Removal of Tidal Strain Components from Borehole Strain Data Based on Minimum Noise Separation

Abstract

The invention relates to a method for removing tidal strain components of borehole strain data based on minimum noise separation, which uses an adaptive window width filtering algorithm to estimate the high-frequency signal of the borehole strain data sample matrix; calculates the covariance matrix of the estimated high-frequency signal , and perform eigenvalue decomposition; use the covariance matrix of the high-frequency signal to construct the adjustment matrix; use the constructed adjustment matrix to adjust the covariance matrix of the borehole strain data sample matrix; The covariance matrix is ​​subjected to the minimum noise separation transformation and the minimum noise separation transformation components are obtained. The matrix formed by the minimum noise separation transformation components is expressed as; the harmonic period of the minimum noise separation component is calculated; the harmonic period is selected to be the same as the tidal strain component harmonic period Reconstruct the corresponding minimum noise separation components; calculate and remove the data of the tidal strain component, and remove the tidal strain component in a targeted manner, without calculating the theoretical solid tide.

Description

technical field

[0001] The invention relates to the field of borehole strain data processing, in particular to a method for removing tidal strain components of borehole strain data based on minimum noise separation. Background technique

[0002] The deformation of the earth's surface, the tectonic movement inside the crust and various geological disasters are closely related to the crustal stress. The change of the stress-strain state of the crust is the most direct cause of fractures, folds and even earthquakes. Borehole strain observation is an important earthquake monitoring method to discover and grasp the (long) medium-term-short-term-imminent earthquake strain precursor and the temporal and spatial distribution and development law of post-earthquake adjustment through the fine observation of the continuous change of the stratum's internal strain state according to time. Precursor observation means. Borehole strain observation can clearly record the tidal response of s...

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