Infragravity wave source regions determined from ambient noise correlation

We use a backprojection method to determine dominant directions of ocean infragravity waves from 60–200 s period from cross correlations between 5 ocean bottom differential pressure gauges located off the coast of Sumatra. We observe infragravity waves arriving from all directions, but there is a dominant source direction that represents coherent propagation along the coast from the southeast or from the south. This study demonstrates the effectiveness of our projection technique, which may be applied to past and future seismic data to improve models of ocean infragravity wave generation and tsunami propagation.