Observation of fore-seismic disturbance of the Mw7.6 Tonga earthquake (2009/03/19)
2009年3月19日Mw7.6级汤加大地震的“震前扰动”现象

It has beenreported that we discovered significant gravity disturbance before the 2008 Wenchuan earthquake (Ms=8. 0) at the Wuhan national field scientific observational station for geodesy , and we confirmed our observation by broadband seismometers data from several tens station across the country. On 19 Mar, 2009 the Mw7.6 earthquake struck the South Pacific island country of Tonga. We found that the significant fore-seismic disturbance was also be observed by broadband seismometers. The disturbance signals started on 16 Mar, 16 days before the Tonga earthquake, with its period mainly in band of 4~8 s.