CN-121998970-A - Hidden movable fault geometric parameter discrimination method based on multi-track InSAR and stress field constraint

Abstract

The invention discloses a hidden movable fault geometric parameter discrimination method based on multi-track InSAR and stress field constraint, and belongs to the technical field of remote sensing. The method comprises the steps of obtaining an InSAR isoseism deformation map of a target area, extracting a space connecting line of a deformation gradient maximum value as a fault agent trace, constructing a mutual exclusion trend assumption based on the trace, screening reasonable trends by predicting and comparing multi-track deformation symbol distribution, and simultaneously judging whether a maximum rising area is positioned on the P-axis pointing side by combining with the P-direction of a local principal compression stress axis of field geological inversion so as to restrict the sliding type. According to the invention, a fault model is not required to be preset, the high confidence degree judgment of the trend and the mechanism is realized by utilizing the physical self-consistency of the multi-view InSAR and the actually measured stress field, the problem of fault geometric multi-resolution under the condition of no surface fracture is effectively solved, the interpretation reliability of the seismic structure is obviously improved, and key parameter support is provided for seismic risk assessment.

Inventors

• LI HUXIONG
• ZHANG JIALE
• LI DONGDONG
• QIN XUEYUAN
• JIN HONGYI
• Wei Samu
• AI MAN
• HA NI
• MARYAM
• Sai Yide
• LI QI
• FANG CHAOXI
• Wang Jiangda
• DONG YUANYUAN
• YU DONGHUA
• GUO YUJIE
• WANG YU

Assignees

• 绍兴文理学院

Dates

Publication Date

20260508

Application Date

20260313

Claims (10)

1. 1. A hidden active fault geometric parameter discrimination method based on multi-track InSAR and stress field constraint is characterized by comprising the following steps: S1, acquiring an ascending rail and descending rail InSAR isoseism deformation map of a target seismic area, and extracting a space connecting line of a deformation gradient maximum value as a ground surface projection proxy trace of a hidden fault; S2, constructing at least two mutually exclusive fault tendency assumptions based on the agent trace; S3, predicting deformation symbol distribution generated on two sides of the faults under the observation geometry of the ascending and descending InSAR according to each fault trend hypothesis; S4, comparing the predicted deformation symbol distribution with an actual track lifting InSAR deformation map and a track lowering InSAR deformation map respectively, and reserving a trend assumption that deformation symbols are consistent to obtain a primary screening result; s5, performing field geological investigation in the target area, measuring scratch directions of a plurality of fault outcrops, and inverting to obtain a concentrated azimuth interval of the local main compressive stress axis P; S6, combining a concentrated azimuth interval of a local main compressive stress axis P, judging whether a maximum elevation area in actual InSAR deformation is positioned at one side pointed by the P axis, if not, excluding a thrust sliding mechanism, if so, reserving the thrust sliding mechanism and adding a sliding mechanism candidate set; S7, integrating the preliminary screening result and the sliding mechanism candidate set, and outputting a fault trend direction and sliding type combination which are physically self-consistent to serve as a geometrical parameter discrimination result of the hidden movable fault based on multi-track InSAR and stress field constraint with high confidence.
2. 2. The hidden active fault geometric parameter discrimination method based on multi-track InSAR and stress field constraint according to claim 1, wherein the deformation sign coincidence means that for any trend assumption, the predicted upper disc deformation sign is the same as the sign of an actual InSAR observed value under the condition of track lifting and track descending, and the lower disc sign is the same.
3. 3. The hidden active fault geometry discrimination method based on multi-track InSAR and stress field constraints of claim 2, wherein said at least two mutually exclusive fault trend hypotheses comprise taking said proxy trace as trend, assuming fault trends as orthogonal sides of its trend normal direction, respectively.
4. 4. The hidden active fault geometry discrimination method based on multi-orbit InSAR and stress field constraints as set forth in claim 1, wherein said P-axis pointing side is determined by taking the azimuth angle of the local principal compressive stress axis P as reference with respect to the proxy trace trend Define the P-axis pointing sector as: Wherein, the Is the azimuth angle of the local principal compressive stress axis P, in degrees, The unit is the earth azimuth angle of the central point of the maximum elevation area, if Satisfy the following requirements It is determined that the P-axis is located on the direction side.
5. 5. The hidden movable fault geometric parameter discrimination method based on multi-orbit InSAR and stress field constraint according to claim 1, wherein the ascending and descending InSAR isoseism deformation map is obtained based on TOPS mode images of a Sentinel-1 satellite through differential interferometry DINSAR processing, and deformation inversion accuracy is better than +/-1.0 mm.
6. 6. The hidden active fault geometric parameter discriminating method based on multi-orbit InSAR and stress field constraint according to claim 1 wherein the local principal compressive stress axis P is obtained by not less than three outcrop inversion, the concentrated azimuth interval inverts scratch data by a PBT method or a right two-column method, and the P-axis azimuth standard deviation of each outcrop inversion result is required to be less than 15 degrees.
7. 7. The hidden active fault geometric parameter discrimination method based on multi-track InSAR and stress field constraint according to claim 1, wherein the spatial connection of the deformation gradient maximum is generated by the following steps: S11, carrying out spatial gradient calculation on LOS direction deformation d (x, y) in the InSAR deformation map to obtain a gradient module length: Wherein d (x, y) is the surface deformation amount of the line-of-sight LOS, and the unit is millimeter; S12, calculating the maximum value max (∇ d) of the gradient module length in the whole deformation graph; S13, extracting to meet As a spatial connection of the maximum values of the deformation gradient.
8. 8. The hidden movable fault geometric parameter judging method based on multi-track InSAR and stress field constraint according to claim 1, wherein if the maximum rising area is positioned on the P-axis directional side and the absolute value of the ratio of the maximum rising value of an upper disc to the maximum sedimentation value of a lower disc is not less than 3, judging the hidden movable fault geometric parameter judging method as a thrust sliding mechanism, and if the deformation is in near-symmetrical distribution and the included angle between the P-axis and the fault trend is less than 30 degrees, judging the hidden movable fault geometric parameter judging method as a walk sliding mechanism.
9. 9. The hidden active fault geometric parameter discrimination method based on multi-track InSAR and stress field constraint according to claim 1, wherein the method is suitable for shallow source construction seismic events with a range of magnitude Mw5.5-6.8, a depth of a seismic source less than 20km and no continuous simultaneous seismic fractures on the earth surface.
10. 10. The hidden mobile fault geometry discrimination method based on multi-track InSAR and stress field constraints of claim 1 further comprising inputting the discriminated fault trend direction and slip type into a probabilistic seismic risk analysis PSHA model for correcting the maximum expected magnitude and recurrence period of a potential source region.

Description

Hidden movable fault geometric parameter discrimination method based on multi-track InSAR and stress field constraint Technical Field The invention relates to the technical field of remote sensing, in particular to a hidden active fault geometric parameter discrimination method based on multi-track InSAR and stress field constraint. Background In the research of earthquake construction and disaster risk assessment, the accurate identification of geometrical parameters such as tendency and sliding type of the earthquake fault is a key premise for understanding the earthquake breaking mechanism and developing the probability earthquake risk analysis (PSHA). In recent years, synthetic aperture radar interferometry (InSAR) technology has become an important means for acquiring a co-seismic deformation field due to its high spatial resolution and wide coverage capability. However, the single-track InSAR can only observe one-dimensional deformation in a line of sight (LOS) direction, and cannot directly reflect real three-dimensional motion characteristics of faults, and more importantly, in a region without surface fracture or complex structure, fault geometric parameters often have multiple resolvability, for example, the same deformation mode can be generated by an eastern or western inclined backflushing fault, and the fault geometric parameters are difficult to distinguish only by a single visual angle. The existing method generally relies on regional seismic source mechanism solution or simplified fault models as prior input, but under the condition that a local stress field and a regional average field deviate or a fault system is highly broken, systematic erroneous judgment is easily introduced by the prior, so that seismic risk assessment distortion is caused. Therefore, a new method for realizing high-confidence discrimination of fault geometric parameters through multi-source observation self-consistency test without depending on a preset fault model is needed. Aiming at the challenges, chinese patent CN112233232B discloses a three-dimensional crust deformation conversion method based on monorail InSAR observation, which is characterized in that a simplified rectangular dislocation fault model is introduced, three-dimensional deformation direction vectors are obtained through forward modeling of elastic dislocation theory, and monorail LOS deformation is decomposed into east, north and vertical three components through the constraint. Although the method relieves the problem of insufficient monorail InSAR dimension to a certain extent, the fundamental premise is that the fault geometric parameters are known or reasonably assumed. Once the preset model is inconsistent with the actual earthquake generating structure, deformation direction vectors generated in the earthquake with the dominant hidden fault area or secondary fracture generate deviation, and three-dimensional deformation reconstruction distortion is caused. In addition, the scheme does not consider how to verify or correct the fault geometry itself, and does not fuse local stress field information, so that the problem of fault geometry uncertainty can not be solved fundamentally. Disclosure of Invention In view of the above, the invention provides a hidden active fault geometric parameter discrimination method based on multi-track InSAR and stress field constraint. The invention abandons dependence on a priori model, and utilizes the spatial consistency of deformation symbols of the lifting rail and the lowering rail InSAR, and combines the measured P-axis azimuth to carry out physical mechanism constraint to construct closed loop discrimination logic, thereby realizing reliable identification of hidden movable fault tendency and sliding type based on multi-rail InSAR and stress field constraint under the condition of no surface fracture, and remarkably improving objectivity and reliability of seismic structure interpretation. The invention provides a hidden active fault geometric parameter discrimination method based on multi-track InSAR and stress field constraint, which comprises the following steps: S1, acquiring an ascending rail and descending rail InSAR isoseism deformation map of a target seismic area, and extracting a space connecting line of a deformation gradient maximum value as a ground surface projection proxy trace of a hidden fault; S2, constructing at least two mutually exclusive fault tendency assumptions based on the agent trace; S3, predicting deformation symbol distribution generated on two sides of the faults under the observation geometry of the ascending and descending InSAR according to each fault trend hypothesis; S4, comparing the predicted deformation symbol distribution with an actual track lifting InSAR deformation map and a track lowering InSAR deformation map respectively, and reserving a trend assumption that deformation symbols are consistent to obtain a primary screening result; s5, performing field geologi