A seismic analysis and calculation system based on tide theory and a method for using the same

Abstract

An earthquake analysis and calculation system based on tidal theory includes a tidal theory calculation module, a fault parameter and stress projection module, an earthquake event import module, and an analysis module. The output of the tidal theory calculation module is connected to the input of the fault parameter and stress projection module, the output of the fault parameter and stress projection module is connected to the input of the earthquake event import module, and the output of the earthquake event import module is connected to the input of the analysis module. The tidal theory calculation module includes input time and spatial parameters and outputs a tidal stress tensor. The fault parameter and stress projection module includes input fault plane parameters and outputs tidal shear stress and normal stress. The earthquake event import module includes inputting earthquake event data and outputting tidal stress and earthquake event data, which are then transferred to the analysis module. The analysis module includes outputting a fused visualization result of tidal stress and earthquake events. This invention integrates solid tidal theory calculation and earthquake analysis.

Description

Technical Field

[0001] This invention relates to an improvement of tidal theory and seismic analysis and calculation technology, belonging to the field of geophysics, and particularly to a seismic analysis and calculation system based on tidal theory and its usage method. Background Technology

[0002] In the field of research on tidal-triggered earthquake mechanisms, solid tidal theory calculations and seismic activity analysis are two core components. However, in current technologies, solid tidal theory calculations and seismic analysis are completely separate: on the one hand, solid tidal theory calculations rely on specialized theories such as the PREM Earth model, tidal wave expansion term analysis, and stress tensor solving, and must be completed through independent calculations, with the output being only raw data; on the other hand, seismic activity analysis is mostly based on independent seismic catalog data processing tools, which cannot directly interface with solid tidal calculation results.

[0003] To complete the entire calculation process, it is necessary to manually switch between multiple tools / scripts, which is not only cumbersome and inefficient, but also makes it difficult to complete the entire calculation process independently. Often, a lot of time needs to be spent learning professional techniques or relying on the assistance of professionals, which greatly reduces the efficiency of tidal and seismic correlation analysis for specific faults.

[0004] Chinese patent application CN202310098881.4, filed on January 29, 2023, discloses a shallow seismic analysis method and apparatus based on surface waves and P-waves, belonging to the field of geophysical exploration. The method includes: extracting surface wave information for each excitation point based on shallow reflection seismic data; inverting the surface wave depth curve for each excitation point based on the surface wave information; combining and interpolating the surface wave depth curves of all excitation points according to their spatial coordinates to obtain the subsurface medium shear wave velocity volume; converting the subsurface medium shear wave velocity volume into P-wave layer velocity, and based on the horizontal layered medium distribution, converting the P-wave layer velocity into a superimposed velocity. This method avoids the problems of incomplete separation of reflected and refracted waves, resulting in overlapping and affecting analysis accuracy, and the problem of incorrectly cutting reflected waves affecting analysis accuracy when extracting reflected waves in existing methods. The above scheme is less susceptible to interference from surface waves and refracted waves when calculating the velocity spectrum, thus improving the accuracy of velocity analysis. However, it still does not integrate solid tidal theory calculations with seismic analysis.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this patent application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to overcome the problem in the prior art that it is impossible to integrate solid tidal theory calculations and seismic analysis, and to provide a seismic analysis and calculation system based on tidal theory that can integrate solid tidal theory calculations and seismic analysis, as well as its usage method.

[0007] To achieve the above objectives, the technical solution of the present invention is: an earthquake analysis and calculation system based on tidal theory, wherein the earthquake analysis and calculation system based on tidal theory includes a tidal theory calculation module, a fault parameter and stress projection module, an earthquake event import module, and an analysis module;

[0008] The output of the tidal theory calculation module is connected to the input of the fault parameter and stress projection module, the output of the fault parameter and stress projection module is connected to the input of the earthquake event import module, and the output of the earthquake event import module is connected to the input of the analysis module.

[0009] The tidal theory calculation module includes input time parameters and spatial parameters, and outputs tidal stress tensor.

[0010] The fault parameter and stress projection module includes input fault plane parameters and output tidal shear stress and normal stress.

[0011] The earthquake event import module includes inputting earthquake event data, outputting tidal stress and earthquake event data, and transmitting them to the corresponding analysis module;

[0012] The analysis module includes outputting a fusion visualization of tidal stress and seismic events.

[0013] The tidal theory calculation module is used to calculate the tidal stress tensor at a specified location on the surface or underground at any time period.

[0014] The fault parameter and stress projection module is used to project the tidal stress tensor onto the fault plane according to the fault plane parameters input by the user, so as to obtain the tidal shear stress and normal stress.

[0015] The earthquake event import module is used to import external earthquake catalog data and convert the imported earthquake data into an earthquake time series format that the system can recognize, and then transmit it to the analysis module.

[0016] The analysis module is used to assess the correlation between earthquake occurrence and tidal changes and to display the calculation results.

[0017] The fault plane parameters include fault strike, fault dip angle, and fault slip angle.

[0018] The analysis module also includes generating a comparison graph between seismic events and changes in solid tidal stress.

[0019] A method for using a seismic analysis and calculation system based on tidal theory, comprising the following steps:

[0020] Step 1: Enter the spatial parameters and time parameters in the tidal theory calculation module in sequence, and then click the Start Calculation button to start the tidal stress calculation and obtain the tidal stress tensor.

[0021] The second step is to first input the fault strike, fault dip angle, and fault slip angle in the fault plane parameter input area of ​​the fault parameter and stress projection module, and then combine them with spatial and time parameters. Then click the "Start Calculation" button to start calculating the stress changes on the fault plane to obtain the tidal shear stress and normal stress.

[0022] The third step is to first click the "Import Earthquake Data" button in the earthquake event import module to import the external earthquake data directory. Then, click the "Plot" button. The analysis module will generate a graph showing the correspondence between tidal parameters and the time of earthquake occurrence based on the earthquake data and the tidal stress tensor, tidal shear stress, and normal stress data. This will give you the correlation between tidal parameters and earthquakes. At this point, the method ends.

[0023] The correlation between tidal parameters and earthquakes in the third step includes whether earthquakes have periodic characteristics, whether the time of earthquake occurrence corresponds to the maximum or minimum value of tidal shear stress, and whether they are concentrated in a specific phase interval.

[0024] In the first step, while obtaining the tidal stress tensor, the interface also displays an image of the stress components changing over time. After clicking the "Export Data" button, the tidal stress tensor data file is exported.

[0025] In the second step, while obtaining the tidal normal stress and shear stress data, the interface displays an image of the shear stress of the fault plane changing over time. Then, click "Export Data 2" to export the tidal normal stress and shear stress data.

[0026] The tidal stress calculation is specifically as follows:

[0027] According to the expanded table of tidal bores, the tidal bore is represented as:

[0028] ;

[0029] in, It's about latitude. The distance from a point inside the Earth to the Earth's center. The function is the geodetic coefficient. It is the order of the spherical harmonic expansion. It represents the number of expansions, expanding n to order 4;

[0030] The second-order expression is:

[0031] ;

[0032] The third-order expression is:

[0033] ;

[0034] The fourth-order expression is:

[0035] ;

[0036] Where D2 is the Doodson constant;

[0037] It is a function of time, and is related to the trigonometric functions of linear combinations of astronomical parameters and the amplitude of the partial waves;

[0038] ;

[0039] in, These are the expansions of G. , The upper and lower wave numbers of the same tidal wave, The coefficients of the astronomical parameters form the Doodson code; This represents the relative amplitude at the corresponding frequency.

[0040] The above astronomical parameters are calculated as follows:

[0041] ;

[0042] in, Julian Day for calculating time, For time, Time zone.

[0043] The Love number is defined as follows:

[0044] ;

[0045] The Earth's surface to a depth of 800 km is divided into layers at 100m intervals, and the solutions obtained correspond to the second, third, and fourth orders of gravity. as well as and ;

[0046] ;

[0047] in These represent the radial displacement, radial stress, horizontal displacement, and horizontal stress generated inside and on the surface of the Earth under the influence of tidal forces, respectively.

[0048] The vertical and horizontal displacements of any point inside or on the Earth are:

[0049] ;

[0050] Based on the relationship between strain and displacement, the expressions for the six independent components of the strain tensor can be obtained as follows:

[0051] ;

[0052] Then, based on the relationship between stress and strain: ;

[0053] That is, to obtain the tidal stress inside the Earth, among which, and for Lamé constant at that location, For the volumetric expansion due to strain, i.e., the trace of the strain tensor matrix, For Kronecker symbols.

[0054] The specific stress changes at the calculated fault plane are as follows:

[0055] Rotate the coordinate system on the fault plane. Here, the strike, dip, and slip angles of the fault are given, with a negative sign added to the strike and dip angles. The direction cosine matrix after rotating the spherical coordinates to the Cartesian coordinates is:

[0056] ;

[0057] Therefore, the stress matrix in spherical coordinates is expressed as: .

[0058] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0059] 1. In the earthquake analysis and calculation system based on tidal theory and its usage method of the present invention, the output end of the tidal theory calculation module is connected to the input end of the fault parameter and stress projection module, the output end of the fault parameter and stress projection module is connected to the input end of the earthquake event import module, and the output end of the earthquake event import module is connected to the input end of the analysis module; the tidal theory calculation module includes input time parameters and spatial parameters, and outputs tidal stress tensors; the fault parameter and stress projection module includes input fault plane parameters, and outputs tidal shear stress and normal stress; the earthquake event import module includes inputting earthquake event data, outputting tidal stress and earthquake event data, and transmitting them to the corresponding analysis module; the analysis module includes outputting the fusion visualization results of tidal stress and earthquake events. In application, the tidal theory calculation module... First, input the spatial and temporal parameters, then click the "Start Calculation 1" button to begin tidal stress calculation and obtain the tidal stress tensor. Next, input the fault strike, dip angle, and slip angle in the fault plane parameter input area of ​​the fault parameter and stress projection module, combining them with the spatial and temporal parameters. Then click the "Start Calculation 2" button to begin calculating the stress changes on the fault plane and obtain the tidal shear stress and normal stress. Finally, click the "Import Seismic Data" button in the earthquake event import module to import the external seismic data directory. Then click the "Plot" button. The analysis module generates a graph showing the correspondence between tidal parameters and earthquake occurrence times based on the seismic data and the tidal stress tensor, tidal shear stress, and normal stress data, thus obtaining the correlation between tidal parameters and earthquakes. At this point, the method ends. The advantages of this design are as follows:

[0060] First, the tidal theory calculation module, fault parameter and stress projection module, seismic event import module, and analysis module are deeply integrated into the same system, realizing a closed-loop process of parameter input, tidal stress calculation, seismic data import, and correlation comparison analysis results output. Data between modules does not require manual extraction, conversion, or transmission, and there is no human intervention throughout the process. This completely eliminates the need for repeated switching between programming scripts, mechanical analysis tools, and seismic data software in traditional research, and can be completed in one stop within a single system.

[0061] Secondly, after inputting the spatial parameters and fault plane parameters of the target fault, the system automatically focuses on the fault region. The tidal calculation module outputs the stress tensor of the region specifically, and the fault stress projection module directly generates the shear stress and normal stress data of the fault without the need for additional data filtering.

[0062] Thirdly, all calculations, such as solving the tidal stress tensor, fault stress projection, and data time series alignment, are completed automatically by the system. You only need to input parameters through the interface and click the corresponding function button to obtain targeted correlation analysis results.

[0063] Therefore, this invention can integrate solid tide theory calculations and seismic analysis.

[0064] 2. In this invention, an earthquake analysis and calculation system based on tidal theory and its usage method, the system performs real-time verification and matching of spatial parameters, fault plane parameters, and epicenter information of earthquake data, associating only data within the same spatial and temporal range to ensure consistency of the analysis object. The tidal stress calculation results are automatically time-series aligned with earthquake events, eliminating the need for manual annotation of stress values ​​corresponding to the earthquake occurrence time; the system directly outputs a dataset of associated earthquake events and corresponding stress states. Compared to traditional command-line tidal calculation programs, the system achieves integrated parameter configuration and result visualization through a graphical interface, enabling multi-parameter combination calculations and significantly improving ease of use. Therefore, this invention offers strong consistency and convenient result viewing.

[0065] 3. In this invention, a seismic analysis and calculation system based on tidal theory and its application method are described. This design employs a wavelet decomposition method containing 2934 tidal wave numbers, achieving a tidal level decomposition accuracy of approximately 6 × 10⁻¹¹ m / s². Through multi-order Love number calculations, tidal stresses at different depths can be calculated, providing more accurate physical parameters for underground tidal stress calculations. Therefore, this invention improves calculation and analysis efficiency.

[0066] 4. In the seismic analysis and calculation system based on tidal theory and its usage method of this invention, after the analysis module completes the comparison, it does not only output single data, but presents the results in three forms: visual and intuitive charts, structured and quantitative data, and qualitative / semi-quantitative correlation judgments, progressing layer by layer. This satisfies both the basic need for quickly observing correlation trends and the professional need for in-depth analysis. Therefore, the results presented by this invention are more diverse and more intuitive.

[0067] 5. In the seismic analysis and calculation system and its usage method based on tidal theory of this invention, tidal stress calculation and fault stress projection are separated into independent calculations, each outputting clear results. The first step outputs the tidal stress tensor, the second step outputs the shear stress and normal stress, and the comparison step outputs the correlation results. The accuracy of the results is verified step by step. If the stress tensor is abnormal, the parameters in the first step are directly checked; if the fault stress is abnormal, the parameters in the second step are directly corrected, making the problem location more precise. Therefore, this invention provides clear output and accurate problem location. Attached Figure Description

[0068] Figure 1 This is a system block diagram of the present invention.

[0069] Figure 2 This is a flowchart of the present invention.

[0070] Figure 3 This is a schematic diagram of the result interface of the present invention.

[0071] Figure 4This is a schematic diagram of the stress tensors rr, tt, and ll in this invention.

[0072] Figure 5 This is a schematic diagram of the stress tensors tl, rl, and rt in this invention.

[0073] Figure 6 This is a comparison diagram of the stress tensors rr, tt, and ll in this invention.

[0074] Figure 7 This is a comparison diagram of the stress tensors tl, rl, and rt in this invention.

[0075] Figure 8 This is a schematic diagram of tidal stress components at different depths in this invention.

[0076] Figure 9 This is a graph showing the change of tidal stress tensor over time on the interrupted layer of this invention.

[0077] Figure 10 This is a schematic diagram of the basic interface of the present invention.

[0078] The diagram shows: 1. Tidal theory calculation module; 2. Fault parameters and stress projection module; 3. Seismic event import module; 4. Analysis module. Detailed Implementation

[0079] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0080] See Figures 1 to 10 An earthquake analysis and calculation system based on tidal theory, comprising a tidal theory calculation module 1, a fault parameter and stress projection module 2, an earthquake event import module 3, and an analysis module 4;

[0081] The output of the tidal theory calculation module 1 is connected to the input of the fault parameter and stress projection module 2, the output of the fault parameter and stress projection module 2 is connected to the input of the earthquake event import module 3, and the output of the earthquake event import module 3 is connected to the input of the analysis module 4.

[0082] The tidal theory calculation module 1 includes input time parameters and spatial parameters, and outputs tidal stress tensor.

[0083] The fault parameter and stress projection module 2 includes input fault plane parameters and output tidal shear stress and normal stress.

[0084] The earthquake event import module 3 includes inputting earthquake event data, outputting tidal stress and earthquake event data, and transmitting them to the corresponding analysis module 4;

[0085] The analysis module 4 includes outputting a fusion visualization of tidal stress and seismic events.

[0086] The tidal theory calculation module 1 is used to calculate the tidal stress tensor at a specified location on the surface or underground at any time period.

[0087] The fault parameter and stress projection module 2 is used to project the tidal stress tensor onto the fault plane according to the fault plane parameters input by the user, so as to obtain the tidal shear stress and normal stress.

[0088] The earthquake event import module 3 is used to import external earthquake catalog data and convert the imported earthquake data into an earthquake time series format that the system can recognize, and then transmit it to the analysis module 4.

[0089] The analysis module 4 is used to assess the correlation between earthquake occurrence and tidal changes and to display the calculation results.

[0090] The fault plane parameters include fault strike, fault dip angle, and fault slip angle.

[0091] The analysis module 4 also includes generating a comparison graph between earthquake events and changes in solid tidal stress.

[0092] A method for using a seismic analysis and calculation system based on tidal theory, comprising the following steps:

[0093] Step 1: Input the spatial parameters and time parameters in the tidal theory calculation module 1 in sequence, and then click the Start Calculation button to start the tidal stress calculation to obtain the tidal stress tensor.

[0094] The second step is to input the fault strike, fault dip angle, and fault slip angle in the fault plane parameter input area of ​​the fault parameter and stress projection module 2, and combine them with spatial and time parameters. Then, click the "Start Calculation" button to start calculating the stress changes on the fault plane to obtain the tidal shear stress and normal stress.

[0095] The third step is to first click the "Import Earthquake Data" button in the earthquake event import module 3 to import the external earthquake data directory. Then, click the "Draw" button. The analysis module 4 will generate a graph showing the correspondence between tidal parameters and the time of earthquake occurrence based on the earthquake data and the tidal stress tensor, tidal shear stress, and normal stress data. This will give you the correlation between tidal parameters and earthquakes. At this point, the method ends.

[0096] The correlation between tidal parameters and earthquakes in the third step includes whether earthquakes have periodic characteristics, whether the time of earthquake occurrence corresponds to the maximum or minimum value of tidal shear stress, and whether they are concentrated in a specific phase interval.

[0097] In the first step, while obtaining the tidal stress tensor, the interface also displays an image of the stress components changing over time. After clicking the "Export Data" button, the tidal stress tensor data file is exported.

[0098] In the second step, while obtaining the tidal normal stress and shear stress data, the interface displays an image of the shear stress of the fault plane changing over time. Then, click "Export Data 2" to export the tidal normal stress and shear stress data.

[0099] The tidal stress calculation is specifically as follows:

[0100] According to the expanded table of tidal bores, the tidal bore is represented as:

[0101] ;

[0102] in, It's about latitude. The distance from a point inside the Earth to the Earth's center. The function is the geodetic coefficient. It is the order of the spherical harmonic expansion. It represents the number of expansions, expanding n to order 4;

[0103] The second-order expression is:

[0104] ;

[0105] The third-order expression is:

[0106] ;

[0107] The fourth-order expression is:

[0108] ;

[0109] Where D2 is the Doodson constant;

[0110] It is a function of time, and is related to the trigonometric functions of linear combinations of astronomical parameters and the amplitude of the partial waves;

[0111] ;

[0112] in, These are the expansions of G. , The upper and lower wave numbers of the same tidal wave, The coefficients of the astronomical parameters form the Doodson code; This represents the relative amplitude at the corresponding frequency.

[0113] The above astronomical parameters are calculated as follows:

[0114] ;

[0115] in, Julian Day for calculating time, For time, Time zone.

[0116] The Love number is defined as follows:

[0117] ;

[0118] The Earth's surface to a depth of 800 km is divided into layers at 100m intervals, and the solutions obtained correspond to the second, third, and fourth orders of gravity. as well as and ;

[0119] ;

[0120] in These represent the radial displacement, radial stress, horizontal displacement, and horizontal stress generated inside and on the surface of the Earth under the influence of tidal forces, respectively.

[0121] The vertical and horizontal displacements of any point inside or on the Earth are:

[0122] ;

[0123] Based on the relationship between strain and displacement, the expressions for the six independent components of the strain tensor can be obtained as follows:

[0124] ;

[0125] Then, based on the relationship between stress and strain: ;

[0126] That is, to obtain the tidal stress inside the Earth, among which, and for Lamé constant at that location, For the volumetric expansion due to strain, i.e., the trace of the strain tensor matrix, For Kronecker symbols.

[0127] The specific stress changes at the calculated fault plane are as follows:

[0128] Rotate the coordinate system on the fault plane. Here, the strike, dip, and slip angles of the fault are given, with a negative sign added to the strike and dip angles. The direction cosine matrix after rotating the spherical coordinates to the Cartesian coordinates is:

[0129] ;

[0130] Therefore, the stress matrix in spherical coordinates is expressed as: .

[0131] In the tidal theory calculation module, based on the spherically symmetric, non-rotating, elastic and isotropic PREM Earth model, the liquid ocean layer and the upper crust are averaged. By solving the boundary value problem of the corresponding differential equation system, the second, third and fourth order Love numbers are obtained. With 2934 tidal wave expansion terms, the accuracy is higher. The program can calculate the tidal stress tensor at any specified location on the surface or underground at any time period at any location on the globe.

[0132] Example 1:

[0133] An earthquake analysis and calculation system based on tidal theory, comprising a tidal theory calculation module 1, a fault parameter and stress projection module 2, an earthquake event import module 3, and an analysis module 4;

[0134] The output of the tidal theory calculation module 1 is connected to the input of the fault parameter and stress projection module 2, the output of the fault parameter and stress projection module 2 is connected to the input of the earthquake event import module 3, and the output of the earthquake event import module 3 is connected to the input of the analysis module 4.

[0135] The tidal theory calculation module 1 includes input time parameters and spatial parameters, and outputs tidal stress tensor.

[0136] The fault parameter and stress projection module 2 includes input fault plane parameters and output tidal shear stress and normal stress.

[0137] The earthquake event import module 3 includes inputting earthquake event data, outputting tidal stress and earthquake event data, and transmitting them to the corresponding analysis module 4;

[0138] The analysis module 4 includes outputting a fusion visualization of tidal stress and seismic events;

[0139] A method for using a seismic analysis and calculation system based on tidal theory, comprising the following steps:

[0140] Step 1: Input the spatial parameters and time parameters in the tidal theory calculation module 1 in sequence, and then click the Start Calculation button to start the tidal stress calculation to obtain the tidal stress tensor.

[0141] The second step is to input the fault strike, fault dip angle, and fault slip angle in the fault plane parameter input area of ​​the fault parameter and stress projection module 2, and combine them with spatial and time parameters. Then, click the "Start Calculation" button to start calculating the stress changes on the fault plane to obtain the tidal shear stress and normal stress.

[0142] The third step is to first click the "Import Earthquake Data" button in the earthquake event import module 3 to import the external earthquake data directory. Then, click the "Draw" button. The analysis module 4 will generate a graph showing the correspondence between tidal parameters and the time of earthquake occurrence based on the earthquake data and the tidal stress tensor, tidal shear stress, and normal stress data. This will give you the correlation between tidal parameters and earthquakes. At this point, the method ends.

[0143] Example 2:

[0144] Example 2 is basically the same as Example 1, except that:

[0145] An earthquake analysis and calculation system based on tidal theory includes a tidal theory calculation module 1 for calculating the tidal stress tensor at a specified location on the surface or underground at any time interval; a fault parameter and stress projection module 2 for projecting the tidal stress tensor onto the fault plane based on user-inputted fault plane parameters to obtain tidal shear stress and normal stress; an earthquake event import module 3 for importing external earthquake catalog data, converting the imported earthquake data into a system-recognizable earthquake time series format, and transmitting it to an analysis module 4; and an analysis module 4 for evaluating the correlation between earthquake occurrence and tidal changes and displaying the calculation results. The fault plane parameters include fault strike, fault dip, and fault slip angle.

[0146] Step 1: Input the spatial parameters and time parameters in the tidal theory calculation module 1 in sequence, and then click the Start Calculation button to start the tidal stress calculation to obtain the tidal stress tensor. At the same time, the interface also displays the image of stress components changing with time. After clicking the Export Data button, export the tidal stress tensor data file.

[0147] The second step is to first input the fault strike, fault dip angle, and fault slip angle in the fault plane parameter input area of ​​the fault parameter and stress projection module 2, and then combine the spatial parameters and time parameters. Then click the Start Calculation II button to start calculating the stress change on the fault plane to obtain the tidal shear stress and normal stress. At the same time, the interface displays the image of the fault plane shear stress changing with time. Then click Export Data II to export the tidal normal stress and shear stress data.

[0148] The third step is to first click the "Import Earthquake Data" button in the earthquake event import module 3 to import the external earthquake data directory. Then, click the "Draw" button. The analysis module 4 will generate a graph showing the correspondence between tidal parameters and the time of earthquake occurrence based on the earthquake data and the tidal stress tensor, tidal shear stress and normal stress data, thereby obtaining the correlation between tidal parameters and earthquakes. At this point, the method ends.

[0149] The correlation between tidal parameters and earthquakes includes whether earthquakes have periodic characteristics, whether the time of earthquake occurrence corresponds to the maximum or minimum value of tidal shear stress, and whether they are concentrated in a specific phase interval.

[0150] Supported imported seismic data formats: "*.txt": space-separated seismic directory files;

[0151] The data imported from the general earthquake catalog field must include at least the following fields: 1. Event occurrence time UTC or local time, 2. Magnitude such as ML, Ms, Mw, 3. Epicenter longitude and latitude, 4. Focal depth. Optional fields include event number, location error, and phase information.

[0152] The software provides an example of earthquake data format, which users can use to organize the original earthquake catalog.

[0153] Spatial parameters include: longitude input range: -180 to 180, latitude input range: -90 to 90, and depth input range: greater than 0.

[0154] Time parameters include: Year: greater than 0, Month: 1 to 12, Day: 1 to 31, Hour: 0 to 23, Minute: 0 to 59, Second: 0 to 59, Number of outputs: greater than 0

[0155] Orientation: 0-360°, Tilt angle: 0-90°, Slip angle: -180° to 180°

[0156] These input ranges are already built into the system. If the input is not within this range, the system will provide a prompt.

[0157] Meanwhile, by synchronously displaying the seismic event sequence and the tidal stress time series in the same time coordinate system, the temporal alignment and visual comparison of the earthquake occurrence time and the tidal stress state are realized, with the earthquake occurrence time as the reference point; the tidal stress value corresponding to that time is extracted; and the distribution characteristics of the earthquake event in the tidal cycle, such as peak value, valley value or specific phase, can be viewed intuitively.

[0158] Example 3:

[0159] Example 3 is basically the same as Example 1, except that:

[0160] The tidal stress calculation specifically employs a scheme that utilizes the PREM Earth model for optimization, calculation of 293 tidal wave expansion terms, and boundary value problem solving to calculate the tidal stress tensor.

[0161] To average the liquid ocean layer and the upper crust, due to the presence of a 3km seawater layer in the PREM model, the following treatment was performed: the crustal layer with r values ​​of 6356km-6368km and the seawater layer with r values ​​of 6368-6371km were considered as homogeneous elastic layers, and their density was taken as the average of the two layers, 2.2834 g / cm³. 3 .

[0162] Meanwhile, by introducing actual fault parameters in the study area, including strike, dip angle and slip angle, the tidal stress can be further projected onto the specific fault plane, and the tidal normal stress and tidal shear stress on the fault can be calculated, thus reflecting the influence of fault tectonic conditions in different regions on the calculation results.

[0163] The tidal level expansion table used includes a total of 2934 items, including long-period items, diurnal waves, semi-diurnal waves, and third-period waves;

[0164] According to the expanded table of tidal bores, the tidal bore is represented as:

[0165] ;

[0166] in, It's about latitude. The distance from a point inside the Earth to the Earth's center. The function is the geodetic coefficient. It is the order of the spherical harmonic expansion. It represents the number of expansions, expanding n to order 4;

[0167] The second-order expression is:

[0168] ;

[0169] The third-order expression is:

[0170] ;

[0171] The fourth-order expression is:

[0172] ;

[0173] Where D2 is the Doodson constant;

[0174] It is a function of time, and is related to the trigonometric functions of linear combinations of astronomical parameters and the amplitude of the partial waves;

[0175] ;

[0176] in, These are the expansions of G. , The upper and lower wave numbers of the same tidal wave, The coefficients of the astronomical parameters form the Doodson code; This represents the relative amplitude at the corresponding frequency.

[0177] The above astronomical parameters are calculated as follows:

[0178] ;

[0179] in, 2415020.0 represents the Julian day of the calculation time. For time, Time zone.

[0180] The Love number is defined as follows:

[0181] ;

[0182] The Earth's surface to a depth of 800 km is divided into layers at 100m intervals, and the solutions obtained correspond to the second, third, and fourth orders of gravity. as well as and ;

[0183] ;

[0184] in These represent the radial displacement, radial stress, horizontal displacement, and horizontal stress generated inside and on the surface of the Earth under the influence of tidal forces, respectively.

[0185] The vertical and horizontal displacements of any point inside or on the Earth are:

[0186] ;

[0187] Based on the relationship between strain and displacement, the expressions for the six independent components of the strain tensor can be obtained as follows:

[0188] ;

[0189] Then, based on the relationship between stress and strain: ;

[0190] That is, to obtain the tidal stress inside the Earth, among which, and for Lamé constant at that location, For the volumetric expansion due to strain, i.e., the trace of the strain tensor matrix, Kronecker symbol;

[0191] The table below shows the formulas for calculating six astronomical parameters:

[0192] .

[0193] Example 4:

[0194] Example 4 is basically the same as Example 1, except that:

[0195] The specific stress changes at the calculated fault plane are as follows:

[0196] Rotate the coordinate system on the fault plane. Here, the strike, dip, and slip angles of the fault are given, with a negative sign added to the strike and dip angles. The direction cosine matrix after rotating the spherical coordinates to the Cartesian coordinates is:

[0197] ;

[0198] Therefore, the stress matrix in spherical coordinates is expressed as: .

[0199] Example 5:

[0200] Example 5 is basically the same as Example 1, except that:

[0201] I. Basic Parameter Settings

[0202] 1. Spatial parameters: Input the longitude, latitude, and depth of the calculation location.

[0203] 2. Time parameters: Input the start time of the calculation, select the sampling interval: 1 minute, 15 minutes, 1 hour, and the number of outputs m.

[0204] After completing the above parameter settings, the system will calculate the stress changes within a specified time period based on the solid tide theory.

[0205] II. Calculation of Tidal Stress in Solids

[0206] 1. Calculation of tidal stress tensor of solids

[0207] After clicking the "Start Calculation 1" button, the system will perform the calculation of the solid tidal stress tensor, and the interface will display an image of the stress components in the rr direction changing over time.

[0208] After clicking the "Export Data 1" button, a data file in ".csv" format will be exported. The output data has 9 columns and m rows. Each column represents the following stress components: rr, rt, rl, tr, tt, tl, lr, lt, ll, where: r represents the radial direction; t represents the coaxial direction; and l represents the longitudinal direction. The above components contain 6 independent components of the stress tensor.

[0209] III. Stress Calculation at the Fault Plane

[0210] 1. Fault plane parameter settings

[0211] Users can input the following parameters in the fault plane parameter input area: fault strike; fault dip angle; fault slip angle.

[0212] 2. Calculation of stress at the fault plane

[0213] After clicking the "Start Calculation 2" button, the system will calculate the stress change on the fault plane based on the input fault plane parameters, and the interface will display an image of the shear stress on the fault plane changing over time.

[0214] After clicking the "Export Data 2" button, a data file in ".csv" format will be exported. The output data consists of 3 columns and m rows. Each column represents the following stress components: normal stress at the fault plane; shear stress at the fault plane; and the first stress invariant.

[0215] IV. Seismic Data Import and Comparative Analysis

[0216] 1. Import earthquake data

[0217] Click the "Import Earthquake Data" button to import external earthquake catalog data into the system.

[0218] The system will automatically convert earthquake data into an earthquake time series format that the software can recognize.

[0219] The software includes sample earthquake data formats, which users can use to organize the original earthquake catalog.

[0220] 2. Visualization of earthquake and stress comparison

[0221] After clicking the "Draw" button, the system will mark the time of earthquake occurrence in the tidal stress time series graph, thereby enabling a direct comparative analysis between earthquake events and changes in solid tidal stress.

[0222] V. Results Output Instructions

[0223] All calculation results can be exported as ".csv" files for easy subsequent data processing and analysis; image results can be directly used for scientific research analysis, reports, or paper illustration references.

[0224] As shown in the figure, this system can calculate the stress tensor, where Figure 4 , Figure 5 The results are for 6 independent tidal stress tensors. Case 1 is from 15:00:00 (UTC) on May 31, 2008, with geographic coordinates of 39.03°N, 140.88°E, a depth of 8 km, and a projected strike of 209°, dip angle of 39°, and slip angle of 101° onto this fault plane. The sampling interval is 15 minutes, and the output is 1500, approximately 16 days later. Figure 2-3 );

[0225] Example 2 is from 15:00:00 (UTC) on May 31, 2008, with geographic coordinates of 33.92°N, 133.72°E, a depth of 30km, a strike of 250°, a dip of 10°, a slip angle of 100°, a time interval of 15 minutes, and an output count of 1500 to 16 days. This calculation system can obtain normal stress, shear stress, and the first invariant of the stress tensor.

[0226] In the following text, J1 is the first invariant of the stress tensor divided by three. The stress tensor is calculated using the parameters given in Example 1. There are a total of 6 independent tensors. As can be seen from the figure, some components have a magnitude of kPa, and the tidal variations of the three principal stress components have good consistency in phase.

[0227] This system can calculate the strain tensor. This paper also compares the strain tensor results with the stress tensor results from TidalStrain2. Figure 6 , 7 The amplitudes of the strains are all on the order of 10⁻⁸, which shows that, apart from some minor differences, the waveforms are basically the same, indicating the correctness of the system.

[0228] Tidal stress changes with depth, but the extent of this change needs further investigation. This is because, when calculating the normal and shear stresses of a fault plane, firstly, the accuracy of obtaining earthquake depth using seismographs is not always guaranteed for certain earthquakes; secondly, for slow earthquakes, the depth of plate boundaries is generally used. Regardless of the case, the influence of depth must be considered when calculating the tidal normal and shear stresses at relative earthquake depths. Therefore, the following experiment was conducted, using the Hindu Kush earthquake (36.04°N, 70.53°E) as an example. According to the GCMT (The Global Centroid-Moment-Tensor), a magnitude 6.2 earthquake occurred in Hindu Kush on May 12, 2000, with a focal depth of 105.6 km. Figure 8 This describes the changes in tidal stress over time at depths of 20km, 40km, 60km, 80km, 100km, and 120km. Figure 9 The variation of tidal stress tensor with time at different depths on the fault plane with strike = 233°, dip = 82°, and slip angle = -106° is shown. It can be observed that in shallow layers (<20km), the amplitude of the tidal strain tensor decreases, while at depths greater than 40km, the amplitude and phase changes are almost negligible. The phase change is minimal, but the amplitude changes significantly with depth.

[0229] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention should be included within the scope of protection set forth in the claims.

Claims

1. A seismic analysis and calculation system based on tidal theory, characterized in that: The earthquake analysis and calculation system based on tidal theory includes a tidal theory calculation module (1), a fault parameter and stress projection module (2), an earthquake event import module (3), and an analysis module (4). The output end of the tidal theory calculation module (1) is connected to the input end of the fault parameter and stress projection module (2), the output end of the fault parameter and stress projection module (2) is connected to the input end of the earthquake event import module (3), and the output end of the earthquake event import module (3) is connected to the input end of the analysis module (4). The tidal theory calculation module (1) includes input time parameters and spatial parameters, and outputs tidal stress tensor; The fault parameter and stress projection module (2) includes input fault plane parameters and output tidal shear stress and normal stress; The earthquake event import module (3) includes inputting earthquake event data, outputting tidal stress and earthquake event data, and transmitting them to the corresponding analysis module (4). The analysis module (4) includes outputting a fusion visualization of tidal stress and seismic events.

2. The seismic analysis and calculation system based on tidal theory according to claim 2, characterized in that: The tidal theory calculation module (1) is used to calculate the tidal stress tensor at a specified location on the surface or underground at any time period; The fault parameter and stress projection module (2) is used to project the tidal stress tensor onto the fault plane according to the fault plane parameters input by the user, so as to obtain the tidal shear stress and normal stress. The earthquake event import module (3) is used to import external earthquake catalog data and convert the imported earthquake data into an earthquake time series format that the system can recognize, and then transmit it to the analysis module (4); The analysis module (4) is used to assess the correlation between earthquake occurrence and tidal changes and to display the calculation results.

3. The seismic analysis and calculation system based on tidal theory according to claim 2, characterized in that: The fault plane parameters include fault strike, fault dip angle, and fault slip angle.

4. The seismic analysis and calculation system based on tidal theory according to claim 1, characterized in that: The analysis module (4) also includes generating a comparison graph between earthquake events and changes in solid tidal stress.

5. A method of using the seismic analysis and calculation system based on tidal theory as described in claim 1, characterized in that: The method of using the earthquake analysis and calculation system based on tidal theory includes the following steps: Step 1: In the tidal theory calculation module (1), input the spatial parameters and time parameters in sequence, and then click the Start Calculation button to start the tidal stress calculation to obtain the tidal stress tensor. The second step is to input the fault strike, fault dip angle, and fault slip angle in the fault plane parameter input area of ​​the fault parameter and stress projection module (2), and combine them with spatial parameters and time parameters. Then click the Start Calculation button to start calculating the stress change on the fault plane to obtain the tidal shear stress and normal stress. The third step is to first click the "Import Earthquake Data" button in the earthquake event import module (3) to import the external earthquake data directory, and then click the "Draw" button. The analysis module (4) generates a graph of the relationship between tidal parameters and the time of earthquake occurrence based on the earthquake data and the tidal stress tensor, tidal shear stress and normal stress data, so as to obtain the correlation between tidal parameters and earthquake. At this point, the method ends.

6. The method of using the seismic analysis and calculation system based on tidal theory according to claim 5, characterized in that: The correlation between tidal parameters and earthquakes in the third step includes whether earthquakes have periodic characteristics, whether the time of earthquake occurrence corresponds to the maximum or minimum value of tidal shear stress, and whether they are concentrated in a specific phase interval.

7. The method of using the seismic analysis and calculation system based on tidal theory according to claim 5, characterized in that: In the first step, while obtaining the tidal stress tensor, the interface also displays an image of the stress components changing over time. After clicking the "Export Data" button, the tidal stress tensor data file is exported. In the second step, while obtaining the tidal normal stress and shear stress data, the interface displays an image of the shear stress of the fault plane changing over time. Then, click "Export Data 2" to export the tidal normal stress and shear stress data.

8. The method of using the seismic analysis and calculation system based on tidal theory according to claim 5, characterized in that: The tidal stress calculation is specifically as follows: According to the expanded table of tidal bores, the tidal bore is represented as: ； in, It's about latitude. The distance from a point inside the Earth to the Earth's center. The function is the geodetic coefficient. It is the order of the spherical harmonic expansion. It represents the number of expansions, expanding n to order 4; The second-order expression is: ； The third-order expression is: ； The fourth-order expression is: ； Where D2 is the Doodson constant; It is a function of time, and is related to the trigonometric functions of linear combinations of astronomical parameters and the amplitude of the partial waves; ； in, These are the expansions of G. , The upper and lower wave numbers of the same tidal wave, The coefficients of the astronomical parameters form the Doodson code; This represents the relative amplitude at the corresponding frequency. The above astronomical parameters are calculated as follows: ； in, Julian Day for calculating time, For time, Time zone.

9. The method of using the seismic analysis and calculation system based on tidal theory according to claim 8, characterized in that: The Love number is defined as follows: ； The Earth's surface to a depth of 800 km is divided into layers at 100m intervals, and the solutions obtained correspond to the second, third, and fourth orders of gravity. as well as and ; ； in These represent the radial displacement, radial stress, horizontal displacement, and horizontal stress generated inside and on the surface of the Earth under the influence of tidal forces, respectively. The vertical and horizontal displacements of any point inside or on the Earth are: ； Based on the relationship between strain and displacement, the expressions for the six independent components of the strain tensor can be obtained as follows: ； Then, based on the relationship between stress and strain: ; That is, to obtain the tidal stress inside the Earth, among which, and for Lamé constant at that location, For the volumetric expansion due to strain, i.e., the trace of the strain tensor matrix, For Kronecker symbols.

10. The method of using the seismic analysis and calculation system based on tidal theory according to claim 5, characterized in that: The specific stress changes at the calculated fault plane are as follows: Rotate the coordinate system on the fault plane. Here, the strike, dip, and slip angles of the fault are given, with a negative sign added to the strike and dip angles. The direction cosine matrix after rotating the spherical coordinates to the Cartesian coordinates is: ； Therefore, the stress matrix in spherical coordinates is expressed as: .

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