Rapid real-time correction and evaluation method for post-earthquake earthquake damage influence field

Abstract

The invention discloses a rapid real-time correction and evaluation method for a post-earthquake earthquake damage influence field. The method comprises the following steps: (1) determining a macroscopic epicenter position according to microscopic epicenter and nearby fault distribution; (2) determining the long axis trend of an intensity iso-seismic graph according to a seismic source mechanism solution and aftershock distribution; (3) establishing a long-axis radius and short-axis radius length matrix of the isoseismic line; (4) drawing a blindly estimated intensity iso-seismic graph; (5) correcting the length matrix of the long axis radius and the short axis radius of the isoseismic line in real time based on a correction algorithm in combination with a field intensity survey point; and (6) drawing an intensity iso-seismic diagram which is continuously improved. The seismic intensity evaluation method is simple and practical in seismic intensity evaluation, the correlation between the initial estimation result of each intensity circle before field investigation and the seismic lines such as the previous actual seismic intensity is obviously superior to the estimation result of an intensity attenuation formula, and the seismic intensity can be evaluated along with the gradual increase of the number of investigation points. The intensity seismic line graph drawn in real time and the actual seismic damage condition have the trend of continuously approaching to the height coincidence.

Description

Technical Field

[0001] The present invention belongs to the technical field of seismic intensity assessment, and particularly relates to a method for rapidly and real-time correcting and evaluating the post-earthquake seismic damage influence field. Background Art

[0002] After a destructive earthquake occurs, in order to implement rapid and effective earthquake emergency decision-making and emergency response, it is necessary to first understand the degree and scope of the earthquake's impact. Seismic intensity is the most commonly used indicator to measure the strength of the earthquake's impact on a certain area. Currently, there are mainly two ways to quickly assess seismic intensity: one is instrument intensity rapid reporting, and the other is to use the intensity attenuation relationship for macro-seismic intensity rapid reporting.

[0003] There are two core elements in instrument intensity rapid reporting: one is that the strong motion network should be densely constructed, and the other is that the correlation between ground motion parameters and intensity should be accurate. Currently, the network spacing of the seismic monitoring network in China is about 90 km, but the number of strong motion stations that can achieve intensity rapid reporting is still far from sufficient, mainly concentrated in the North-South seismic belt and the Beijing-Tianjin region, and there is no generally recognized correlation between ground motion parameters and intensity suitable for China.

[0004] Through the method of intensity attenuation relationship, the disaster area can be quickly evaluated, but the accuracy is low and it is only suitable for roughly judging the disaster distribution. When based on the continuously emerging disaster investigation point information on-site, the coefficients in the intensity attenuation relationship (Formula 1) are corrected based on a correction algorithm, so that the model is consistent with the actual earthquake damage, but the effect is very unsatisfactory. This is because each isoseismal line is only determined by three coefficients in the attenuation formula, which are coupled with each other, inevitably reducing the area of the high-intensity area and enlarging the area of the low-intensity area, and unable to be corrected to the actual earthquake damage situation. Summary of the Invention

[0005] The present invention discloses a method for rapidly and real-time correcting and evaluating the post-earthquake seismic damage influence field, breaking the limitations of the traditional intensity attenuation relationship method, overcoming the problem of mutual restriction of the three parameters in this method, being simple and practical in seismic intensity assessment. The initial estimation results of each intensity circle before on-site investigation have a significantly better correlation with the isoseismal lines of past actual seismic intensities than those estimated by the intensity attenuation formula, and as the number of investigation points gradually increases, the real-time drawn isoseismal line map has a trend of continuously approaching and highly matching the actual earthquake damage situation.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A method for rapidly and real-time correcting and evaluating the post-earthquake seismic damage influence field, comprising the following steps:

[0008] (1) Determine the location of the macroseismic epicenter according to the microseismic epicenter and the distribution of nearby faults;

[0009] (2) Determine the major axis orientation of the isoseismal map based on the focal mechanism solution and the aftershock distribution;

[0010] (3) Establish a length matrix of the major axis radius and the minor axis radius of the isoseismal;

[0011] (4) Draw the blindly estimated isoseismal map of intensity;

[0012] (5) Combine the on-site intensity survey points and perform real-time correction on the length matrix of the major axis radius and the minor axis radius of the isoseismal based on the correction algorithm;

[0013] (6) Draw the continuously improved isoseismal map of intensity.

[0014] Preferably, the step (1) includes the following specific steps:

[0015] (11) Take the micro-earthquake epicenter located by the seismic instrument as the center and draw a concentric circle with a radius of 40 km as the selected area for determining the macro-earthquake epicenter position;

[0016] (12) If there is no fault distribution in the selected area, directly take the position of the micro-earthquake epicenter as the set macro-earthquake epicenter position;

[0017] (13) If the micro-earthquake epicenter is already in a special tectonic position, the special tectonic positions include the end of the fault, the intersection of faults, the junction of faults, the middle of the vertical fault sandwiched by closely spaced parallel faults, and the arc protrusion of the fault, then take the position of the micro-earthquake epicenter as the set macro-earthquake epicenter position;

[0018] (14) If the micro-earthquake epicenter is on the fault or very close to the fault, the very close means less than 5 km, then select the nearest special tectonic position on the fault to the micro-earthquake epicenter as the set macro-earthquake epicenter position;

[0019] (15) If the micro-earthquake epicenter is neither in a special tectonic position nor on the fault, then find the special tectonic position points in the selected area and determine the set macro-earthquake epicenter position according to the fault scale, activity age and the principle of proximity.

[0020] Preferably, in the step (3):

[0021] The length matrix of the major axis radius is:

[0022] R a =[R 6a ,R 7a ,R 8a ,R 9a ,R 10a T (1)

[0023] The length matrix of the minor axis radius is:​

[0024] R b = [R 6b , R 7b , R 8b , R 9b , R 10b T (2)

[0025] In formulas (1)-(2), R a is the major axis radius length matrix, and R 6a to R 10a are the major axis radii of the intensity circles from intensity 6 to intensity 10 respectively. R b is the minor axis radius length matrix, and R 6b to R 10b are the minor axis radii of the intensity circles from intensity 6 to intensity 10 respectively.

[0026] Preferably, in step (5), the rule for correcting the isoseismal line is as follows: Based on the blindly estimated isoseismal line map of intensity, investigate according to the actual geographical location where a certain earthquake intensity on the isoseismal line map is located. If the actual geographical location falls within the earthquake intensity area corresponding to the isoseismal line map, there is no need to correct the isoseismal line; if the actual geographical location falls outside the corresponding earthquake intensity area, the isoseismal line needs to be repaired.

[0027] Preferably, in step (5), according to the projections of the sampling survey points in the major and minor axis directions, initially calculate the major and minor axis radii of the ellipse where the survey point is located according to the ratio of the major axis to the minor axis being 2:1 and Adopt a correction algorithm. Taking the correction of the major axis radius of the intensity I circle as an example, it is shown as follows:

[0028]

[0029] In formula (3), R Ia is the corrected major axis radius of the intensity I circle; R Ia ' is the major axis radius of the intensity I circle before correction; is the major axis radius of the ellipse where the actual geographical location point obtained by the survey is located; η is the learning rate, taking a number between 0 and 1, with a step size of 0.01, and performing 101 value-taking operations on η from 0 to 1, and selecting the value that makes the result standard deviation the smallest as the finally adopted result; the correction calculations for other earthquake intensity circles are carried out analogously.

[0030] The beneficial effects of a method for quickly and real-time correcting and evaluating the post-earthquake earthquake damage influence field of the present invention are as follows:

[0031] ​The present invention breaks through the limitations of the traditional intensity attenuation relationship method, overcomes the problem of mutual restriction of the three parameters in this method, is simple and practical in seismic intensity assessment. The initial estimation results of each intensity circle before on-site investigation have a significantly better correlation with the actual seismic intensity isoseismal lines in the past than the results estimated by the intensity attenuation formula. Moreover, as the number of investigation points gradually increases, the real-time drawn intensity isoseismal map shows a trend of getting closer and closer to a high degree of coincidence with the actual earthquake damage situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flowchart of the method of the present invention.

[0033] Figure 2 It is a schematic diagram for isoseismal line correction. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The following description is only for the preferred embodiments of the present invention and is not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

[0035] The following embodiments can be understood as separately expressing a part of the local structure or method of the present invention, or can also be understood as the embodiments combined with each other to explain the connotation of the structure or method in a larger scope of the present invention.

[0036] Embodiment 1

[0037] A rapid real-time correction and assessment method for the earthquake damage influence field after an earthquake includes the following steps:

[0038] (1) Determine the location of the macro epicenter according to the micro epicenter and the distribution of nearby faults;

[0039] (2) Determine the long-axis trend of the intensity isoseismal map according to the focal mechanism solution and the aftershock distribution;

[0040] (3) Establish a length matrix of the long-axis radius and the short-axis radius of the isoseismal line;

[0041] (4) Draw a blindly estimated intensity isoseismal map;

[0042] (5) Combine the on-site intensity investigation points and perform real-time correction on the length matrix of the long-axis radius and the short-axis radius of the isoseismal line based on the correction algorithm;

[0043] (6) Draw an intensively improved intensity isoseismal map.

[0044] Embodiment 2

[0045] Based on Embodiment 1, this embodiment discloses that the step (1) includes the following specific steps:

[0046] (11) Draw concentric circles with the micro - epicenter located by the seismic instrument as the center and a radius of 40 km as the selected area for determining the location of the macro - epicenter;

[0047] (12) If there is no fault distribution in the selected area, directly take the location of the micro - epicenter as the set macro - epicenter location;

[0048] (13) If the micro - epicenter is already at a special tectonic position, the special tectonic positions include the end of the fault, the intersection of faults, the confluence of faults, the middle of the vertical fault sandwiched by closely - spaced parallel faults, and the arc - shaped protrusion of the fault, then take the location of the micro - epicenter as the set macro - epicenter location;

[0049] (14) If the micro - epicenter is on the fault or very close to the fault, where'very close' means less than 5 km, then select the nearest special tectonic position on the fault to the micro - epicenter as the set macro - epicenter location;

[0050] (15) If the micro - epicenter is neither at a special tectonic position nor on the fault, then find the special tectonic position points in the selected area, and determine the set macro - epicenter location according to the fault scale, activity age, and the principle of proximity.

[0051] Example 3

[0052] Based on Examples 1 and 2, this example discloses that in step (3):

[0053] The major - axis radius - length matrix is:

[0054] R a =[R 6a ,R 7a ,R 8a ,R 9a ,R 10a T (1)

[0055] The minor - axis radius - length matrix is:

[0056] R b =[R 6b ,R 7b ,R 8b ,R 9b ,R 10b T (2)

[0057] In the formula, R a is the major - axis radius - length matrix, and R 6a ~R 10a are the major - axis radii of the intensity circles from degree 6 to degree 10 respectively, R b is the minor - axis radius - length matrix, and R 6b ​​~R 10b They are the minor axis radii of the isoseismal intensity circles from 6 degrees to 10 degrees respectively. The initial values of the major and minor axis radii of the isoseismal lines are shown in Table 1 - Table 3.

[0058] Table 1 Initial values of the major and minor axis radii of the isoseismal lines (M≥7.5)

[0059]

[0060] Table 2 Initial values of the major and minor axis radii of the isoseismal lines (6.0≤M≤7.4)

[0061]

[0062] Table 3 Initial values of the major and minor axis radii of the isoseismal lines (5.0≤M≤5.9)

[0063]

[0064] Example 4

[0065] In the step (5) described above, the rule for correcting the isoseismal line is: based on the blindly estimated isoseismal intensity map, conduct an investigation on the actual geographical location where a certain earthquake intensity of the isoseismal intensity map is located. If the actual geographical location falls within the earthquake intensity area corresponding to the isoseismal intensity map, there is no need to correct the isoseismal line; if the actual geographical location falls outside the corresponding earthquake intensity area, the isoseismal line needs to be repaired.

[0066] As Figure 2 shown, the solid line is the preliminarily determined isoseismal map. Conduct an investigation on the actual geographical location with an intensity of I. If the actual geographical location falls at point 1 in the figure, there is no need to correct the isoseismal map; if the actual geographical location falls at point 2 in the figure, the intensity circle of I + 1 degree needs to be corrected; if the actual geographical location falls at point 3 in the figure, the intensity circle of I degree needs to be corrected.

[0067] Example 5

[0068] In the step (5) described above, according to the projection of the sampling survey point in the major and minor axis directions, initially calculate the major and minor axis radii of the ellipse where the survey point is located according to the ratio of the major and minor axes of 2:1 and Adopt the correction algorithm. Taking the correction of the major axis radius of the I-degree circle as an example, as shown in the following formula:

[0069]

[0070] In formula (3), R Ia is the corrected major axis radius of the I-degree circle; R Ia ' is the major axis radius of the I-degree circle before correction; The semi-major axis radius of the ellipse where the actual geographical location points obtained from the investigation are located; η is the learning rate, which takes a number between 0 and 1, and performs 101 value operations on η from 0 to 1 with a step of 0.01. The value that makes the result standard deviation the smallest is selected as the final result adopted; the correction calculations for other seismic intensity circles are carried out analogously.

[0071] Example 6

[0072] Taking the magnitude 7.0 earthquake in a certain area in 1996 as an example, the application of the matrix model for seismic intensity attenuation proposed by the present invention in disaster emergency assessment is verified. According to the determination of the seismic network in this area, a strong earthquake of MS7.0 occurred in the territory of this area at 19:14:18.1 on February 3, 1996, and the focal depth of the main shock was 10 km. The fault in front of a certain mountain was the main seismogenic structure of this earthquake, and the trend of the isoseismal line was basically the same as its trend. It is considered that both the macroscopic epicenter of the earthquake and the trend of the isoseismal line are known conditions. 20 intensity investigation points were randomly selected in this area to simulate the application of the matrix model for seismic intensity attenuation in earthquake disaster emergency assessment. The positions and intensity values of each investigation point are shown in Table 4.

[0073] Table 4 Positions and intensity values of each investigation point

[0074]

[0075] By applying the correction method proposed by the present invention, the length matrix of the major and minor axis radii of the isoseismal line maps calibrated by different numbers of investigation points can be obtained, as shown in Table 5 and Table 6. Among them, the standard deviation σ in the table is the standard deviation between the current intensity investigation point and the currently drawn isoseismal line.

[0076] Table 5 Comparison of the major axis radius lengths of the isoseismal lines calibrated by different numbers of investigation points

[0077]

[0078] Table 6 Comparison of the minor axis radius lengths of the isoseismal lines calibrated by different numbers of investigation points

[0079]

[0080] Through the above examples, it can be proved that the present invention breaks through the limitations of the traditional seismic intensity attenuation relationship method, overcomes the problem of mutual restriction of the three parameters in this method, is simple and practical in seismic intensity assessment. The correlation between the initial estimation results of each seismic intensity circle before on-site investigation and the actual seismic isoseismal lines in the past is significantly better than the results estimated by the seismic intensity attenuation formula. And as the number of investigation points gradually increases, the real-time drawn isoseismal line map and the actual earthquake damage situation have a trend of continuously approaching a high degree of coincidence.

Claims

1. A rapid real-time correction assessment method for a post-earthquake earthquake damage impact field, characterized by: The steps include: (1) Determine the macroscopic epicenter location based on the microscopic epicenter and the distribution of nearby faults; (2) Determine the major axis direction of the intensity isoseismal line diagram based on the focal mechanism solution and aftershock distribution; (3) Establish the length matrix of the major axis radius and minor axis radius of the isoseismal lines; (4) Draw blind estimated intensity isoseismal maps; (5) Combined with the on-site intensity survey points, the length matrix of the major axis radius and minor axis radius of the isoseismal lines is corrected in real time based on the correction algorithm; (6) Draw an ever-improving intensity isoseismal map.

2. A method for rapid real-time correction and assessment of a post-earthquake earthquake damage impact field as claimed in claim 1, characterized in that: The step (1) comprises the following specific steps: (11) With the microscopic epicenter located by the seismic instrument as the center, concentric circles with a radius of 40 km are drawn as the selected area for determining the macroscopic epicenter location; (12) If there is no fault distribution in the selected area, the microscopic epicenter position is directly taken as the set macroscopic epicenter position; (13) If the micro-epicenter is already in a special structural position, such as the end of a fault, the intersection of faults, the intersection of faults, the middle of a vertical fault sandwiched between closely parallel faults, or the arc-shaped protrusion of a fault, the position of the micro-epicenter is taken as the set macro-epicenter position; (14) If the micro-epicenter is on a fault or very close to the fault, where very close means less than 5 km, then the special structural part on the fault closest to the micro-epicenter is selected as the set macro-epicenter position; (15) If the micro-epicenter is neither located in a special structural position nor on a fault, a special structural position point is found in the selected area, and the macro-epicenter position is determined based on the scale of the fault, the age of activity and the principle of proximity.

3. A method for rapid real-time correction and assessment of a post-earthquake earthquake damage impact field as claimed in claim 2, characterized in that, in said step (3): The major axis radius length matrix is: R a =[R 6a ,R 7a ,R 8a ,R 9a ,R 10a ] T (1) The minor axis radius length matrix is: R b =[R 6b ,R 7b ,R 8b ,R 9b ,R 10b ] T (2) In formula (1)-(2), R a is the major axis radius length matrix, R 6a ~R 10a are the major axis radius of the 6-10 degree intensity circle, R b is the minor axis radius length matrix, R 6b ~R 10b They are the minor axis radii of the intensity circle from 6 degrees to 10 degrees respectively.

4. A method for rapid real-time correction and assessment of a post-earthquake earthquake damage impact field as claimed in claim 3, characterized in that: In the step (5), the rule for correcting the isoseismal lines is: based on the blind estimated intensity isoseismal line map, an investigation is conducted on the actual geographical location where a certain earthquake intensity on the intensity isoseismal line map is located; if the actual geographical location falls within the earthquake intensity area corresponding to the intensity isoseismal line map, there is no need to correct the isoseismal lines; If the actual geographical location falls outside the corresponding earthquake intensity area, the isoseismal lines need to be repaired.

5. A method for rapid real-time correction and assessment of a post-earthquake earthquake damage impact field as claimed in claim 4, characterized in that: In the step (5), based on the projection of the sampling survey point in the direction of the major and minor axes, the major and minor axis radii of the ellipse where the survey point is located are calculated according to the ratio of the major and minor axes being 2:

1. and Using the correction algorithm, taking the correction of the major axis radius of the I-degree circle as an example, it is shown in the following formula: In formula (3), R Ia R is the corrected radius of the major axis of the I-degree circle; Ia ' is the major axis radius of the I degree circle before correction; The radius of the major axis of the ellipse where the actual geographical location point obtained by the survey is located; η is the learning rate, which is a number between 0 and 1. The step length is 0.

01. η is calculated from 0 to 1 101 times, and the value with the smallest standard deviation is selected as the final result. The correction calculations for other seismic intensity zones are similar.

Images