Coseismic static tilt measurement method, device, medium, computer program product and application based on triaxial accelerometer

Abstract

The present invention relates to the technical field of earthquake rotation field observation, and more specifically to a coseismic static tilt measurement method, apparatus, medium, computer program product, and application based on a triaxial accelerometer. The method comprises the following steps: using a triaxial accelerometer at a strong earthquake station to collect raw acceleration data in real time; calculating the gravitational acceleration at the strong earthquake station based on locally stored position coordinates of the strong earthquake station; calculating a corrected acceleration sequence at the strong earthquake station based on the raw acceleration data and the gravitational acceleration; and calculating the coseismic static tilt at the strong earthquake station based on the corrected acceleration sequence and the gravitational acceleration. The present invention can rapidly measure the coseismic static tilt field by utilizing an existing strong earthquake observation network and based on the relationship between the three-component projections of gravitational acceleration before and after an earthquake.

Description

Technical Field

[0001] The present invention relates to the technical field of earthquake rotation field observation, and in particular to a co-seismic static tilt measurement method, equipment, medium, computer program product and application based on a three-axis accelerometer. Background Art

[0002] A complete description of the kinematic state of an earthquake deformation body includes six components of strain, three components of translation (displacement, velocity, and acceleration), and three components of rotation (torsion and tilt). Currently, coseismic translation measurement technology is relatively mature, and earthquake translation fields can be measured using a variety of methods, including seismic inertial measurement instruments (broadband seismometers and strong motion meters), global navigation satellite systems (GNSS), and synthetic aperture radar interferometry (InSAR). However, seismic rotation has long been considered meaningless and difficult to observe, and thus often overlooked by researchers. Only recently have seismologists gradually recognized the importance of coseismic rotation to seismological research. For example, studies have shown that near-field observations of earthquake rotation are one to two orders of magnitude larger than those derived from classical elastic theory. This error is the fundamental reason why near-field strong earthquake acceleration data cannot accurately reconstruct coseismic displacement signals.

[0003] Unfortunately, accurate coseismic rotation remains difficult to measure. Inertial gyroscopes can measure angular velocity with high precision, but widespread deployment of these expensive instruments is unaffordable for the seismological community. Some researchers have proposed using dense arrays of seismic stations to indirectly measure coseismic rotation. However, these arrays can only measure dynamic earthquake rotation, which is an average value over a specific region. Others have proposed combining high-frequency GPS with triaxial accelerometers to recover coseismic rotation at ground points. However, this seismic geodetic method may have three potential problems. First, the Kalman filter's state equation is inaccurate. The near-field region of a major earthquake typically experiences intense vibration, and in such a highly dynamic environment, the uniform acceleration model may also contain errors. Second, the Kalman filter's observation equation is also inaccurate. The observation equation undergoes two simplifications: first, linearizing it using a small-angle approximation; and second, introducing pseudotilts to replace the tilt and torsion parameters to address the rank deficiency of the linearized observation equation. Finally, this seismic geodetic method relies on data from high-frequency GPS and accelerometer co-located stations. In the near-field of a major earthquake, even two observation stations with a small separation distance are likely to record significant differences in seismic waveforms. However, strictly co-located high-frequency GPS and accelerometer stations (with zero separation distance) are generally uncommon. Summary of the Invention

[0004] Because the ground near a major earthquake often undergoes permanent rotation, the coordinate axes of a triaxial accelerometer fixed to the ground often point differently before and after the earthquake. Consequently, the projection of the three components of gravity acceleration on the triaxial accelerometer also changes before and after the earthquake. The present invention provides a coseismic static tilt measurement method, apparatus, medium, computer program product, and application based on a triaxial accelerometer to address the shortcomings of the prior art.

[0005] A first aspect of the present invention provides a co-seismic static tilt measurement method based on a triaxial accelerometer, which uses only triaxial accelerometer data to quickly determine the co-seismic static tilt of a ground point, comprising the following steps:

[0006] The original acceleration data are collected in real time using the triaxial accelerometer of the strong motion station;

[0007] Calculating the gravitational acceleration at the strong earthquake station according to the position coordinates of the strong earthquake station stored locally;

[0008] Calculating a corrected acceleration sequence at the strong motion station based on the original acceleration data and the gravitational acceleration;

[0009] The co-seismic static tilt at the strong earthquake station is calculated based on the corrected acceleration sequence and the gravitational acceleration.

[0010] Preferably, the coordinate axis orientation of the three-axis accelerometer is corrected before the earthquake so that the coordinate axis orientation of the three-axis accelerometer before the earthquake is consistent with the coordinate axis orientation of the station center coordinate system at the strong earthquake station.

[0011] Preferably, the calculating of the corrected acceleration sequence at the strong motion station based on the original acceleration data and the gravitational acceleration comprises the following steps:

[0012] detecting the arrival time of the P wave at the strong earthquake station according to the raw acceleration data;

[0013] Calculating a constant deviation of a triaxial accelerometer at the strong motion station based on the raw acceleration data, the P-wave arrival time, and the gravitational acceleration;

[0014] A corrected acceleration sequence at the strong motion station is calculated based on the original acceleration data and the constant deviation.

[0015] Preferably, the long-short time averaging method is used to detect the arrival time of the P wave at the strong earthquake station.

[0016] Preferably, the calculating of the co-seismic static tilt at the strong earthquake station according to the corrected acceleration sequence and the gravitational acceleration comprises the following steps:

[0017] Constructing a projection vector of three components of gravity acceleration before the earthquake according to the gravity acceleration;

[0018] Determining the moment when the vibration of the strong earthquake station tends to stabilize according to the corrected acceleration sequence;

[0019] Constructing a three-component projection vector of gravity acceleration after the earthquake based on the modified acceleration sequence and the moment when the vibration tends to be stable;

[0020] The co-seismic static tilt at the strong earthquake station is calculated based on the projection vector of the three components of gravity acceleration before the earthquake and the projection vector of the three components of gravity acceleration after the earthquake.

[0021] Preferably, the moment when the vibration of the strong earthquake station tends to be stable is determined by using an empirical threshold method based on the modified acceleration sequence.

[0022] A second aspect of the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the co-seismic static tilt measurement method based on a three-axis accelerometer when executing the program.

[0023] A third aspect of the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the co-seismic static tilt measurement method based on a three-axis accelerometer.

[0024] A fourth aspect of the present invention provides a computer program product, comprising a computer program, which implements the co-seismic static tilt measurement method based on a three-axis accelerometer when executed by a processor.

[0025] The fifth aspect of the present invention provides an application of a co-seismic static tilt measurement method based on a three-axis accelerometer, and the co-seismic static tilt measured by this method is sent to an earthquake early warning center to provide accurate static rotation field information for applications such as rotational seismology research and earthquake early warning.

[0026] The present invention has the following advantages and beneficial effects:

[0027] This method leverages the existing strong-seismic observation network to rapidly determine the coseismic static tilt field based on the relationship between the three-component projections of gravitational acceleration before and after an earthquake. Compared to traditional coseismic rotation measurement methods, this method offers a richer data source, not relying on expensive gyroscopes or the limited availability of high-frequency GPS / accelerometer co-located stations.

[0028] The method of the present invention can obtain the rotation amount of ground points, rather than the rotation "average value." The solution of the present invention is simple and convenient to implement, with strong practicality and universal applicability. It solves the problems of low practicality and practical application inconvenience in related technologies, can improve user experience, and has significant market value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a flowchart of a co-seismic static tilt measurement method based on a three-axis accelerometer. DETAILED DESCRIPTION

[0030] The technical solutions of the present invention are described in detail below with reference to the accompanying drawings and embodiments. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0031] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art in the art to which the present invention pertains. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with those in the context of the prior art and, unless specifically defined, will not be interpreted in an idealized or overly formal sense.

[0032] Because the ground near a major earthquake often undergoes permanent rotation, the coordinate axes of a triaxial accelerometer fixed to the ground typically point differently before and after an earthquake. Consequently, the three-component projection of gravity on the triaxial accelerometer also changes before and after an earthquake. This paper discloses a coseismic static tilt measurement method based on a triaxial accelerometer. By leveraging the relationship between the three-component projections of gravity before and after an earthquake, the method rapidly measures the coseismic static tilt of a major earthquake, thereby providing accurate static rotation field information for applications such as rotational seismology research and earthquake early warning.

[0033] Figure 1 This embodiment provides a flow chart of a co-seismic static tilt measurement method based on a triaxial accelerometer. The specific steps are as follows:

[0034] S11. The triaxial accelerometer of the strong earthquake station collects raw acceleration data in real time and sends the collected raw acceleration data to a ground computing center;

[0035] S12. The ground computing center calculates the gravitational acceleration at the strong earthquake station based on the locally stored position coordinates of the strong earthquake station;

[0036] S13. The ground computing center calculates a corrected acceleration sequence at the strong motion station based on the original acceleration data and the gravitational acceleration;

[0037] S14. The ground computing center calculates the coseismic static tilt at the strong earthquake station based on the corrected acceleration sequence and the gravitational acceleration;

[0038] S15. The ground computing center sends the co-seismic static tilt to an earthquake early warning center, etc., in order to provide accurate static rotation field information for applications such as rotational seismology research and earthquake early warning.

[0039] Furthermore, in S12, the ground computing center calculates the gravitational acceleration at the strong earthquake station based on the locally stored position coordinates of the strong earthquake station. The specific formula is as follows:

[0040]

[0041] Where, and h are the latitude and geoid height of the strong earthquake station, respectively; a and b are the lengths of the major and minor axes of the Earth reference ellipsoid, respectively; f is the flattening of the Earth reference ellipsoid; ω e is the Earth's rotational angular velocity; GM is the Earth's gravitational constant; r a and r b are the gravitational accelerations at the equator and the poles, respectively; is the acceleration due to gravity at a point near the Earth.

[0042] For the GRS80 reference ellipsoid

[0043]

[0044] Furthermore, in S13, the ground computing center calculates the corrected acceleration sequence at the strong motion station based on the original acceleration data and the gravitational acceleration, which is achieved through the following specific process:

[0045] Step 1: The ground computing center detects the P-wave arrival time of the strong earthquake station using the long-short time averaging method (STA / LTA) based on the original acceleration data;

[0046] Step 2: The ground computing center calculates the constant deviation of the triaxial accelerometer at the strong motion station based on the original acceleration data, the P-wave arrival time, and the gravitational acceleration. The specific formula is as follows:

[0047]

[0048] Where, e, n, and u represent the east-west, north-south, and vertical directions, respectively; b is the constant deviation of the accelerometer; A is the original acceleration data; t p is the arrival time of the P wave at the strong earthquake station; g is the gravitational acceleration at the strong earthquake station.

[0049] Step 3: The ground computing center calculates the corrected acceleration sequence at the strong motion station based on the original acceleration data and the constant deviation. The specific formula is as follows:

[0050]

[0051] Where, t k represents the k moment; α is the corrected acceleration at the strong motion station. More specifically, and are the original accelerations of the east-west axis, north-south axis, and vertical axis of the three-axis accelerometer at the strong earthquake station at time k; and are the corrected accelerations of the east-west axis, north-south axis, and vertical axis of the three-axis accelerometer at the strong earthquake station at time k.

[0052] Furthermore, in S14, the ground computing center calculates the coseismic static tilt at the strong earthquake station based on the corrected acceleration sequence and the gravitational acceleration, which is achieved through the following specific process:

[0053] Step 1: The ground computing center constructs the three-component projection vector of the gravity acceleration before the earthquake based on the gravity acceleration, which can be specifically:

[0054] g pre =[0, 0, g] Τ (5)

[0055] Where g pre is the projection vector of the three components of gravitational acceleration before the earthquake;[*] Τ It is worth noting that the method of the present invention requires the calibration of the coordinate axis orientation of the triaxial accelerometer before the earthquake to ensure that the coordinate axis orientation of the triaxial accelerometer before the earthquake is consistent with the coordinate axis orientation of the station center coordinate system at the strong earthquake station.

[0056] Step 2: The ground computing center determines the moment when the "vibration tends to be stable" of the strong earthquake station based on the modified acceleration sequence and using the empirical threshold method;

[0057] Step 3: The ground computing center constructs the three-component projection vector of gravity acceleration after the earthquake based on the modified acceleration sequence and the moment when the vibration stabilizes, which can be specifically:

[0058]

[0059] Where g pos is the projection vector of the three components of gravitational acceleration after the earthquake, t s is the moment when the vibration of the strong earthquake station becomes stable. and are the t values ​​of the east-west axis, north-south axis, and vertical axis of the three-axis accelerometer at the strong earthquake station. s Corrected acceleration.

[0060] Step 4: The ground computing center calculates the coseismic static tilt at the strong earthquake station based on the projection vector of the three components of gravity acceleration before the earthquake and the projection vector of the three components of gravity acceleration after the earthquake. The specific formula is as follows:

[0061]

[0062] Where ψ, θ and φ are heading angle, pitch angle and roll angle respectively; c* and s* represent cos(*) and sin(*) respectively. Taking into account equations (5) and (6), we can get

[0063]

[0064] Where t* represents tan(*). When implementing this in a program, φ should be calculated first, followed by θ. It is worth noting that ψ has infinite solutions, so the method presented here cannot uniquely determine the torsion angle; it can only measure the static tilt.

[0065] A second aspect of the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the co-seismic static tilt measurement method based on a three-axis accelerometer when executing the program.

[0066] A third aspect of the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the co-seismic static tilt measurement method based on a three-axis accelerometer.

[0067] A fourth aspect of the present invention provides a computer program product, comprising a computer program, which implements the co-seismic static tilt measurement method based on a three-axis accelerometer when executed by a processor.

[0068] The fifth aspect of the present invention provides an application of a co-seismic static tilt measurement method based on a three-axis accelerometer, and the co-seismic static tilt measured by this method is sent to an earthquake early warning center to provide accurate static rotation field information for applications such as rotational seismology research and earthquake early warning.

[0069] For simplicity of description, the method embodiments are described as a series of actions. However, those skilled in the art should be aware that the embodiments of the present invention are not limited by the order of the actions described, because certain steps can be performed in other orders or simultaneously according to the embodiments of the present invention. Secondly, those skilled in the art should also be aware that the embodiments described in this specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present invention.

[0070] In specific implementation, the method proposed in the technical solution of the present invention can be automatically run by those skilled in the art using computer software technology. System devices that implement the method, such as computer-readable storage media that store the corresponding computer program of the technical solution of the present invention and computer equipment that runs the corresponding computer program, should also be within the scope of protection of the present invention.

[0071] The above description is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and changes can be made without departing from the principles of the present invention. These improvements and changes are also considered to be within the scope of protection of the present invention.

Claims

1. A co-seismic static tilt measurement method based on a triaxial accelerometer, characterized by: The rapid determination of the coseismic static tilt of a ground point using only triaxial accelerometer data involves the following steps: The original acceleration data are collected in real time using the triaxial accelerometer of the strong motion station; Calculating the gravitational acceleration at the strong earthquake station according to the position coordinates of the strong earthquake station stored locally; Calculating a corrected acceleration sequence at the strong motion station based on the original acceleration data and the gravitational acceleration; Calculating the coseismic static tilt at the strong motion station according to the corrected acceleration sequence and the gravitational acceleration comprises the following steps: Constructing a projection vector of three components of gravity acceleration before the earthquake according to the gravity acceleration; Determining the moment when the vibration of the strong earthquake station tends to stabilize according to the corrected acceleration sequence; Constructing a three-component projection vector of gravity acceleration after the earthquake based on the modified acceleration sequence and the moment when the vibration tends to be stable; The co-seismic static tilt at the strong earthquake station is calculated based on the projection vector of the three components of gravity acceleration before the earthquake and the projection vector of the three components of gravity acceleration after the earthquake.

2. The co-seismic static tilt measurement method based on a triaxial accelerometer according to claim 1, characterized in that: Before the earthquake, the coordinate axis orientation of the three-axis accelerometer is corrected so that the coordinate axis orientation of the three-axis accelerometer before the earthquake is consistent with the coordinate axis orientation of the station center coordinate system at the strong earthquake station.

3. The co-seismic static tilt measurement method based on a triaxial accelerometer according to claim 1, characterized in that: The step of calculating the corrected acceleration sequence at the strong motion station based on the original acceleration data and the gravitational acceleration comprises the following steps: detecting the arrival time of the P wave at the strong earthquake station according to the raw acceleration data; Calculating a constant deviation of a triaxial accelerometer at the strong motion station based on the raw acceleration data, the P-wave arrival time, and the gravitational acceleration; A corrected acceleration sequence at the strong motion station is calculated based on the original acceleration data and the constant deviation.

4. The co-seismic static tilt measurement method based on a triaxial accelerometer according to claim 3, characterized in that: The long-short time averaging method is used to detect the P-wave arrival time of the strong earthquake station.

5. The co-seismic static tilt measurement method based on a triaxial accelerometer according to claim 1, characterized in that: The moment when the vibration of the strong earthquake station tends to be stable is determined by using the empirical threshold method based on the modified acceleration sequence.

6. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the co-seismic static tilt measurement method based on a three-axis accelerometer as described in any one of claims 1 to 5 is implemented.

7. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the co-seismic static tilt measurement method based on a three-axis accelerometer as described in any one of claims 1 to 5 is implemented.

8. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the co-seismic static tilt measurement method based on a three-axis accelerometer as described in any one of claims 1 to 5 is implemented.

9. An application of the co-seismic static tilt measurement method based on a triaxial accelerometer according to any one of claims 1 to 5, characterized in that: The co-seismic static tilt measured by this method will be sent to the earthquake early warning center to provide accurate static rotation field information for rotational seismology research and earthquake early warning applications.

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