A method for detecting the end of a seismic signal

Abstract

This application provides a method for detecting endpoints of seismic signals, relating to the field of seismic signal processing. This method involves acquiring an initial seismic triaxial signal; processing the initial seismic triaxial signal to obtain multiple frames of target seismic triaxial signals; then, determining the component information corresponding to each frame of the target seismic triaxial signal based on the component information; furthermore, determining the short-time energy and short-time autocorrelation function values ​​corresponding to each frame of the target seismic triaxial signal based on the component information; and finally, determining the endpoints of each frame of the target seismic triaxial signal based on the short-time energy and short-time autocorrelation function values. This method can replace manual judgment to detect small seismic signals, thereby reducing false positives and false negatives.

Description

Technical Field

[0001] This application relates to the field of seismic signal processing, and in particular to a method for detecting the endpoints of seismic signals. Background Technology

[0002] In seismic signal processing, endpoint detection is of paramount importance. Especially when the magnitude is small and the epicentral distance is large, resulting in a low signal-to-noise ratio, the accuracy of endpoint detection directly impacts the location, magnitude calculation, and identification of seismic events. For a long time, accurate endpoint detection has primarily relied on time-domain waveform envelopes and seismic signal travel time tables, with manual judgment. However, because the time-domain waveform envelope is significantly affected by magnitude and epicentral distance, manual judgment based on the time-domain waveform envelope is prone to misjudgments and omissions when the signal-to-noise ratio is low. Summary of the Invention

[0003] This application proposes a method for detecting the endpoints of seismic signals, which can determine the component information of the three-dimensional seismic signals and, based on the component information, determine the short-time energy and short-time autocorrelation function values ​​corresponding to each frame of the three-dimensional seismic signals, thereby determining the endpoints of the target three-dimensional seismic signals and realizing the detection of small seismic signals; thus, it can replace manual judgment and reduce misjudgment and missed judgment.

[0004] This application provides a method for detecting the endpoints of a seismic signal, including:

[0005] Acquire the initial three-dimensional seismic signals;

[0006] The initial seismic triaxial signal is processed to obtain multiple frames of target seismic triaxial signal;

[0007] Based on the target seismic triaxial signals of each frame, determine the component information corresponding to the target seismic triaxial signals of each frame;

[0008] Based on the component information corresponding to the three-dimensional target earthquake signal of each frame, the short-time energy and short-time autocorrelation function values ​​corresponding to the three-dimensional target earthquake signal of each frame are determined.

[0009] Based on the short-time energy and short-time autocorrelation function values ​​corresponding to the three-dimensional target seismic signals of each frame, the endpoints of the three-dimensional target seismic signals of each frame are determined.

[0010] In the above scheme, the processing of the initial seismic triaxial signal to obtain multiple frames of target seismic triaxial signal includes:

[0011] The initial seismic triaxial signal is filtered to obtain the filtered seismic triaxial signal.

[0012] The filtered seismic triaxial signal is framed to obtain multiple frames of the target seismic triaxial signal.

[0013] In the above scheme, the initial seismic triaxial signal includes east-west seismic signals, north-south seismic signals, and vertical seismic signals;

[0014] The step of filtering the initial seismic triaxial signal to obtain the filtered seismic triaxial signal includes:

[0015] The east-west, north-south, and vertical seismic signals are filtered using a high-pass filter to obtain filtered east-west, north-south, and vertical seismic signals, thus obtaining the filtered seismic triaxial signals.

[0016] In the above scheme, the step of dividing the filtered seismic triaxial signal into frames to obtain the multi-frame target seismic triaxial signal includes:

[0017] Based on a preset Hamming window function and a preset signal length, the filtered seismic triaxial signal is framed to obtain multiple frames of the target seismic triaxial signal.

[0018] In the above scheme, determining the component information corresponding to the three-dimensional target seismic signals of each frame based on the three-dimensional target seismic signals of each frame includes:

[0019] Determine the data matrix corresponding to the target seismic triaxial signals in each frame;

[0020] Eigenvalue decomposition is performed on the data matrix corresponding to the three-dimensional target earthquake signals of each frame to obtain the feature vectors corresponding to the three-dimensional target earthquake signals of each frame.

[0021] Based on the feature vector, the component information corresponding to the three-dimensional target seismic signal in each frame is determined.

[0022] In the above scheme, the short-time energy is determined by the following formula:

[0023]

[0024] in, Indicates the first The short-time energy corresponding to the target seismic triaxial signal described in the frame. Indicates the first The first frame of the target seismic triaxial signal corresponds to the third Component information of each data sampling point.

[0025] In the above scheme, the short-time autocorrelation function value is:

[0026]

[0027] in, Indicates the first The frame contains the short-time autocorrelation function value corresponding to the target seismic triaxial signal. Indicates the offset. Indicates the first The frame contains the component information of the m-th data sampling point corresponding to the target seismic triaxial signal.

[0028] In the above scheme, determining the endpoints of the target seismic triaxial signals in each frame based on the short-time energy and short-time autocorrelation function values ​​corresponding to the target seismic triaxial signals in each frame includes:

[0029] Based on the short-time energy and short-time autocorrelation function values ​​corresponding to the three target seismic signals in each frame, the endpoints of the three target seismic signals in each frame are determined using the dual-threshold method.

[0030] In the above scheme, the step of determining the endpoints of the target seismic triaxial signals in each frame using a dual-threshold method based on the short-time energy and short-time autocorrelation function values ​​corresponding to the target seismic triaxial signals in each frame includes:

[0031] Based on the short-time energy and short-time autocorrelation function values ​​corresponding to the target seismic triaxial signals in each frame, the prediction points are determined;

[0032] Based on a first preset threshold, the predicted point is judged for the first time;

[0033] Search from the starting point of the first judgment in the first preset direction to determine the first intersection point of the predicted point and the second preset value;

[0034] Searching from the endpoint of the first judgment towards the second preset direction, the second intersection point of the predicted point and the second preset value is determined; wherein, the endpoints of the target earthquake triaxial signal include the first intersection point and the second intersection point; the first preset threshold is greater than the second preset threshold, and the first preset direction and the second preset direction are opposite.

[0035] This application provides a method for detecting the endpoints of seismic signals. The method involves acquiring an initial seismic triaxial signal; processing the initial seismic triaxial signal to obtain multiple frames of target seismic triaxial signals; then, determining the component information corresponding to each frame of the target seismic triaxial signal based on the component information; furthermore, determining the short-time energy and short-time autocorrelation function value corresponding to each frame of the target seismic triaxial signal based on the component information; and finally, determining the endpoints of each frame of the target seismic triaxial signal based on the short-time energy and short-time autocorrelation function value. This method can replace manual judgment to detect small seismic signals, thereby reducing false positives and false negatives.

[0036] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more obvious and understandable, specific implementation methods of this application are described below. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is one of the flowcharts illustrating a seismic signal endpoint detection method provided in an embodiment of this application;

[0039] Figure 2 A second schematic flowchart illustrating a seismic signal endpoint detection method provided in this application embodiment;

[0040] Figure 3 The third schematic flowchart of a seismic signal endpoint detection method provided in this application embodiment;

[0041] Figure 4 This is the fourth flowchart illustrating a seismic signal endpoint detection method provided in this application embodiment. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims and drawings of this application are intended to cover non-exclusive inclusion.

[0044] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0045] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists, A and B exist simultaneously, or B exists. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0046] Furthermore, the terms "first," "second," etc., in the specification and claims of this application or in the aforementioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0047] In the description of this application, unless otherwise stated, "multiple" means two or more (including two), and similarly, "multiple groups" means two or more (including two groups).

[0048] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0049] like Figure 1 As shown, this application provides a method for detecting the endpoints of a seismic signal, including steps S101-S105.

[0050] S101. Obtain the initial three-dimensional seismic signals.

[0051] In some embodiments, the initial seismic triad signal represents real-time seismic waveform data with triads, which correspond to the east-west, north-south, and vertical directions, respectively.

[0052] In some embodiments, the initial seismic triad signal includes an east-west seismic signal, a north-south seismic signal, and a vertical seismic signal.

[0053] S102. Process the initial seismic three-axis signal to obtain multiple frames of target seismic three-axis signal.

[0054] like Figure 2 As shown, in some embodiments, S102 may include:

[0055] S1021. Filter the initial seismic three-axis signal to obtain the filtered seismic three-axis signal.

[0056] In some embodiments, a high-pass filter is used to filter the east-west, north-south, and vertical seismic signals respectively to obtain filtered east-west, north-south, and vertical seismic signals, thereby obtaining filtered seismic triaxial signals.

[0057] For example, suppose the initial seismic three-axis signal (three-axis observation data matrix) is given. As shown below:

[0058] X = A + W = [ x 1 , x 2 , x 3 ] ∈ R M × 3

[0059] in, This indicates an east-west oriented seismic signal (east-west waveform data). This indicates an east-west oriented seismic signal (north-south oriented waveform data). This represents the vertical seismic signal (vertical waveform data). Represents the signal matrix, Represents the noise matrix. This indicates the signal duration. The lower cutoff frequency of the high-pass filter is set to 1Hz. After filtering the east-west, north-south, and vertical seismic signals separately using the high-pass filter, the filtered seismic triaxial signals (filtered data matrix) are obtained. .

[0060] Understandably, high-pass filtering of the initial three-dimensional seismic signals can eliminate low-frequency pulsation noise and DC components in the east-west, north-south, and vertical seismic signals, reduce the impact of noise on subsequent endpoint discrimination, and improve the detection accuracy of small seismic signals.

[0061] S1022. The filtered seismic three-axis signal is divided into frames to obtain multiple frames of target seismic three-axis signal.

[0062] In some embodiments, the filtered seismic triaxial signal is framed based on a preset Hamming window function and a preset signal length to obtain multiple frames of target seismic triaxial signal.

[0063] For example, the filtered seismic triaxial signal is framed using a Hamming window function, with each frame having a signal length of 1 second, i.e., the preset signal length is 1 second. Each frame of the target seismic triaxial signal overlaps for 0.75 seconds, and each frame includes L sampling points.

[0064] It should be noted that the Hamming window function is existing technology, therefore, it will not be described in detail here.

[0065] S103. Based on the three-dimensional seismic signals of each frame, determine the component information corresponding to the three-dimensional seismic signals of each frame.

[0066] like Figure 3 As shown, in some embodiments, S103 may include:

[0067] S1031. Determine the data matrix corresponding to the three-dimensional seismic signals of the target in each frame.

[0068] For example, since the filtered seismic triaxial signal (the filtered data matrix) is Therefore, let the first... The target seismic triaxial signal of the frame is At this time, the first The data matrix corresponding to the three-dimensional seismic signal of the target frame will be as follows:

[0069]

[0070] in, Indicates the first The data matrix corresponding to the three-dimensional seismic signals of the target frame, where E represents the identity matrix. Indicates the first Frame target seismic three-dimensional signal.

[0071] S1032. Perform eigenvalue decomposition on the data matrix corresponding to the three-dimensional seismic signals of the target in each frame to obtain the eigenvectors corresponding to the three-dimensional seismic signals of the target in each frame.

[0072] For example, for the first Data matrix corresponding to the three-dimensional seismic signal of the frame target Performing eigenvalue decomposition will yield the th The eigenvalue diagonal matrix and eigenvector matrix corresponding to the three-dimensional seismic signals of the target frame are used to obtain the first... The eigenvectors corresponding to the three-dimensional seismic signals of the target frame. Among them, the eigenvectors of the target frame. Data matrix corresponding to the three-dimensional seismic signal of the frame target After eigenvalue decomposition, it will look like this:

[0073]

[0074] in, Represents an eigenvalue diagonal matrix. This represents the characteristic value of the east-west direction target earthquake signal in the three-dimensional target earthquake signal. This represents the characteristic value of the target earthquake signal in the north-south direction within the three-dimensional target earthquake signal. This represents the characteristic value of the target seismic signal in the vertical direction among the three-dimensional target seismic signals. U = [ u 1 , u 2 , u 3 ] This represents the eigenvector matrix corresponding to the eigenvalues; in In this case, Indicates and The corresponding feature vector.

[0075] S1033. Based on the feature vector, determine the component information corresponding to the three-dimensional seismic signals of the target in each frame.

[0076] For example, the first obtained based on S1032 The eigenvectors of the three-dimensional seismic signals of the target frame can determine the first... The component information of the three-dimensional seismic signal of the target frame is shown below:

[0077]

[0078] in, Indicates the first Component information of the three-dimensional seismic signal of the target frame. Indicates the first Frame target seismic three-dimensional signal, Indicates the first The feature vector of the three-dimensional seismic signal of the target frame.

[0079] S104. Based on the component information corresponding to the three-dimensional target seismic signals of each frame, determine the short-time energy and short-time autocorrelation function values ​​corresponding to the three-dimensional target seismic signals of each frame.

[0080] In some embodiments, the short-time energy is determined by the following formula:

[0081]

[0082] in, Indicates the first The short-time energy corresponding to the three-dimensional seismic signal of the target frame. Indicates the first The first frame of the target seismic triaxial signal corresponding to the third Component information of each data sampling point.

[0083] In some embodiments, the short-time autocorrelation function value is:

[0084]

[0085] in, Indicates the first The short-time autocorrelation function values ​​corresponding to the three-dimensional seismic signals of the target frame. Indicates the offset. Indicates the first The component information of the m-th data sampling point corresponding to the three-dimensional seismic signal of the target frame.

[0086] S105. Based on the short-time energy and short-time autocorrelation function values ​​corresponding to the three-dimensional target seismic signals of each frame, determine the endpoints of the three-dimensional target seismic signals of each frame.

[0087] In some embodiments, the endpoints of the three target seismic signals in each frame are determined using a dual-threshold method based on the short-time energy and short-time autocorrelation function values ​​corresponding to the three target seismic signals in each frame.

[0088] For example, let the high threshold of short-time energy be... The low threshold is Thus, the short-time energy of the target seismic triaxial signal in the i-th frame will be as follows:

[0089]

[0090] Let the high threshold of the short-time autocorrelation function value be... The low threshold is Thus, the short-time autocorrelation function values ​​of the target seismic triaxial signal in the i-th frame will be as follows:

[0091]

[0092] In some embodiments, prediction points are determined based on the short-time energy and short-time autocorrelation function values ​​corresponding to the three-dimensional seismic signals of each frame.

[0093] For example, based on the short-time autocorrelation function value of the target seismic triaxial signal in the i-th frame. The short-time energy of the target seismic triaxial signal in the i-th frame Determine the prediction points of the target seismic triaxial signal in the i-th frame. That is, the prediction point. .

[0094] In some embodiments, after determining the prediction point, a first decision is made on the prediction point based on a first preset threshold. Then, a search is performed from the starting point of the first decision in a first preset direction to determine the first intersection point between the prediction point and the second preset value; finally, a search is performed from the ending point of the first decision in a second preset direction to determine the second intersection point between the prediction point and the second preset value.

[0095] The endpoints of the target seismic triaxial signal include the first intersection point and the second intersection point; the first preset threshold is greater than the second preset threshold point, and the first preset direction and the second preset direction are opposite.

[0096] For example, the first preset threshold The second preset threshold In determining the prediction point Then, using The first judgment (preliminary judgment) was rendered. Among them, That is, the signal part. This refers to the noise component, and the start and end points of the target seismic triaxial signal in the i-th frame will be located at... and Beyond the time point corresponding to the intersection. Therefore, utilizing Proceed to the second judgment (detailed judgment), and search to the left from the starting point of the first judgment to find... and The first intersection; search to the right from the end of the first judgment to find and The second intersection point. That is, the first preset direction is to the left of the starting point of the first judgment, and the second preset direction is to the right of the ending point of the first judgment. Wherein, and The first intersection point is the starting point of the three-dimensional seismic signal of the target in the i-th frame. and The second intersection point is the endpoint of the three-dimensional earthquake signal of the target in the i-th frame.

[0097] It is understood that, through filtering and framing the initial seismic triaxial signal, this embodiment of the application can obtain multiple frames of target seismic triaxial signals. Then, based on each frame of target seismic triaxial signals, the component information corresponding to each frame of target seismic triaxial signals is determined. Next, based on the component information corresponding to each frame of target seismic triaxial signals, the short-time energy and short-time autocorrelation function values ​​corresponding to each frame of target seismic triaxial signals are determined. Finally, based on the short-time energy and short-time autocorrelation function values ​​corresponding to each frame of target seismic triaxial signals, the endpoints (start and end points) of each frame of target seismic triaxial signals are determined. In this way, the detection of small seismic signals can be achieved by replacing manual judgment, thereby reducing false positives and false negatives and improving the accuracy of small seismic signal detection.

[0098] In some embodiments, this application also provides a method for detecting seismic signal endpoints, including:

[0099] S201. Perform high-pass filtering on the received seismic three-axis signals (initial seismic three-axis signals) to obtain the filtered seismic three-axis signals.

[0100] S202. The filtered seismic three-axis signal is divided into frames, and the principal components (component information) are extracted to obtain the principal components of each frame signal (target seismic three-axis signal).

[0101] S203. Based on the principal components of each frame of signal, calculate the short-time energy and short-time autocorrelation function value of each frame of signal.

[0102] S204. Based on the short-time energy and short-time autocorrelation function value of each frame of signal, the endpoints of each frame of signal are detected by the dual-threshold method.

[0103] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for detecting the endpoints of a seismic signal, characterized in that, include: Acquire the initial three-dimensional seismic signals; The initial seismic triaxial signal is processed to obtain multiple frames of target seismic triaxial signal; Based on the target seismic triaxial signals of each frame, determine the component information corresponding to the target seismic triaxial signals of each frame; Based on the component information corresponding to the three-dimensional target earthquake signal of each frame, the short-time energy and short-time autocorrelation function values ​​corresponding to the three-dimensional target earthquake signal of each frame are determined. Based on the short-time energy and short-time autocorrelation function values ​​corresponding to the three-dimensional target seismic signals of each frame, the endpoints of the three-dimensional target seismic signals of each frame are determined; wherein, The step of determining the component information corresponding to the three-dimensional target seismic signals of each frame based on the three-dimensional target seismic signals of each frame includes: Determine the data matrix corresponding to the three-dimensional target seismic signals in each frame; Eigenvalue decomposition is performed on the data matrix corresponding to the three-dimensional target earthquake signals of each frame to obtain the feature vectors corresponding to the three-dimensional target earthquake signals of each frame. Based on the feature vector, the component information corresponding to the three-dimensional target seismic signal in each frame is determined; The determination of the endpoints of the target seismic triaxial signals in each frame based on the short-time energy and short-time autocorrelation function values ​​corresponding to the three-dimensional signals of the target seismic signal in each frame includes: Based on the short-time energy and short-time autocorrelation function values ​​corresponding to the three-dimensional target seismic signals of each frame, the endpoints of the three-dimensional target seismic signals of each frame are determined using the dual-threshold method. The determination of the endpoints of the three-way target seismic signals in each frame, based on the short-time energy and short-time autocorrelation function values ​​corresponding to the three-way target seismic signals in each frame, using a dual-threshold method, includes: Based on the short-time energy and short-time autocorrelation function values ​​corresponding to the target seismic triaxial signals in each frame, the prediction points are determined; Based on a first preset threshold, the predicted point is judged for the first time; Search from the starting point of the first judgment in the first preset direction to determine the first intersection point of the prediction point and the second preset threshold; Searching from the endpoint of the first judgment towards the second preset direction, the second intersection point of the predicted point and the second preset threshold is determined; wherein, the endpoints of the target earthquake triaxial signal include the first intersection point and the second intersection point; the first preset threshold is greater than the second preset threshold, and the first preset direction and the second preset direction are opposite.

2. The method according to claim 1, characterized in that, The process of processing the initial seismic triaxial signal to obtain multiple frames of target seismic triaxial signal includes: The initial seismic triaxial signal is filtered to obtain the filtered seismic triaxial signal. The filtered seismic triaxial signal is divided into frames to obtain multiple frames of the target seismic triaxial signal.

3. The method according to claim 2, characterized in that, The initial three-dimensional earthquake signal includes east-west earthquake signals, north-south earthquake signals, and vertical earthquake signals; The step of filtering the initial seismic triaxial signal to obtain the filtered seismic triaxial signal includes: The east-west, north-south, and vertical seismic signals are filtered using a high-pass filter to obtain filtered east-west, north-south, and vertical seismic signals, thus obtaining the filtered seismic triaxial signals.

4. The method according to claim 2, characterized in that, The step of framing the filtered seismic triaxial signal to obtain the multi-frame target seismic triaxial signal includes: Based on a preset Hamming window function and a preset signal length, the filtered seismic triaxial signal is framed to obtain multiple frames of the target seismic triaxial signal.

5. The method according to claim 1, characterized in that, The short-time energy is determined by the following formula: ； in, Indicates the first The short-time energy corresponding to the target seismic triaxial signal described in the frame. Indicates the first The first frame of the target seismic triaxial signal corresponds to the third Composition information of each data sampling point.

6. The method according to claim 1, characterized in that, The short-time autocorrelation function value is: ； in, Indicates the first The frame contains the short-time autocorrelation function value corresponding to the target seismic triaxial signal. Indicates the offset. Indicates the first The frame contains the component information of the m-th data sampling point corresponding to the target seismic triaxial signal.

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