Date of Award

Spring 2012

Degree Name

Bachelor of Science


Environmental Science

First Advisor

Jonathan Gourley


On November 8th, 2009 the Trinity College Seismograph Station (TCCT) recorded an earthquake of magnitude Mw = 6.7 with body wave amplitudes that were larger than expected. This earthquake, located in Sumbawa-Indonesia, generated similar body wave amplitudes as earthquakes of the same magnitude (Mw = 6.7) and comparable depth (shallow focus: 0th, 2010 and the Alaska earthquake on July 18th, 2010. The large body wave amplitudes were caused by a set of consecutive PKP waves that constructively interfered. The distance from the Sumbawa-Indonesia earthquake to TCCT of 144.96° falls between the lower and higher estimates for the PKP caustic point. The observations at TCCT helped establish a theoretical region, in which future seismic events could create a caustic at or in the proximity of TCCT. It is suggested to use the IRIS network to better estimate the distance to the caustic point for future events occurring in the theoretical region.


Senior thesis completed at Trinity College for the degree of Bachelor of Science in Environmental Science.