Calculating the seismic wave stress requires observing the three-component particle vibration process generated by the seismic wave at the observation point. To avoid the situation where the fitting result of one direction component is excellent while the results of the other two directions are not ideal, the average convergence of the three-component waveform fitting similarity (i.e., the difference between the average values of the three-component waveform fitting similarity obtained from two consecutive parameter adjustments tends to decrease and is less than a certain value) is used as the standard for evaluating the best fitting effect.

[0081] Phase fitting orthogonal experiment: Select the first 9 parameters with larger sensitivity ΔC as the parameters to be adjusted for further phase fitting. These 9 parameters are: h s (Seismic source depth), d f (Dip angle of the seismogenic fault), λ f (Slip angle of the seismogenic fault), h1 (Thickness of the first layer of the crust model), c P1 (P-wave velocity of the first layer of the crust model), c S1 (S-wave velocity of the first layer of the crust model), c P2 (P-wave velocity of the second layer of the crust model), c S2 (S-wave velocity of the second layer of the crust model), h3 (Thickness of the third layer of the crust model). Further phase fitting adopts the method of orthogonal experiment to improve the efficiency of phase fitting.

[0082] Step 104: Use the seismic wave stress formula to determine the time history of the stress components generated by each dominant seismic phase respectively.

[0083] Taking the local observation coordinate system (x m , y m , z m ) of the observation point as a reference, according to the elastic wave theory, the calculation formulas of the seismic wave stress generated by the basic seismic phases (P-wave, SV-wave, SH-wave) corresponding to the last wave path of the seismic wave radiated from the seismic source to the observation point are derived. The seismic wave stress formula includes: P-wave stress tensor formula, SV-wave stress tensor formula, and SH-wave stress tensor formula. The P-wave stress tensor formula includes: the formula for the stress component generated by the compressional wave P + and the formula for the stress component generated by the tensile wave P - . The SV-wave stress tensor formula includes: the formula for the stress component generated by the down shear wave SV + and the formula for the stress component generated by the up shear wave SV - . The SH-wave stress tensor formula includes: the formula for the right shear wave SH+ The formula for the generated fluctuating stress component and the left shear wave SH - The formula for the generated fluctuating stress component. When calculating the time history curve of the fluctuating stress generated by the P wave, the seismic phase at the observation point is the compressive wave P with the initial displacement forward + , then the formula for the fluctuating stress component generated by the compressive wave P + is used to calculate the stress component; the seismic phase is the tensile wave P with the initial displacement backward - , then the formula for the fluctuating stress component generated by the tensile wave P - is used to calculate the stress component. When calculating the time history curve of the fluctuating stress generated by the SV wave, the seismic phase at the observation point is the down shear wave SV with the initial vertical component downward + , then the formula for the fluctuating stress component generated by the down shear wave SV + is used to calculate the stress component; the seismic phase is the up shear wave SV with the initial vertical component upward - , then the formula for the fluctuating stress component generated by the up shear wave SV - is used to calculate the stress component. When calculating the time history curve of the fluctuating stress generated by the SH wave, the seismic phase at the observation point is the right shear wave SH with the initial tangential displacement to the right + , then the formula for the fluctuating stress component generated by the right shear wave SH + is used to calculate the stress component; the seismic phase is the left shear wave SH with the initial tangential displacement to the left - , then the formula for the fluctuating stress component generated by the left shear wave SH - is used to calculate the stress component. Finally, the seismic fluctuating stress components caused by all seismic phases in the same seismic fluctuation process at the same observation point are superimposed (algebraic sum of components) in the order of arrival at the observation point, and the time history curve of the fluctuating stress reflecting the change process of the seismic fluctuating stress in the rock and soil mass within a certain depth (half wavelength) range of the observation point can be obtained.

[0084] Specifically, the formula for the fluctuating stress component generated by the compressive wave P + is as follows:

[0085]

[0086] Among them, is the normal stress component generated by the compressive wave P + on the horizontal plane with the coordinate axis z as the normal at the observation point. is the shear stress component generated by the compressive wave P + shearing along the x-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point. is the shear stress component generated by the compressive wave P + shearing along the y-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point. V PThe modulus of the particle vibration velocity time history generated by the P wave. λ and μ are collectively called Lame constants. c P is the longitudinal wave velocity. θ m is the incident angle of the seismic wave. α m is the incident direction angle of the seismic wave.

[0087] Tensile wave P - The formula for the generated wave stress component is:

[0088]

[0089] Among them, is the normal stress component generated by the tensile wave P - on the horizontal plane with the coordinate axis z as the normal at the observation point. is the tensile wave P - The shear stress component that shears along the x-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point. is the tensile wave P - The shear stress component that shears along the y-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point.

[0090] Lower shear wave SV + The formula for the generated wave stress component is:

[0091]

[0092] Among them, is the normal stress component generated by the lower shear wave SV + on the horizontal plane with the coordinate axis z as the normal at the observation point. is the lower shear wave SV + The shear stress component that shears along the x-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point. is the lower shear wave SV + The shear stress component that shears along the y-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point. V V is the modulus of the particle vibration velocity time history generated by the SV wave. c S is the shear wave velocity.

[0093] Upper shear wave SV - The formula for the generated wave stress component is:

[0094]

[0095] Among them, is the normal stress component generated by the upper shear wave SV - on the horizontal plane with the coordinate axis z as the normal at the observation point. is the upper shear wave SV -The shear stress component that is sheared along the x-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point. is the up shear wave SV - The shear stress component that is sheared along the y-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point.

[0096] The formula for the wave stress component generated by the right shear wave SH+ is:

[0097]

[0098] where is the right shear wave SH + The normal stress component generated on the horizontal plane with the coordinate axis z as the normal at the observation point. is the right shear wave SH + The shear stress component that is sheared along the x-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point. is the right shear wave SH + The shear stress component that is sheared along the y-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point. V H is the modulus of the time history of the particle vibration velocity generated by the SH wave.

[0099] The left shear wave SH - The formula for the wave stress component generated is:

[0100]

[0101] where is the left shear wave SH - The normal stress component generated on the horizontal plane with the coordinate axis z as the normal at the observation point. is the left shear wave SH - The shear stress component that is sheared along the x-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point. is the left shear wave SH - The shear stress component that is sheared along the y-axis direction in the horizontal plane with the coordinate axis z as the normal at the observation point.

[0102] Step 105: Superimpose the time histories of the wave stress components generated by all the prominent seismic phases in the order of their arrival at the observation point to obtain the time history of the seismic wave stress generated at the observation point during the earthquake process. The time history of the wave stress component generated by the prominent seismic phase is determined by substituting the time history of the particle vibration velocity of the basic seismic phase fluctuation of the last wave path of the prominent seismic phase arriving at the observation point into the seismic wave stress formula. The wave path is a segment of the seismic wave ray corresponding to the seismic phase, which is used to describe the process of a basic seismic phase propagating from the earthquake source to the observation point along the seismic phase propagation path (ray) in a crustal layer. The basic seismic phases include: P wave, SV wave, and SH wave.

[0103] Strip the fluctuation time history of the dominant seismic phase from the measured seismic waves; then, apply the seismic wave stress formulas for different basic seismic phases to calculate the time history of the fluctuation stress components generated by the dominant seismic phase, and superimpose the time histories of all the fluctuation stress components of the dominant seismic phases in the optimal seismic phase combination according to the time sequence of the seismic phases arriving at the observation point, so as to obtain the time history of the seismic wave stress generated at the observation point during the earthquake process.

[0104] The specific steps for calculating the seismic wave stress are as follows: Substitute the time history of the particle vibration velocity of the seismic wave of the last wave path (ray segment) of each dominant seismic phase arriving at the observation point in the optimal seismic phase combination finally determined by seismic phase fitting into the corresponding basic seismic phase wave stress formula to obtain the time history of the fluctuation stress component of each seismic phase; then, according to the time sequence of each seismic phase arriving at the observation point (assuming the earthquake origin time t = 0, the seismic phase propagation time from the earthquake source to the observation point obtained by ray tracing is the time when the seismic wave of the seismic phase arrives at the observation point, and the time sequence of each seismic phase arriving at the observation point is the time sequence), superimpose the stress components of each seismic phase (algebraic sum of the components), and the time history of the seismic wave stress generated by the measured seismic wave at the observation point can be obtained. The specific steps are as follows:

[0105] Calculation parameters: It can be seen from the seismic wave stress calculation formula that to calculate the seismic wave stress, it is necessary to know the incident direction angle α m and the incident angle θ m ; the Lame constants λ and μ of the medium where the observation point is located (the shallowest layer of the crust model, that is, the first-layer medium), as well as the density ρ, longitudinal wave velocity c P and shear wave velocity c S ; the time history of the particle vibration velocity V(t) generated by the seismic wave of this seismic phase at the observation point, corresponding to the particle vibration velocities of the basic seismic phases P, SV, and SH, and V(t) is expressed as V P 、V V 、V H respectively. The time history of the particle vibration velocity V(t) of the incident wave of each seismic phase at the observation point can be calculated using the CPS330 software based on the parameters obtained in the previous section. According to the epicenter azimuth of the Jiuzhaigou M7.0 earthquake relative to the Wenxian seismic station the incident direction angle α m of the seismic wave is 340°. The incident angle θ m of the last wave path of each seismic phase can be determined according to Snell's law based on the propagation path of each seismic phase. According to the crust model parameters determined by seismic phase fitting, the density ρ of the medium near the observation point (the first-layer medium of the crust model) is 2.3 g / cm 3 , the longitudinal wave velocity c P = 5.31 km / s, and the shear wave velocity c S = 3.15 km / s. The Lame constants (λ, μ) can be obtained from the seismic wave velocities c P and cS Obtained by back-calculation: λ = 19.2 GPa, μ = 22.8 GPa.

[0106] Calibration of the initial motion direction of seismic wave phases: Calculation of the components of seismic wave dynamic stress also requires clarifying the relationship between the initial motion direction of the displacement of the basic seismic wave phases (P wave, SV wave, and SH wave) of the last wave path segment of each seismic phase arriving at the observation point participating in the superposition of synthetic seismic waves and the wave propagation direction: P wave - forward (compression wave P + ), backward (tensile wave P - ); SV wave vertical displacement - downward (down shear wave SV + ), upward (up shear wave SV - ); SH wave tangential displacement - to the right (right shear wave SH + ), to the left (left shear wave SH - ). Only in this way can we determine which formula in the dynamic stress is used to calculate the dynamic stress at the observation point. The determination of the initial motion direction of the basic seismic wave displacement of the last wave path segment of different seismic phases depends on the correspondence between the initial motion direction of the seismic wave displacement waveform and the source fault dislocation direction (source mechanism). Affected by the change in interface wave impedance, the seismic waves of different seismic phases are reflected by different interfaces, and the initial motion displacement direction will change. The correspondence between the initial motion directions of the seismic waves of different seismic phases at the observation point and the source fault dislocation direction is relatively complex; however, the direct wave starts from the source and only passes through the transmission of different crustal layer interfaces. Therefore, the initial motion direction of the direct wave displacement is consistent with the radiation wave displacement direction of the source fault. Therefore, through the correspondence between the initial motion direction of the basic seismic wave displacement waveform of the last wave path segment of the direct wave and the source fault dislocation direction, the positive and negative (up and down) of the initial motion direction of the basic seismic wave displacement waveform of the seismic wave at the observation point generated by the software can be calibrated with the corresponding relationship between the actual (physical) dynamic displacement initial motion direction at the observation point (P wave incident direction displacement initial motion - forward, backward; SV wave vertical displacement initial motion - upward, downward; SH wave tangential displacement initial motion - to the right, to the left).

[0107] The specific method for calculating the dynamic stress is as follows:

[0108] (1) Calculation of P-wave dynamic stress

[0109] Reference Figure 2The focal mechanism solution shown by Yi Guixi (the figure shows the lower hemisphere stereographic projection of the P-wave first motion solution of the double couple source. The white area is the tensile stress area, and the black area is the compressive stress area). Wen County Seismic Station (62WEX) falls within the azimuth corresponding to the tensile stress area of the stereographic projection of the focal mechanism solution of the Jiuzhaigou M7.0 earthquake. Therefore, it can be determined that in the direction from the focal point to the observation point, the wave stress generated by the first motion of the P-wave displacement radiated by the focal point in the surrounding medium (including the observation point) is tensile stress, and the actual first motion direction of the direct P-wave (P2 - P1) at the observation point points to the focal point. Considering that the direct wave ray starts from the focal point and reaches the observation point obliquely upward, and the first motion of the vertical component of the P-wave displacement at the observation point points downward (the P-wave displacement vector is backward along the ray direction, pointing to the focal point), so the nature of the direct P-wave is a tensile wave P - , formula (2) should be used to calculate the wave stress.

[0110] From Figure 3 the vertical displacement time history diagram of the direct P-wave phase (P2 - P1) at the observation point calculated by the CPS software as shown, it can be seen that the first motion of the vertical component of the calculated waveform (analysis) of the direct P-wave at the observation point is negative (downward). Comparing with the first motion direction of the direct P-wave displacement at the observation point determined by the above focal mechanism solution, in the local observation coordinate system (x m (E), y m (N), z m (U)) of the observation point, the negative (downward) first motion of the vertical component waveform of the calculated displacement of the direct P-wave at the observation point corresponds to the downward (backward, tensile wave P - ) of the actual (physical) vertical component displacement of the P-wave at the observation point; conversely, the positive (upward) first motion of the vertical component waveform of the calculated displacement of the direct P-wave at the observation point corresponds to the upward (forward, compressive wave P + ) of the actual (physical) vertical component displacement of the P-wave at the observation point. This correspondence applies to all phases whose last segment of the wave path is basically a P-wave. Therefore, this is the calibration result of the positive and negative of the first motion of the vertical component displacement of the calculated displacement waveform of all phases whose last segment of the wave path is basically a P-wave reaching the observation point with respect to the upward (forward, compressive wave P + ) or downward (backward, tensile wave P - ) of the actual (physical) vertical component displacement of the P-wave at the observation point by using the correspondence between the first motion direction of the calculated displacement waveform of the last segment of the wave path of the direct P-wave and the fault dislocation direction at the focal point.

[0111] Figure 4 are the vertical displacement time history diagrams of the other three dominant phase waves of the last segment of the wave path that are P-waves except for the direct P-wave (P2 - P1) calculated and generated by the CPS software. From Figure 4It can be seen that when the SV wave is incident from the upper crust to the interface of the overlying layer, it is converted into a P wave through waveform conversion and enters the overlying layer to reach the observation point. The first motion of the SV2-P1 seismic phase is downward (backward), which is a tensile wave P - , which is consistent with the direct P wave. The formula (2) should be used to calculate the stress component; the first motion of the P wave in the last wave path of the remaining seismic phases is upward (forward), which is a compressive wave P + . The formula (1) is used to calculate the stress.

[0112] (2) Calculation of the fluctuating stress of the SV wave

[0113] From the stereographic projection of the focal mechanism solution (attached Figure 2 ), it can be seen that the strike of the seismogenic fault of the Jiuzhaigou M7.0 earthquake is SSW, the dip is SWW, the fault plane is nearly vertical, and the fault movement is left-lateral strike-slip and reverse thrust; the strong compressive-torsional movement downward of the hanging wall (the disk where the observation point is located) of the seismogenic fault causes the SV wave radiation with downward first motion displacement to be generated at the focal point. Accordingly, the first motion of the vertical component of the displacement of the direct SV wave (SV2-SV1) reaching the observation point is downward. According to the relationship between the first motion direction of the displacement and the wave propagation direction, the property of the SV wave in the last wave path of the direct SV wave is a downward shear wave (SV + ). The formula (3) should be used to calculate the fluctuating stress of the direct SV wave.

[0114] From Figure 5 the vertical displacement time history diagram of the direct SV wave at the observation point calculated by the CPS software as shown, it can be seen that the first motion of the vertical component of the displacement of the calculated waveform of the direct SV wave at the observation point is negative (downward). Comparing with the first motion direction of the displacement of the direct SV wave at the observation point determined by the above focal mechanism solution (seismogenic fault movement), in the local observation coordinate system (x m (E), y m (N), z m (U)) of the observation point, the negative (downward) first motion of the vertical component of the calculated displacement waveform of the direct SV wave at the observation point corresponds to the downward first motion direction of the actual (physical) vertical component of the displacement of the SV wave at the observation point (downward shear wave SV + ); conversely, the positive (upward) first motion of the vertical component of the calculated displacement waveform of the direct SV wave at the observation point corresponds to the upward first motion direction of the actual (physical) vertical component of the displacement of the SV wave at the observation point (upward shear wave SV - ). This correspondence applies to all seismic phases whose last wave path basic seismic phase is the SV wave. Therefore, this is the calibration result of the positive and negative correspondence of the first motion of the vertical component of the displacement waveform of the fluctuation calculation of all seismic phases whose last wave path basic seismic phase is the SV wave reaching the observation point by using the correspondence between the first motion direction of the displacement waveform of the fluctuation calculation of the last wave path basic seismic phase of the direct SV wave and the seismogenic fault movement direction, corresponding to the upward (upward shear wave SV - ) or downward (downward shear wave SV + ) first motion of the actual (physical) vertical component of the displacement of the SV wave at the observation point.

[0115] Figure 6 It shows the vertical displacement time history of the other three dominant seismic phase fluctuations of SV waves with the last wave path being SV waves (except for the direct SV wave (SV2 - SV1)) calculated by the CPS software. From Figure 6 it can be seen that for the SV wave phase SV2 - SV2 - SV1 that propagates to the Conrad discontinuity and reflects to the observation point, the initial motion of the wave displacement is upward, which is an up - shear SV wave (SV - ), and the corresponding wave stress should be calculated using formula (4). The initial motion directions of the vertical component displacements of the other dominant seismic phase fluctuations with the last wave path being SV waves are all the same as that of the direct SV wave (downward), which are down - shear SV waves (SV+). Therefore, the corresponding wave stresses of these seismic phases should be calculated using formula (3).

[0116] (3) Calculation of SH - wave wave stress

[0117] As mentioned above, the source fault dislocation is mainly left - lateral strike - slip with reverse thrust. Facing the observation point direction (the direction of seismic wave propagation), the horizontal dislocation direction of the lower plate of the source fault (the plate where the observation point is located) is to the left. Thus, the SH wave radiated by the source is also a left - shear wave (SH - ) with the initial motion of displacement to the left. Furthermore, the direct SH wave (SH2 - SH1) arriving at the observation point is also a left - shear wave (SH - ). According to the convention in Section 1, the wave stress of the direct SH wave should be calculated using formula (6).

[0118] From Figure 7 the tangential displacement initial motion time history diagram of the direct SH wave calculated by the CPS software as shown, it can be seen that the initial motion of the tangential component displacement of the calculated waveform of the direct SH wave at the observation point is negative (downward). Comparing with the initial motion direction of the direct SH wave at the observation point determined by the source mechanism solution analysis above, the negative (downward) initial motion of the tangential component of the calculated displacement of the direct SH wave at the observation point corresponds to the left initial motion direction of the actual (physical) tangential component of the SH wave at the observation point; conversely, the positive (upward) tangential component of the calculated displacement of the direct SH wave at the observation point corresponds to the right initial motion direction of the actual (physical) tangential component of the SH wave at the observation point. This correspondence applies to all seismic phases with the last wave path being the basic SH wave. Therefore, this is the calibration result of the positive and negative correspondence of the initial motion of the tangential component displacement of the actual (physical) tangential component of the SH wave at the observation point, where the initial motion is to the right (right - shear wave SH + ) or to the left (left - shear wave SH - ) by using the correspondence between the initial motion direction of the displacement waveform of the last wave path basic seismic phase of the direct SH wave and the source fault dislocation direction for all seismic phases with the last wave path being the basic SH wave arriving at the observation point.

[0119] Figure 8The figure shows the displacement time history diagram of all SH-wave dominant phases except the direct SH wave (SH2 - SH1) generated by the CPS software calculation. From Figure 8 it can be seen that the initial motions of the tangential displacements of the four seismic phases SH2 - SH2 - SH1, SH2 - SH1 - SH1 - SH1 - SH1 - SH1, SH2 - SH1 - SH1 - SH1 - SH1 - SH1 - SH1 - SH1 - SH1 - SH1, and SH2 - SH1 - SH1 - SH1 - SH1 - SH1 - SH1 - SH1 - SH1 - SH1 - SH1 - SH1 are positive, which are right - shear SH waves (SH + ), and the stress components are calculated using formula (5); the initial motions of the displacements of the remaining seismic phases are negative, which are left - shear SH waves (SH - ), and the stress components are calculated using formula (6).

[0120] (4) Calculation results of seismic wave dynamic stress

[0121] According to the above discussion, the seismic wave dynamic stresses generated by the 16 dominant phases separated by phase fitting are calculated respectively, and the results are as Figures 9 - 11 shown. In order to visually compare the contributions of each seismic phase to the synthetic seismic wave, the coordinate axes with the same scale as the vertical coordinate axis of the stress component of the direct SV - wave phase (SV2 - SV1) with the largest dynamic stress are uniformly used to display the dynamic stress components of each seismic phase.

[0122] The dynamic stress components of all the determined dominant seismic phases are superimposed according to the time sequence when they reach the observation point, and the time history of the seismic wave dynamic stress generated by the Jiuzhaigou M7.0 earthquake within a certain depth range of the site where the Wenxian Seismic Station is located is obtained, as Figure 12 shown. Figure 12 (a) is the time history diagram of σ z generated by the Jiuzhaigou M7.0 earthquake within a certain depth range of the ground surface at the observation point of the Wenxian Seismic Station in an embodiment of the present application; Figure 12 (b) is the time history diagram of τ zx generated by the Jiuzhaigou M7.0 earthquake within a certain depth range of the ground surface at the observation point of the Wenxian Seismic Station in an embodiment of the present application; Figure 12 (c) is the time history diagram of τ zy generated by the Jiuzhaigou M7.0 earthquake within a certain depth range of the ground surface at the observation point of the Wenxian Seismic Station in an embodiment of the present application. From Figure 12 it can be seen that the first wave peak of the seismic wave dynamic stress tensor on the horizontal plane at the observation point of the Wenxian Seismic Station (62WEX) is triggered by the direct P - wave phase (P2 - P1), and it arrives about 23 s after the earthquake occurs; the moment when the maximum value of the seismic wave dynamic stress arrives is about 40 s, which is approximately the same as the moment when the displacement peak of the direct SV wave (SV2 - SV1) arrives. It can be seen that the maximum value of the synthetic seismic wave dynamic stress is mainly caused by the direct SV wave. σ zhas a peak value of 16747 Pa, τ zx has a peak value of 16752 Pa, τ zy has a peak value of -10619 Pa.

[0123] This application provides a method for calculating seismic wave stress from measured seismic waves - the seismic phase fitting method. As long as all the seismic phase combinations during a seismic wave process at an observation point are known, the seismic wave stress in the rock and soil mass within a certain depth range at this observation point can be calculated according to the elastic wave theory. Examples of seismic phase fitting and seismic wave stress calculation for the measured seismic waves at the Wenxian Seismic Station during the 7.0-magnitude strong earthquake in Jiuzhaigou, Sichuan Province, prove the feasibility of the seismic phase fitting method for calculating seismic wave stress.

[0124] In an exemplary embodiment, a computer device is provided. The computer device can be a server or a terminal. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device communicates with external terminals through a network connection. When the computer program is executed by the processor, it implements a method for calculating seismic wave stress.

[0125] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, which when executed by a processor, implements the steps in the above method embodiments.

[0126] In an exemplary embodiment, a computer program product is provided, including a computer program, which when executed by a processor, implements the steps in the above method embodiments.

[0127] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0128] Those of ordinary skill in the art can understand that all or part of the processes in the above-described example methods can be implemented by relevant hardware through computer program instructions. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above-described example methods of each method. Among them, any reference to a memory, database, or other medium used in the various embodiments provided in this application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAMs), magnetoresistive random access memories (MRAMs), ferroelectric random access memories (FRAMs), phase change memories (PCMs), graphene memories, etc. Volatile memories can include random access memories (RAMs) or external caches, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0129] The databases involved in the various embodiments provided in this application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchains, etc., without limitation. The processors involved in the various embodiments provided in this application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logics, data processing logics based on quantum computing, etc., without limitation.

[0130] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0131] Specific examples are used in this article to elaborate on the principles and implementation manners of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. A method for calculating earthquake wave stress, characterized in that: include: Constructing a crustal model of the observation area according to the crustal structural parameters of the observation area; the observation area is the area between the earthquake source and the observation point; Obtain the measured seismic waves at the observation point and the earthquake focal mechanism parameters corresponding to the measured seismic waves; Determine the outstanding seismic phases and their optimal seismic phase combination that significantly contribute to the energy of the measured seismic waves at the observation point based on the crust model of the observation area and the earthquake focal mechanism parameters corresponding to the measured seismic waves; the optimal seismic phase combination includes multiple outstanding seismic phases; Using the earthquake wave stress formula, the time history of the wave stress component generated by each prominent seismic phase is determined respectively; The time history of the wave stress components generated by all the prominent seismic phases is superimposed according to the time sequence of arrival at the observation point to obtain the seismic wave stress time history generated by the earthquake process at the observation point.

2. The earthquake wave stress calculation method according to claim 1, characterized in that: The crustal model of the observation area is used to simulate multiple crustal layers in the observation area; the crustal layers include: a sedimentary cover layer, an upper crustal layer and a lower crustal layer.

3. The earthquake wave stress calculation method according to claim 2, characterized in that: According to the crust model of the observation area and the earthquake focal mechanism parameters corresponding to the measured seismic waves, the outstanding seismic phases and the best seismic phase combination at the observation point that significantly contribute to the energy of the measured seismic waves are determined, including: The sensitivity analysis and phase fitting orthogonal test were used to optimize the source parameters and the crustal model parameters of the observation area. Based on the crustal model of the observation area after parameter optimization, all seismic phases that satisfy Snell's law are determined; From all the seismic phases that satisfy Snell's law, the outstanding seismic phases that contribute significantly to the measured seismic wave energy at the observation point are selected to form the best seismic phase combination of the measured seismic waves at the observation point.

4. The earthquake wave stress calculation method according to claim 3, characterized in that: The outstanding phase fluctuation energy amplitude ratio is greater than the outstanding phase amplitude ratio threshold; the outstanding phase amplitude ratio threshold is 1% of the amplitude ratio of the maximum value of the phase fluctuation vector modulus to the maximum value of the direct SV wave vector modulus.

5. The earthquake wave stress calculation method according to claim 2, characterized in that: The time history of the wave stress component generated by the outstanding seismic phase is determined by substituting the particle vibration velocity time history of the basic seismic phase of the last wave path of the outstanding seismic phase to the observation point into the seismic wave stress formula; the wave path is a section of the seismic wave ray corresponding to the seismic phase, which is used to describe the process of a basic seismic phase propagating from the earthquake source to the observation point in a crust layer along the seismic phase wave propagation path; the basic seismic phases include: P waves, SV waves and SH waves.

6. The earthquake wave stress calculation method according to claim 5, characterized in that: The earthquake wave stress formulas include: P wave stress tensor formula, SV wave stress tensor formula and SH wave stress tensor formula; The P-wave stress tensor formula includes: + The resulting wave stress component formula and tensile wave Formula for the fluctuating stress component generated by P; The SV wave stress tensor formula includes: + The resulting fluctuating stress component formula and upper shear Formula for the wave stress component generated by wave SV; The SH wave stress tensor formula includes: + The resulting fluctuating stress component formula and left shear Formula for the wave stress component generated by wave SH.

7. The earthquake wave stress calculation method according to claim 6, characterized in that: The compression wave P + The formula for the resulting fluctuating stress component is: in, is the compression wave P + The normal stress component generated on the horizontal plane with the coordinate axis z as the normal at the observation point; is the compression wave P + The shear stress component generated along the x-axis in the horizontal plane with the coordinate axis z as the normal at the observation point; is the compression wave P + The shear stress component along the y-axis direction generated in the horizontal plane with the coordinate axis z as the normal at the observation point; V P is the modulus of the particle vibration velocity time history generated by the P wave; λ and μ are collectively referred to as the Lame constant; c P is the longitudinal wave velocity; θ m is the incident angle of the seismic wave; α m is the incident angle of the seismic wave; The formula for the fluctuating stress component generated by the tensile wave P is: in, is the normal direction generated by the tensile wave P on the horizontal plane with the coordinate axis z as the normal at the observation point Stress components; is the shear stress component along the x-axis direction generated by the tensile wave P in the horizontal plane with the coordinate axis z as the normal at the observation point; is the shear stress component along the y-axis direction generated by the tensile wave P in the horizontal plane with the coordinate axis z as the normal at the observation point; The lower shear wave SV + The formula for the resulting fluctuating stress component is: in, SV for the lower shear wave + The normal stress component generated on the horizontal plane with the coordinate axis z as the normal at the observation point; SV for the lower shear wave + The shear stress component generated along the x-axis in the horizontal plane with the coordinate axis z as the normal at the observation point; SV for the lower shear wave + The shear stress component along the y-axis direction generated in the horizontal plane with the coordinate axis z as the normal at the observation point; V V is the modulus of the particle vibration velocity time history generated by the SV wave; c S is the shear wave velocity; The formula for the fluctuating stress component generated by the upper shear wave SV is: in, is the normal generated by the upper shear wave SV on the horizontal plane with the coordinate axis z as the normal at the observation point axial stress component; is the shear stress component along the x-axis direction generated by the upper shear wave SV in the horizontal plane with the coordinate axis z as the normal at the observation point; is the shear stress component along the y-axis direction generated by the upper shear wave SV in the horizontal plane with the coordinate axis z as the normal at the observation point; The right shear wave SH + The formula for the resulting fluctuating stress component is: in, Right shear wave SH + The normal stress component generated on the horizontal plane with the coordinate axis z as the normal at the observation point; Right shear wave SH + The shear stress component generated along the x-axis in the horizontal plane with the coordinate axis z as the normal at the observation point; Right shear wave SH + The shear stress component along the y-axis direction generated in the horizontal plane with the coordinate axis z as the normal at the observation point; V H is the modulus of the particle vibration velocity time history generated by the SH wave; The formula of the fluctuating stress component generated by the left shear wave SH is: in, is the normal stress component generated by the left shear wave SH- on the horizontal plane with the coordinate axis z as the normal at the observation point; is the shear stress component along the x-axis direction generated by the left shear wave SH in the horizontal plane with the coordinate axis z as the normal at the observation point; It is the shear stress component along the y-axis direction generated by the left shear wave SH in the horizontal plane with the coordinate axis z as the normal at the observation point.

8. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the earthquake wave stress estimation method according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the earthquake wave stress calculation method described in any one of claims 1 to 7 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the earthquake wave stress calculation method described in any one of claims 1 to 7 is implemented.

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