A method for estimating the maximum magnitude of earthquakes based on the GR relationship weighted by fault characteristics

Abstract

The present invention relates to the fields of seismology and geology, and in particular to a method for estimating the maximum magnitude of an earthquake based on a G-R relationship weighted by fault characteristics, comprising extracting geometrical and structural characteristics of a target fault, fitting a regional Gutenberg-Richter relationship, calculating a comprehensive weight factor of the fault, and adjusting a regional a value based on the weight to obtain a specific a value for a single fault; by combining the adjusted specific a value with a regional b value, an empirical relationship is used to estimate the maximum magnitude of the single fault; the present invention improves the accuracy and reliability of estimating the maximum magnitude of an earthquake, and is particularly superior in areas where earthquake catalog data are insufficient.

Description

Technical Field

[0001] The invention relates to the fields of seismology and geology, and in particular to a method for estimating the maximum magnitude of an earthquake based on a GR relationship weighted by fault characteristics. Background Art

[0002] Accurate estimation of the maximum magnitude of an earthquake plays a vital role in earthquake risk assessment, urban planning, construction engineering design, and disaster reduction and prevention. Existing earthquake prediction methods mainly rely on the regional Gutenberg-Richter (GR) relationship. The GR relationship is a classic model that describes the statistical relationship between earthquake magnitude and frequency. By statistically analyzing the magnitude distribution of earthquake events in a certain region, the a value and b value of the region can be fitted. The a value reflects the seismic activity of the region, while the b value describes the steepness of the magnitude distribution. Based on this model, people can predict the maximum magnitude that may occur in the region in the future.

[0003] However, existing technologies have some significant deficiencies and limitations when estimating maximum magnitude. The traditional GR relationship method can achieve good results in areas with relatively rich historical earthquake data, but for those areas with less seismic activity and incomplete historical earthquake catalogs, directly using the a and b values ​​of the region to estimate the maximum magnitude of a single fault often leads to large errors. This is because these methods do not fully consider the geometric characteristics and tectonic activity of a single fault. Specifically, the existing GR relationship ignores key factors such as fault length, segment length, historical magnitude, activity level, fault depth and stress concentration, which directly affect the seismic activity and stress state of the fault. In addition, because it only relies on statistical regional historical earthquake data, the traditional method has low accuracy in risk assessment of faults in areas with insufficient historical data and cannot accurately reflect the specific characteristics of the fault. Summary of the invention

[0004] In view of the many problems existing in the above-mentioned prior arts, the present invention provides a method for estimating the maximum magnitude of an earthquake based on the GR relationship weighted by fault characteristics. The present invention collects the geometric characteristics and structural characteristics of the target fault, calculates the weight factor of each fault, and uses these weight factors to adjust the a value of the region to obtain the specific a value of a single fault; in combination with the b value of the region, an empirical formula is used to estimate the maximum magnitude of a single fault; the present invention can significantly improve the evaluation effect of the seismic activity of a single fault without relying on a large amount of historical earthquake data.

[0005] A method for estimating the maximum magnitude of an earthquake based on a GR relationship weighted by fault characteristics comprises the following steps:

[0006] Collect the geometric parameters and structural characteristics of the target fault, including the fault length, segment length of the fault, the maximum historical magnitude, activity level, fault depth and stress concentration, and normalize all characteristic parameters to obtain normalized geometric parameters and normalized structural characteristics;

[0007] Based on the regional earthquake catalog data, the regional Gutenberg-Richter relationship is fitted, and the regional a value and b value are calculated and determined, where the a value reflects the level of seismic activity in the study area, and the b value is used to describe the slope of the earthquake magnitude distribution;

[0008] According to the normalized geometric parameters and normalized structural characteristics of the target fault, a comprehensive weight factor of the target fault is calculated using a predetermined weighting formula, and the comprehensive weight factor of the target fault is used to reflect the relative seismic activity of the target fault in the region;

[0009] Based on the comprehensive weight factor of the target fault, the a value of the region is weighted and adjusted, and the specific a value of the target fault is calculated and determined to reflect the seismic activity intensity of the target fault;

[0010] The maximum magnitude of the target fault is calculated using the specific a value of the target fault and the b value of the region. The maximum magnitude of the target fault reflects the earthquake risk characteristics of the target fault.

[0011] Preferably, the geometric parameters and structural features of the target fracture are normalized by maximum value, and the normalization is used to eliminate the dimensional differences between different features so that the normalized feature parameter values ​​are all between 0 and 1.

[0012] Preferably, the calculation of the comprehensive weight factor of the target fracture is performed based on the following formula:

[0013]

[0014] Among them, W fault is the comprehensive weight factor; W i is the value after feature normalization; α i is the corresponding weight coefficient.

[0015] Preferably, the characteristic weight coefficients of the target fault include a fracture length weight coefficient, a fracture segment length weight coefficient, a maximum historical magnitude weight coefficient, an activity level weight coefficient, a fracture depth weight coefficient and a stress concentration degree weight coefficient of the target fault, and each characteristic weight coefficient is set according to the importance of the geometric characteristics of the target fault and the characteristics of the tectonic activity.

[0016] Preferably, the Gutenberg-Richter relationship of the fitting area is fitted by the least squares method, and the least squares method determines the a value and b value of the area based on the following steps: extracting the magnitude-frequency distribution from the earthquake catalog data of the area, and minimizing the fitting error using the least squares method to determine the a value and b value of the area.

[0017] Preferably, the maximum magnitude of the target fault is estimated based on the following empirical formula:

[0018]

[0019] Among them, M max_fault is the maximum magnitude of the target fault; c 1 、c 2 and c 3 is the empirical relationship fitting coefficient; a fault is the specific a value for the target fracture.

[0020] Preferably, the empirical fitting coefficient c 1 、c 2 and c 3 The determination is made by statistically analyzing the relationship between the maximum magnitude of different target faults in multiple seismic cells and the specific a value of the target fault and the b value of the region. Multiple iterative corrections are performed using the least squares method during the analysis process.

[0021] Preferably, the specific a value of the target fault is used to characterize the intensity of seismic activity of the target fault within a small magnitude range, and the adjustment of the specific a value of the target fault is corrected by the comprehensive weight factor of the target fault, and the comprehensive weight factor of the target fault is obtained by weighted calculation of the normalized values ​​of the geometric parameters and structural characteristics of the target fault.

[0022] Preferably, the characteristic parameters of the target fault are extracted based on the regional seismic activity observation data and the geological survey results of the target fault structure. The geological survey results of the target fault structure include the surface geological characteristics of the target fault, the inclination of the target fault surface, the strike of the target fault surface, the width of the target fault zone, the sliding rate of the target fault and the ground stress observation data.

[0023] Preferably, the method is particularly suitable for areas with low frequency of seismic activity and limited historical seismic data. By weighted adjustment of the geometric characteristics and tectonic activity characteristics of the target faults, the estimation results can accurately reflect the seismic activity and seismic risk characteristics of different target faults.

[0024] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0025] By introducing the geometric characteristics and structural activity characteristics of the fault, the present invention proposes a method for estimating the maximum magnitude of an earthquake based on the Gutenberg-Richter relationship weighted by fault characteristics; the present invention collects the geometric characteristics and structural characteristics of the target fault, calculates the comprehensive weight factor using a preset weight formula, and implements weighted adjustment of the regional a value to obtain a specific a value for each fault; through this weighted adjustment, the seismic activity of the fault can be more accurately reflected; finally, combining the adjusted specific a value and the regional b value, an empirical relationship is used to estimate the maximum magnitude of a single fault;

[0026] The present invention achieves higher estimation accuracy by comprehensively analyzing the geometric and structural characteristics of the fault, and shows strong adaptability in areas with insufficient historical data and low seismic activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the process of the present invention;

[0028] Figure 2 The seismic structure map of the target area in the embodiment of the present invention;

[0029] Figure 3a , 3b They are schematic diagrams of cumulative probability curves of earthquakes with magnitudes of 6.0 and 6.5 at the Liuji-Xiquanjie fault according to an embodiment of the present invention;

[0030] Figure 4a , 4b They are schematic diagrams of cumulative probability curves of earthquakes with magnitudes of 6.0 and 6.5 on the Zhangji-Longzihe fault according to an embodiment of the present invention;

[0031] Figure 5a , 5b They are schematic diagrams of cumulative probability curves of earthquakes with magnitudes of 6.0 and 6.5 on the Huaiyuan-Huangjiawan fault according to an embodiment of the present invention;

[0032] Figure 6a , 6b They are schematic diagrams of cumulative probability curves of earthquakes of magnitude 6.0 and 6.5 on the Taoshan-Shangwujia fault according to the embodiments of the present invention. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is obvious that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0034] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0035] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0036] The present invention proposes a method for estimating the maximum magnitude of the GR relationship based on weighted fault characteristics. The method of the present invention calculates the weights of the geometric parameters, tectonic activity, and stress concentration of a single fault, and adjusts the regional a value based on these weights, thereby deriving the a value of a single fault. fault The value is combined with the b value to calculate the maximum magnitude of the fault.

[0037] The technical solution of the present invention comprises the following steps:

[0038] 1. Fault feature extraction: Collect the geometric and structural features of the target fault, including fault length, segment length, historical maximum magnitude, activity level, depth, stress concentration, etc.

[0039] Collect the geometric parameters and structural characteristics of the target fracture, including fracture length (L), segment length (L segment ), the largest historical magnitude (M seismic ), activity level (A), fracture depth (D) and stress concentration (S). All parameters are normalized.

[0040] 2. Regional GR relationship fitting: Use the earthquake catalog data within the region to fit the regional GR relationship and calculate the a and b values ​​of the region.

[0041] The physical meanings of a and b values ​​include:

[0042] a-value: The a-value reflects the overall level of seismic activity. The larger the value, the more frequent earthquakes occur in the area. It represents the total number of earthquakes greater than or equal to a certain magnitude (usually the lowest magnitude) in the study area within a given period of time. The a-value usually changes with the seismic activity of the area, and the a-value is higher in active seismic areas.

[0043] b-value: The b-value describes the slope of the magnitude distribution and reflects the rarity of earthquake events as the magnitude increases. A smaller b-value means that the relative probability of high-magnitude earthquakes is higher, while a larger b-value indicates that the frequency of high-magnitude earthquakes is lower. Usually, the b-value fluctuates between 0.8 and 1.2, and the value is affected by geological conditions such as tectonic environment and stress state.

[0044] 3. Calculation of fracture weight factor: According to the geometric and structural characteristics of the fracture (such as length, sliding rate, depth, etc.), a comprehensive weight factor W is calculated for each fracture. fault The specific weight calculation formula is:

[0045]

[0046] Among them, W i is the value after feature normalization, α i is the corresponding weight coefficient.

[0047] For each fault, its weight factor W is calculated based on its geometric and structural characteristics. fault , the formula is as follows:

[0048]

[0049] Among them, the breaking length (L), segment length (L segment ), the largest historical magnitude (M seismic ), activity level (A), fracture depth (D) and stress concentration (S). All parameters are normalized.

[0050] In this formula, the weight factor W falut It is used to describe the relative importance of each fault in seismic activity. The physical meanings of the specific parameters are as follows:

[0051] 1) Meaning of weight factor

[0052] α L : Fault length weight factor. Reflects the effect of fault length on its seismicity. Longer faults usually have a higher probability of earthquake occurrence, so the relative value of length (relative to the maximum length L max The ratio of ) plays an important role in weight calculation.

[0053] α segment : Weight factor of fault segmentation. Considering that a fault may be divided into multiple segments, the seismic activity of each segment may be different, so the effect of segmentation also needs to be taken into account.

[0054] α seismic : The weight factor of the earthquake magnitude associated with the fault. Reflects the impact of the magnitude of the earthquake that has occurred on the potential for future earthquakes.

[0055] α A : A weighting factor for the area associated with the fault. Considering the size of the area affected by the fault, a fault with a large area may have a higher earthquake risk.

[0056] α D : A weighting factor related to the depth of the fault. The effect of depth on seismicity. Deeper faults may produce different earthquake patterns.

[0057] α S : A weighting factor related to the slip rate of the fault. The higher the slip rate, the greater the seismic potential of the fault generally is.

[0058] 2) Meaning of target fault parameters

[0059] L: The actual length of the target fault. Used to quantify its size. Longer faults generally produce stronger earthquakes.

[0060] L segment : Length of the target fault segment. The physical length of a particular segment of the fault, which affects the seismic potential of that segment.

[0061] M seismic : The maximum historical earthquake magnitude associated with the target fault. Used to assess the potential earthquake intensity of the fault.

[0062] A: The actual impact area of ​​the target fault. Reflects the scale of the area that the fault may affect.

[0063] D: Depth of the target fault. Refers to the physical depth of the fault, which affects its likelihood of producing an earthquake.

[0064] S: The stress value of the fault. Refers to the stress state of the fault, which affects its seismic activity.

[0065] 3) Meaning of regional fault parameters

[0066] L max : The maximum length of all faults in the sample. Used to normalize the length of this fault for comparison with other faults.

[0067] The longest segment length among all segments of all faults in the region. Used for normalization to compare the effects of various segment lengths.

[0068] Maximum historical earthquake magnitude on all faults. A normalized benchmark used to compare the magnitude impacts of different faults.

[0069] A max : The largest affected area among all faults. Used for normalization to compare the impact of different fault affected areas.

[0070] D max : Maximum depth among all faults. Used for normalization to compare the effects of different fault depths.

[0071] S max : Maximum stress among all faults. Used for normalization to compare the effects of different fault slip rates.

[0072] 4. Adjust the a value: According to the calculated fracture weight factor W fault , adjust the a value of the region to obtain a single fracture fault The specific adjustment formula is:

[0073] a fault =a region +log(W fault )

[0074] By formula a fault =a region +log(W fault ), adjust the region a value according to the calculated weight factor to obtain a for the fracture fault value.

[0075] In calculating the adjustment of the a value, the physical meaning of the parameters is as follows:

[0076] a fault : The a value calculated for a specific fault. This value reflects the intensity of seismic activity on the target fault and is usually used to indicate the frequency of small earthquakes.

[0077] a region : Baseline a value for a region. The average activity of all faults in the region, used as a basis for comparison.

[0078] W fault : Weight factor for calculating the target fault's a-value. This value incorporates the effect of the fault's characteristics into the calculation to adjust the regional benchmark a-value to make it more consistent with the characteristics of the target fault.

[0079] 5. Maximum magnitude estimation: In theory, the a / b value can be used to estimate the maximum magnitude, also known as the maximum intercept magnitude. However, in many areas, the actual maximum magnitude recorded is inconsistent with the theoretical value. This is mainly because the number of high-magnitude earthquakes is insufficient, resulting in steps or gaps in the GR relationship in the high-magnitude range. Previous researchers have established an empirical relationship between the a / b value and the maximum magnitude of multiple seismic cells by fitting them. The method of the present invention combines the adjusted fault feature a fault The maximum magnitude of a single fault is calculated by applying the empirical relationship of predecessors based on the regional b value. The empirical relationship is:

[0080]

[0081] Here, c 1 、c 2 、c 3 is the empirical relationship fitting coefficient. fault By substituting the values ​​of a and b into the empirical formula, the maximum magnitude of a single fault can be calculated.

[0082] 6. Result verification and analysis: The calculation results are verified and corrected through existing earthquake records and fault rupture models.

[0083] In an application example, according to the overall requirements of active faults in Bengbu City and the needs of special research, the Quaternary active faults Liuji-Xiquanjie Fault (F1), Zhangji-Longzihe Fault (F2), Huaiyuan-Huangjiawan Fault (F3), and Taoshan-Shangwujia Fault (F5) in the target area are selected as the target faults for this earthquake risk assessment topic (e.g. Figure 2 shown).

[0084] Target fault characteristics:

[0085] 1) The Liuji-Xiquanjie fault (F1) strikes about 20°, dips to SE, and has a dip angle of 50-60°. It passes through Liuji and Jiuwan in Guzhen in the north, passes through the south of the Huaihe River to Xiquanjie in Fengyang County. In Xiquanjie, there is a compressional and crushed breccia zone with a width of about 50-70m. The rocks in the compressional zone are foliated and mylonitic, and there are oblique impact marks on the surface. The fault is 50 kilometers long. The Guzhen M5 earthquake occurred near the fault in 1979.

[0086] 2) Zhangji-Longzihe Fault (F2) strikes at about 35° and dips to SE. It runs from northeast to southwest through Wangzhuang, Feihe River, Huaihe River, Longzihe River, and reaches near Liufu. It is an alternating positive and negative gravity anomaly zone. Aeromagnetic performance is a beaded anomaly zone. In the aeromagnetic anomaly map extending 1,000 meters upward, this anomaly feature is still clearly visible. The scale of the fault is large and it is a grade III fault in the area. Two-dimensional seismic exploration believes that the fault dips to the southeast and has the characteristics of a normal fault. The two plates of the fault have a drop of 200-500m. The fault is 65 kilometers long. There is no historical earthquake record on the fault.

[0087] 3) Huaiyuan-Huangjiawan Fault (F3) strikes nearly east-west, dips south, and has a steep section. The fault is roughly distributed along the northern wing of the Bengbu anticline, and is basically parallel to the anticline axis. It is located west of Huaiyuan County, through Jiaodaying, Mohekou, and Huangjiawan. It is a thrust hidden fault. The fault is located in a gravity gradient intensive zone and a positive and negative magnetic anomaly alternating zone. The Bouguer gravity anomaly is a nearly east-west gravity step zone. The aeromagnetic anomaly is a magnetic field reduction zone in the western section of the fault, and a magnetic step zone in the eastern section. The gravity and magnetic features are still clearly visible with a thickness of 2,000 meters. The fault is large in scale and is a level I fault in the region. The fault is 120 kilometers long and has no historical earthquake records.

[0088] 4) The Taoshan-Shangwujia Fault (F5) strikes about 295°, runs northwest from Wohe, passes Huaiyuan, and extends to the southeast along the northeast edge of Tushan. The fault is clearly shown on the geophysical and geochemical interpretation map, and is a large-scale fault. The Bouguer gravity anomaly appears as a gravity step zone in the SE and middle sections of the fault. Except for the Lilou section, the aeromagnetic shows an abnormal dislocation relationship, and the remaining sections are all positive anomalies arranged in a beaded pattern. The gravity and magnetic anomaly map extending 1,000 meters above shows the above gravity and magnetic characteristics. The fault is large in scale and is a level II fault in the area. The results of the combined drilling profile detection show that the latest active period of the fault is the late Middle Pleistocene. There is no historical earthquake record.

[0089] Table 1: Target fault characteristic parameters

[0090]

[0091] Table 2: Maximum characteristic parameters of regional faults

[0092]

[0093] Table 3: Weighting factors

[0094] <![CDATA[α L ]]> <![CDATA[α segment ]]> <![CDATA[α seismic ]]> <![CDATA[α A ]]> <![CDATA[α D ]]> <![CDATA[α S ]]> 1.5 0.8 0.8 1.0 1.3 1.2

[0095] Parameter Description:

[0096] The study area is a weak earthquake zone with few historical earthquakes. Some fault characteristic parameters are not clear. We use the background earthquake level in the area as the seismic activity level of the fault, that is, magnitude 4.5. The length of the fault rupture is based on the length of the rupture trace on the surface. The affected area is assigned a relevant value based on the geological structural characteristics of the fault. The slip velocity is the slip rate of the target fault calculated based on the regional slip rate and the strike and dip of the target fault. The weight factor takes into account the accuracy of the fault parameters. For example, for seismic activity and fault segment length, the target fault has weak seismic activity, and the segment length is estimated based on the surface geological characteristics, so the corresponding weight is lower. Parameters such as fault length, fault depth, and slip rate are relatively clear and have relatively high weights.

[0097] Without using the fault characteristic weighted adjustment a value, the calculated a and b values ​​only reflect the overall level of regional seismic activity, and it is difficult to refine to the maximum magnitude and seismic period of each fault. By introducing the fault characteristic weighted adjustment a value, we can obtain a unique a value for each fault, and further calculate its maximum magnitude and seismic period, thereby effectively distinguishing the seismic activity characteristics of each fault.

[0098] According to Tables 4 to 8 and Figure 3a , Figure 3b , Figure 4a , Figure 4b , Figure 5a , Figure 5b , Figure 6a and Figure 6b From the calculation results, it can be seen that after weighting the fault characteristics, each fault has a different a value, maximum magnitude and seismic period. The comparative analysis shows that there is a significant correlation between the maximum magnitude of each fault and its characteristics, which verifies the expected analysis objectives.

[0099] Table 4: a value, maximum magnitude and earthquake occurrence period of the region and each target fault

[0100] Fault name a_fault Maximum magnitude Seismic period area 5.85 6.5 8029 Liuji-Xiquanjie Fault 5.43 6.2 10171 Zhangji-Longzihe Fault 5.51 6.3 9842 Huaiyuan-Huangjiawan Fault 5.71 6.4 8795 Taoshan-Shangwujia Fault 5.56 6.3 9586

[0101] Table 5 Probability of earthquakes with magnitudes of 6.0 and 6.5 occurring on the Liuji-Xiquanjie fault in 50, 100, and 200 years

[0102] Magnitude 50 years 100 years 200 years 6.0 0.015781759 0.03140608 0.062188672 6.5 0.004567695 0.009122202 0.018191803

[0103] Table 6 Probability of occurrence of earthquakes with magnitudes of 6.0 and 6.5 on the Zhangji-Longzihe fault in 50, 100 and 200 years

[0104] Magnitude 50 years 100 years 200 years 6.0 0.016740337 0.03330353 0.065905959 6.5 0.004846145 0.009677444 0.019295688

[0105] Table 7 Probability of earthquakes with magnitudes of 6.0 and 6.5 on the Huaiyuan-Huangjiawan fault in 50, 100, and 200 years

[0106] Magnitude 50 years 100 years 200 years 6.0 0.026967918 0.053476114 0.105144557 6.5 0.007824579 0.015610458 0.031066877

[0107] Table 8 Probability of earthquakes with magnitudes of 6.0 and 6.5 on the Taoshan-Shangwujia fault in 50, 100, and 200 years

[0108]

[0109]

[0110] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware.

[0111] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for estimating the maximum magnitude of an earthquake based on the GR relationship weighted by fault characteristics, characterized in that: The following steps are involved: Collect the geometric parameters and structural characteristics of the target fault, including the total length of the fault, the segment length of the fault, the maximum historical magnitude, the activity level, the fault depth and the stress concentration, and normalize all characteristic parameters to obtain normalized geometric parameters and normalized structural characteristics; Based on the regional earthquake catalog data, the regional Gutenberg-Richter relationship is fitted, and the regional a value and b value are calculated and determined, where the a value reflects the level of seismic activity in the study area, and the b value is used to describe the slope of the earthquake magnitude distribution; According to the normalized geometric parameters and normalized structural characteristics of the target fault, the comprehensive weight factor of the target fault is calculated using a predetermined weighting formula. The comprehensive weight factor of the target fault is used to reflect the relative seismic activity of the target fault in the region. The calculation of the comprehensive weight factor of the target fault is based on the following formula: Among them, W fault is the comprehensive weight factor; W i is the normalized value of the feature parameter; α i is the corresponding feature weight coefficient; Based on the comprehensive weight factor of the target fault, the a value of the region is weighted and adjusted, and the specific a value of the target fault is calculated and determined to reflect the seismic activity intensity of the target fault. fault =a region +log(W fault ) to obtain a specific a value for the target fracture, where a fault is the specific a value of the target fracture, a region is the a value of the region; The maximum magnitude of the target fault is calculated using the specific a value of the target fault and the b value of the region, and the maximum magnitude of the target fault reflects the earthquake risk characteristics of the target fault.

2. The method for estimating the maximum magnitude of an earthquake based on the GR relationship weighted by fault characteristics according to claim 1, characterized in that: The geometric parameters and structural features of the target fracture are normalized by maximum value, and the normalization process is used to eliminate the dimensional differences between different features so that the normalized feature parameter values ​​are all between 0 and 1.

3. The method for estimating the maximum magnitude of an earthquake based on the GR relationship weighted by fault characteristics according to claim 1, characterized in that: The characteristic weight coefficients of the target fault include the total length weight coefficient of the target fault, the segment length weight coefficient of the fault, the maximum historical magnitude weight coefficient, the activity level weight coefficient, the fault depth weight coefficient and the stress concentration degree weight coefficient. Each characteristic weight coefficient is set according to the importance of the geometric characteristics of the target fault and the tectonic activity characteristics.

4. The method for estimating the maximum magnitude of an earthquake based on the GR relationship weighted by fault characteristics according to claim 1, characterized in that: The least squares method is used to fit the Gutenberg-Richter relationship of the region. The least squares method determines the a and b values ​​of the region based on the following steps: extract the magnitude-frequency distribution from the earthquake catalog data of the region, and use the least squares method to minimize the fitting error to determine the a and b values ​​of the region.

5. The method for estimating the maximum magnitude of an earthquake based on the GR relationship weighted by fault characteristics according to claim 1, characterized in that: The maximum magnitude of the target fault is estimated based on the following empirical formula: Among them, M max_fault is the maximum magnitude of the target fault; c1, c2 and c3 are the empirical relationship fitting coefficients; a fault is the specific a value for the target fracture.

6. The method for estimating the maximum magnitude of an earthquake based on the GR relationship weighted by fault characteristics according to claim 5, characterized in that: The empirical fitting coefficients c1, c2 and c3 are determined by statistically analyzing the relationship between the maximum magnitude of different target faults in multiple seismic cells and the specific a value of the target fault and the b value of the region. Multiple iterative corrections are performed using the least squares method during the analysis process.

7. The method for estimating the maximum magnitude of an earthquake based on the GR relationship weighted by fault characteristics according to claim 1, characterized in that: The extraction of characteristic parameters of the target fault is based on the regional seismic activity observation data and the geological survey results of the target fault structure. The geological survey results of the target fault structure include the surface geological characteristics of the target fault, the inclination of the target fault surface, the strike of the target fault surface, the width of the target fault zone and the slip rate of the target fault.

8. The method for estimating the maximum magnitude of an earthquake based on the GR relationship weighted by fault characteristics according to claim 1, characterized in that: The method is suitable for areas with low frequency of seismic activity and limited historical seismic data. By weighting the geometric characteristics and tectonic activity characteristics of the target faults, the estimation results can accurately reflect the seismic activity and seismic risk characteristics of different target faults.

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