Sketch drawing of time-lapse video showing location of the August 12 ,1999 pyroclastic flow with time.  The sketch is viewing south.
 
 

Amplitude based location for August 12, 1999 pyroclastic flow in Tar River. The * is the Long Ground seismic station and the video camera position is to the top of the map.  The distance between the dome and the station at Long Ground is 1.9 km.

Amplitude vs. time for the August 12, 1999 event.
 
 

Seismograms for three stations of the Montserrat network. (A) Brodricks Yard is on the opposite side of the volcano.  Long ground (C) is in the direction of the observed Pyroclastic flow (note the strong secondary phase associated with the flow).  The fourth panel shows the match in runout distance from the dome for the amplitude based location (line) and the video (diamonds).  It is important to note that the video is not time referenced to the seismic data but the first point matches distance of video and amplitude location about 400 meters from the summit.  Note the strong agreement in distance from the dome and velocity (slope of the relation) for video and amplitude based locations.