A background-constrained composite seismic source model generation method, system, electronic device and storage medium

Abstract

The application discloses a background-constrained composite seismic source model generation method and system, electronic equipment and a storage medium, and belongs to the technical field of earthquake engineering and strong motion simulation; the application comprises the following steps: obtaining target moment magnitude, fault geometric parameters, source position, average sliding angle, sub-fault size and background mode identifier based on target acquisition; and generating a fault plane regular discrete target sub-fault grid according to the fault geometric parameters and the sub-fault size; constructing a low-wave-number background sliding model according to the background mode identifier; and when the background mode identifier is a set earthquake mode, constructing a concave-convex body background sliding field according to a fault rupture area and the moment magnitude. The application integrates a set earthquake and an actual earthquake background model into a unified process, improves the spatial coordination of a hybrid seismic source rupture model while keeping the target earthquake moment consistent, and is suitable for wide-band strong motion simulation, scenario earthquake analysis and engineering anti-seismic input construction.

Description

Technical Field

[0001] This invention relates to the field of earthquake engineering and strong motion simulation technology, specifically to a method, system, electronic device, and storage medium for generating a composite source model with background constraints. Background Technology

[0002] In the fields of engineering seismology and earthquake hazard risk assessment, the accuracy of seismic motion input largely depends on the rational construction of the source model. Kinematic source models, due to their high computational efficiency and intuitive parameter representation, have been widely used in strong motion simulation and engineering analysis. Kinematic source models describe the fault rupture process by providing parameters such as fault geometry, slip distribution, rupture initiation time, rise time, and slip rate function. They offer significant advantages in balancing physical rationality and computational efficiency, and have become an important source input for current broadband synthetic ground motions.

[0003] In light of the above, it's important to note that numerical simulations of seismic motion are primarily divided into simulated earthquakes and actual earthquakes. In simulated earthquake scenarios, common methods typically generate fault geometry parameters and slip distributions based on scaling law relationships and introduce uncertainties through random field methods. However, such methods struggle to reflect the complex rupture characteristics of real earthquakes. In actual earthquake simulations, while relatively realistic slip distributions can be obtained using finite fault inversion results, these results often lack sufficient resolution to characterize rupture details, making them difficult to directly apply in numerical simulations. Existing research attempts to increase model complexity by introducing random perturbations, but there are still shortcomings in the coupling mechanism between the perturbation field and the background slip field. For example, random perturbations are often generated independently of the background field, failing to consider their consistency control in the wavenumber domain. Regarding rupture propagation, some models use constant rupture velocities, neglecting the influence of depth-dependent structures on rupture propagation. Furthermore, the construction of rise time rarely considers deep transition and local slip coupling effects. These shortcomings make it difficult for existing models to simultaneously meet the comprehensive requirements of physical rationality, statistical consistency, and computational operability in engineering applications.

[0004] To address the aforementioned technical shortcomings, a solution is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method, system, electronic device, and storage medium for generating composite seismic source models with background constraints, in order to solve the problems mentioned above.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for generating a composite seismic source model with background constraints, comprising the following steps:

[0007] Step S1: Based on the acquisition target, obtain the target moment magnitude, fault geometric parameters, source location, average slip angle, sub-fault size and background pattern identifier, and generate a target sub-fault mesh with regular discrete fault plane based on the fault geometric parameters and the sub-fault size.

[0008] Step S2: Construct a low wavenumber background slip model based on the background mode identifier. When the background mode identifier is a set earthquake mode, construct a concave-convex background slip field based on the fault rupture area and moment magnitude. When the background mode identifier is an actual earthquake mode, construct a trimmed and resampled background slip field based on the inverted slip model.

[0009] Step S3: Based on the low wavenumber background sliding model, generate spatially correlated random perturbation fields of slip amount and random perturbation fields of slip angle, and couple them with the corresponding background fields to obtain mixed slip amount field and mixed slip angle field;

[0010] Step S4: Based on the source location, target sub-fault grid, depth-related rupture propagation velocity field, and local slip parameters, generate the rupture initiation time field and rise time field;

[0011] Step S5: Construct a slip rate function based on the slip amount, slip angle, rupture initiation time, and rise time of each sub-fault, and output a kinematic source model containing the source parameters of each sub-fault.

[0012] Furthermore, in step S2, the concave-convex background slip field is constructed under the set earthquake mode as follows:

[0013] The total fault rupture area is determined based on the fault length and width, and the total area of ​​the concave-convex body is determined according to a preset ratio of 20%-30%. A preset moment magnitude threshold is retrieved and compared with the target moment magnitude for analysis. The moment magnitude threshold is set to Mw, with a value range of 5-8, which is the pre-set grading critical value range of the model. If the target moment magnitude is not greater than the lower limit of the moment magnitude threshold range, the total area of ​​the concave-convex body is allocated to a single main concave-convex body; if the target moment magnitude is within the moment magnitude threshold range, the total area of ​​the concave-convex body is allocated to the main concave-convex body and the secondary concave-convex body. The concave-convex body is classified into three levels: primary, secondary, and tertiary concave-convex bodies. If the target moment magnitude is not less than the upper limit of the moment magnitude threshold range, the total area of ​​the concave-convex body is allocated to the primary, secondary, and tertiary concave-convex bodies in proportions of 60%, 30%, and 10%, respectively. Constraints are applied to the primary, secondary, and tertiary concave-convex bodies, with a boundary spacing ≥ 1 / 10 of the fault length / width and a mutual spacing ≥ 1 / 2 of the equivalent diameter of the primary concave-convex body. The center position of the concave-convex body is determined according to a random seed. The background slip volume between the concave-convex body region and the non-concave-convex body region is determined according to the consistency requirements of the target seismic moment.

[0014] Furthermore, the process of constructing the background slip field in the actual seismic mode in step S2 is as follows:

[0015] The data from the finite fault inversion slip model are read, and the original sub-fault slip and slip angle are reconstructed into two-dimensional distributions along the strike and dip directions. Effective rupture areas are identified based on a threshold of slip ≥ 5%-15% of the overall average slip, and low-slip areas at the edges are trimmed to form effective slip surfaces. The original sub-fault grid coordinates are reconstructed on the effective slip surfaces, and the slip field and slip angle field are resampled to the target sub-fault grid using bilinear interpolation. The source moment consistency of the resampled slip field is calibrated.

[0016] Furthermore, the specific process of step S3 is as follows:

[0017] The low-wavenumber background slip field is transformed to the wavenumber domain; a random perturbation spectrum of slip is generated according to the characteristic corner wavenumbers kcx=2π / L and kcy=2π / W, where L is the fault length and W is the fault width, and the spatial domain slip random perturbation field is obtained through inverse transformation; the spatial domain slip random perturbation field is superimposed on the background slip field and its amplitude is scaled to make the seismic moment corresponding to the mixed slip field consistent with the target seismic moment; a slip angle random perturbation field that is spatially related to the slip random perturbation field but whose amplitude is independently controlled is generated, and a mixed slip angle field is formed under the constraint of the average slip angle.

[0018] Furthermore, the depth-dependent rupture propagation velocity field in step S4 is formed in the following manner:

[0019] Based on the one-dimensional crustal shear wave velocity structure of the China Seismic Ground Motion Parameter Zoning Map, shear wave velocities at different depths were obtained. These shear wave velocities were then scaled piecewise with a scaling factor of 0.6-0.9 for the shallow region (0-10 km) and 0.5-0.8 for the deep region (10-20 km), and Gaussian smoothing was performed along the dip direction to obtain a continuous background rupture propagation velocity distribution. Based on the propagation path from the epicenter to the center of each sub-fault and the continuous background rupture propagation velocity distribution, the basic rupture initiation time of each sub-fault was calculated. Finally, combining magnitude-related delay correction and local slip correction, the final rupture initiation time field was obtained.

[0020] Furthermore, the rise time field in step S4 is formed in the following manner:

[0021] The fault center depth is divided into shallow, middle, and deep sections according to the fault burial depth ratio, and background rise time adjustment coefficients are set for different depth sections. In the preset deep transition zone, the rise time is adjusted by a linear transition method to characterize the deep fracture weakening effect. The background rise time is weighted according to the local slip to form the initial value of local rise time. Spatial correlation random disturbances are superimposed on the initial value of local rise time, and the overall level of the rise time field is kept consistent with the target constraint by normalization processing with full field scaling to 0.5-3.0s.

[0022] Furthermore, in step S5, the slip rate function is a normalized bell-shaped symmetric function, the time integral of which is equal to the slip amount of the corresponding sub-fault, and time shift is performed according to the rupture initiation time of the corresponding sub-fault to form the sub-fault source time function.

[0023] A background-constrained composite source model generation system, comprising:

[0024] The parameter input and mesh generation module is used to receive magnitude, fault geometry parameters, source location, mean slip angle, sub-fault size and background pattern identifier, and generate target sub-fault mesh.

[0025] The background sliding model generation module is used to construct a set earthquake background sliding field or an actual earthquake background sliding field based on the background mode identifier. It uses a common data format for data interaction and switches between the set / actual earthquake processing unit through the mode identifier bit.

[0026] The hybrid slip field generation module is used to couple a spatially correlated slip amount random perturbation field and a slip angle random perturbation field onto the background slip field to generate a hybrid slip amount field and a hybrid slip angle field.

[0027] The rupture time parameter generation module is used to generate the rupture initiation time field and rise time field;

[0028] The sliding rate function construction and output module is used to generate the kinematic source model output by the sliding rate function.

[0029] An electronic device includes a processor and a memory, wherein the memory stores a computer program that, when executed by the processor, implements the method according to any one of claims 1 to 7.

[0030] A storage medium having a computer program stored thereon, which, when executed by a processor, implements the method of any one of claims 1 to 7.

[0031] The beneficial effects of this invention are: First, it achieves unified modeling and flexible switching between the set earthquake and the actual earthquake background model, and perfectly matches the distribution characteristics of high slip zones of different magnitudes by covering the entire range of moderate to large earthquakes through multi-convex-concave body hierarchical coverage; Second, it improves the spatial correlation and statistical rationality of the slip field through the wavenumber domain controlled random perturbation construction method; Third, it improves the physical consistency of the rupture time field by introducing a depth-correlated rupture propagation velocity model; Fourth, it improves the overall coordination of the source model through multi-parameter coupling constraints, thereby significantly enhancing its applicability in broadband strong ground motion simulation and engineering applications. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0033] Figure 1 This is a flowchart illustrating the method steps provided in an embodiment of the present invention;

[0034] Figure 2 This invention provides a composite source model based on the constraints of a concave-convex body model under a set earthquake scenario.

[0035] Figure 3 This invention provides a composite source model based on inversion model constraints under actual earthquake scenarios, as provided in this embodiment.

[0036] Figure 4 A block diagram of a background-constrained composite seismic source model generation device provided in an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the computer system of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1: Please refer to Figure 1 - Figure 5 As shown, this embodiment is a method, system, electronic device, and storage medium for generating a composite seismic source model with background constraints, including the following steps:

[0040] In step S1, the basic input parameters required for generating the source model are obtained based on the acquisition target. These input parameters may include, but are not limited to: target moment magnitude Mw, fault geometric parameters, source location, mean slip angle, sub-fault discrete dimensions, and background identifier. Among them, the fault geometric parameters may include fault strike, fault dip angle, fault length L, fault width W, and fault crest depth. The sub-fault discrete dimensions may include the discrete step size ∆d along the strike direction and the discrete step size ∆w along the dip direction. The background mode identifier is used to indicate whether the current earthquake mode or the actual earthquake mode is used. It should be noted that this step mainly completes the input and collection of basic parameters required for subsequent source model construction.

[0041] Based on fault geometry parameters and sub-fault discrete dimensions, a regularly discrete target sub-fault mesh is established within the fault's local coordinate system. Let the number of meshes along the strike direction be Nx, and the number of meshes along the dip direction be Ny, then we can have... and Thus we obtain × Each sub-fault unit (i,j) corresponds to a unique center location, area, and spatial index, and its area can be represented as... ;

[0042] In this embodiment, the aforementioned target sub-fault grid serves not only as a discrete carrier for the subsequent slip field and slip angle field, but also as a unified spatial reference for the rupture time parameter field and the source time function. In other words, all subsequent source parameters are expressed and coupled based on this unified discrete framework, which helps to ensure the consistency between different parameters.

[0043] The discrete scale of the target sub-fault grid can be adjusted according to the target simulation frequency band, the resolution requirements in engineering applications, and the fault geometry scale. Step S1 not only completes the geometric discretization of the fault plane, but also establishes a spatial reference basis for the unified projection, unified mapping, and unified calibration of various parameter fields.

[0044] In step S2, a low wavenumber background slip model is constructed based on the background mode identifier. The low wavenumber background slip model includes at least a background slip magnitude field and a background slip angle field, which are mainly used to characterize the non-uniform distribution characteristics of fault rupture on a macro scale and serve as the basis field for subsequent local random disturbance superposition. It should be noted that, based on different background modes, step S2 can be implemented in two ways: setting the seismic mode and using the actual seismic mode.

[0045] In one implementation, when the background mode is identified as the set earthquake mode, a macroscopic background slip distribution that satisfies the target earthquake moment constraint can be established first based on the target moment magnitude and fault geometry scale input in step S1; the total fault rupture area is first determined based on the fault length L and fault width W. Subsequently, the corresponding target seismic moment M0 is determined based on the target moment magnitude.

[0046] Based on the target seismic moment and the total fault rupture area, the average slip across the entire field can be obtained, according to the formula... ,in, This is expressed as the medium shear modulus. Through the above processing, it provides an overall-scale constraint for the subsequent construction of the background sliding field. This is expressed as the average slippage over the entire game;

[0047] To reflect the spatial characteristics of the coexistence of high-slip control zones and general slip zones on the fault plane of a major earthquake, in this embodiment, a low-wavenumber background slip field is constructed using several constrained high-slip control sub-regions; the background slip field is expressed by the formula... ,in, It is represented as a boundary attenuation constraint function, used to control the smooth transition of the background field at the fault edge; This is represented by the number of high-slip control sub-regions; This is represented as the amplitude coefficient of the m-th control sub-region; This is represented by a smoothed distribution function that characterizes the spatial influence range of the control sub-region. Represented as the background sliding field;

[0048] The total area of ​​the concave-convex body is determined according to a preset ratio of 20%-30%. The target moment magnitude input in step S1 is used as the judgment basis. The preset moment magnitude threshold is Mw, which can be in the range of 5-8. The target moment magnitude is compared and analyzed with the moment magnitude threshold.

[0049] If the target moment magnitude is not greater than the lower limit of the moment magnitude threshold range, the total area of ​​the concave-convex body will be allocated to a single main concave-convex body.

[0050] If the target moment magnitude is within the moment magnitude threshold range, the total area of ​​the concave and convex bodies is allocated to the primary and secondary concave and convex bodies.

[0051] If the target moment magnitude is not less than the upper limit of the moment magnitude threshold range, the total area of ​​the concave and convex bodies will be allocated to the primary concave and convex bodies, secondary concave and convex bodies, and tertiary concave and convex bodies in proportions of 60%, 30%, and 10%, respectively.

[0052] Constraints are applied to the primary, secondary, and tertiary concave-convex bodies: the boundary spacing is ≥ 1 / 10 of the fault length / width, and the mutual spacing is ≥ 1 / 2 of the equivalent diameter of the primary concave-convex body. The center position of the concave-convex body is determined according to the random seed. The background slip volume of the concave-convex body region and the non-concave-convex body region is determined according to the consistency requirements of the target seismic moment.

[0053] The background sliding angle field can be initially taken as the average sliding angle as the initial value of the entire field, according to the formula... ,in, The average slip angle is represented as the input. In the initial case, the background slip angle field can be uniformly given by the average slip angle. It should be noted that, without departing from the concept of this invention, a small smoothing correction can be applied to the local area according to the needs of the specific fault rupture mode, so that the background slip angle field can better match the target rupture features.

[0054] In another implementation, when the background mode is identified as the actual seismic mode, the low wavenumber background slip model is not directly generated by the scaling relation, but is obtained by converting the existing finite fault inversion results. It should be noted that the slip distribution and slip angle distribution data in the original inversion slip model can be read first and reconstructed into a two-dimensional field expression on the fault plane, thereby providing a basis for subsequent trimming, resampling and calibration processing.

[0055] Since the original inversion results often suffer from irregular grid patterns, excessive low-slip noise at the edges, and irregular effective fracture regions, this embodiment further performs effective fracture region identification, edge clipping, and resampling processing on the original inversion field. Specifically, regions that meet a preset sliding threshold and have connectivity can be identified as effective fracture regions. The edge regions below the threshold are cropped to obtain a constraint region that more closely resembles the actual main fracture surface. The cropped inverted slip field is then resampled onto the regular target sub-fault grid established in step S1 to obtain the resampled intermediate slip field. and intermediate sliding angle field To ensure that the resampled results are consistent with the target seismic moment, source moment consistency calibration is performed on the intermediate slip field, which can be done in the following way:

[0056]

[0057]

[0058]

[0059]

[0060] in, This represents the current seismic moment corresponding to the resampled slip field; This is expressed as a global moment consistency scaling factor; through this process, the original inversion results can be converted into a low wavenumber background sliding model that satisfies the regular grid expression and the target moment constraint.

[0061] In step S3, based on the low wavenumber background slip model obtained in step S2, spatially correlated local random perturbations are further introduced to characterize the non-uniformity of fault rupture at the microscale. It should be noted that, unlike the method of perturbing only the slip amount, this invention simultaneously couples the slip amount field and the slip angle field with interrelated but independently controllable perturbations, thereby forming a mixed slip amount field and a mixed slip angle field respectively. The key point of this step is to further supplement local random details while maintaining macroscopic background constraints.

[0062] First, the background sliding field is... Mapping to the wavenumber domain, to generate a slip perturbation field with spatially correlated structure, a stochastic spectral weighting function related to the fault scale can be constructed, according to the formula: ,in, and These are represented as wavenumbers for the direction of strike and the dip, respectively. and This is represented as the characteristic cutoff wavenumber, the value of which can be determined by the fault length and fault width. and The parameters are represented as control spectral decay characteristics; in terms of complex Gaussian random variables. As a fundamental random source, the slip perturbation spectrum can be obtained, according to the formula: After performing an inverse transformation, the spatial domain slip random perturbation field is obtained. ;

[0063] After obtaining the random perturbation field of the slip, it can be coupled with the background slip field to form a hybrid slip field. The coupling relationship can be expressed as follows: ,in, This is expressed as the magnitude of the disturbance used to control the slippage. Represented as a nonnegativity constraint and smoothing limit operator, used to suppress non-physical negative slip or anomalous spikes; This is represented as a recalibration factor, used to ensure that the hybrid slip field meets the consistency requirements of the target seismic moment. The recalibration factor can be determined based on the relationship between the seismic moment corresponding to the coupled slip field and the target seismic moment, according to the formula... In this way, spatially correlated local slip undulations can be introduced while preserving the low wavenumber characteristics of the background field.

[0064] For the slip angle field, in this embodiment, a random perturbation field with a similar spatial correlation structure to the slip amount perturbation field but with its amplitude controlled independently can be used to generate the slip angle perturbation spectrum first. The spatial domain sliding angle perturbation field is obtained through inverse transformation, and then coupled with the background sliding angle field according to the formula. ,in, This is expressed as the amplitude used to control the slip angle disturbance; This is used to constrain the range of angle values, and post-processing is used to keep the overall average value consistent with the input average sliding angle. Through the above dual-field coupling method of sliding quantity field and sliding angle field, local spatial non-uniformity can be further introduced while maintaining the macroscopic background physical meaning.

[0065] Example 2: In step S4, based on the source location, target sub-fault grid, depth-related rupture propagation velocity field, and local slip parameters, a rupture initiation time field and a rise time field are generated. It should be noted that, compared with the traditional method of giving the rupture time sequence only based on geometric distance, this example further incorporates depth variation, magnitude effect, local slip state, and random disturbances into the time parameter modeling process, thereby improving the coordination and consistency between the rupture time sequence field and the slip parameter field.

[0066] First, a depth-dependent fracture propagation velocity field can be established based on the one-dimensional shear wave velocity structure of the regional crust; let the fracture propagation velocity at depth z be Vr(z). Then it can be determined by the shear wave velocity Vs(z) at the corresponding depth. The sample was obtained by scaling down the shallow section (0-10km) with a scaling factor of 0.6-0.9 and the deep section (10-20km) with a scaling factor of 0.5-0.8, and then performing Gaussian smoothing along the dip direction. The window size is equal to two sub-faults, according to the formula... ,in, This is expressed as a velocity scaling factor that varies with depth; based on the rupture propagation velocity field and the propagation path from the epicenter to the center of each sub-fault, the basic rupture initiation time of each sub-fault unit can be calculated according to the formula. ,in, This represents the propagation from the epicenter to the sub-fault unit. The path; in this way, the determination of the rupture initiation time can take into account not only geometric distance factors, but also the propagation differences caused by the change of medium with depth.

[0067] To reflect the modulating effect of magnitude variation and local slip inhomogeneity on the rupture time sequence, a joint correction can be made to the basic rupture initiation time. Specifically, the corrected rupture initiation time field can comprehensively consider magnitude-related correction terms, local slip correction terms, and spatially related random disturbance terms, and is expressed as: ,in, This is represented as a magnitude-related correction term, used to reflect changes in the overall rupture duration scale under larger earthquakes; This is represented as a local slip correction term, used to reflect the difference in the advance of the fracture front between the high slip zone and the low slip zone; It is represented as a spatially correlated random disturbance term, used to reflect the local irregularities of rupture propagation.

[0068] For the rise time field, in one implementation, the fault plane can be first divided into multiple depth segments according to the center depth of the sub-fault, and a corresponding background rise time adjustment coefficient can be set for each depth segment. For sub-fault units located within a preset deep transition zone, a linear transition or other smooth transition method can be used to ensure that the background rise time remains continuously varied between adjacent depth segments. The background rise time can be written as: ,in, Represented as the baseline rise time scale; This can be represented as a depth adjustment function. Through the above processing, the rise time field can have more reasonable variation characteristics in the depth direction.

[0069] The background rise time is weighted and corrected based on the local slippage to form the initial value of the local rise time: ,in, It is expressed as the overall average value of the mixed slip field; Represented as the local sliding adjustment index; To prevent the denominator from being zero, a spatially correlated random disturbance is superimposed on the initial value of the local rise time. After performing full-field normalization, the final rise time field is obtained: ,in, Represented as positive value and smoothing constraint operator; It is represented as the overall normalization factor; it is used to ensure that the overall level of the final rise time field is consistent with the target constraint.

[0070] In step S5, a corresponding slip rate function is constructed based on the mixed slip amount, mixed slip angle, rupture initiation time and rise time of each sub-fault unit, and a complete kinematic source mode is output based on this function.

[0071] This can be each sub-fault unit i,j Construct a normalized bell-shaped symmetric function, including but not limited to the Brune model; the time kernel function satisfies the non-negativity requirement and its time integral is 1, and is expressed as the rise time Trise(i,j) corresponding to the sub-fault unit. As control parameters, the slip rate function of the corresponding sub-fault unit can be further constructed, ensuring that the integral of the slip rate function over time equals the final slip of the sub-fault unit. A time shift is then performed according to the rupture initiation time of the corresponding sub-fault to form the sub-fault source time function. By repeating the above calculation process for all sub-fault units, a complete kinematic source model containing the sub-fault location, slip, slip angle, rupture initiation time, rise time, and slip rate function can be formed. Furthermore, the kinematic source model can be encapsulated into a standardized output file suitable for broadband strong ground motion simulation, scenario earthquake analysis, and engineering seismic input construction, thereby realizing a unified modeling process from macroscopic background constraints and local non-uniform parameter coupling to complete time history output.

[0072] In summary, this invention integrates the low wavenumber background modeling of the set earthquake mode and the actual earthquake mode into the same process through the coordinated execution of steps S1 to S5. It also jointly generates the slip field, slip angle field, rupture initiation time field, and rise time field on a unified spatial grid, ultimately forming a composite kinematic source model that satisfies the target seismic moment constraint and has good spatial coordination. Compared with existing methods that only process a certain type of parameter separately, this invention is more conducive to improving the physical consistency between various source parameters and the applicability of engineering applications.

[0073] Please see Figure 2 , Figure 2 The diagram illustrates a composite source model constrained by a concave-convex background under a set earthquake mode according to the present invention. In this embodiment, the low wavenumber background slip field is constructed based on the target moment magnitude, fault geometric parameters, and target seismic moment constraints. A high slip control zone constrained by boundary spacing can be set within the fault plane, and a background slip field and a background slip angle field are generated on it. Then, spatially correlated local random disturbances are superimposed to further generate a mixed slip field and a mixed slip angle field, and combined with the rupture initiation time field and rise time field to form a complete kinematic source model. Figure 2 This invention is mainly used to illustrate how it generates a composite source model based on a macroscopic background configuration under a given earthquake scenario.

[0074] Please see Figure 3 , Figure 3This diagram illustrates the composite source model of the present invention constrained by the inverted background under a real seismic mode. The low wavenumber background slip field is derived from existing finite fault inversion results. First, effective rupture region identification, edge trimming, regular grid resampling, and seismic moment consistency calibration are performed on the original inverted slip model to obtain the background slip magnitude field and background slip angle field suitable for the target sub-fault grid. Then, spatially correlated local random perturbations are superimposed on the background field, and further, the rupture initiation time field, rise time field, and slip rate function corresponding to each sub-fault are generated, thus forming a complete kinematic source model. Figure 3 This invention is mainly used to illustrate the model transformation and parameter co-generation process under actual seismic constraints.

[0075] Based on the above method embodiments, the present invention also provides a background-constrained composite source model generation system. The system can be used to execute all or part of the aforementioned steps S1 to S5, thereby achieving an automated processing flow from source parameter input to kinematic source model file output.

[0076] In one embodiment, please refer to Figure 4 The background-constrained composite source model generation system can include at least a parameter input and mesh generation module, a background slip model generation module, a hybrid slip field generation module, a rupture time parameter generation module, and a slip rate function construction and output module. It should be noted that the data interaction between the above modules can be achieved through sequential calls, data bus transmission, or shared storage mapping, etc., and this invention does not make specific limitations on this.

[0077] The parameter input and mesh generation module receives magnitude, fault geometry parameters, source location, mean slip angle, sub-fault size, and background mode identifier, and generates a regular discrete target sub-fault mesh based on the fault geometry parameters and sub-fault size. The target sub-fault mesh can serve as a unified spatial carrier for the background slip model, mixed slip field, rupture time parameter field, and slip rate function. This module enables unified coordinate expression and consistent coupling of multiple types of source parameters.

[0078] The background sliding model generation module is used to construct a low wavenumber background sliding model based on the background mode identifier. The low wavenumber background sliding model includes at least a background slip field and a background slip angle field. In one embodiment, the background sliding model generation module may further include setting earthquake background units and actual earthquake background units to correspond to the background field construction process under the set earthquake mode and the actual earthquake mode, respectively.

[0079] The earthquake background unit is used to construct a background slip field based on the target moment magnitude, fault length, fault width, and target moment constraints when the background mode identifier indicates the earthquake mode. It can switch between single-control zone configuration and dual-control zone configuration according to the moment magnitude threshold, and further constrain the boundary spacing, mutual spacing, area ratio, and amplitude of the control zones to form a low-wavenumber background slip field that meets the macroscopic slip distribution characteristics. The earthquake background unit can also generate a corresponding background slip angle field based on the input average slip angle.

[0080] The actual seismic background element is used to read the finite fault inversion slip model data when the background mode identifier indicates the actual seismic mode, and to perform effective rupture zone identification, edge clipping, regular grid resampling, and seismic moment consistency calibration on the data to generate an actual seismic background slip model adapted to the target sub-fault grid. Through the above processing, the original inversion results can be converted into a background field that meets the requirements of unified spatial discretization and is convenient for subsequent multi-parameter coupling.

[0081] The hybrid slip field generation module is used to generate a spatially correlated random perturbation field of slip volume and a random perturbation field of slip angle based on the background slip model, and couples the random perturbation field with the background slip volume field and the background slip angle field respectively to obtain the hybrid slip volume field and the hybrid slip angle field. In one embodiment, the hybrid slip field generation module may further include a wavenumber domain transformation unit, a random spectrum generation unit, a spatial domain reconstruction unit, and a consistency calibration unit. Among them, the wavenumber domain transformation unit is used to map the background field to the wavenumber domain, the random spectrum generation unit is used to construct the perturbation spectrum based on the fault scale characteristics and spatially correlated control parameters, the spatial domain reconstruction unit is used to recover the random perturbation field through inverse transformation, and the consistency calibration unit is used to perform target seismic moment consistency correction on the coupled hybrid slip volume field.

[0082] The rupture time parameter generation module is used to generate a rupture initiation time field and a rise time field based on the seismic source location, the target sub-fault grid, the depth-related rupture propagation velocity field, and local slip parameters. In one embodiment, the rupture time parameter generation module may further include a velocity field construction sub-unit, a rupture initiation time sub-unit, and a rise time sub-unit.

[0083] The velocity field construction sub-unit is used to construct a rupture propagation velocity field related to the fault depth based on the one-dimensional shear wave velocity structure, a given medium profile, or other preset velocity information, and to perform necessary segmentation, scaling, and smoothing on the velocity field to form a continuous background rupture propagation velocity distribution.

[0084] The rupture initiation time sub-unit is used to calculate the basic rupture initiation time of each sub-fault unit based on the propagation path from the source location to the center location of each sub-fault and the depth-related rupture propagation velocity field. It is further combined with magnitude-related corrections, local slip corrections, and spatially related stochastic corrections to generate the final rupture initiation time field.

[0085] The rise time subunit is used to divide the fault plane into multiple depth segments according to the center depth of the sub-fault, and set different background rise time adjustment coefficients for different depth segments. For deep transition regions, a smooth transition method can be used to determine the background rise time of the corresponding sub-fault, and then the final rise time field is generated by combining local slip and spatially correlated random disturbances. The overall rise time level is kept consistent with the preset target by full field normalization.

[0086] The slip rate function construction and output module is used to construct the corresponding slip rate function based on the mixed slip amount, mixed slip angle, rupture initiation time, and rise time of each sub-fault, and output a complete kinematic source model. The slip rate function construction and output module can construct a normalized bell-shaped symmetric time function for each sub-fault unit whose time integral is equal to the corresponding slip amount, and time-shift it according to the corresponding rupture initiation time to form the slip rate function or seismic moment function of the sub-fault. Then, the source parameters and corresponding time functions of all sub-faults are packaged and output to form a kinematic source model file that meets the requirements of engineering applications.

[0087] It should be understood that the modules, units, or sub-units in the above system embodiments can be implemented by software, hardware, or a combination of software and hardware. For example, the modules can be deployed on the same server, the same workstation, the same graphics computing platform, or a distributed computing environment, or they can be implemented by different processor cores, different execution threads, or different functional boards. Data transfer between modules can be achieved through file transfer, shared memory, message queues, database read / write, or network communication, and this invention does not impose specific limitations on these methods.

[0088] The present invention also provides an electronic device, please refer to [link / reference]. Figure 5 Electronic devices may include processors, memory, and computer programs stored in the memory and capable of running on the processor; the processor may be a central processing unit, a graphics processing unit, a digital signal processor, a field-programmable gate array, an application-specific integrated circuit, or one or more combinations of the above devices; the memory may include high-speed random access memory, or may include non-volatile storage media, such as read-only memory, flash memory, disk storage, or solid-state memory.

[0089] When the computer program is executed by the processor, the electronic device can implement the background-constrained composite source model generation method of the aforementioned method embodiment. The processor can call the parameter input and mesh generation program segment to establish the target sub-fault mesh; call the background slip model generation program segment to construct a low wavenumber background slip model under the set earthquake mode or the actual earthquake mode; call the mixed slip field generation program segment to form a mixed slip magnitude field and a mixed slip angle field; call the rupture time parameter generation program segment to obtain the rupture initiation time field and rise time field; and call the slip rate function construction and output program segment to output a complete kinematic source model file.

[0090] The present invention also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, it can implement the background-constrained composite source model generation method of the aforementioned method embodiments. The computer-readable storage medium may be a magnetic storage medium, an optical storage medium, a semiconductor storage medium, or other tangible medium capable of storing program code and being read by a computing device.

[0091] For example, the following program instructions can be stored sequentially in a computer-readable storage medium: a first instruction for receiving source parameters and generating a target sub-fault grid; a second instruction for constructing a low wavenumber background slip model based on the background pattern; a third instruction for generating and coupling a random perturbation field of slip amount and a random perturbation field of slip angle; a fourth instruction for generating a rupture initiation time field and a rise time field; and a fifth instruction for constructing a slip rate function and outputting a kinematic source model; when the program instructions are executed, all or part of the steps in the aforementioned method embodiments can be completed.

[0092] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can also be implemented by computer program instructions in conjunction with related hardware. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the corresponding processes in the foregoing method embodiments. The program instructions can exist in any form, such as source code, object code, executable file, or some intermediate form. The computer-readable storage medium can include an entity or device capable of carrying program instructions, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory, and a random access memory, etc.

[0093] It should be noted that the above description of the implementation methods of the system, electronic device and computer-readable storage medium is only for the purpose of illustrating the implementation structure and deployment form of the technical solution of the present invention, and does not mean that the present invention must be strictly limited to the above-mentioned number of modules, hardware type, program organization method or interface form; without departing from the concept of the present invention, any combination, splitting, replacement or redeployment of the above modules by those skilled in the art should be regarded as falling within the protection scope of the present invention.

[0094] Thus, this invention forms a composite kinematic source model generation scheme with overall physical consistency and engineering applicability by unifying spatial discretization, dual-mode background constraints, dual-field coupling of sliding parameters, collaborative generation of rupture time parameters, and construction and output of sliding rate functions. This scheme can be applied to the construction of engineering inputs under set earthquake scenarios, as well as the reconstruction of source models constrained by actual earthquake inversion results, thus having good application scalability and engineering implementation value.

[0095] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for generating a composite seismic source model with background constraints, characterized in that, Includes the following steps: Step S1: Based on the acquisition target, obtain the target moment magnitude, fault geometric parameters, source location, average slip angle, sub-fault size and background pattern identifier, and generate a target sub-fault mesh with regular discrete fault plane based on the fault geometric parameters and the sub-fault size. Step S2: Construct a low wavenumber background slip model based on the background mode identifier. When the background mode identifier is a set earthquake mode, construct a concave-convex background slip field based on the fault rupture area and moment magnitude. When the background mode identifier is an actual earthquake mode, construct a trimmed and resampled background slip field based on the inverted slip model. Step S3: Based on the low wavenumber background sliding model, generate spatially correlated random perturbation fields of slip amount and random perturbation fields of slip angle, and couple them with the corresponding background fields to obtain mixed slip amount field and mixed slip angle field; Step S4: Based on the source location, target sub-fault grid, depth-related rupture propagation velocity field, and local slip parameters, generate the rupture initiation time field and rise time field; Step S5: Construct a slip rate function based on the slip amount, slip angle, rupture initiation time, and rise time of each sub-fault, and output a kinematic source model containing the source parameters of each sub-fault.

2. The method for generating a background-constrained composite source model according to claim 1, characterized in that, In step S2, the concave-convex background slip field is constructed under the set earthquake mode as follows: The total fault rupture area is determined based on the fault length and width, and the total area of ​​the concave-convex body is determined according to a preset ratio. A preset moment magnitude threshold is retrieved and compared with the target moment magnitude. If the target moment magnitude is not greater than the lower limit of the moment magnitude threshold range, the total area of ​​the concave-convex body is allocated to a single primary concave-convex body. If the target moment magnitude is within the moment magnitude threshold range, the total area of ​​the concave-convex body is allocated to the primary and secondary concave-convex bodies. If the target moment magnitude is not less than the upper limit of the moment magnitude threshold range, the total area of ​​the concave-convex body is allocated to the primary, secondary, and tertiary concave-convex bodies in proportions of 60%, 30%, and 10%, respectively. Constraints are applied to the primary, secondary, and tertiary concave-convex bodies: boundary spacing ≥ 1 / 10 of the fault length / width, and mutual spacing ≥ 1 / 2 of the equivalent diameter of the primary concave-convex body. The center position of the concave-convex body is determined according to a random seed. The background slip volume between the concave-convex body region and the non-concave-convex body region is determined according to the target earthquake moment consistency requirements.

3. The method for generating a background-constrained composite source model according to claim 1, characterized in that, The process of constructing the background slip field under the actual earthquake mode in step S2 is as follows: The data from the finite fault inversion slip model are read, and the original sub-fault slip and slip angle are reconstructed into two-dimensional distributions along the strike and dip directions. Effective rupture regions are identified based on the threshold that the slip is greater than or equal to the average slip across the entire field, and low-slip regions at the edges are trimmed to form effective slip surfaces. The original sub-fault grid coordinates are reconstructed on the effective slip surfaces, and the slip field and slip angle field are resampled to the target sub-fault grid using bilinear interpolation. The source moment consistency of the resampled slip field is then calibrated.

4. The method for generating a background-constrained composite source model according to claim 1, characterized in that, The specific process of step S3 is as follows: Transform the low wavenumber background slip field to the wavenumber domain; A random perturbation spectrum of slip volume is generated according to the characteristic corner wavenumber, and a random perturbation field of slip volume in the spatial domain is obtained through inverse transformation. The random perturbation field of slip volume in the spatial domain is superimposed on the background slip volume field and the amplitude is scaled so that the seismic moment corresponding to the mixed slip volume field is consistent with the target seismic moment. A random perturbation field of slip angle is generated that is spatially related to the random perturbation field of slip volume but whose amplitude is independently controlled, and a mixed slip angle field is formed under the constraint of the average slip angle.

5. The method for generating a background-constrained composite source model according to claim 1, characterized in that, The depth-related rupture propagation velocity field in step S4 is formed in the following manner: Shear wave velocities at different depths are obtained based on a one-dimensional shear wave velocity structure; the shear wave velocities are segmented and scaled for shallow and deep regions, and Gaussian smoothing is performed along the dip direction to obtain a continuous background rupture propagation velocity distribution; the basic rupture initiation time of each sub-fault is calculated based on the propagation path from the source location to the center of each sub-fault and the continuous background rupture propagation velocity distribution; the final rupture initiation time field is obtained by combining magnitude-related delay correction and local slip correction.

6. The method for generating a background-constrained composite source model according to claim 1, characterized in that, The rise time field in step S4 is formed in the following manner: The fault center depth is divided into shallow, middle, and deep sections according to the fault burial depth ratio, and background rise time adjustment coefficients are set for different depth sections. In the preset deep transition zone, the rise time is adjusted by a linear transition method to characterize the deep fracture weakening effect. The background rise time is weighted according to the local slip to form the initial value of local rise time. Spatial correlation random disturbances are superimposed on the initial value of local rise time, and normalization is used to keep the overall level of the rise time field consistent with the target constraint.

7. The method for generating a background-constrained composite source model according to claim 1, characterized in that, The slip rate function in step S5 is a normalized bell-shaped symmetric function. The time integral of the function is equal to the slip amount of the corresponding sub-fault, and the time shift is performed according to the rupture initiation time of the corresponding sub-fault to form the sub-fault source time function.

8. A background-constrained composite source model generation system, used in the background-constrained composite source model generation method according to any one of claims 1-7, characterized in that, include: The parameter input and mesh generation module is used to receive magnitude, fault geometry parameters, source location, mean slip angle, sub-fault size and background pattern identifier, and generate target sub-fault mesh. The background sliding model generation module is used to construct a set earthquake background sliding field or an actual earthquake background sliding field based on the background mode identifier. It uses a common data format for data interaction and switches between the set / actual earthquake processing unit through the mode identifier bit. The hybrid slip field generation module is used to couple a spatially correlated slip amount random perturbation field and a slip angle random perturbation field onto the background slip field to generate a hybrid slip amount field and a hybrid slip angle field. The rupture time parameter generation module is used to generate the rupture initiation time field and rise time field; The sliding rate function construction and output module is used to generate the kinematic source model output by the sliding rate function.

9. An electronic device, characterized in that, It includes a processor and a memory, wherein the memory stores a computer program that, when executed by the processor, implements the method according to any one of claims 1 to 7.

10. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method described in any one of claims 1 to 7.

Images