Fig. 2.
From: ‘Negative repeating doublets’ in an aftershock sequence
Background seismicity (from 2008/10/01 to 2011/09/15, gray dots) and the Wenchuan seismic station (WCH, red triangle). Circles highlight the 2,631 aftershocks under study, centered at the WFSD-1 drilling site (red hexagon). The red dot in the left corner stands for the epicenter, or the initiation point, of the 2008 Wenchuan mainshock. The location of the figure is shown in the inset map, highlighting the position of the WFSD-1 drilling site. Blue dots, with light green lines interconnected, show the 150 ‘repeating doublets’ identified by waveform cross-correlation at the WCH station. Red dots, with pink lines interconnected, show the 5 ‘negative repeating doublets’ discussed in this paper.