A double bubble seismic source monitoring method based on water seismic detection

Abstract

This invention relates to the field of seismic source monitoring and discloses a dual-bubble seismic source monitoring method based on marine seismic detection. The method involves deploying a seismic detector array in a target sea area, recording seismic wave data generated by the dual bubbles, using the frequency data of the seismic waves as the first target monitoring data for seismic source identification, and using the propagation velocity of the seismic waves as the second target monitoring data. The method analyzes the arrival time of the seismic waves at different detectors to locate the seismic source. It also analyzes the amplitude attenuation characteristics and propagation path of the seismic waves during propagation to assess the earthquake magnitude and calculate the probability of earthquake occurrence based on the assessed earthquake risk level. This method improves the accuracy of seismic source data acquisition, enables accurate identification and location of the seismic source, and thus improves the accuracy of earthquake probability prediction.

Description

Technical Field

[0001] This invention relates to the field of seismic source monitoring technology, and more specifically to a dual-bubble seismic source monitoring method based on offshore seismic detection. Background Technology

[0002] Seismic exploration relies on the propagation characteristics of seismic waves in the subsurface medium. Seismic waves include longitudinal waves (P-waves) and transverse waves (S-waves), which propagate at different speeds when encountering strata of varying densities and elasticities, resulting in reflection and refraction. Traditional seismic exploration methods typically use explosions or vibrators as seismic sources to detect subsurface structures through seismic waves. However, the application of these methods in underwater environments is limited. Therefore, a seismic source monitoring method based on offshore seismic exploration has emerged. This method achieves efficient data acquisition by setting up two seismic sources on the exploration vessel and precisely controlling the excitation sequence and timing of the two sources through a control device.

[0003] However, the above process still has the following drawbacks:

[0004] Firstly, traditional seismic detection technology may have limitations in high-resolution imaging, especially in complex geological structures, where it is difficult to clearly identify small-scale or shallow geological features, thus affecting the accuracy of source data acquisition.

[0005] Secondly, traditional earthquake detection technology relies more on traditional seismic wave recording and analysis methods, which may be affected by various factors, such as ship and marine environmental noise and weather conditions. These factors may cause interference and distortion of seismic wave signals, which limits the accuracy of source location and thus affects the accurate calculation of the source location.

[0006] Third, traditional earthquake detection techniques may have difficulty analyzing the attenuation changes and path propagation of seismic waves, and lack detailed earthquake risk assessment, thus affecting the accuracy of earthquake assessment. Summary of the Invention

[0007] In order to overcome the above-mentioned defects of the prior art, the present invention provides a dual-bubble source monitoring method based on underwater seismic detection to solve the problems existing in the background art.

[0008] This invention provides the following technical solution: a dual-bubble source monitoring method based on offshore seismic detection, comprising:

[0009] S1: By deploying a seismic detector array in the target sea area and installing a dual-bubble source system on the water surface;

[0010] S2: The release of the dual bubbles is controlled by the controller, and the seismic wave data generated by the dual bubbles is recorded by the seismic detector array;

[0011] S3: By using the frequency data of seismic waves as the first target monitoring data, the changing characteristics of the first target monitoring data are analyzed to identify the earthquake source;

[0012] S4: By using the propagation speed of seismic waves as the second target monitoring data, the second target monitoring data and the time it takes for seismic waves to arrive at different detectors are analyzed to calculate the source location, which is used to locate the source location.

[0013] S5: Based on the location of the seismic source, monitor the activity status of the seismic source, analyze the changes in the amplitude attenuation characteristics of the seismic waves during propagation to obtain the attenuation coefficient, and analyze the propagation path of the seismic waves to obtain the path propagation coefficient.

[0014] S6: The earthquake magnitude is evaluated and analyzed based on the changes in the amplitude attenuation characteristics and propagation path of seismic waves, and the earthquake magnitude evaluation coefficient is obtained.

[0015] S7: Assess earthquake risk levels based on earthquake magnitude assessment coefficients, and recommend calculation models for earthquake probability based on the assessed earthquake risk levels.

[0016] Preferably, in step S1, a suitable target sea area is first selected, and detectors are deployed based on the seabed topography, water depth and seabed structure of the target sea area. The location of each deployed detector is determined using GPS, the detector is fixed on the seabed, and then connected to a data logger via a cable. At the same time, a dual-bubble source system is installed on the water surface at a location far away from ships and other obstacles, and then connected to a power supply for the charge and discharge control circuit.

[0017] Preferably, in step S2, the two bubbles are used as the seismic source, and the seismic detector array receives and records the pressure wave signal generated when the bubbles are rapidly released in the water as the seismic wave signal. The seismic wave data is then recorded in real time by a data logger. The collected seismic wave data includes the amplitude, frequency and arrival time of the seismic waves.

[0018] Preferably, the specific steps of S2 for the controller to control the release of the two bubbles are as follows:

[0019] Step S211: Open the valve of the gas cylinder, pre-charge a certain amount of gas into the gas bladder of the dual-bubble vibrator, and use GPS to locate the correct position of the vibrator release.

[0020] Step S212: The controller instructs the seismic source system to descend to the predetermined depth. According to the preset parameters, the controller opens the valve of the first bubble, releases the first bubble, and records the release time and initial state of the bubble.

[0021] Step S213: After a preset time interval, the controller opens the valve of the second bubble, releases the second bubble, and records the release time and status of the second bubble.

[0022] Preferably, step S3 involves performing spectral analysis on the seismic wave signal, converting the time-domain signal to a frequency-domain signal using a fast Fourier transform, calculating the amplitude and phase spectra, determining the characteristic frequency range of the dual-bubble source, and extracting the amplitude and phase within the characteristic frequency range as the first target monitoring data. By performing feature analysis on the changes in the first target monitoring data, the change characteristics of the first target monitoring data are calculated. , Indicates a point in time Monitor the amplitude spectrum of frequency domain signals. Indicates a point in time Monitor the amplitude spectrum of frequency domain signals. Indicates a point in time Monitor the phase spectrum of the frequency domain signal. Indicates a point in time Monitor the phase spectrum of frequency domain signals;

[0023] By comparing the change feature H of the first target monitoring data with a preset feature threshold If a comparison is made, This indicates that seismic activity has been identified, and the analysis of the seismic source location continues. If no seismic activity is detected, monitoring of the target sea area will continue.

[0024] Preferably, the specific analysis method for locating the earthquake source in S4 is as follows:

[0025] Step S411: Seismic waves are generated by releasing two bubbles in the water, and the arrival time of the seismic waves is recorded using multiple detectors distributed at different locations;

[0026] Step S412: Preprocess the signal recorded by the detector, including noise reduction and filtering, to extract the seismic wave signal;

[0027] Step S413: Based on the signal between each detector pair, calculate the P-wave velocity and S-wave velocity respectively, i.e. , ,in, This represents the P-wave velocity, i.e., the body wave. This represents the S-wave velocity, i.e., the surface wave velocity, and d represents the distance between the two detectors. This indicates the time difference between the arrival of the P-wave at the two detectors. It represents the time difference between the arrival of the S-wave at the two detectors. By using the P-wave velocity and S-wave velocity as the second target monitoring data, it is used to monitor the propagation speed of seismic waves in the medium in real time.

[0028] Step S414: Set the location coordinates of the seismic source as follows The location of the earthquake source was calculated by establishing a system of equations using the locations of three or more geophones, P-wave velocity, and S-wave velocity. for ,in, Indicates the coordinates of the earthquake source location. This represents the position coordinates of the i-th detector. This indicates the time it takes for the P-wave to reach the i-th detector. This indicates the time it takes for the S-wave to reach the i-th detector. This indicates the time of seismic wave origin, usually set to the time when the first detector receives the P-wave.

[0029] Preferably, step S5 records the amplitude of the seismic wave at each detector, identifies and extracts the first arrival wave, analyzes the change of the first arrival wave amplitude with distance, and thus calculates the attenuation coefficient. ,in, This represents the amplitude of the first arrival wave at a distance r from the earthquake source. denoted by r, which represents the amplitude of the first arrival wave at the source, and r represents the distance from the source to the detector.

[0030] The specific analysis method for the path propagation coefficient is as follows:

[0031] Step S511: Record the time when the seismic wave arrives at each detector. And calculate the straight-line distance between the detector and the seismic source. ;

[0032] Step S512: Analyze the propagation path of seismic waves from the source to the underground medium of the detector using ray tracing technology;

[0033] Step S513: Select a clear P-wave or S-wave first arrival as the analysis object to analyze the wave velocity arriving at each detector. The specific calculation formula is as follows: ,in, This represents the wave velocity of the seismic wave reaching the i-th detector;

[0034] Step S513: Perform statistical analysis on the wave velocities of all detectors and calculate the path propagation coefficient. ,in, This represents the average wave velocity of the seismic wave reaching all the detectors, and N represents the total number of detectors.

[0035] Preferably, step S6 involves a comprehensive analysis combining the attenuation coefficient and the path propagation coefficient to calculate the earthquake magnitude assessment coefficient. M represents the magnitude of the earthquake, and R represents the path propagation coefficient. denoted by , where D represents the distance from the seismic source to the detector, and e represents a constant.

[0036] Preferably, step S7 classifies earthquakes into different risk levels based on earthquake magnitude assessment coefficients, namely low, medium, and high risk levels; based on the determined risk levels, different statistical models are assigned to the earthquake occurrence probability calculation method; and a first threshold is set for each level. Second threshold The risk level of an earthquake is determined by comparing it with the earthquake magnitude assessment coefficient C. Then, the magnitude of earthquakes is classified into low levels, and the probability of earthquake occurrence is calculated using the Poisson distribution model. Then, the magnitude of earthquakes is classified as medium, and the probability of earthquake occurrence is calculated using a time-dependent model. The earthquake magnitude is then classified into high levels, and the probability of earthquake occurrence is calculated using a clustering model or a conditional probability model.

[0037] Preferably, step S7 involves visually displaying the earthquake risk level assessment results and earthquake occurrence probability results through an application, thereby pushing earthquake risk information to the user terminal in real time.

[0038] The technical effects and advantages of this invention are as follows:

[0039] This invention deploys a seismic detector array in a target sea area and installs a dual-bubble seismic source system on the water surface. A controller controls the release of the dual bubbles, and the seismic detector array records the seismic wave data generated by the dual bubbles. The frequency data of the seismic waves is used as the first target monitoring data, and the changing characteristics of this data are analyzed to identify the seismic source. The propagation velocity of the seismic waves is used as the second target monitoring data, and the arrival time of the seismic waves at different detectors is analyzed to locate the seismic source. Based on the seismic source location, the activity state of the seismic source is monitored. The changes in amplitude attenuation characteristics and propagation path of the seismic waves during propagation are analyzed to monitor the characteristic changes in seismic wave propagation. Based on the changes in amplitude attenuation characteristics and propagation path, the earthquake magnitude is assessed, thereby evaluating the earthquake risk level. Based on the assessed earthquake risk level, the probability of earthquake occurrence is calculated. This helps improve the resolution of seismic data, better detect small-scale structures and details, and improve the accuracy of seismic source data acquisition. It solves the problem of inaccurate seismic source location calculation caused by environmental factors in traditional seismic detection technology, and is conducive to detailed analysis and assessment of earthquake risk, thus improving the accuracy of earthquake assessment. Attached Figure Description

[0040] Figure 1 This is a diagram illustrating the method steps of the present invention.

[0041] Figure 2This is a system structure block diagram of the present invention. Detailed Implementation

[0042] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. In addition, the forms of the various structures described in the following embodiments are merely illustrative. The dual-bubble seismic source monitoring method based on underwater seismic detection involved in the present invention is not limited to the structures described in the following embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] like Figure 1 The embodiment shown provides a dual-bubble source monitoring method based on offshore seismic detection, including:

[0044] S1: By deploying a seismic detector array in the target sea area and installing a dual-bubble source system on the water surface.

[0045] In this embodiment, S1 first selects a suitable target sea area, deploys detectors based on the seabed topography, water depth and seabed structure of the target sea area, uses GPS to determine the position of each deployed detector, fixes the detectors on the seabed, and then connects them to a data logger via cables. At the same time, at least one location on the water surface away from ships and other obstacles is selected to install a dual bubble source system, and then connects it to a power supply via a charge and discharge control circuit.

[0046] It should be noted that by deploying at least one array of seismic detectors on the water surface, seismic waves from different directions of the seismic source can be received simultaneously. The dual-bubble seismic source can precisely control the timing and location of bubble release, allowing the location and activity of the seismic source to be accurately monitored.

[0047] S2: The release of the dual bubbles is controlled by the controller, and the seismic wave data generated by the dual bubbles is recorded by the seismic detector array.

[0048] In this embodiment, S2 uses two bubbles as the seismic source, and the seismic detector array receives and records the pressure wave signal generated when the bubbles are rapidly released in the water as the seismic wave signal. The seismic wave data is then recorded in real time by a data logger. The collected seismic wave data includes the amplitude, frequency and arrival time of the seismic waves.

[0049] The specific steps for the controller to control the release of the two bubbles are as follows:

[0050] Step S211: Open the valve of the gas cylinder, pre-charge a certain amount of gas into the gas bladder of the dual-bubble vibrator, and use GPS to locate the correct position of the vibrator release.

[0051] Step S212: The controller instructs the seismic source system to descend to the predetermined depth. According to the preset parameters, the controller opens the valve of the first bubble, releases the first bubble, and records the release time and initial state of the bubble.

[0052] Step S213: After a preset time interval, the controller opens the valve of the second bubble, releases the second bubble, and records the release time and status of the second bubble.

[0053] It should be specifically explained that the control circuit excites the dual bubble source to generate seismic waves. During the propagation process, the seismic waves will interact with the underground medium, producing phenomena such as reflection and refraction. These seismic wave signals are received and recorded by the receiver, and then the data recorder starts to continuously record the time, amplitude and frequency of the seismic waves arriving at each detector.

[0054] S3: By using the frequency data of seismic waves as the first target monitoring data, the changing characteristics of the first target monitoring data are analyzed to identify the earthquake source.

[0055] In this embodiment, S3 performs spectral analysis on the seismic wave signal, converts the time-domain signal into a frequency-domain signal using Fast Fourier Transform, calculates the amplitude spectrum and phase spectrum, determines the characteristic frequency range of the dual-bubble source, and extracts the amplitude and phase within the characteristic frequency range as the first target monitoring data. By performing feature analysis on the changes in the first target monitoring data, the change characteristics of the first target monitoring data are calculated. , Indicates a point in time Monitor the amplitude spectrum of frequency domain signals. Indicates a point in time Monitor the amplitude spectrum of frequency domain signals. Indicates a point in time Monitor the phase spectrum of the frequency domain signal. Indicates a point in time Monitor the phase spectrum of frequency domain signals.

[0056] By comparing the change feature H of the first target monitoring data with a preset feature threshold If a comparison is made, This indicates that seismic activity has been identified, and the analysis of the seismic source location continues. If no seismic activity is detected, monitoring of the target sea area will continue.

[0057] It should be noted that, firstly, frequency domain analysis is performed on the seismic wave signal, and the specific calculation formula for extracting the frequency data using Fast Fourier Transform is as follows:

[0058]

[0059] in, Represents frequency domain signals, Let j represent the time-domain signal, f represent the imaginary unit, and e represent the frequency.

[0060] Then calculate the amplitude spectrum of the frequency domain signal separately. and phase spectrum for

[0061]

[0062]

[0063] in, and They represent The real and imaginary parts.

[0064] The feature extraction formula for extracting amplitude and phase within the characteristic frequency range as the first target monitoring data is as follows:

[0065]

[0066] in, The set representing characteristic frequencies. Indicates the amplitude threshold. and Indicates the range of characteristic frequencies.

[0067] Different types of seismic waves, such as P-waves and S-waves, have different frequency characteristics, which can help identify the type of earthquake source.

[0068] S4: By using the propagation speed of seismic waves as the second target monitoring data, the seismic source location is calculated by analyzing the second target monitoring data and the time it takes for the seismic waves to arrive at different detectors. This information is then used to locate the seismic source.

[0069] In this embodiment, the specific analysis process for locating the earthquake source in step S4 includes:

[0070] Step S411: Seismic waves are generated by releasing two bubbles in the water, and the arrival time of the seismic waves is recorded using multiple detectors distributed at different locations;

[0071] Step S412: Preprocess the signal recorded by the detector, including noise reduction and filtering, to extract the seismic wave signal;

[0072] Step S413: Based on the signal between each detector pair, calculate the P-wave velocity and S-wave velocity respectively, i.e. , ,in, This represents the P-wave velocity, i.e., the body wave. This represents the S-wave velocity, i.e., the surface wave velocity, and d represents the distance between the two detectors. This indicates the time difference between the arrival of the P-wave at the two detectors. It represents the time difference between the arrival of the S-wave at the two detectors. By using the P-wave velocity and S-wave velocity as the second target monitoring data, it is used to monitor the propagation speed of seismic waves in the medium in real time.

[0073] Step S414: Set the location coordinates of the seismic source as follows The location of the earthquake source was calculated by establishing a system of equations using the locations of three or more geophones, P-wave velocity, and S-wave velocity. for ,in, Indicates the coordinates of the earthquake source location. This represents the position coordinates of the i-th detector. This indicates the time it takes for the P-wave to reach the i-th detector. This indicates the time it takes for the S-wave to reach the i-th detector. This indicates the time of seismic wave origin, usually set to the time when the first detector receives the P-wave.

[0074] S5: Based on the location of the seismic source, monitor the activity status of the seismic source, analyze the changes in the amplitude attenuation characteristics of the seismic waves during propagation to obtain the attenuation coefficient, and analyze the propagation path of the seismic waves to obtain the path propagation coefficient.

[0075] In this embodiment, step S5 records the amplitude of the seismic wave at each detector, identifies and extracts the first arrival wave, analyzes the change of the first arrival wave amplitude with distance, and then calculates the attenuation coefficient. ,in, This represents the amplitude of the first arrival wave at a distance r from the earthquake source. denoted by r, which represents the amplitude of the first arrival wave at the source, and r represents the distance from the source to the detector.

[0076] The specific analysis process of the path propagation coefficient includes:

[0077] Step S511: Record the time when the seismic wave arrives at each detector. And calculate the straight-line distance between the detector and the seismic source. ;

[0078] Step S512: Analyze the propagation path of seismic waves from the source to the underground medium of the detector using ray tracing technology;

[0079] Step S513: Select a clear P-wave or S-wave first arrival as the analysis object to analyze the wave velocity arriving at each detector. The specific calculation formula is as follows: ,in, This represents the wave velocity of the seismic wave reaching the i-th detector;

[0080] Step S513: Perform statistical analysis on the wave velocities of all detectors and calculate the path propagation coefficient. ,in, This represents the average wave velocity of the seismic wave reaching all the detectors, and N represents the total number of detectors.

[0081] S6: The earthquake magnitude is evaluated and analyzed based on the changes in the amplitude attenuation characteristics and propagation path of seismic waves, and the earthquake magnitude evaluation coefficient is obtained.

[0082] In this embodiment, step S6 performs a comprehensive analysis by combining the attenuation coefficient and the path propagation coefficient, and calculates the earthquake magnitude assessment coefficient as follows: M represents the magnitude of the earthquake, and R represents the path propagation coefficient. denoted by , where D represents the distance from the seismic source to the detector, and e represents a constant.

[0083] S7: Assess earthquake risk levels based on earthquake magnitude assessment coefficients, and recommend calculation models for earthquake probability based on the assessed earthquake risk levels.

[0084] In this embodiment, step S7 classifies earthquakes into different risk levels based on earthquake magnitude assessment coefficients, namely low, medium, and high risk levels; based on the determined risk levels, different statistical models are assigned to the earthquake occurrence probability calculation method; and a first threshold is set for each level. Second threshold The risk level of an earthquake is determined by comparing it with the earthquake magnitude assessment coefficient C. Then, the magnitude of earthquakes is classified into low levels, and the probability of earthquake occurrence is calculated using the Poisson distribution model. Then, the magnitude of earthquakes is classified as medium, and the probability of earthquake occurrence is calculated using a time-dependent model. The earthquake magnitude is then classified into high levels, and the probability of earthquake occurrence is calculated using a clustering model or a conditional probability model.

[0085] By visually displaying the earthquake risk level assessment results and earthquake occurrence probability results through the application, earthquake risk information can be pushed to the user's terminal in real time.

[0086] like Figure 2This embodiment provides an implementation system for a dual-bubble source monitoring method based on offshore seismic detection. The system includes a detector deployment module, a data acquisition module, a source identification module, a source location detection module, a source activity analysis module, a source size assessment module, and a source classification module. The detector deployment module is connected to the data acquisition module, which is also connected to the source identification module. The source identification module is connected to the source location detection module, which is connected to the source activity analysis module, which is connected to the source size assessment module, which is connected to the source size classification module, and a database is connected to all modules.

[0087] The detector deployment module deploys a seismic detector array in the target sea area and installs a dual-bubble source system on the water surface.

[0088] The data acquisition module controls the release of the double bubbles through a controller, and the seismic wave data generated by the double bubbles is recorded by the seismic detector array.

[0089] The seismic source identification module uses the frequency data of seismic waves as the first target monitoring data and analyzes the changing characteristics of the first target monitoring data to identify the seismic source.

[0090] The source location detection module uses the propagation speed of seismic waves as the second target monitoring data, analyzes the second target monitoring data and the time it takes for seismic waves to arrive at different detectors, and calculates the source location to locate the source.

[0091] The source activity analysis module monitors the source activity status based on the source location, obtains the attenuation coefficient by analyzing the changes in amplitude attenuation characteristics of seismic waves during propagation, and obtains the path propagation coefficient by analyzing the propagation path of seismic waves.

[0092] The earthquake magnitude assessment module evaluates and analyzes the earthquake magnitude based on the changes in the amplitude attenuation characteristics and propagation path of the seismic waves, and obtains the earthquake magnitude assessment coefficient.

[0093] The earthquake source level classification module assesses earthquake risk level based on earthquake magnitude assessment coefficient, and recommends a calculation model for earthquake occurrence probability based on the assessed earthquake risk level.

[0094] The database is used to store the data output by all modules.

[0095] This invention deploys a seismic detector array in a target sea area and installs a dual-bubble seismic source system on the water surface. A controller controls the release of the dual bubbles, and the seismic detector array records the seismic wave data generated by the dual bubbles. The frequency data of the seismic waves is used as the first target monitoring data, and the changing characteristics of this data are analyzed to identify the seismic source. The propagation velocity of the seismic waves is used as the second target monitoring data, and the arrival time of the seismic waves at different detectors is analyzed to locate the seismic source. Based on the seismic source location, the activity state of the seismic source is monitored. The changes in amplitude attenuation characteristics and propagation path of the seismic waves during propagation are analyzed to monitor the characteristic changes in seismic wave propagation. Based on the changes in amplitude attenuation characteristics and propagation path, the earthquake magnitude is assessed, thereby evaluating the earthquake risk level. Based on the assessed earthquake risk level, the probability of earthquake occurrence is calculated. This helps improve the resolution of seismic data, better detect small-scale structures and details, and improve the accuracy of seismic source data acquisition. It solves the problem of inaccurate seismic source location calculation caused by environmental factors in traditional seismic detection technology, and is conducive to detailed analysis and assessment of earthquake risk, thus improving the accuracy of earthquake assessment.

[0096] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0097] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A dual-bubble source monitoring method based on offshore seismic detection, characterized in that: include: S1: By deploying a seismic detector array in the target sea area and installing a dual-bubble source system on the water surface; S2: The release of the dual bubbles is controlled by the controller, and the seismic wave data generated by the dual bubbles is recorded by the seismic detector array; S3: By using the frequency data of seismic waves as the first target monitoring data, the changing characteristics of the first target monitoring data are analyzed to identify the earthquake source; S3 performs spectral analysis on the seismic wave signal, converts the time-domain signal to a frequency-domain signal using Fast Fourier Transform, calculates the amplitude and phase spectra, determines the characteristic frequency range of the dual-bubble source, and extracts the amplitude and phase within the characteristic frequency range as the first target monitoring data. By performing feature analysis on the changes in the first target monitoring data, the characteristic features of the changes in the first target monitoring data are calculated. , Indicates a point in time Monitor the amplitude spectrum of frequency domain signals. Indicates a point in time Monitor the amplitude spectrum of frequency domain signals. Indicates a point in time Monitor the phase spectrum of the frequency domain signal. Indicates a point in time Monitor the phase spectrum of frequency domain signals; By comparing the change feature H of the first target monitoring data with a preset feature threshold If a comparison is made, This indicates that seismic activity has been identified, and the analysis of the seismic source location continues. If no seismic activity is detected, monitoring of the target sea area will continue. S4: By using the propagation speed of seismic waves as the second target monitoring data, the second target monitoring data and the time it takes for seismic waves to arrive at different detectors are analyzed to calculate the source location, which is used to locate the source location. S5: Based on the location of the seismic source, monitor the activity status of the seismic source, analyze the changes in the amplitude attenuation characteristics of the seismic waves during propagation to obtain the attenuation coefficient, and analyze the propagation path of the seismic waves to obtain the path propagation coefficient. S6: The earthquake magnitude is evaluated and analyzed based on the changes in the amplitude attenuation characteristics and propagation path of seismic waves, and the earthquake magnitude evaluation coefficient is obtained. The S6 method combines the attenuation coefficient and path propagation coefficient for comprehensive analysis, and calculates the earthquake magnitude assessment coefficient as follows: M represents the magnitude of the earthquake, and R represents the path propagation coefficient. The attenuation coefficient is represented by D, the distance from the source to the detector is represented by e, and e is a constant. S7: Assess earthquake risk levels based on earthquake magnitude assessment coefficients, and recommend calculation models for earthquake probability based on the assessed earthquake risk levels.

2. The dual-bubble source monitoring method based on offshore seismic detection according to claim 1, characterized in that: S1 first selects a suitable target sea area, deploys detectors based on the seabed topography, water depth and seabed structure of the target sea area, uses GPS to determine the position of each deployed detector, fixes the detectors on the seabed, and then connects them to the data logger through cables. At the same time, selects a location on the water surface away from ships and other obstacles to install a dual bubble source system, and then connects it to the power supply of the charge and discharge control circuit.

3. The dual-bubble source monitoring method based on offshore seismic detection according to claim 1, characterized in that: The S2 uses two bubbles as the seismic source, and the seismic detector array receives and records the pressure wave signal generated when the bubbles are rapidly released in the water as the seismic wave signal. The seismic wave data is then recorded in real time by a data logger. The collected seismic wave data includes the amplitude, frequency and arrival time of the seismic waves.

4. The dual-bubble source monitoring method based on offshore seismic detection according to claim 1, characterized in that: The specific steps of S2 for the controller to control the release of the two bubbles are as follows: Step S211: Open the valve of the gas cylinder, pre-charge a certain amount of gas into the gas bladder of the dual-bubble vibrator, and use GPS to locate the correct position of the vibrator release. Step S212: The controller instructs the seismic source system to descend to the predetermined depth. According to the preset parameters, the controller opens the valve of the first bubble, releases the first bubble, and records the release time and initial state of the bubble. Step S213: After a preset time interval, the controller opens the valve of the second bubble, releases the second bubble, and records the release time and status of the second bubble.

5. The dual-bubble source monitoring method based on offshore seismic detection according to claim 1, characterized in that: The specific analysis method for locating the earthquake source in S4 is as follows: Step S411: Seismic waves are generated by releasing two bubbles in the water, and the arrival time of the seismic waves is recorded using multiple detectors distributed at different locations; Step S412: Preprocess the signal recorded by the detector, including noise reduction and filtering, to extract the seismic wave signal; Step S413: Based on the signal between each detector pair, calculate the P-wave velocity and S-wave velocity respectively, i.e. , ,in, This represents the P-wave velocity, i.e., the body wave. This represents the S-wave velocity, i.e., the surface wave velocity, and d represents the distance between the two detectors. This indicates the time difference between the arrival of the P-wave at the two detectors. It represents the time difference between the arrival of the S-wave at the two detectors. By using the P-wave velocity and S-wave velocity as the second target monitoring data, it is used to monitor the propagation speed of seismic waves in the medium in real time. Step S414: Set the location coordinates of the seismic source as follows The location of the earthquake source was calculated by establishing a system of equations using the locations of three or more geophones, P-wave velocity, and S-wave velocity. for ,in, Indicates the coordinates of the earthquake source location. This represents the position coordinates of the i-th detector. This indicates the time it takes for the P-wave to reach the i-th detector. This indicates the time it takes for the S-wave to reach the i-th detector. This indicates the time of seismic wave origin, usually set to the time when the first detector receives the P-wave.

6. The dual-bubble source monitoring method based on offshore seismic detection according to claim 1, characterized in that: S5 records the amplitude of seismic waves at each detector, identifies and extracts the first arrival wave, and then analyzes the change of the first arrival wave amplitude with distance to calculate the attenuation coefficient. ,in, This represents the amplitude of the first arrival wave at a distance r from the earthquake source. denoted by r, which represents the amplitude of the first arrival wave at the source, and r represents the distance from the source to the detector. The specific analysis method for the path propagation coefficient is as follows: Step S511: Record the time when the seismic wave arrives at each detector. And calculate the straight-line distance between the detector and the seismic source. ; Step S512: Analyze the propagation path of seismic waves from the source to the underground medium of the detector using ray tracing technology; Step S513: Select a clear P-wave or S-wave first arrival as the analysis object to analyze the wave velocity arriving at each detector. The specific calculation formula is as follows: ,in, This represents the wave velocity of the seismic wave reaching the i-th detector; Step S513: Perform statistical analysis on the wave velocities of all detectors and calculate the path propagation coefficient. ,in, This represents the average wave velocity of the seismic wave reaching all the detectors, and N represents the total number of detectors.

7. The dual-bubble source monitoring method based on offshore seismic detection according to claim 1, characterized in that: S7, based on the earthquake magnitude assessment coefficient, classifies earthquakes into different risk levels: low, medium, and high. Based on these risk levels, different statistical models are assigned to calculate the probability of earthquake occurrence. A first threshold is set for each model. Second threshold The risk level of an earthquake is determined by comparing it with the earthquake magnitude assessment coefficient C. Then, the magnitude of earthquakes is classified into low levels, and the probability of earthquake occurrence is calculated using the Poisson distribution model. Then, the magnitude of earthquakes is classified as medium, and the probability of earthquake occurrence is calculated using a time-dependent model. The earthquake magnitude is then classified into high levels, and the probability of earthquake occurrence is calculated using a clustering model or a conditional probability model.

8. The dual-bubble source monitoring method based on offshore seismic detection according to claim 1, characterized in that: The S7 is based on visually displaying the earthquake risk level assessment results and earthquake occurrence probability results through the application, thereby pushing earthquake risk information to the user terminal in real time.

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