Comprehensive precursor anomaly research based on earthquake corresponding relevancy spectrum

Abstract

With the aim to the quantification of anomaly identification and extraction for observed or analyzed records， we present two statistical methods of earthquake corresponding relevancy spectrum (ECRS) and sliding mean relevancy (SMR). With ECRS method, we can obtain the abnormal confidence attribute of data in different value ranges. Based on the relevancy spectrum in different studied time-intervals, we convert the original time sequence into relevancy time sequence, and can obtain the SMR time series by using the multi-point cumulative sliding mean method. Then we can identify the seismic precursor anomaly. We test this method by taking the time sequence of η-value in the northern Tianshan region as original data. The result shows that when the studied time-interval is 18 months, the precursor anomaly can be identified better from sliding mean relevancy. The anomaly corresponding rate is 83 percent, the earthquake corresponding rate is 86 percent, and the anomaly is characteristic of the middle term. To try the research on multi-parameter comprehensive application, we take the Kalpin tectonic block in Xinjiang as our studied region, and analyze the spatial and temporal abnormal characters of multi-parameter sliding extreme-value relevancy (MSER) before mid-strong earthquakes in the Kalpin block. The result indicates that ECRS and SMR sequence in different time-intervals can not only be used to identify the precursor anomaly of single-item data, but also offer the data of quantitative single-item anomaly for comprehensive earthquake analysis and prediction.Key words: earthquake corresponding relevancy spectrum(ECRS); sliding mean relevancy (SMR); multi-parameter sliding extreme-value relevancy(MSER); comprehensive precursor anomaly CLC number: P315.72 Document code: A

Machine Learning-Based Precursor Detection Using Seismic Multi-Parameter Data

“…The comprehensive analysis method of seismic parameters can combine single parameters related to physical processes at different stages of earthquake preparation, which could extract the comprehensive abnormal characteristics during the earthquake preparation process more accurately. Wang [10] conducted a comprehensive multi-parameter study on earthquakes from 1979 to 2008 in the western section of southern The extrapolation test period for the central and western sections of the Qilian Mountains began in January 2016. The spatial evolution of the MSER anomaly before the 8 January 2022 Qinghai Menyuan M L 7.1 earthquake showed that the anomaly amplitude in the study area began to increase from August 2020, with the largest anomaly increase in November 2021 (Figure 12).…”

“…Based on this idea, the study was conducted on the quantitative identification and extraction of anomalies from observation data using mathematical-statistical methods. For example, Wang Haitao [8] transformed the time series of original data into a probability time series based on the corresponding relevancy spectrum in different investigation durations, and used the multi-point cumulative moving average method to obtain the time curve of average probability; then, the earthquake precursor anomalies were identified, providing quantitative single factor data for the comprehensive method. Bo [9] used the multi-point group slope method and composite information flow method to convert the deformation data into the 'standardized information curve'.…”

“…Bo [9] used the multi-point group slope method and composite information flow method to convert the deformation data into the 'standardized information curve'. Wang [10] quantitatively identified and extracted anomalies from various seismic parameter data in the western section of the southern Tianshan of Xinjiang by using the multi-parameter sliding extreme-value relevancy based on the earthquake-corresponding relevancy spectrum. Lu also conducted a long-term tracking study on the central and southern sections of the Tanlu fault, utilizing the earthquake-corresponding relevancy spectrum of seismic multi-parameters, and found that the earthquake-corresponding efficiency calculated by combining multiple advantageous parameters was indeed better than that of a single parameter [11].…”

Identification of Precursory Anomalies before Moderate-strong Earthquakes in Junction of Shanxi-Hebei-Inner Mongolia Area

“…Such as precursory recognition method of comprehensive information entropy [1], dynamic subordinate function method based on fuzzy mathematics [2], multipoint group slope and synthetic information flow method [3][4], normalized rate (slope) method [5]. Earthquake corresponding relevancy spectrum method (ECRS) was proposed by Wang Haitao et al to identify comprehensive precursory anomaly before earthquakes and has been applied in many studies areas [6][7][8][9][10][11][12][13][14]. Here we will carry out precursory anomaly identification analysis with ECRS method.…”

“…The theory of ECRS method is as follows: According to Wang Haitao et al [6], for the observed time sequence 1…”