Broadband seismic oscillation simulation method and system based on probabilistic seismic hazard analysis

Abstract

The invention discloses a broadband seismic oscillation simulation method and system based on probabilistic seismic risk analysis, and relates to the technical field of field seismic oscillation, and the method comprises the steps: carrying out the seismic risk decoupling through employing a Chinese probabilistic seismic risk analysis method, determining a target potential source area corresponding to the maximum contribution degree with probability significance and a potential source magnitude and an epicentral distance of the target potential source area; calculating a fault size parameter of the target potential source area based on the potential source magnitude and a preset scaling rate; calculating fault distribution parameters of the target potential source area based on the fault size parameters and the mixed seismic source model; combining the three-dimensional longitudinal wave velocity model and the shallow structure model to construct a three-dimensional calculation model; and performing deterministic low-frequency simulation and deterministic high-frequency simulation on the three-dimensional calculation model based on a spectral element method and a three-way stochastic finite fault method respectively, and then performing broadband time program sequence synthesis to obtain a broadband seismic oscillation simulation result. The technical problem of low simulation result accuracy in the prior art is relieved.

Description

Technical Field

[0001] This invention relates to the field of site ground motion technology, and in particular to a broadband ground motion simulation method and system based on probabilistic seismic hazard analysis. Background Technology

[0002] my country has numerous earthquake fault zones, and many cities are located near faults or within earthquake zones. The complex source rupture process leads to complex characteristics of ground motion in near-fault areas (hanging wall effect, impulse effect, directional effect, etc.). Furthermore, seismic records from stations show that strong near-fault earthquakes are not only determined by magnitude but are also closely related to specific site characteristics; moderate earthquakes can cause severe damage in specific sites. Simultaneously, near-fault ground motions often contain high-amplitude, long-period velocity pulses, making high-rise buildings and long-span bridges more susceptible to entering nonlinear response states, leading to material yielding, structural plastic deformation, and even collapse. Chinese standards such as the "Earthquake Safety Evaluation of Engineering Sites" (GB17741-2005) and the "Seismic Design Standard for Hydraulic Structures" (GB51247-2018), as well as international standards such as the "Guidelines for the Selection of Seismic Ground Motion Parameters for Dams" and the US standard "Response Spectrum and Seismic Analysis of Concrete Hydraulic Structures" (EM1110-2-605), all require that for major projects, the specific seismic environment and target hazard level of the site must be considered, and site-specific ground motions must be used.

[0003] Currently, there are several main approaches to obtaining or predicting ground motion time histories: (1) Traditional artificial ground motion method based on consistent probability spectrum: Based on the ground motion attenuation relationship, probabilistic seismic hazard analysis (PSHA) is performed to obtain the consistent probability spectrum of the bedrock site as the target spectrum, and the ground motion time history is artificially synthesized through mathematical methods such as trigonometric series. In addition, for near-fault pulse-type ground motion, the approach of scholars at home and abroad is to use mathematical functions to characterize the amplitude, period and shape of velocity pulses, such as equivalent velocity pulse model, white noise-based model, etc.; (2) Based on existing seismic records of stations, according to PSHA and set seismic decomposition results, and considering structural characteristics and seismic hazard, a target spectrum with real spectral characteristics under the target seismic hazard level is constructed, such as the conditional mean spectrum (CMS) and conditional spectrum (CS) proposed by Baker; (3) Ground motion simulation methods based on physical methods, such as spectral element method (SEM), boundary element method (BEM), finite element method (FEM), finite difference method (FDM), broadband hybrid method, etc.

[0004] The first two methods mentioned above are both probabilistic hazard methods based on PSHA, which conform to the requirements of the specifications in form, but they also have some shortcomings. The first method can consider historical earthquakes and the distribution and patterns of potential source areas, and can calculate the uniform hazard spectrum (UHS) for a specific location. However, the UHS has envelope characteristics of seismic response spectra with different magnitudes (M) and epicentral distances (R), so the results are usually overestimated. The synthetic ground motion component has certain limitations when simulating near-fault effects, considering specific local site conditions, and pulse parameters of engineering sites. CMS / CS can overcome the shortcomings of the uniform probabilistic spectrum to some extent, but due to the limited existing station records, it is impossible to precisely consider factors such as rupture mechanisms, faults, seismic wave paths, and directions in the selection of records for seismic design specifications. Otherwise, the wave selection process would be very complex, resulting in a relatively small number of strong earthquake records selected.

[0005] Currently, there is little research on the nonlinear seismic effects of sedimentary layers, and the effective simulation frequencies are mostly too low. However, the frequency band of near-fault ground motion is actually quite wide, and the effective frequency needs to reach 10-20 Hz to fully consider the influence of higher-order vibration modes in general engineering seismic design. However, current simulations of the entire physical process from fault dynamic rupture to site response are mostly limited to frequencies below 5 Hz. The stochastic finite fault method (EXSIM) is theoretically easy to understand and computationally fast, proving to be a relatively efficient tool for high-frequency ground motion simulation. However, this method cannot reflect the scattering effect of seismic waves on complex sites, has poor simulation accuracy for low frequencies (<1 Hz), and the results obtained are only the total horizontal acceleration time history. Summary of the Invention

[0006] To address the aforementioned technical problems in existing technologies, embodiments of the present invention provide a broadband ground motion simulation method and system based on probabilistic seismic hazard analysis. The technical solution is as follows:

[0007] On the one hand, a broadband ground motion simulation method based on probabilistic seismic hazard analysis is provided. The method includes: decoupling seismic hazard using the Chinese probabilistic seismic hazard analysis method based on historical geological information of the target field point to determine the target potential source area corresponding to the maximum contribution with probabilistic significance, and the potential source magnitude and epicentral distance of the target potential source area; calculating the fault size parameters of the target potential source area based on the potential source magnitude and a preset calibration rate; calculating the fault distribution parameters of the target potential source area based on the fault size parameters and a hybrid source model; constructing a three-dimensional calculation model of the target potential source area based on the epicentral distance, the fault size parameters, the fault distribution parameters, and the elevation information of the target potential source area, combined with a three-dimensional P-wave velocity model and a shallow subsurface structure model of mainland China; performing deterministic low-frequency simulation and deterministic high-frequency simulation on the three-dimensional calculation model based on the spectral element method and the three-dimensional stochastic finite fault method, respectively, to obtain low-frequency and high-frequency ground motion simulation results; and synthesizing the low-frequency and high-frequency ground motion simulation results using a broadband time sequence to obtain broadband ground motion simulation results.

[0008] Optionally, based on the historical geological information of the target site, the seismic hazard decoupling method of China is adopted, including: based on the Chinese probabilistic seismic hazard analysis method and the ground motion attenuation relationship model, taking the potential source area as the basis and combining the historical geological information of the target site, the potential source area is discretized and regarded as a point source, and the exceedance probability of each point source is calculated to obtain the annual exceedance probability curve corresponding to the target potential source area; based on the annual exceedance probability curve, the probabilistic seismic hazard decomposition of the target potential source area is performed.

[0009] Optionally, the fault size parameters include global fault size parameters and local fault size parameters; wherein, the global fault size parameters include the fracture area, fracture length, fracture width, and average slip on the fault plane; the local fault size parameters include: the area, length, width, average slip, strike coordinates and dip coordinates of each concave-convex body, and strike coordinates and dip coordinates of the fracture initiation point.

[0010] Optionally, the hybrid source model includes the GP15.4 hybrid source model; the fault distribution parameters include concave-convex body distribution, hybrid slip distribution, rupture time distribution, and rise time distribution.

[0011] Optionally, broadband time-sequence synthesis of the low-frequency and high-frequency ground motion simulation results includes: using a fourth-order Butterworth filter based on phase difference to synthesize the low-frequency and high-frequency ground motion simulation results with a crossover frequency of 1 Hz.

[0012] On the other hand, a broadband ground motion simulation system based on probabilistic seismic hazard analysis is also provided, including: a determination module, a first calculation module, a second calculation module, a construction module, a simulation module, and a synthesis module; wherein, the determination module is used to determine the target potential source area corresponding to the maximum contribution with probabilistic significance, the potential source magnitude, and the epicentral distance of the target potential source area based on the historical geological information of the target site and using the Chinese probabilistic seismic hazard analysis method for seismic hazard decoupling; the first calculation module is used to calculate the fault size parameters of the target potential source area based on the potential source magnitude and a preset calibration rate; the second calculation module is used to calculate the fault size parameters and a hybrid source model. The system calculates fault distribution parameters of the target potential source area; the construction module is used to construct a three-dimensional calculation model of the target potential source area based on the epicentral distance, fault size parameters, fault distribution parameters, and elevation information of the target potential source area, combined with a three-dimensional P-wave velocity model and a shallow subsurface structure model of mainland China; the simulation module is used to perform deterministic low-frequency simulation and deterministic high-frequency simulation on the three-dimensional calculation model based on the spectral element method and the three-dimensional stochastic finite fault method, respectively, to obtain low-frequency and high-frequency ground motion simulation results; the synthesis module is used to synthesize the low-frequency and high-frequency ground motion simulation results using a broadband time sequence to obtain broadband ground motion simulation results.

[0013] Optionally, the determining module is further configured to: based on the Chinese probabilistic seismic hazard analysis method and the ground motion attenuation relationship model, discretize the potential seismic source area and treat it as a point source based on the potential source area and combined with the historical geological information of the target field point, calculate the exceedance probability of each point source respectively, and obtain the annual exceedance probability curve corresponding to the target potential source area; and perform probabilistic seismic hazard decomposition on the target potential source area based on the annual exceedance probability curve.

[0014] Optionally, the synthesis module is further configured to: synthesize the low-frequency simulation results of the ground motion and the high-frequency simulation results of the ground motion using a fourth-order Butterworth filter based on phase difference, using a wideband time sequence with a crossover frequency of 1 Hz.

[0015] On the other hand, an electronic device is also provided, including: 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 method provided in the embodiments of the present invention.

[0016] On the other hand, a computer-readable storage medium is also provided, wherein program code is stored in the computer-readable storage medium, and the program code can be called by a processor to execute the method provided in the embodiments of the present invention.

[0017] This invention provides a broadband ground motion simulation method and system based on probabilistic seismic hazard analysis. It employs a probabilistic method based on CPSHA calculation and decomposition for seismic activity and hazard calculation, obtaining a probabilistically meaningful hypothetical earthquake. Then, it uses a deterministic broadband ground motion hybrid simulation method considering a hybrid source model for fault-induced seismogenesis and seismic influence fields. This method can characterize complex source rupture processes, propagation paths, local site conditions, and soil nonlinearity in detail. The calculation results show a prominent near-fault effect, providing scientifically reasonable ground motion inputs and related parameters for near-fault site planning and design, thus alleviating the technical problem of low accuracy in existing simulation methods. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of a broadband ground motion simulation method based on probabilistic seismic hazard analysis provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the probabilistic seismic hazard decomposition results provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of a three-dimensional earthquake calculation model provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the dynamic shear modulus ratio and damping ratio curves provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of a kinematic hybrid source model of a hypothetical earthquake provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the time history synthesis results of broadband ground motion acceleration at the research site provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the geometric mean distribution of the horizontal components of the earthquake PGA and PGV provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of the synthesized broadband ground motion response spectrum of the research field provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the broadband ground motion Fourier spectrum synthesis results provided in an embodiment of the present invention; Figure 10 This is a schematic diagram of a broadband ground motion simulation system based on probabilistic seismic hazard analysis provided in an embodiment of the present invention. Detailed Implementation

[0020] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0021] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0022] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0023] Figure 1 This is a flowchart illustrating a broadband ground motion simulation method based on probabilistic seismic hazard analysis according to an embodiment of the present invention. Figure 1 As shown, the method specifically includes the following steps:

[0024] Step S102: Based on the historical geological information of the target site, the seismic hazard decoupling is performed using the Chinese probabilistic seismic hazard analysis method to determine the target potential source area corresponding to the maximum contribution with probabilistic significance, as well as the potential source magnitude and epicentral distance of the target potential source area.

[0025] Specifically, based on the China Probabilistic Seismic Hazard Analysis (CPSHA) method and the ground motion attenuation relationship model, the potential source area is discretized and treated as a point source by combining the historical geological information of the target field point. The exceedance probability of each point source is calculated to obtain the annual exceedance probability curve corresponding to the target potential source area. Based on the annual exceedance probability curve, the probabilistic seismic hazard of the target potential source area is decomposed.

[0026] Specifically, based on the CPSHA theory, and using the seismic motion attenuation relationship model of North China from the fifth-generation regional map of my country, and employing ArcGIS software, these regions are discretized and treated as point sources, taking potential source areas as the basis and combining seismic activity parameters. Then, the exceedance probability of each point source is calculated using Python programming, thus obtaining the study field points. The corresponding annual exceedance probability curve is used for probabilistic seismic hazard decomposition.

[0027] In this embodiment of the invention, the CPSHA method differs from the PSHA framework in that it adopts a three-level potential source area division scheme of seismic statistical area, background source and tectonic source. It also uses a spatial distribution function to describe the uneven seismic activity of different potential source areas within the seismic statistical area, thus solving the problem that the traditional PSHA method may underestimate the seismic hazard due to the large area of ​​the potential source area.

[0028] Step S104: Calculate the fault size parameters of the target source region based on the potential source magnitude and the preset calibration rate.

[0029] Step S106: Calculate the fault distribution parameters of the target potential source region based on the fault size parameters and the hybrid source model.

[0030] Optionally, the fault size is calibrated using the Jiang Wei fault local and global calibration method; the hybrid source model adopts the GP15.4 hybrid source model proposed by Graves and Pitarka. This hybrid source model can effectively combine deterministic source models and high-frequency random source models, so that it can include both low-frequency information components inverted from ground motion and random high-frequency scattering generated by local changes in the fault medium during the fault rupture process.

[0031] Specifically, since the rupture process of a future earthquake source cannot be determined through inversion methods, this invention establishes a concave-convex body model based on the scaling rate results. Using this model as a background model for the slip distribution, the concave-convex body slip is transformed into the wavenumber domain using a two-dimensional Fourier transform to obtain a deterministic low-frequency wavenumber spectrum. Considering the complexity of the fault rupture model and the uncertainty of the entire spatiotemporal evolution of the rupture, a stochastic high-frequency wavenumber spectrum is introduced.

[0032] Step S108: Based on the epicentral distance, fault size parameters, fault distribution parameters, and elevation information of the target source area, a three-dimensional calculation model of the target source area is constructed by combining the three-dimensional longitudinal wave velocity model and the shallow structure model of the Chinese mainland.

[0033] Optionally, the surface of the three-dimensional calculation model is established based on the elevation information of the research site, while the remaining soil layers are established using the HBCrust1.0 three-dimensional model of North China and the shallow structure model of mainland China provided by the Geophysical Exploration Center of China Earthquake Administration.

[0034] Step S110: Based on the spectral element method and the three-dimensional stochastic finite fault method, respectively, deterministic low-frequency simulation and deterministic high-frequency simulation are performed on the three-dimensional calculation model to obtain the low-frequency simulation results and high-frequency simulation results of ground motion.

[0035] Alternatively, low-frequency simulations can be performed using the SPEED open-source program, developed by Politecnico di Milano, which is based on the spectral element method. This open-source program can consider both linear and nonlinear elastic ground motion propagation and can perform coupled analysis of source-propagation path-complex site effects based on a kinematic hybrid source model. It is an effective three-dimensional ground motion simulation tool that can supplement the deficiencies of empirical ground motion models and can be used for seismic hazard and risk assessment in large urban areas.

[0036] Optionally, the three-dimensional stochastic finite fault method 3D-EXSIM is used to simulate high-frequency ground motion. Based on empirical statistics and relevant research results, the source parameters, propagation path parameters and site effect parameters under the target site earthquake are set.

[0037] Step S112: Perform broadband time sequence synthesis on the low-frequency and high-frequency ground motion simulation results to obtain broadband ground motion simulation results.

[0038] Specifically, based on a fourth-order Butterworth filter with phase difference, the low-frequency and high-frequency simulation results of ground motion are synthesized using a wideband time sequence with a crossover frequency of 1 Hz.

[0039] To better illustrate the method provided by the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0040] Step 1: In this example, a rare earthquake scenario analysis was conducted on a near-fault area in Tianjin with a 50-year exceedance probability of 2%. Based on the CPSHA theory, the seismic motion attenuation relationship model for North China, as shown in the fifth-generation regional map of my country, was used. Using ArcGIS software, potential source areas were discretized into 2km×2km grids and treated as point sources, combined with seismic activity parameters. The exceedance probability of each point source was calculated using Python programming, according to the formula:

[0041] In the formula, , The GR relationship coefficients within the seismic statistical zone. Within the earthquake statistics area Annual incidence of earthquakes of magnitude 4 or above Let be the spatial distribution function, representing The magnitude 6.0 earthquake occurred at the 1st The probability of a potential source region For the first The area of ​​each potential source region, The coordinates of the i-th potential source region within the z-th seismic statistical zone. point, The number of magnitude scales. This represents the number of potential seismic source areas within the z-th seismic statistical zone.

[0042] Wherein, probability density distribution function for: In the formula, For the first Each earthquake magnitude range The central value, This is the magnitude interval. and These are the upper and lower limits of the earthquake magnitude.

[0043] By analyzing the study area By considering the impact of different seismic statistical zones on the site, the exceedance probability of the site is obtained. : Based on the assumption that earthquake events are independent of each other, it is possible to calculate the time period within a specific time frame. Probability of exceeding within the year : Using Bayesian theory to decompose the relative contributions of different sources and magnitudes to the exceedance probability of a given ground motion intensity will affect the calculation of all contributing factors to the ground motion parameters at the site. The combined discretization is performed, and the contribution ratio of various combinations is calculated to decompose the set seismic parameters.

[0044] In the formula, For ground motion intensity parameters greater than hour, Joint probability distribution of the combinations; The annual exceedance probability of the seismic ground motion intensity parameter. The magnitude is The distance is hour, The annual exceedance probability.

[0045] Based on the above methods, the research sites were finally obtained. The corresponding annual exceedance probability curve and 50-year exceedance probability curve. Based on the seismic activity parameters given by the fifth-generation seismic zoning map, combined with the formula... Perform probabilistic seismic hazard decomposition and calculate separately. The relative contribution rates of ground motion intensity with a 50-year exceedance probability of 2% at different epicentral distances under magnitude ranges of 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, and 8.0 are decomposed as follows: Figure 2 As shown.

[0046] Step 2: The Quaternary sedimentary layers in the example area are mainly composed of fluvial and lacustrine sandstone and sandy clay. The distribution and characteristics of these sedimentary layers are significantly affected by regional faulting activities such as faults, resulting in complex sedimentary characteristics in the fault-controlled areas, especially the unevenness of sedimentary thickness.

[0047] Based on the project safety assessment report, wave velocity data from 15 boreholes with a depth of about 100m were collected. The least squares method was used to fit the shear wave velocity structure of the sedimentary layer. Considering the computational efficiency and model accuracy, the average shear wave velocity of the overburden layer with a thickness between 45m and 120m in the study area was finally determined to be 250m / s.

[0048] Combined with the HBCrust1.0 3D data of North China provided by the China Earthquake Administration Geophysical Exploration Center Based on the model and the shallow structure model of mainland China, the shear wave velocity was obtained according to the empirical formula given by Brocher. and medium density Ultimately, the wave velocity structure from the bottom of the surface to a depth of 40 km was determined, with a resolution of [missing information]. The vertical spacing is 0.5 km. This invention uses the coarse-grain method (Day Bradley 2001) to derive the crustal wave velocity structure and inelastic attenuation (quality factor). Relationship, ( by (in units) and This provides support for refined seismic motion simulation. Based on the above, the medium parameters for the seismic SEM calculation model are obtained, as shown in Table 1:

[0049] Table 1. Setting the medium parameters for the seismic SEM calculation model Step 3, the fault size parameters include global fault size parameters and local fault size parameters; among which, The global dimensional parameters of the fault include the fracture area, fracture length, fracture width, and average slip on the fault plane. The corresponding scaling rate calculation formulas are shown in Table 2. Table 2 Global Fault Parameters Among them, M W It is a latent earthquake magnitude.

[0050] The local dimensional parameters of the fault include: the area, length, width, average slip, strike coordinates and dip coordinates of each concave-convex body, the strike coordinates and dip coordinates of the rupture initiation point, and the corresponding scaling rate calculation formulas are shown in Table 3. Table 3 Local parameters of the fault Preferably, the hybrid source model includes the GP15.4 hybrid source model; the fault distribution parameters include concave-convex body distribution, hybrid slip distribution, rupture time distribution, and rise time distribution. The concave-convex body distribution, hybrid slip distribution, rupture time distribution, and rise time distribution are respectively as follows: Figure 5 The four distribution maps are shown in the figure.

[0051] Specifically, the GP15.4 hybrid source model used in this embodiment of the invention can effectively combine deterministic source models (such as concave-convex body models or inverted fault models) and high-frequency random source models, so that it can contain both low-frequency information components inverted through ground motion and random high-frequency scattering generated by local changes in the fault medium during the fault rupture process.

[0052] Since the rupture process of a future hypocenter cannot be determined through inversion methods, this invention establishes a concave-convex body model based on the calibration rate results. This model serves as the background model for the slip distribution, and the concave-convex body slip amount is... After a two-dimensional Fourier transform to the wavenumber domain, a deterministic low-frequency wavenumber spectrum is obtained: In the formula, and These represent the wave numbers along the strike and dip of the fault, respectively. These represent the local coordinates of the fault plane. Considering the complexity of the fault rupture model and the uncertainty of the entire spatiotemporal evolution of the rupture, a stochastic high-frequency wavenumber spectrum is introduced. :

[0053] In the formula, This represents the sliding wavenumber spectrum where the strike and dip are both zero. This represents the wavenumber spectrum of the Von Karman type autocorrelation function. For in- The random numbers are uniformly distributed between the numbers, where H is the Hurst exponent, and according to Graves and Pitarka (2010), the value in this paper is 0.75. and Representing the relevant lengths along the strike and dip, respectively, the empirical relationship with the potential source magnitude is as follows:

[0054] Using the filter combination function F: In the formula, N represents the sharpness controlling the combination of low and high wavenumbers. and These represent the spatial corner wavenumbers along the direction and dip, respectively. In this embodiment of the invention, N=1. = , = L and W represent the length and width of the sliding model.

[0055] Will and By combining these factors appropriately and performing a two-dimensional inverse Fourier transform, the sliding distribution of the hybrid source model in the spatial domain can be obtained. : use Represent the two-dimensional random wavenumber spectrum of the slip distribution, and generate two two-dimensional random wavenumber spectra filtered using the Von Karman correlation function. and Related to: Will and After undergoing a two-dimensional Fourier inverse transform to the spatial domain, we obtain and According to the GP15.4 program, the fault rupture time and rise time distribution can be generated, and the coefficients can be... and Set between 0 and 1.0 to correlate the rupture time perturbation and rise time distribution with the local slip portion.

[0056] Regarding rupture time, GP15.4 incorporates the background shear wave velocity of the fault rupture surface. For fault rupture in moderate to large crustal earthquakes, when the depth exceeds 8 km, the rupture velocity is typically 80% of the surrounding shear wave velocity. In shallow crust at depths less than 5 km, due to the presence of weak rupture zones, the rupture velocity is further reduced to 56% of the background shear wave velocity. A linear transition is applied to the weak rupture zones in the shallow (Z<5 km) and deep (Z>18 km) faults, further reducing the background rupture velocity by 60%. The rupture initiation time is then determined based on the distance between each sub-source and the rupture initiation point, as well as the background rupture velocity, using random numbers with a mean of 0 and a variance of 1. A time perturbation is applied to the rupture initiation time of each sub-source to finally obtain the rupture time value. :

[0057] Regarding the rise time, Scaling is applied to adjust the mean to 1 and the standard deviation to 0.85, and the rise time of each sub-source is calculated: Adjustment factor along depth: The constant K represents the mean rise time of the fault. right The proportional adjustment coefficient is used to constrain the amplitude of the sub-source rise time. The average rise time of the fault plane. This conforms to the modified empirical relation proposed by Graves and Pitarka (2010) for Somerville et al. (1999):

[0058] In the formula, , The total seismic moment, To the average dip angle of the fault and sliding angle The relevant focal mechanism factors are expressed as: In the formula, =0.1, The inclination factor. This is the sliding angle coefficient.

[0059] Step 4: Perform deterministic low-frequency simulation using the SPEED open-source program based on the spectral element method, developed by Politecnico di Milano, Italy.

[0060] The fourth-order precision SEM used in this embodiment of the invention requires that the shortest wavelength of the seismic wave contain at least 5 GLL integration points, and the element size... Spectral unit order and shortest wavelength Need to meet Requirements. This invention uses a 4th-order Lagrange polynomial to simulate the seismic field, with each spectral unit containing the following number of GLL points. Deposition site setup Grid size, in The cutoff frequency is used. The total number of meshes in this physical model is approximately 330 × 10⁴, and five absorbing boundaries are set except for the surface. The three-dimensional computational model is as follows: Figure 3 As shown.

[0061] In the spectral element method calculation, a nonlinear viscoelastic algorithm is introduced for the spectral element points in the sedimentary layer to account for the changes in soil stiffness and damping caused by soil nonlinearity. The dynamic shear modulus ratio and damping ratio curves are shown below. Figure 4 As shown.

[0062] Step 5: Perform high-frequency simulation using the three-dimensional stochastic finite tomography method 3D-EXSIM.

[0063] Source parameters: A hybrid source model was constructed, with sub-fault lengths of 1km × 1km. For stress drop, this invention adopts the average value of 50 bar suggested by Knanmor and Aaderson (1975), which is also consistent with the research results of Wang Qincai et al. on stress drop in North China. The medium density, P-wave velocity, and S-wave velocity in the initial rupture zone of the source are 2760 kg / m³, 6200 m / s, and 3050 m / s, respectively.

[0064] This invention uses the relationship proposed by Beresnev et al. to determine the seismic motion path duration, and refers to the Lg wave quality factor in North China and the research results of Zhao Cuiping et al. to determine the quality factor. It takes into account the influence of factors such as crustal damping and scattering on the attenuation of seismic wave energy, and can better reflect the attenuation characteristics of seismic ground motion in the Tianjin area.

[0065] Based on the research results of Laba Ciren et al., the kappa value was set to 0.04 s in this seismic motion simulation. The crustal amplification effect model adopted the empirical model corresponding to the amplification effect of site class B / C in the National Earthquake Hazard Reduction Program (NEHRP) of the United States. In order to consider the site-specific geological conditions in the high-frequency response, a periodically related nonlinear amplification factor was also applied in the simulation time history to account for the local site amplification effect. This factor was calculated based on the equivalent linear site response analysis implemented in VS30 and the Ground Motion Prediction Equation (GMPE) of Campbell and Bozorgnia.

[0066] The input parameters are shown in Table 4: Table 4. Setting Input Parameters for Seismic Random Finite Fault Simulation Step 6: Based on the phase difference, a wideband time sequence synthesis with a crossover frequency of 1 Hz is performed using a fourth-order Butterworth filter.

[0067] Before combining the low-frequency calculation results based on SEM with the high-frequency ground motion calculation results based on the improved 3D-EXSIM, waveform cross-correlation is used to estimate the difference in shear wave propagation time between the time histories calculated by the two algorithms. Based on the calculation results, the time histories obtained from SEM are shifted to ensure that the first shear wave of the ground motion calculated by the two algorithms arrives approximately simultaneously, thus ensuring the shear wave travel time matches and ensuring the rationality of the broadband ground motion amplitude and spectral characteristics. Finally, using high-pass and low-pass phaseless Butterworth filters with the same corner frequency and attenuation, with f=1Hz as the crossover frequency, a fourth-order low-pass filter is applied to the three components of SEM, and a fourth-order high-pass filter is applied to the three components of 3D-EXSIM, combining them into a single broadband time series. The filters do not change the phase of the signal, which helps to combine the low-frequency and high-frequency components of the two algorithms. The synthesis result is shown below. Figures 6-9 .in, Figure 6 This is a schematic diagram of the time history synthesis results of broadband ground motion acceleration at the research site provided by an embodiment of the present invention. Figure 7 This is a schematic diagram illustrating the geometric mean distribution of the horizontal components of earthquake PGA and PGV according to an embodiment of the present invention. Figure 8 This is a schematic diagram of the synthesized broadband ground motion response spectrum of the research field provided in an embodiment of the present invention. Figure 9 This is a schematic diagram of the broadband ground motion Fourier spectrum synthesis results provided by an embodiment of the present invention.

[0068] As can be seen from the above description, this invention comprehensively considers the advantages of both probabilistic and deterministic methods, and proposes a broadband ground motion simulation method based on probabilistic seismic hazard analysis: in the calculation of seismic activity and hazard, a probabilistic method based on CPSHA calculation and decomposition is adopted to obtain a set earthquake with probabilistic significance; in the fault-induced seismogenic mechanism and seismic influence field, a broadband ground motion hybrid (SEM-3DEXSIM) simulation method based on a hybrid source model is adopted.

[0069] The broadband hybrid method provided by this invention can characterize in detail the complex source rupture process, propagation path, local site conditions, and soil nonlinearity. The calculation results show a prominent near-fault effect, providing scientific and reasonable seismic inputs and related parameters for near-fault site planning and design.

[0070] Figure 10 This is a schematic diagram of a broadband ground motion simulation system based on probabilistic seismic hazard analysis according to an embodiment of the present invention. Figure 10 As shown, the system includes: a determination module 10, a first calculation module 20, a second calculation module 30, a construction module 40, a simulation module 50, and a synthesis module 60.

[0071] Specifically, module 10 is used to decouple seismic hazard based on the historical geological information of the target site and the Chinese probabilistic seismic hazard analysis method to determine the target potential source area corresponding to the maximum contribution with probabilistic significance, as well as the potential source magnitude and epicentral distance of the target potential source area. The first calculation module 20 is used to calculate the fault size parameters of the target potential source area based on the potential source magnitude and the preset calibration rate. The second calculation module 30 is used to calculate the fault distribution parameters of the target potential source area based on fault size parameters and a hybrid source model. Module 40 is used to construct a three-dimensional calculation model of the target source area based on the epicentral distance, fault size parameters, fault distribution parameters and elevation information of the target source area, combined with a three-dimensional P-wave velocity model and a shallow structure model. The simulation module 50 is used to perform deterministic low-frequency simulation and deterministic high-frequency simulation on the three-dimensional calculation model based on the spectral element method and the three-dimensional stochastic finite fault method, respectively, to obtain the low-frequency simulation results and high-frequency simulation results of ground motion. The synthesis module 60 is used to synthesize the low-frequency and high-frequency simulation results of ground motion in a wideband time sequence to obtain wideband ground motion simulation results.

[0072] Specifically, module 10 is also used to: based on the Chinese probabilistic seismic hazard analysis method and the ground motion attenuation relationship model, discretize the potential seismic source area and treat it as a point source based on the potential source area and combined with the historical geological information of the target field point, calculate the exceedance probability of each point source, and obtain the annual exceedance probability curve corresponding to the target potential source area; and perform probabilistic seismic hazard decomposition on the target potential source area based on the annual exceedance probability curve.

[0073] Specifically, the synthesis module 60 is also used to: synthesize the low-frequency and high-frequency simulation results of ground motion with a wideband time sequence at a crossover frequency of 1 Hz using a fourth-order Butterworth filter based on phase difference.

[0074] The present invention also provides an electronic device, including: 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 method provided in the embodiments of the present invention.

[0075] The present invention also provides a computer-readable storage medium storing program code, which can be called by a processor to execute the method provided in the embodiments of the present invention.

[0076] It should be understood that the memory in the embodiments of the present invention can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate synchronous DRAM (DDR SDRAM), enhanced synchronous DRAM (ESDRAM), synchronous linked DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0077] The above embodiments can be implemented, in whole or in part, by software, hardware (such as circuits), firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. A semiconductor medium can be a solid-state drive.

[0078] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0079] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0080] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the devices, apparatuses, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0081] In the several embodiments provided by this invention, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0082] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0083] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0084] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0085] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A broadband ground motion simulation method based on probabilistic seismic hazard analysis, characterized in that, The method includes: Based on the historical geological information of the target site, the Chinese probabilistic seismic hazard analysis method is used to decouple the seismic hazard and determine the target potential source area corresponding to the maximum contribution with probabilistic significance, as well as the potential source magnitude and epicentral distance of the target potential source area. Based on the potential source magnitude and the preset calibration rate, calculate the fault size parameters of the target potential source region; Based on the fault size parameters and the hybrid source model, the fault distribution parameters of the target potential source region are calculated; Based on the epicentral distance, the fault size parameters, the fault distribution parameters, and the elevation information of the target potential source area, a three-dimensional calculation model of the target potential source area is constructed by combining the three-dimensional longitudinal wave velocity model and the shallow structure model. Based on the spectral element method and the three-dimensional stochastic finite fault method, deterministic low-frequency simulation and deterministic high-frequency simulation are performed on the three-dimensional calculation model to obtain the low-frequency simulation results and high-frequency simulation results of ground motion. The low-frequency and high-frequency ground motion simulation results are combined using a broadband time sequence to obtain broadband ground motion simulation results.

2. The method according to claim 1, characterized in that, Based on historical geological information of the target site, seismic hazard decoupling is performed using the Chinese probabilistic seismic hazard analysis method, including: Based on the Chinese probabilistic seismic hazard analysis method and ground motion attenuation relationship model, taking the potential source area as the basis and combining the historical geological information of the target field point, the potential source area is discretized and regarded as a point source. The exceedance probability of each point source is calculated to obtain the annual exceedance probability curve corresponding to the target potential source area. Based on the annual exceedance probability curve, the probabilistic seismic hazard decomposition of the target potential source area is performed.

3. The method according to claim 1, characterized in that, The fault size parameters include global fault size parameters and local fault size parameters; wherein... The global dimensional parameters of the fault include the fracture area, fracture length, fracture width, and average slip on the fault plane; The local dimensional parameters of the fault include: the area, length, width, average slip, strike coordinates and dip coordinates of each concave-convex body, and strike coordinates and dip coordinates of the rupture initiation point.

4. The method according to claim 1, characterized in that, The hybrid source model includes the GP15.4 hybrid source model; the fault distribution parameters include concave-convex body distribution, hybrid slip distribution, rupture time distribution, and rise time distribution.

5. The method according to claim 1, characterized in that, The broadband time sequence synthesis of the low-frequency and high-frequency ground motion simulation results includes: using a fourth-order Butterworth filter based on phase difference to synthesize the low-frequency and high-frequency ground motion simulation results with a crossover frequency of 1 Hz.

6. A broadband ground motion simulation system based on probabilistic seismic hazard analysis, characterized in that, include: The module comprises a determination module, a first calculation module, a second calculation module, a construction module, a simulation module, and a synthesis module; among which, The determination module is used to decouple seismic hazard based on the historical geological information of the target site and the Chinese probabilistic seismic hazard analysis method to determine the target potential source area corresponding to the maximum contribution with probabilistic significance, as well as the potential source magnitude and epicentral distance of the target potential source area. The first calculation module is used to calculate the fault size parameters of the target potential source area based on the potential source magnitude and a preset calibration rate; The second calculation module is used to calculate the fault distribution parameters of the target potential source region based on the fault size parameters and the hybrid source model; The construction module is used to construct a three-dimensional calculation model of the target potential source area based on the epicentral distance, the fault size parameters, the fault distribution parameters, and the elevation information of the target potential source area, combined with a three-dimensional longitudinal wave velocity model and a shallow structure model. The simulation module is used to perform deterministic low-frequency simulation and deterministic high-frequency simulation on the three-dimensional calculation model based on the spectral element method and the three-dimensional stochastic finite tomography method, respectively, to obtain the low-frequency simulation results and high-frequency simulation results of ground motion. The synthesis module is used to perform broadband time sequence synthesis of the low-frequency simulation results and the high-frequency simulation results of the ground motion to obtain broadband ground motion simulation results.

7. The system according to claim 6, characterized in that, The determining module is further configured to: Based on the Chinese probabilistic seismic hazard analysis method and ground motion attenuation relationship model, taking the potential source area as the basis and combining the historical geological information of the target field point, the potential source area is discretized and regarded as a point source. The exceedance probability of each point source is calculated to obtain the annual exceedance probability curve corresponding to the target potential source area. Based on the annual exceedance probability curve, the probabilistic seismic hazard decomposition of the target potential source area is performed.

8. The system according to claim 6, characterized in that, The synthesis module is also used to: synthesize the low-frequency simulation results of the ground motion and the high-frequency simulation results of the ground motion using a wideband time sequence with a crossover frequency of 1 Hz based on a fourth-order Butterworth filter with phase difference.

9. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor, when executing the computer program, implements the method as described in any one of claims 1-5.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium contains program code that can be invoked by a processor to execute the method as described in any one of claims 1 to 5.

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