Natural source surface wave collecting and processing device and method based on asynchronous common midpoint gather method

Abstract

The invention provides a natural source surface wave collecting and processing device and method based on an asynchronous common midpoint gather method. The method comprises the following steps that multi-stage surface wave data is collected through stage laying and rolling arrangement; constructing a synchronous surface wave signal library by using a background noise cross-correlation technology; performing secondary cross-correlation on two pairs of station synchronizing signals of the same fixed station through an asynchronous data algorithm to obtain asynchronous surface wave signals; extracting synchronous and asynchronous gather pairs of the same center point and combining the synchronous and asynchronous gather pairs into a common center point gather; and extracting a frequency dispersion curve to invert a shear wave velocity structure. By optimizing an array layout scheme and utilizing an asynchronous data fusion algorithm, support is provided for engineering geological survey, speed structure investigation and the like by utilizing an asynchronous natural source surface wave method, and the overall acquisition period is effectively shortened, so that the time and economic cost is remarkably reduced.

Description

Technical Field

[0001] This invention relates to the field of engineering geophysics, specifically to a device and method for acquiring and processing surface waves from natural sources based on the asynchronous common center point gather method. Background Technology

[0002] When using natural source surface waves for underground structure detection, a relatively long period of observation data is typically required to suppress random noise interference and obtain stable coherent surface wave signals. However, in engineering survey practice, extending the observation time directly leads to increased operating costs and decreased overall efficiency. To balance economic benefits and detection efficiency, the conventional approach usually involves configuring a large number of acquisition devices and using a phased, rolling deployment method for data acquisition; however, this also increases costs.

[0003] To overcome the aforementioned trade-off between efficiency and cost, the applicant proposes an asynchronous data fusion algorithm to integrate and process asynchronously acquired surface wave data. This method optimizes the array layout, reducing the number of instrument deployment phases and effectively shortening the overall acquisition cycle, thereby significantly reducing time and economic costs, while achieving inversion results consistent with traditional synchronous acquisition methods. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of long acquisition time and low efficiency in engineering applications of natural source surface waves by providing a natural source surface wave acquisition and processing device and method based on the asynchronous common center point gather method. This provides support for engineering geological surveys and velocity structure exploration using the asynchronous natural source surface wave method, thereby improving the efficiency of natural source surface wave data acquisition and saving costs.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A natural source surface wave acquisition and processing device using the asynchronous common-center-point gathering method, characterized in that it comprises:

[0007] The acquisition unit is used to acquire multi-phase natural source surface wave data from virtual source stations and observation stations;

[0008] A processing unit, connected to the acquisition unit, includes:

[0009] The synchronization signal construction module is used to obtain the synchronization surface wave signal of the data from the same secondary station using background noise cross-correlation technology, and to extract the synchronization surface wave signal of the fixed station and the multiple secondary stations in the same time period at different time periods.

[0010] The asynchronous signal acquisition module is used to perform secondary cross-correlation on the synchronous surface wave signals of two pairs of stations with the same fixed station using an asynchronous data algorithm to obtain asynchronous cross-correlation and generate asynchronous surface wave signals.

[0011] The gather extraction module is used to extract synchronous gather pairs from synchronous surface wave signals, extract asynchronous gather pairs from asynchronous surface wave signals, and merge synchronous gather pairs and asynchronous gather pairs with the same center point into a common center point gather.

[0012] The dispersion curve extraction module is used to extract dispersion curves from common center point gathers;

[0013] The inversion module is used to receive the dispersion curve extracted by the dispersion curve extraction module and invert it to obtain the shear wave velocity structure at each point.

[0014] The shear wave velocity profile generation module is used to integrate multi-point shear wave velocity structures and generate shear wave velocity profiles.

[0015] Furthermore, the observation stations are arranged linearly or in an array around the observation points, and are rolled up and observed in multiple periods along the measurement points or measurement lines. The virtual source stations are located outside the observation stations, and all virtual source stations are evenly distributed relative to the observation stations or located within the stable phase zone of the observation stations. In addition, the virtual source stations must have data from at least two periods of shared observation time with the observation stations.

[0016] Furthermore, the time periods of the multi-period rolling observations do not overlap or partially overlap; the virtual source station and the observation station form an acquisition arrangement or array;

[0017] When linear data acquisition is used, the virtual source station and the observation station are on the same straight line;

[0018] When array acquisition is used, the virtual source stations are evenly distributed around the observation station with the observation point as the center.

[0019] Furthermore, the asynchronous signal acquisition module utilizes an asynchronous data algorithm to perform a secondary cross-correlation on the synchronous surface wave signals of two pairs of stations with the same fixed station, obtaining asynchronous cross-correlation and generating asynchronous surface wave signals, specifically including:

[0020] 1) The obtained synchronous surface wave signal is represented in the form of (5-1):

[0021] (5-1);

[0022] in The term represents the phase delay during surface wave propagation. The term arises because the empirical Green's function and the background noise cross-correlation function have a negative time partial derivative, which produces a... Phase shift, The term represents the phase shift caused by the distribution of noise sources during integration. Additionally, due to the periodic ambiguity problem inherent in surface waves, this is addressed by adding... To represent by items;

[0023] Based on the partial derivative relationship between the background noise cross-correlation function and the empirical Green's function, the phase of the synchronous cross-correlation function is expressed as shown in equation (5-2):

[0024] (5-2);

[0025] Based on equation (5-2), through and This represents the synchronization cross-correlation between two pairs of stations, S-R1 and S-R2, that have the same fixed station S.

[0026] and The phase of ) is specifically expressed as shown in (5-3) and (5-4):

[0027] (5-3);

[0028] (5-4);

[0029] 2) Using the same observation station as a bridge, secondary cross-correlation

[0030] Based on the principle of cross-correlation, eliminating phase information along the same path, the asynchronous cross-correlation phase of stations for R1-R2 is expressed as shown in equation (5-5):

[0031] (5-5);

[0032] Substituting equations (5-3) and (5-4) into (5-5):

[0033] (5-6);

[0034] 3) Perform phase offset correction to obtain asynchronous surface wave signal.

[0035] Synchronization cross-correlation function of stations to R1-R2 The phase is expressed according to equation (5-2) as follows:

[0036] (5-7);

[0037] The phase of the cross-correlation function obtained from station pairs R1-R2 using background noise cross-correlation technique and asynchronous cross-correlation method. and A comparison was made to discover a relationship between synchronous and asynchronous cross-correlation functions. The phase shift will The phase offset is corrected to obtain the surface wave signal between asynchronous data.

[0038] A method for acquiring and processing surface waves from natural sources based on the asynchronous common center point gathering method includes the following steps:

[0039] S1. Design acquisition array or arrangement: Design an acquisition array or arrangement consisting of virtual source stations and observation stations for the survey target;

[0040] S2. Acquire multi-phase data: Obtain multi-phase natural source surface wave data from virtual source stations and observation stations through the acquisition unit;

[0041] S3. Construct a synchronous surface wave signal library: Use background noise cross-correlation technology to obtain synchronous surface wave signals from the natural source surface wave data collected in step S2, and extract synchronous surface wave signals from fixed stations at different time periods and from multiple stations in the same time period.

[0042] S4. Obtain asynchronous surface wave signal: Based on the synchronous surface wave signal in step S3, use the asynchronous data algorithm to perform secondary cross-correlation on the synchronous surface wave signals of two pairs of stations with the same fixed station to obtain asynchronous cross-correlation and generate asynchronous surface wave signal;

[0043] S5. Extract common center point gathers: Extract synchronous gather pairs from the synchronous signals in step S3, extract asynchronous gather pairs from the asynchronous surface wave signals in step S4, and merge synchronous gather pairs and asynchronous gather pairs with the same center point into a common center point gather.

[0044] S6. Extract dispersion curves: Extract dispersion curves from the common center point gathers obtained in step S5;

[0045] S7. Invert the shear wave velocity structure: Invert the dispersion curve extracted in step S6 to obtain the shear wave velocity structure at each point.

[0046] S8. Generate a shear wave velocity profile: Integrate the multi-point shear wave velocity structure from step S7 to generate a shear wave velocity profile.

[0047] Furthermore, the observation stations are arranged linearly or in an array around the observation points, and are rolled up and observed in multiple periods along the measurement points or measurement lines. The virtual source stations are located outside the observation stations, and all virtual source stations are evenly distributed relative to the observation stations or located within the stable phase zone of the observation stations. In addition, the virtual source stations must have data from at least two periods of shared observation time with the observation stations.

[0048] Furthermore, the time periods of the multi-period rolling observations do not overlap or partially overlap; the virtual source station and the observation station form an acquisition arrangement or array;

[0049] When linear data acquisition is used, the virtual source station and the observation station are on the same straight line;

[0050] When array acquisition is used, the virtual source stations are evenly distributed around the observation station with the observation point as the center.

[0051] Furthermore, S4 specifically includes:

[0052] 1) The obtained synchronous surface wave signal is represented in the form of (5-1):

[0053] (5-1);

[0054] in The term represents the phase delay during surface wave propagation. The term arises because the empirical Green's function and the background noise cross-correlation function have a negative time partial derivative, which produces a... Phase shift, The term represents the phase shift caused by the distribution of noise sources during integration. Additionally, due to the periodic ambiguity problem inherent in surface waves, this is addressed by adding... To represent by items;

[0055] Based on the partial derivative relationship between the background noise cross-correlation function and the empirical Green's function, the phase of the synchronous cross-correlation function is expressed as shown in equation (5-2):

[0056] (5-2);

[0057] Based on equation (5-2), through and This represents the synchronization cross-correlation between two pairs of stations, S-R1 and S-R2, that have the same fixed station S.

[0058] and The phase of ) is specifically expressed as shown in (5-3) and (5-4):

[0059] (5-3);

[0060] (5-4);

[0061] 2) Using the same observation station as a bridge, secondary cross-correlation

[0062] Based on the principle of cross-correlation, eliminating phase information along the same path, the asynchronous cross-correlation phase of stations for R1-R2 is expressed as shown in equation (5-5):

[0063] (5-5);

[0064] Substituting equations (5-3) and (5-4) into (5-5):

[0065] (5-6);

[0066] 3) Perform phase offset correction to obtain asynchronous surface wave signal.

[0067] Synchronization cross-correlation function of stations to R1-R2 The phase is expressed according to equation (5-2) as follows:

[0068] (5-7);

[0069] The phase of the cross-correlation function obtained from station pairs R1-R2 using background noise cross-correlation technique and asynchronous cross-correlation method. and A comparison was made to discover a relationship between synchronous and asynchronous cross-correlation functions. The phase shift will The phase offset is corrected to obtain the surface wave signal between asynchronous data.

[0070] Compared with the prior art, the present invention has the following significant advantages:

[0071] 1. Overcame the technical limitations of synchronous observation: enabled joint analysis of data from stations that did not have observation records for the same time period, thereby significantly expanding the data sources and coverage available for scientific research.

[0072] 2. Significantly improves data utilization efficiency: It can effectively integrate historical observation data, fragmented data obtained from faulty stations, and asynchronous observation and experimental data, greatly reducing data redundancy and waste.

[0073] 3. Effectively reduces observation costs: Allows for phased and asynchronous station deployment schemes, significantly reducing equipment investment and the complexity of operation and maintenance.

[0074] 4. Enhance the monitoring capability of the spatiotemporal evolution of underground media: Provide a new technical approach for studying time-varying phenomena such as volcanic activity, groundwater migration and earthquake healing processes based on long-term, discontinuous observation data.

[0075] 5. It has anti-interference performance against directional noise sources: It has the advantage of being insensitive to directional noise sources, and the extracted signal has high stability and reliability. Attached Figure Description

[0076] Figure 1 This is a flowchart of a natural source surface wave acquisition and processing method based on the asynchronous common center point gather method according to the present invention;

[0077] Figure 2 This is an example diagram of a natural source surface wave acquisition and processing method based on the asynchronous common center point gather method of the present invention. Detailed Implementation

[0078] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. 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.

[0079] Please see Figure 1 This invention provides a method for acquiring and processing surface waves from natural sources based on the asynchronous common center point gather method, comprising the following steps:

[0080] S1. Design acquisition array or arrangement: Design an acquisition array or arrangement consisting of virtual source stations and observation stations for the survey target;

[0081] The observation stations are arranged linearly or in an array around the observation points, and are rolled up and observed in multiple periods along the measurement points or measurement lines. The virtual source stations are located outside the observation stations, and all virtual source stations are evenly distributed relative to the observation stations or located within the stable phase zone of the observation stations. The virtual source stations must have data from at least two periods of shared observation time with the observation stations.

[0082] Virtual source stations and observation stations form a data acquisition array or arrangement.

[0083] When linear data acquisition is used, the virtual source station and the observation station are on the same straight line;

[0084] When array acquisition is used, the virtual source stations are evenly distributed around the observation station with the observation point as the center.

[0085] S2. Acquire multi-period data: Acquire multi-period natural source surface wave data from virtual source stations and observation stations through the acquisition unit; the time periods of the multi-period rolling observations do not overlap or partially overlap.

[0086] S3. Construct a synchronous surface wave signal library: Use background noise cross-correlation technology to obtain synchronous surface wave signals from the natural source surface wave data collected in step S2, and extract synchronous surface wave signals from fixed stations at different time periods and from multiple stations in the same time period.

[0087] S4. Obtain asynchronous surface wave signal: Based on the synchronous surface wave signal in step S3, use the asynchronous data algorithm to perform secondary cross-correlation on the synchronous surface wave signals of two pairs of stations with the same fixed station to obtain asynchronous cross-correlation and generate asynchronous surface wave signal;

[0088] Specifically, for a pair of stations R1 and R2 acquired at different times, an asynchronous gather is constructed using a virtual source station. Taking the virtual source station S as an example, data with synchronous time is acquired at different periods from the two stations of station pair R1-R2. Therefore, the synchronous gather pair SR1 of S and R1 and the synchronous gather pair SR2 of S and R2 can be extracted first. Then, the synchronous gather data of SR1 and SR2 are cross-correlated twice to obtain the asynchronous surface wave signal between R1 and R2.

[0089] S4 specifically includes:

[0090] 1) The obtained synchronous surface wave signal is represented in the form of (5-1):

[0091] (5-1);

[0092] in The term represents the phase delay during surface wave propagation. The term arises because the empirical Green's function and the background noise cross-correlation function have a negative time partial derivative, which produces a... Phase shift, The term represents the phase shift caused by the distribution of noise sources during integration. Additionally, due to the periodic ambiguity problem inherent in surface waves, this is addressed by adding... To represent by items;

[0093] Based on the partial derivative relationship between the background noise cross-correlation function and the empirical Green's function, the phase of the synchronous cross-correlation function is expressed as shown in equation (5-2):

[0094] (5-2);

[0095] Based on equation (5-2), through and This represents the synchronization cross-correlation between two pairs of stations, S-R1 and S-R2, that have the same fixed station S.

[0096] and The phase of ) is specifically expressed as shown in (5-3) and (5-4):

[0097] (5-3);

[0098] (5-4);

[0099] 2) Using the same observation station as a bridge, secondary cross-correlation

[0100] Based on the principle of cross-correlation, eliminating phase information along the same path, the asynchronous cross-correlation phase of stations for R1-R2 is expressed as shown in equation (5-5):

[0101] (5-5);

[0102] Substituting equations (5-3) and (5-4) into (5-5):

[0103] (5-6);

[0104] 3) Perform phase offset correction to obtain asynchronous surface wave signal.

[0105] Synchronization cross-correlation function of stations to R1-R2 The phase is expressed according to equation (5-2) as follows:

[0106] (5-7);

[0107] The phase of the cross-correlation function obtained from station pairs R1-R2 using background noise cross-correlation technique and asynchronous cross-correlation method. and A comparison was made to discover a relationship between synchronous and asynchronous cross-correlation functions. The phase shift will The phase offset is corrected to obtain the surface wave signal between asynchronous data.

[0108] S5. Extract common center point gathers: Extract synchronous gather pairs from the synchronous signals in step S3, extract asynchronous gather pairs from the asynchronous surface wave signals in step S4, and merge synchronous gather pairs and asynchronous gather pairs with the same center point into a common center point gather.

[0109] S6. Extract dispersion curves: Extract dispersion curves from the common center point gathers obtained in step S5;

[0110] S7. Invert the shear wave velocity structure: Invert the dispersion curve extracted in step S6 to obtain the shear wave velocity structure at each point.

[0111] S8. Generate a shear wave velocity profile: Integrate the multi-point shear wave velocity structure from step S7 to generate a shear wave velocity profile.

[0112] This invention also provides a natural source surface wave acquisition and processing device using the asynchronous common center point gather method, comprising:

[0113] The acquisition unit is used to acquire multi-phase natural source surface wave data from virtual source stations and observation stations;

[0114] A processing unit, connected to the acquisition unit, includes:

[0115] The synchronization signal construction module is used to obtain the synchronization surface wave signal of the data from the same secondary station using background noise cross-correlation technology, and to extract the synchronization surface wave signal of the fixed station and the multiple secondary stations in the same time period at different time periods.

[0116] The asynchronous signal acquisition module is used to perform secondary cross-correlation on the synchronous surface wave signals of two pairs of stations with the same fixed station using an asynchronous data algorithm to obtain asynchronous cross-correlation and generate asynchronous surface wave signals.

[0117] The gather extraction module is used to extract synchronous gather pairs from synchronous surface wave signals, extract asynchronous gather pairs from asynchronous surface wave signals, and merge synchronous gather pairs and asynchronous gather pairs with the same center point into a common center point gather.

[0118] The dispersion curve extraction module is used to extract dispersion curves from common center point gathers;

[0119] The inversion module is used to receive the dispersion curve extracted by the dispersion curve extraction module and invert it to obtain the shear wave velocity structure at each point.

[0120] The shear wave velocity profile generation module is used to integrate multi-point shear wave velocity structures and generate shear wave velocity profiles.

[0121] The following is a specific example to illustrate this.

[0122] like Figure 2 As shown, the surface wave method needs to be applied to investigate the structure below points 1, 2 and 3.

[0123] 1) Taking a group of 12 nodal instruments as an example, select one additional nodal instrument as a fixed station S and place it at one end of the linear arrangement (the pentagram). The 12 nodal instruments are used as observation stations T1-T. 12 Two phases of observations were conducted, with observation points 1 and 3 arranged linearly as the center (phase one stations: black triangle, phase two stations: blue triangle).

[0124] 2) Based on the data collected in step 1), the synchronous common-center gathers corresponding to points 1 and 3 can be obtained, corresponding to the black and blue dashed boxes in the figure, respectively. Furthermore, by selecting some Phase I and Phase II stations (within the red dashed box in the figure) and applying the asynchronous common-center gather method proposed in this patent, and using fixed station data as a bridge, the asynchronous common-center gather above point 2 can be obtained, and the shear wave velocity structure below point 2 can then be inverted. Compared to the traditional method which requires a third phase station to be relocated above point 2 (i.e., a total of three phases of observation data are needed), this case only requires two phases of data to achieve the same goal, thus saving approximately 33% of observation time, improving data utilization, and reducing observation time costs.

[0125] All other unspecified parts belong to the prior art.

[0126] The core innovation of this invention, based on the asynchronous common center point gather method (using a fixed station as a bridge to generate asynchronous signals through secondary cross-correlation and integrating multi-period data in a phased rolling arrangement), has the following specific effects:

[0127] 1. Overcoming the limitations of synchronous observation: By using data from fixed stations as a bridge, joint analysis of data from stations with different time periods can be achieved, expanding the data sources and coverage;

[0128] 2. Improve data utilization efficiency: Integrate historical observation data, fault station fragment data, and asynchronous experimental data to reduce data redundancy and waste;

[0129] 3. Reduce observation costs: Supports batch asynchronous deployment of stations, reducing equipment investment and operation and maintenance complexity. For example, in the case, only two phases of data are needed to replace the traditional three phases of observation, saving about 33% of time costs.

[0130] 4. Enhance spatiotemporal evolution monitoring capabilities: Provide new technological pathways for long-term discontinuous observation and research on time-varying phenomena in subsurface media (such as groundwater migration and earthquake healing);

[0131] 5. Excellent anti-interference performance: It is not sensitive to directional noise sources, and the extracted surface wave signal has high stability and reliability.

[0132] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A natural source surface wave acquisition and processing device using the asynchronous common center point gather method, characterized in that, include: The acquisition unit is used to acquire multi-phase natural source surface wave data from virtual source stations and observation stations; A processing unit, connected to the acquisition unit, includes: The synchronization signal construction module is used to obtain the synchronization surface wave signal of the data from the same secondary station using background noise cross-correlation technology, and to extract the synchronization surface wave signal of the fixed station and the multiple secondary stations in the same time period at different time periods. The asynchronous signal acquisition module is used to perform secondary cross-correlation on the synchronous surface wave signals of two pairs of stations with the same fixed station using an asynchronous data algorithm to obtain asynchronous cross-correlation and generate asynchronous surface wave signals. The gather extraction module is used to extract synchronous gather pairs from synchronous surface wave signals, extract asynchronous gather pairs from asynchronous surface wave signals, and merge synchronous gather pairs and asynchronous gather pairs with the same center point into a common center point gather. The dispersion curve extraction module is used to extract dispersion curves from common center point gathers; The inversion module is used to receive the dispersion curve extracted by the dispersion curve extraction module and invert it to obtain the shear wave velocity structure at each point. The shear wave velocity profile generation module is used to integrate multi-point shear wave velocity structures and generate shear wave velocity profiles.

2. The apparatus according to claim 1, characterized in that: The observation stations are located near the observation points, arranged linearly or in an array, and are used for multiple rolling observations along the measurement points or lines. The virtual source stations are located outside the observation stations, and all virtual source stations are evenly distributed relative to the observation stations or located within the stable phase zone of the observation stations. Furthermore, the virtual source stations must have data from at least two periods of shared observation time with the observation stations.

3. The apparatus according to claim 2, characterized in that: The time periods of the multi-period rolling observations do not overlap or partially overlap; the virtual source station and the observation station form an acquisition arrangement or array; When linear data acquisition is used, the virtual source station and the observation station are on the same straight line; When array acquisition is used, the virtual source stations are evenly distributed around the observation station with the observation point as the center.

4. The apparatus according to claim 1, characterized in that: The asynchronous signal acquisition module uses an asynchronous data algorithm to perform secondary cross-correlation on the synchronous surface wave signals of two pairs of stations with the same fixed station, obtains asynchronous cross-correlation, and generates asynchronous surface wave signals, specifically including: 1) The obtained synchronous surface wave signal is represented in the form of (5-1): （5-1）； in The term represents the phase delay during surface wave propagation. The term arises because the empirical Green's function and the background noise cross-correlation function have a negative time partial derivative, which produces a... Phase shift, The term represents the phase shift caused by the distribution of noise sources during integration. Additionally, due to the periodic ambiguity problem inherent in surface waves, this is addressed by adding... To represent by items; Based on the partial derivative relationship between the background noise cross-correlation function and the empirical Green's function, the phase of the synchronous cross-correlation function is expressed as shown in equation (5-2): （5-2）； Based on equation (5-2), through and This represents the synchronization cross-correlation between two pairs of stations, S-R1 and S-R2, that have the same fixed station S. and The phase of ) is specifically expressed as shown in (5-3) and (5-4): （5-3）； （5-4）； 2) Using the same observation station as a bridge, secondary cross-correlation Based on the principle of cross-correlation, eliminating phase information along the same path, the asynchronous cross-correlation phase of stations for R1-R2 is expressed as shown in equation (5-5): （5-5）； Substituting equations (5-3) and (5-4) into (5-5): （5-6）； 3) Perform phase offset correction to obtain asynchronous surface wave signal. Synchronization cross-correlation function of stations to R1-R2 The phase is expressed according to equation (5-2) as follows: （5-7）； The phase of the cross-correlation function obtained from station pairs R1-R2 using background noise cross-correlation technique and asynchronous cross-correlation method. and A comparison was made to discover a relationship between synchronous and asynchronous cross-correlation functions. The phase shift will The phase offset is corrected to obtain the surface wave signal between asynchronous data.

5. A method for acquiring and processing surface waves from natural sources based on the asynchronous common center point gathering method, characterized in that, Includes the following steps: S1. Design acquisition array or arrangement: Design an acquisition array or arrangement consisting of virtual source stations and observation stations for the survey target; S2. Acquire multi-phase data: Obtain multi-phase natural source surface wave data from virtual source stations and observation stations through the acquisition unit; S3. Construct a synchronous surface wave signal library: Use background noise cross-correlation technology to obtain synchronous surface wave signals from the natural source surface wave data collected in step S2, and extract synchronous surface wave signals from fixed stations at different time periods and from multiple stations in the same time period. S4. Obtain asynchronous surface wave signal: Based on the synchronous surface wave signal in step S3, use the asynchronous data algorithm to perform secondary cross-correlation on the synchronous surface wave signals of two pairs of stations with the same fixed station to obtain asynchronous cross-correlation and generate asynchronous surface wave signal; S5. Extract common center point gathers: Extract synchronous gather pairs from the synchronous signals in step S3, extract asynchronous gather pairs from the asynchronous surface wave signals in step S4, and merge synchronous gather pairs and asynchronous gather pairs with the same center point into a common center point gather. S6. Extract dispersion curves: Extract dispersion curves from the common center point gathers obtained in step S5; S7. Invert the shear wave velocity structure: Invert the dispersion curve extracted in step S6 to obtain the shear wave velocity structure at each point. S8. Generate a shear wave velocity profile: Integrate the multi-point shear wave velocity structure from step S7 to generate a shear wave velocity profile.

6. The method according to claim 5, characterized in that, The observation stations are located near the observation points, arranged linearly or in an array, and are used for multiple rolling observations along the measurement points or lines. The virtual source stations are located outside the observation stations, and all virtual source stations are evenly distributed relative to the observation stations or located within the stable phase zone of the observation stations. Furthermore, the virtual source stations must have data from at least two periods of shared observation time with the observation stations.

7. The method according to claim 6, characterized in that, The time periods of the multi-period rolling observations do not overlap or partially overlap; the virtual source station and the observation station form an acquisition arrangement or array; When linear data acquisition is used, the virtual source station and the observation station are on the same straight line; When array acquisition is used, the virtual source stations are evenly distributed around the observation station with the observation point as the center.

8. The method according to claim 5, characterized in that, S4 specifically includes: 1) The obtained synchronous surface wave signal is represented in the form of (5-1): （5-1）； in The term represents the phase delay during surface wave propagation. The term arises because the empirical Green's function and the background noise cross-correlation function have a negative time partial derivative, which produces a... Phase shift, The term represents the phase shift caused by the distribution of noise sources during integration. Additionally, due to the periodic ambiguity problem inherent in surface waves, this is addressed by adding... To represent by items; Based on the partial derivative relationship between the background noise cross-correlation function and the empirical Green's function, the phase of the synchronous cross-correlation function is expressed as shown in equation (5-2): （5-2）； Based on equation (5-2), through and This represents the synchronization cross-correlation between two pairs of stations, S-R1 and S-R2, that have the same fixed station S. and The phase of ) is specifically expressed as shown in (5-3) and (5-4): （5-3）； （5-4）； 2) Using the same observation station as a bridge, secondary cross-correlation Based on the principle of cross-correlation, eliminating phase information along the same path, the asynchronous cross-correlation phase of stations for R1-R2 is expressed as shown in equation (5-5): （5-5）； Substituting equations (5-3) and (5-4) into (5-5): （5-6）； 3) Perform phase offset correction to obtain asynchronous surface wave signal. Synchronization cross-correlation function of stations to R1-R2 The phase is expressed according to equation (5-2) as follows: （5-7）； The phase of the cross-correlation function obtained from station pairs R1-R2 using background noise cross-correlation technique and asynchronous cross-correlation method. and A comparison was made to discover a relationship between synchronous and asynchronous cross-correlation functions. The phase shift will The phase offset is corrected to obtain the surface wave signal between asynchronous data.

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