1. A seismic source rapid determination method based on a single rectangular model is characterized by comprising the following steps: the rapid seismic source determination is realized by jointly using the seismic data and the high-frequency GNSS data, and the realization process is as follows,

the method comprises the steps that a seismograph and a seismograph acquire original motion information of a seismograph station, a GNSS receiver acquires basic navigation positioning information of a GNSS observation station, and transmits the acquired original motion information of the seismograph station and the basic navigation positioning information of the GNSS observation station to a ground computing center;

the ground computing center constructs a seismic station characteristic function time sequence according to the original motion information of the seismic station, and judges whether seismic triggering occurs in the seismic station or not according to the seismic station characteristic function time sequence; if the earthquake triggering does not occur, the ground computing center continuously judges whether the earthquake triggering occurs on the earthquake station; otherwise, the ground computing center starts a seismic mode and accurately picks up the initial motion time of the seismic station according to the characteristic function time sequence of the seismic station;

the ground computing center determines the epicenter position according to the locally stored seismic station position information and the seismic station initial motion time; the ground computing center generates the motion information of the GNSS observation station according to the basic navigation positioning information of the GNSS observation station;

the ground computing center estimates a point source magnitude according to locally stored GNSS observation station position information, the GNSS observation station motion information and the epicenter position, and estimates the initial fault size of the single rectangular model according to the point source magnitude;

and the ground computing center inverts a single rectangular model parameter according to the initial fault size, the GNSS observation station position information, the GNSS observation station ground peak parameter observation value and the epicenter position, and sends earthquake early warning information comprising the epicenter position, the point source magnitude and the single rectangular model parameter to an earthquake early warning center.

2. The single rectangular model based seismic source fast determination method according to claim 1, characterized in that: the ground computing center estimates the magnitude of a point source according to the locally stored position information of the GNSS observation station, the motion information of the GNSS observation station and the epicenter position, and comprises the following steps,

the ground computing center computes the epicenter distance of the GNSS observation station according to the position information of the GNSS observation station and the epicenter position;

the ground computing center extracts a ground peak parameter observation value of the GNSS observation station according to the motion information of the GNSS observation station;

and the ground computing center estimates the magnitude of a point source according to the epicenter distance of the GNSS observation station and the ground peak parameter observation value of the GNSS observation station.

3. The single rectangular model based seismic source fast determination method according to claim 1, characterized in that: when estimating the initial fault size of the single rectangular model according to the point source magnitude, the initial fault size comprises an initial fault length and an initial fault width.

4. The method for fast seismic source determination based on a single rectangular model according to claim 1,2 or 3, characterized in that: the ground computing center inverts a single rectangular model parameter according to the initial fault size, the GNSS observation station position information, the GNSS observation station ground peak parameter observation value and the epicenter position, and sends earthquake early warning information such as the epicenter position, the point source magnitude, the single rectangular model parameter and the like to an earthquake early warning center, and the method comprises the following steps of,

determining a reasonable seismic source parameter traversal range according to the physical meaning of the single rectangular model parameter and prior information, wherein the prior information comprises a seismic center position and an initial fault size;

considering the accuracy and efficiency of the single rectangular model parameter inversion, and determining a reasonable seismic source parameter traversal step length;

generating a seismic source parameter solution space according to the seismic source parameter traversal range and the seismic source parameter traversal step length, and calculating a ground peak parameter theoretical value of the GNSS observation station for each possible solution of the seismic source parameters in the seismic source parameter solution space one by one according to the seismic source parameter solution space, the position information of the GNSS observation station, the ground peak parameter observation value of the GNSS observation station and the epicenter position;

and determining an optimal solution of the seismic source parameters from the seismic source parameter solution space according to the ground peak parameter observed value of the GNSS observation station, the ground peak parameter theoretical value of the GNSS observation station and the target function, and specifically taking the optimal solution of the seismic source parameters as an inversion solution of the single rectangular model parameters at the current moment.

5. The single rectangle model based seismic source fast determination method of claim 4, wherein: calculating the ground peak parameter theoretical value of the GNSS observation station for each possible solution of the seismic source parameter in the seismic source parameter solution space one by one according to the seismic source parameter solution space, the position information of the GNSS observation station, the ground peak parameter observation value of the GNSS observation station and the epicenter position, and comprises the following steps,

calculating the fault distance of the GNSS observation station for each possible solution of the seismic source parameters one by one according to the seismic source parameter solution space, the position information of the GNSS observation station and the epicenter position;

fitting coefficients of an empirical attenuation formula by using least square adjustment according to the GNSS observation station fault distance and the GNSS observation station ground peak parameter observation value;

and calculating a ground peak parameter theoretical value of the GNSS observation station according to the GNSS observation station fault distance and the empirical attenuation formula.

6. A seismic source rapid determination system based on a single rectangular model comprises a seismic station, a GNSS observation station, a ground computing center and a seismic early warning center, wherein the seismic station is provided with a strong seismograph or a seismograph, and the GNSS observation station is provided with a GNSS receiver;

the seismic station is used for acquiring original motion information of the seismic station and sending the acquired original motion information of the seismic station to a ground computing center;

the GNSS observation station is used for acquiring basic navigation positioning information of the GNSS observation station and sending the acquired basic navigation positioning information of the GNSS observation station to a ground computing center;

the ground computing center is used for judging whether the earthquake station has earthquake triggering, determining earthquake epicenter, computing point source magnitude and inverting a single rectangular model parameter according to locally stored earthquake station position information, locally stored GNSS observation station position information, original motion information of the earthquake station and basic navigation and positioning information of the GNSS observation station, and sending earthquake early warning information such as the earthquake epicenter information, the point source magnitude information and the single rectangular model parameter information to the earthquake early warning center;

and the earthquake early warning center is used for making corresponding earthquake early warning measures according to the received earthquake early warning information.

7. The single rectangle model based seismic source fast determination system of claim 6, wherein: the ground computing center comprises the following units,

the receiving unit is used for receiving the original motion information of the seismic station and the basic navigation and positioning information of the GNSS observation station;

the first computing unit is used for judging whether the earthquake station generates earthquake triggering and determining the earthquake epicenter position according to the original motion information of the earthquake station and the locally stored position information of the earthquake station;

the second calculation unit is used for generating a ground peak parameter observation value of the GNSS observation station and estimating the origin magnitude of an earthquake according to the basic navigation and positioning information of the GNSS observation station, the locally stored position information of the GNSS observation station and the earthquake epicenter position;

the processing unit is used for quickly inverting a single rectangular model parameter according to the ground peak parameter observation value of the GNSS observation station, the position information of the GNSS observation station, the initial fault size and the earthquake epicenter information;

and the sending unit is used for sending the earthquake early warning information such as the earthquake epicenter position, the earthquake magnitude of the earthquake point source, the single rectangular model parameter and the like to an earthquake early warning center.

8. The single rectangle model based seismic source fast determination system of claim 7, wherein: the first computing unit is used for constructing a seismic station characteristic function time sequence; judging whether the earthquake station generates earthquake triggering; accurately picking up the initial motion time of the seismic station; and determining the earthquake epicenter position.

9. The single rectangle model based seismic source fast determination system of claim 7, wherein: the second calculation unit is used for generating the motion information of the GNSS observation station; extracting a ground peak parameter observation value of the GNSS observation station; calculating the epicenter distance of the GNSS observation station; estimating the magnitude of a seismic point source; the initial fault size of the single rectangular model is determined.

Background

Earthquakes of different scales frequently occur in the world every year, and great threat is caused to the safety of life and property. Earthquake prediction and forecast are problems which are difficult to solve in a short period, and in such a case, earthquake early warning and emergency disaster relief are particularly important. The method has the advantages that the breaking length and the breaking direction of the seismic source are quickly determined, and the method has great significance for earthquake early warning, earthquake motion field prediction, post-earthquake disaster assessment and quick rescue. The traditional earthquake early warning system brings difficulty to the real-time inversion of earthquake sources because the phenomena of instrument inclination, rotation, range overrun and the like are easily generated in a large earthquake near-field area by using seismographs and strong seismographs.

With the development of high-frequency GNSS receiver technology and the improvement of GNSS positioning accuracy, high-frequency GNSS technology is widely applied to seismology. Currently, the commonly used GNSS technologies include precise single-point positioning, relative positioning, and a GNSS epoch-to-epoch difference method. The precise single-point positioning and the relative positioning are difficult to meet the requirement of earthquake early warning because the precise single-point positioning and the relative positioning need to depend on a reference station or a precise satellite orbit clock error product. By means of the advantages of satellite space reference, broadcast ephemeris, epoch difference ambiguity elimination and the like, the GNSS epoch difference method solves the problems that precise single-point positioning and relative positioning depend on a reference station and the precise ephemeris or long convergence time (10-20 minutes) is needed, makes up the problems that data of a seismograph and a strong seismograph in a large earthquake near field area are unreliable and the like, and provides technical support for application of high-frequency GNSS in earthquake early warning.

In the aspect of seismic source inversion, the seismic source fracture direction is mostly used as prior information in a real-time inversion strategy, for example, a learner considers that a historical fault direction can be approximately regarded as the seismic source fracture direction of the current earthquake, and in this case, the universality of the inversion strategy is seriously reduced. Global Moment Tensor catalog (GCMT) projects and the U.S. geological Survey (USGS) can provide Moment Tensor and fault plane solutions for different scales of earthquakes worldwide, but they rely on long-range seismic broadband seismic data, delaying post-earthquake emergency response and production.

Disclosure of Invention

With the development of high-frequency GNSS receiver technology and the improvement of GNSS positioning accuracy, the GNSS epoch difference method can continuously provide a velocity time sequence with mm/s accuracy in real time in a large earthquake near-field area. The invention discloses a seismic source rapid determination method and system based on a single rectangular model, aiming at making up the unreliable data of a seismograph and a seismograph in a large-earthquake near-field area due to instrument inclination, rotation, range overrun and the like and solving the problems of low universality and low timeliness of the existing seismic source inversion strategy. The method and the device can simultaneously achieve accurate pickup of P waves in time and accurate capture of seismic waves in a large seismic near field area by jointly using the strong seismic data and the high-frequency GNSS data. In addition, the method gives full play to the timeliness of the difference method among the GNSS epochs and the universality of the single rectangular model, and realizes the rapid determination of the fracture length and the fracture direction of the seismic source by means of the seismic source parameter traversal method, so as to provide rapid and reliable seismic source reference information for seismic early warning, seismic dynamic field prediction, post-seismic disaster evaluation, rapid rescue and the like.

In one aspect of the invention, a single rectangular model-based seismic source rapid determination method is provided, which combines seismic data and high-frequency GNSS data to realize rapid determination of a seismic source, and is realized as follows,

the method comprises the steps that a seismograph and a seismograph acquire original motion information of a seismograph station, a GNSS receiver acquires basic navigation positioning information of a GNSS observation station, and transmits the acquired original motion information of the seismograph station and the basic navigation positioning information of the GNSS observation station to a ground computing center;

the ground computing center constructs a seismic station characteristic function time sequence according to the original motion information of the seismic station, and judges whether seismic triggering occurs in the seismic station or not according to the seismic station characteristic function time sequence; if the earthquake triggering does not occur, the ground computing center continuously judges whether the earthquake triggering occurs on the earthquake station; otherwise, the ground computing center starts a seismic mode and accurately picks up the initial motion time of the seismic station according to the characteristic function time sequence of the seismic station;

the ground computing center determines the epicenter position according to the locally stored seismic station position information and the seismic station initial motion time; the ground computing center generates the motion information of the GNSS observation station according to the basic navigation positioning information of the GNSS observation station;

the ground computing center estimates a point source magnitude according to locally stored GNSS observation station position information, the GNSS observation station motion information and the epicenter position, and estimates the initial fault size of the single rectangular model according to the point source magnitude;

and the ground computing center inverts a single rectangular model parameter according to the initial fault size, the GNSS observation station position information, the GNSS observation station ground peak parameter observation value and the epicenter position, and sends earthquake early warning information comprising the epicenter position, the point source magnitude and the single rectangular model parameter to an earthquake early warning center.

And the ground computing center estimates the magnitude of the point source according to the locally stored position information of the GNSS observation station, the motion information of the GNSS observation station and the epicenter position, and comprises the following processes,

the ground computing center computes the epicenter distance of the GNSS observation station according to the position information of the GNSS observation station and the epicenter position;

the ground computing center extracts a ground peak parameter observation value of the GNSS observation station according to the motion information of the GNSS observation station;

and the ground computing center estimates the magnitude of a point source according to the epicenter distance of the GNSS observation station and the ground peak parameter observation value of the GNSS observation station.

Further, when estimating an initial fault size of a single rectangular model from the point source magnitude, the initial fault size includes an initial fault length and an initial fault width.

The ground computing center inverts a single rectangular model parameter according to the initial fault size, the position information of the GNSS observation station, the ground peak parameter observation value of the GNSS observation station and the epicenter position, and sends earthquake early warning information such as the epicenter position, the point source magnitude, the single rectangular model parameter and the like to an earthquake early warning center, wherein the method comprises the following processing of determining a reasonable earthquake source parameter traversal range according to the physical meaning and prior information of the single rectangular model parameter, wherein the prior information comprises the epicenter position and the initial fault size;

considering the accuracy and efficiency of the single rectangular model parameter inversion, and determining a reasonable seismic source parameter traversal step length;

generating a seismic source parameter solution space according to the seismic source parameter traversal range and the seismic source parameter traversal step length, and calculating a ground peak parameter theoretical value of the GNSS observation station for each possible solution of the seismic source parameters in the seismic source parameter solution space one by one according to the seismic source parameter solution space, the position information of the GNSS observation station, the ground peak parameter observation value of the GNSS observation station and the epicenter position;

and determining an optimal solution of the seismic source parameters from the seismic source parameter solution space according to the ground peak parameter observed value of the GNSS observation station, the ground peak parameter theoretical value of the GNSS observation station and the target function, and specifically taking the optimal solution of the seismic source parameters as an inversion solution of the single rectangular model parameters at the current moment.

And calculating the ground peak parameter theoretical value of the GNSS observation station for each possible solution of the seismic source parameter in the seismic source parameter solution space one by one according to the seismic source parameter solution space, the position information of the GNSS observation station, the ground peak parameter observed value of the GNSS observation station and the epicenter position, and comprises the following steps,

calculating the fault distance of the GNSS observation station for each possible solution of the seismic source parameters one by one according to the seismic source parameter solution space, the position information of the GNSS observation station and the epicenter position;

fitting coefficients of an empirical attenuation formula by using least square adjustment according to the GNSS observation station fault distance and the GNSS observation station ground peak parameter observation value;

and calculating a ground peak parameter theoretical value of the GNSS observation station according to the GNSS observation station fault distance and the empirical attenuation formula.

On the other hand, the invention provides a seismic source rapid determination system based on a single rectangular model, which comprises a seismic station, a GNSS observation station, a ground computing center and a seismic early warning center, wherein the seismic station is provided with a strong seismograph or a seismograph, and the GNSS observation station is provided with a GNSS receiver;

the seismic station is used for acquiring original motion information of the seismic station and sending the acquired original motion information of the seismic station to a ground computing center;

the GNSS observation station is used for acquiring basic navigation positioning information of the GNSS observation station and sending the acquired basic navigation positioning information of the GNSS observation station to a ground computing center;

the ground computing center is used for judging whether the earthquake station has earthquake triggering, determining earthquake epicenter, computing point source magnitude and inverting a single rectangular model parameter according to locally stored earthquake station position information, locally stored GNSS observation station position information, original motion information of the earthquake station and basic navigation and positioning information of the GNSS observation station, and sending earthquake early warning information such as the earthquake epicenter information, the point source magnitude information and the single rectangular model parameter information to the earthquake early warning center;

and the earthquake early warning center is used for making corresponding earthquake early warning measures according to the received earthquake early warning information.

Furthermore, the ground computing center comprises the following units,

the receiving unit is used for receiving the original motion information of the seismic station and the basic navigation and positioning information of the GNSS observation station;

the first computing unit is used for judging whether the earthquake station generates earthquake triggering and determining the earthquake epicenter position according to the original motion information of the earthquake station and the locally stored position information of the earthquake station;

the second calculation unit is used for generating a ground peak parameter observation value of the GNSS observation station and estimating the origin magnitude of an earthquake according to the basic navigation and positioning information of the GNSS observation station, the locally stored position information of the GNSS observation station and the earthquake epicenter position;

the processing unit is used for quickly inverting a single rectangular model parameter according to the ground peak parameter observation value of the GNSS observation station, the position information of the GNSS observation station, the initial fault size and the earthquake epicenter information;

and the sending unit is used for sending the earthquake early warning information such as the earthquake epicenter position, the earthquake magnitude of the earthquake point source, the single rectangular model parameter and the like to an earthquake early warning center.

Furthermore, the first computing unit is used for constructing a seismic station characteristic function time sequence; judging whether the earthquake station generates earthquake triggering; accurately picking up the initial motion time of the seismic station; and determining the earthquake epicenter position.

Moreover, the second computing unit is configured to generate GNSS rover motion information; extracting a ground peak parameter observation value of the GNSS observation station; calculating the epicenter distance of the GNSS observation station; estimating the magnitude of a seismic point source; the initial fault size of the single rectangular model is determined.

Compared with the traditional earthquake early warning system, the scheme of the invention is uniquely designed from the inversion data source and the seismic source parameter determination method respectively. The scheme of the invention jointly uses the strong seismic data and the GNSS high-frequency data to simultaneously pick up the arrival time of P waves and accurately capture seismic waves in a large seismic near field area; in addition, the scheme of the invention can provide real-time, continuous and high-precision original input for the subsequent seismic source parameter inversion by depending on a difference method between GNSS epochs. For seismic source parameter inversion, the scheme of the invention does not depend on any prior hypothesis, obtains the optimal solution of the seismic source parameters matched with the observation information by a seismic source parameter traversal method based on a simple and effective rectangular seismic source model, and has strong universality. The scheme of the invention is simple and convenient to implement, has strong practicability and universality, solves the problems of low practicability and inconvenient practical application in the related technology, can improve the user experience, and has important market value.

Drawings

FIG. 1 is a flow chart of a method for fast seismic source determination based on a single rectangular model according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a seismic source fast determination system based on a single rectangular model according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of the internal structure of a single rectangular model-based seismic source fast determination system for ground computation center according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a single rectangular model according to an embodiment of the present invention.

Detailed Description

The technical solution of the present invention is specifically described below with reference to the accompanying drawings and examples. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

With the development of high-frequency GNSS receiver technology and the improvement of GNSS positioning accuracy, the GNSS epoch difference method can continuously provide a velocity time sequence with mm/s accuracy in real time in a large earthquake near-field area. The invention discloses a seismic source rapid determination method and system based on a single rectangular model, aiming at making up the unreliable data of a seismograph and a seismograph in a large-earthquake near-field area due to instrument inclination, rotation, range overrun and the like and solving the problems of low universality and low timeliness of the existing seismic source inversion strategy. The method and the device can simultaneously achieve accurate pickup of P waves in time and accurate capture of seismic waves in a large seismic near field area by jointly using the strong seismic data and the high-frequency GNSS data. In addition, the method gives full play to the timeliness of the difference method among the GNSS epochs and the universality of the single rectangular model, and realizes the rapid determination of the fracture length and the fracture direction of the seismic source by means of the seismic source parameter traversal method, so as to provide rapid and reliable seismic source reference information for seismic early warning, seismic dynamic field prediction, post-seismic disaster evaluation, rapid rescue and the like.

Fig. 1 is a flowchart of a seismic source fast determination method based on a single rectangular model according to an embodiment of the present invention. Referring to fig. 1, the embodiment comprises the following specific steps:

s11, acquiring original motion information of a seismic station by a strong seismograph or a seismograph, acquiring basic navigation and positioning information of a GNSS observation station by a GNSS receiver, and sending the acquired original motion information of the seismic station and the basic navigation and positioning information of the GNSS observation station to a ground computing center;

and S12, the ground computing center constructs a seismic station characteristic function time sequence according to the original motion information of the seismic station, and judges whether the seismic station has seismic triggering or not according to the seismic station characteristic function time sequence. If the earthquake triggering does not occur, the ground computing center continuously judges whether the earthquake triggering occurs on the earthquake station; otherwise, the ground computing center starts a seismic mode and accurately picks up the initial motion time of the seismic station according to the characteristic function time sequence of the seismic station;

s13, the ground computing center determines the epicenter position according to the locally stored seismic station position information and the seismic station initial motion time; the ground computing center generates the motion information of the GNSS observation station according to the basic navigation positioning information of the GNSS observation station;

s14, the ground computing center estimates a point source magnitude according to locally stored GNSS observation station position information, GNSS observation station motion information and the epicenter position, and estimates the initial fault size of the single rectangular model according to the point source magnitude;

and S15, the ground computing center inverts a single rectangular model parameter according to the initial fault size, the position information of the GNSS observation station, the ground peak parameter observation value of the GNSS observation station and the epicenter position, and sends earthquake early warning information such as the epicenter position, the point source magnitude, the single rectangular model parameter and the like to an earthquake early warning center.

Further, in S12, the ground computing center constructs a seismic station characteristic function time sequence according to the original motion information of the seismic station, and determines whether the seismic station has seismic triggering and accurately picks up the initial motion time of the seismic station according to the seismic station characteristic function time sequence, and the method is implemented by the following specific processes:

the first step is as follows: constructing a seismic station characteristic function time sequence considering frequency and amplitude characteristic changes simultaneously, wherein the specific form is as follows:

in the formula, CF_kRepresenting the constructed seismic station characteristic function value at the k-th time; x is the number of_k、x_k-1Respectively representing the original motion information of the seismic station at the k-th time and the k-1 th time, wherein if the seismic station is provided with a strong seismograph, the original motion information of the seismic station is the acceleration of the seismic station; m_kThe weighting factor is related to the environmental noise of the seismic station and the sampling frequency of the instrument, and can be given according to an empirical value, and is generally 3.

The second step is that: and judging whether the earthquake station generates earthquake triggering by using a long-time average method (STA/LTA), and roughly picking up the arrival time of the P wave. The standard formula (2) and the recursive formula (3) are as follows:

wherein STA and LTA represent the average of the time series of the characteristic function in the short and long time windows respectively_kIs the average value of the characteristic function time series at the k-th time within a short time window, LTA_kThe average value of the characteristic function time sequence at the kth moment in a long time window is obtained, and the analogy is carried out on the condition of the kth-1 moment; n is the number of data in the time window, n_STAWithin a short time windowNumber of data, n_LTAThe number of data in the long time window. The standard formula and the recursive formula are numerically equivalent. Here, the embodiment preferably employs a recursive formula with higher computational efficiency.

When the ratio of the STA to the LTA is larger than a preset empirical threshold, k is determined as the P wave is roughly up. It is to be noted that the window lengths of the long time window and the short time window affect the selection of the empirical threshold, and the value suggestions that are generally followed are: the shorter the short time window length is relative to the long time window, the higher the sensitivity of P wave pickup is, and the larger the empirical threshold value is set; the larger the short time window length relative to the long time window, the lower the sensitivity of the picked-up P-waves, and the smaller the empirical threshold should be set. And then, taking k as a center, forwardly intercepting the long time window and backwardly intercepting the short time window data as a time window for accurately picking up the initial motion time of the seismic station. With such a more reasonable time window setting, the pickup result generally has better timeliness and higher accuracy.

The third step: and (3) accurately picking the initial motion time of the seismic station by adopting an information content in Chichi (AIC) criterion. The mathematical formula is as follows:

AIC_k＝k×log10{var(CF[1,k])}+(L-k-1)×log10{var(CF[k+1,L])} (4)

in the formula, L is the data length of the time window of the accurate pick-up initial motion moment; k is a data sequence number from left to right in the time window; var (CF [1, k ]) represents the variance of the data over the time period. And when the AIC obtains the minimum value, the time corresponding to the kth data is the initial motion time of the seismic station.

Further, in S13, the determining, by the ground computing center, the epicenter position according to the locally stored information on the position of the seismic station and the initial movement time of the seismic station specifically includes:

at least 3 stations will have seismic triggers to begin estimating the epicenter. And assuming that the seismic wave propagation speed is constant and isotropic in the seismic wave propagation process, the method comprises the following specific steps:

the first step is as follows: and converting absolute position information (geodetic coordinates) of the triggered seismic stations into station center coordinates with the first triggering station as an origin. Specifically, the geodetic coordinates (BLH) may be first converted into spatial rectangular coordinates (XYZ); and then converting the space rectangular coordinate into a station center coordinate (ENU).

The second step is that: and estimating the epicenter position by adopting least square adjustment in a station center coordinate system. From the time difference of arrival of the P-wave at each seismic station, the following error equation can be obtained:

wherein (E)₀,N₀) Denotes the epicenter coordinate (E)_i,N_i) Representing the seismic station coordinates, where the subscript i (i ═ 1,2,3, L, n) represents the seismic station number at which the seismic trigger occurred, and n represents the total number of seismic stations at which the seismic trigger occurred at that time; d_iRepresenting the epicenter of the ith seismic station; v and T_iRespectively representing the propagation velocity of the seismic wave and the station initial motion moment of the ith seismic station; v. of_i,jThe method represents the comprehensive influence of instrument observation errors, initial motion moment picking errors, seismic station coordinate errors, approximation errors and the like, wherein subscripts i and j represent seismic station serial numbers triggered by earthquakes, and i is larger than j. It should be noted that the determination of the epicenter may also use a grid search method, which is only a feasible implementation solution to facilitate a deeper and thorough understanding of the details and features of the various processes of the present invention, and is not a limitation of the present invention.

The third step: the epicenter position under the station center coordinate system is converted into a geodetic coordinate, specifically, the station center coordinate can be converted into a space rectangular coordinate, and then the space rectangular coordinate is converted into the geodetic coordinate.

Further, in S13, the generating, by the ground computing center, motion information of the GNSS observation station according to the basic navigation and positioning information of the GNSS observation station specifically includes:

the ground computing center continuously and real-timely acquires a speed time sequence (motion information of the GNSS observation station) of the GNSS observation station by adopting a high-frequency GNSS epoch difference method according to the carrier phase observation value information, the pseudo-range observation value information and the broadcast ephemeris (basic navigation positioning information of the GNSS observation station). The mathematical model of the difference method between high-frequency GNSS epochs is as follows:

in the formula, t_kAnd t_k+1Two adjacent GNSS observation epochs are represented, wherein subscripts k and k +1 are GNSS observation epoch identification serial numbers; c is the speed of light; dt_rAnd dt^sRespectively representing receiver and satellite clock offsets;and T_r ^sRespectively representing ionospheric and tropospheric delays;is a multipath error;the combined effect of other errors and observation noise;andrespectively expressed in an epoch t_kAnd t_k+1Unit direction vector from satellite s to receiver r; p is a radical of^s(t_k) And p^s(t_k+1) Respectively expressed in an epoch t_kAnd t_k+1The satellite coordinates of time; p is a radical of_r(t_k) Then it is indicated at epoch t_kThe receiver coordinates of time;single difference between epochs of the carrier phase observations; c Δ dt^s(t_k,t_k+1)＝c×[dt^s(t_k+1)-dt^s(t_k)]For satellite clock error rate(ii) a Receiver displacement increment delta p between epochs_r(t_k,t_k+1) And receiver clock difference variability c Δ t_r(t_k,t_k+1) Using a least squares estimation; the satellite position and the clock error are obtained by broadcast ephemeris calculation, the receiver position is calculated by using a Pseudo-range Single Point location method (Pseudo-range Single Point location), and the ionosphere delay variabilityTropospheric delay variabilityAnd multiple pathsThe effect of (a) is very small and negligible. Δ p_r(t_k,t_k+1) Between adjacent epochs for the receiver (t)_k,t_k+1) The displacement increment of (a) divided by the sampling interval is the average speed of the receiver.

Further, in S14, the ground computation center estimates a magnitude of a point source according to locally stored GNSS observation station position information, GNSS observation station motion information, and the epicenter position, and is implemented by the following specific procedures:

the first step is as follows: and the ground computing center computes the epicenter distance of the GNSS observation station according to the position information of the GNSS observation station and the epicenter position. The epicenter distance calculation formula is as follows:

EPID_i＝arccos(sinB_i sinB₀+cosB_i cosB₀ cos(L_i-L₀))×R_earth (7)

in the formula, B₀And L₀Latitude and longitude in epicenter; b is_iAnd L_iLatitude and longitude for the GNSS rover; r_earth6371km can be taken as the average radius of the earth; EPID_iThe epicenter distance.

The second step is that: and the ground computing center extracts the ground peak value speed (the ground peak value parameter observation value of the GNSS observation station) of the GNSS observation station according to the speed time sequence (the motion information of the GNSS observation station) of the GNSS observation station.

In the formula, PGV represents the three-dimensional ground peak velocity of the GNSS observation station; n is a radical of_v(t)、E_v(t)、U_v(t) represents the velocity components of the GNSS observation station at time t in the north, east and vertical directions, respectively.

The third step: and the ground computing center estimates the magnitude of the seismic point source by adopting an empirical formula (9) according to the epicenter distance of the GNSS observation station and the ground peak value speed of the GNSS observation station (the ground peak value parameter observation value of the GNSS observation station).

log10(PGV)＝-5.025+0.741×Mw-0.111×Mw×log10(EPID) (9)

Wherein Mw is the moment magnitude; log10(×) represents base 10 logarithmic operation.

Further, in S14, the ground calculation center estimates an initial fault size of the single rectangular model according to the point source magnitude using empirical formula (10), specifically, the initial fault size includes an initial fault length and an initial fault width.

Wherein L0 and W0 are the initial fault length and width, respectively, of a single rectangular model; mw is the moment magnitude, which, when actually calculated, can be represented by the point source magnitude.

Further, in S15, the ground computation center inverts a single rectangular model parameter according to the initial fault size, the GNSS observation station position information, the GNSS observation station ground peak parameter observation value, and the epicenter position, and sends the earthquake early warning information such as the epicenter position, the point source magnitude, and the single rectangular model parameter to the earthquake early warning center, which specifically includes:

as shown in FIG. 4, a single rectangular model parameterIncluding the epicenter position (B)₀，L₀) The seismic source depth (H), the fault length (L), the length (L) and the width (W) from the epicenter to one end of the rectangular fault in the main cracking direction, the seismic source cracking direction (theta) and the seismic source relative position (k), and the model assumes that the whole rectangular surface and the seismic source keep the same height. The specific parameter inversion process is as follows:

the first step is as follows: and determining a reasonable seismic source parameter traversal range according to the physical meaning of the single rectangular model parameter and prior information, wherein the prior information comprises the length and the width of an initial fault. One of the more reasonable source parameter traversal ranges that is preferably proposed is as follows:

and determining a reasonable seismic source parameter traversal step length by considering the accuracy and efficiency of the single rectangular model parameter inversion. One of the more reasonable source parameter traversal step sizes that is preferably proposed is as follows:

where Δ H, Δ L, Δ W, Δ θ and Δ k represent the source depth, fault length and width, source fracture direction and the traversal step size of the source relative position, respectively.

The second step is that: generating a seismic source parameter solution space according to the seismic source parameter traversal range and the seismic source parameter traversal step length, calculating a ground peak parameter theoretical value of the GNSS observation station for each possible solution of the seismic source parameters in the seismic source parameter solution space one by one according to the seismic source parameter solution space, the position information of the GNSS observation station, the ground peak parameter observation value of the GNSS observation station and the epicenter position, and specifically realizing the following steps:

firstly: and generating a seismic source parameter solution space according to the seismic source parameter traversal range and the seismic source parameter traversal step length.

Secondly, the method comprises the following steps: and calculating the fault distance of the GNSS observation station for each possible solution of the seismic source parameters one by one according to the seismic source parameter solution space, the position information of the GNSS observation station and the epicenter position. According to the position of the GNSS observation station, calculating the fault distance of the GNSS observation station, and dividing the fault distance into the following two situations:

(a) the GNSS observation station is located on the projection of the rectangular fault on the ground: the seismic source depth is the fault distance of the GNSS observation station;

(b) projection of the GNSS observation station on the ground in a rectangular fault: calculating the fault distance of the GNSS observation station according to the following formula:

in the formula, D_(i,j)Represents the shortest distance from the GNSS observation station to the line segment (i, j), i and j are two adjacent endpoints of the rectangular fault (see FIG. 4), the endpoints are marked as 1,2,3, 4, min (D)_(i,j)) Is the smallest one taken from the above; FD_hRepresenting a horizontal component of a fault distance of the GNSS observation station; h is the depth of a seismic source; FD is the fault distance of the GNSS observation station.

Then: and fitting coefficients of an empirical attenuation formula by using least square adjustment according to the GNSS observation station fault distance and the GNSS observation station ground peak velocity (the GNSS observation station ground peak parameter observation value). A simple, reasonable empirical attenuation formula is as follows:

log10(PGV)＝a+b×log10(FD) (14)

in the formula, PGV is the ground peak velocity of the GNSS observation station; FD is a GNSS observation station fault distance; a and b are the coefficients of the attenuation equation to be fitted.

And finally: and calculating a ground peak velocity theoretical value of the GNSS observation station (the ground peak parameter theoretical value of the GNSS observation station) according to the GNSS observation station fault distance and the empirical attenuation formula.

The third step: and determining an optimal solution of the seismic source parameters from the seismic source parameter solution space according to the ground peak velocity of the GNSS observation station, the ground peak velocity theoretical value of the GNSS observation station and the target function, wherein the optimal solution of the seismic source parameters is specifically used as an inversion solution of the single rectangular model parameters at the current moment. The objective function used is as follows:

in the formula (I), the compound is shown in the specification,representing a ground peak velocity of the GNSS observation station;representing a ground peak velocity theoretical value of the GNSS observation station; n is the number of usable GNSS observation stations at the current moment, and subscript i represents the serial number of the usable GNSS observation stations; min represents the minimum value.

Specifically, in actual work, at least 3 seismic stations are triggered by earthquake, and the earthquake epicenter is calculated; starting the inversion of the seismic source parameters only if at least 2 GNSS observation stations are available; and as long as a new seismograph station or GNSS observation station is added, the seismic center or the seismic source parameters are immediately re-estimated.

For simplicity of explanation, the method embodiments are described as a series of acts or combinations, but those skilled in the art will appreciate that the embodiments are not limited by the order of acts described, as some steps may occur in other orders or concurrently with other steps in accordance with the embodiments of the invention. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred and that no particular act is required to implement the invention.

FIG. 2 is a schematic structural diagram of a seismic source fast determination system based on a single rectangular model according to an embodiment of the invention. Referring to fig. 2, the seismic source rapid determination system based on the single rectangular model in the embodiment of the present invention specifically includes a seismograph station, a GNSS observation station 201, a ground computing center 202, and a ground early warning center 203, where the seismograph station is configured with a strong seismograph or a seismograph, and the GNSS observation station is configured with a GNSS receiver;

the seismic station is used for acquiring original motion information of the seismic station and sending the acquired original motion information of the seismic station to the ground computing center 202;

the GNSS observation station is configured to acquire basic navigation positioning information of the GNSS observation station, and send the acquired basic navigation positioning information of the GNSS observation station to the ground computing center 202;

the ground computing center 202 is configured to determine whether the seismic station has seismic triggering, determine a seismic epicenter, compute a point source magnitude and invert a single rectangular model parameter according to locally stored seismic station position information, locally stored GNSS observation station position information, the seismic station original motion information, and the GNSS observation station basic navigation positioning information, and send seismic early warning information such as the seismic epicenter information, the point source magnitude information, and the single rectangular model parameter information to the seismic early warning center 203;

the earthquake early warning center 203 is configured to make corresponding earthquake early warning measures according to the received earthquake early warning information.

In specific implementation, the ground computing center is communicated with other earthquake stations, the GNSS observation station and the ground early warning center respectively.

In the embodiment of the present invention, as shown in fig. 3, the ground computing center 202 specifically includes a receiving unit 2021, a first computing unit 2022, a second computing unit 2023, a processing unit 2024, and a sending unit 2025, where:

a receiving unit 2021, configured to receive the raw motion information of the seismic station and the basic navigation positioning information of the GNSS observation station;

a first computing unit 2022, configured to determine whether a seismic trigger occurs in a seismic station and determine a seismic epicenter position according to the original motion information of the seismic station and the locally stored position information of the seismic station;

a second calculating unit 2023, configured to generate a GNSS observation station ground peak parameter observation value and estimate an earthquake magnitude of an earthquake point source according to the GNSS observation station basic navigation positioning information, the locally stored GNSS observation station position information, and the earthquake epicenter position;

the processing unit 2024 is configured to quickly invert a single rectangular model parameter according to the GNSS observation station ground peak parameter observation value, the GNSS observation station position information, the initial fault size, and the earthquake epicenter information;

the sending unit 2025 is configured to send the earthquake early warning information, such as the earthquake epicenter position, the earthquake magnitude of the earthquake point source, and the single rectangular model parameter, to an earthquake early warning center.

Further, the first computing unit 2022 is specifically configured to construct a time series of a characteristic function of a seismic station; judging whether the earthquake station generates earthquake triggering; accurately picking up the initial motion time of the seismic station; and determining the earthquake epicenter position.

Further, the second calculating unit 2023 is specifically configured to generate GNSS observation station motion information; extracting a ground peak parameter observation value of the GNSS observation station; calculating the epicenter distance of the GNSS observation station; estimating the magnitude of a seismic point source; the initial fault size of the single rectangular model is determined.

In practical implementation, the receiving unit 2021, the first calculating unit 2022, the second calculating unit 2023, the processing unit 2024, and the transmitting unit 2025 may be connected in sequence.

For the system embodiment, since it is basically similar to the method embodiment, the description is simple, and for the relevant points, refer to the partial description of the method embodiment.

In specific implementation, a person skilled in the art can implement the automatic operation process by using a computer software technology, and a system device for implementing the method, such as a computer-readable storage medium storing a corresponding computer program according to the technical solution of the present invention and a computer device including a corresponding computer program for operating the computer program, should also be within the scope of the present invention.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.