Analysis of anomalies recorded by the quartz horizontal pendulum tiltmeter in Chinese mainland before the New Ireland MS 7.8 earthquake in 2016
MS 7.8 earthquake occurred in New Ireland on December 17,2016,about 1 hour before the earthquake,the quartz horizontal pendulum tiltmeterat Huolashan,Shichang,Yushugou,Balikun,Aheqi,Jinghe,Mulei in Xinjiang area and Huailai and Fengning in Hebei Province observed precursory wave,and the maximum epicenter distance is 9 053 km.It is found that the precursor waves have the following characteristics:① There are certain differences in the duration of abnormal fluctuations recorded in each station.②The amplitude and wave form in the EW direction and NS direction components recorded in the same station are different.③There are differences in the characteristic period at each station,with the longest period up to 660 s.The differences of the precursory wave are also obvious in two different observing directions at the same station.It shows the non-uniformity inpropagation.Finally,through comparative studies of 3 earthquakes above MS 7.8 on the same seismogenic structure belt and the observation of deformation in Chinese mainland,the possible causes,distribution characteristics,generation and propagation of the deformation wave signal were discussed in terms of focal conditions and observation conditions.
New Ireland MS 7.8 earthquakequartz horizonta lpendulum tiltmeterprecursor wavewavelet transform
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