National Tsunami Warning Center, NOAA/NWS

TSUNAMI of 31 August, 2012 (Off the East Coast of the Philippines)

A major earthquake with a moment magnitude of 7.6 (USGS magnitude) occurred at 12:47:34 UTC 31 August, 2012 (day 244) and was located 60 mi/96 km E of Shulangan, Philippines and 464mi/747 km ESE of Manila, Philippines (10.8386N, 126.7037E, 21.7 mi/34.86 km depth--USGS location).

This earthquake occurred as a result of reverse faulting within the oceanic lithosphere of the Philippines Sea plate. The preliminary location of the earthquake indicates this is an intraplate event, 50 or more kilometers to the east of the subduction zone plate boundary between the Philippine Sea and Sunda plates. At the latitude of the earthquake, the Philippine Sea plate moves west-northwest at a velocity of approximately 100 mm/yr (USGS earthquake poster, 2012).

This earthquake produced a tsunami that was recorded at several tide gages monitored by the National Tsunami Warning Center (NTWC). Many observatories provide data to the centers; such as the NOAA National Ocean Service, the U. of Hawaii Sea Level Center, the Chilean Navy, the Japan Meteorological Agency and the National Tidal Facility in Australia among others. Click on the site name to see a graph of the tsunami, when available. Listed wave heights are maximum amplitude in cm (above sea level). Observed Arrival time is the actual tsunami arrival time in UTC on gages where it could be determined. The Computed Arrival time is the estimated time of wave arrival computed at the NTWC based on the earthquake origin time and location. The Sample Interval column shows the time between data samples.