Characteristics of Underground Fluid Anomalies Before MS5.0 Earthquake in Mangshi,Yunnan Province in 2023
YANG Fen
LI Qing
YANG Jianwen
GAO Qiong
ZHANG Huanying
YANG Shufeng
Abstract：In this paper,the characteristics of underground fluid anomalies in Yunnan Province before the MS5.0 earthquake in Mangshi on December 2nd,2023 were summarized in terms of space,time,shape,and synchronism.There were 18 anomalies in underground fluids in Yunnan.Spatially,it was mainly distributed on active structures and adjacent areas within 350 km from the epicenter,with focal precursors and near precursors as the main ones.The dynamic development process of anomaly space was that the focal precursor appeared first,and then the focal precursor,near precursor,and field precursor coexisted.One month before the earthquake,the anomaly measurement term shrank to the focal region.The anomaly time lasted mainly from July 10th to August 9th,during which 13 items reached the anomaly index.Temporally,there were synchronous anomalies in both focal and near precursors,and the synchronous anomalies shrank to the focal region on November 9th,2023.The time course of anomalies was divided into three stages:middle-term,short-term,and impending,with four short-term anomalies and three impending earthquake anomalies in focal precursors,five middle-term anomalies and five short-term anomalies in near precursors,and one middle-term anomaly in field precursors.There were two kinds of anomaly forms:persistent anomaly and sudden anomaly.The anomaly process was characterized by steady-unsteady-steady development,which reflected the dynamic process of earthquake preparation from a steady state to an unsteady state,and then earthquakes occurred.
Keywords：MS5.0 earthquake in MangshiUnderground fluidFocal precursorNear precursorField precursorSynchronous anomalyMiddle-short impending anomaly
Publication Date：2024-12-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 66-76 )