Listening to Tonga Shake (video) Washington University in St. Louis Share Print E-Mail Loading video... Caption Seismologists retrieve an ocean-bottom seismometer that was deployed near the Tonga Trench in the South Pacific from 2009-2010. The data from these and other seismic surveys show that intermediate-depth earthquakes in the slab that descends at the trench are caused by the sudden release of water from minerals in the slab. Credit Video by Doug Wiens; video production by Tom Malkowicz Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.