02 MARCH 2016, M7.8 SOUTHWEST OF SUMATRA, INDONESIA EARTHQUAKE

   ( Last Update:2016-04-18 22:25 CET)

The M7.8, shallow, Indian Ocean earthquake generated a small tsunami that was recorded on Indian Ocean coastal sea level gauges in Australia (Cocos, Christmas Islands), Indonesia (Tanahbala), Maldives (Gan, Male, Hanimadhoo), and Mauritius (Rodrigues Island).  The maximum wave amplitude was 12 cm at Tanahbala.

The USGS reported the earthquake occurred at 12:49 UTC, 4.908 °S 94.275 °E, with a depth of 24.0 km (14.9 mi), roughly in the center of the Cocos Basin, and 600 km southwest of the Sunda-Java Trench off Sumatra, northern Indonesia. This intraplate earthquake had a strike-slip faulting mechanism, which rarely generates dangerous tsunamis (see PTWC RIFT forecast below). In contrast, shallow thrust faulting in subduction zones can cause destructive tsunamis, such as the M9.1 2004 Sumatra earthquake that generated 40-m tsunami runups locally, and propagated across the Indian Ocean killing 228,000 in 15 countries.


16 SEPTEMBER 2015, M8.3 CHILE EARTHQUAKE AND TSUNAMI

   ( Last Update:2016-04-18 22:25 CET)

The 16 September 2015 magnitude 8.3 Mw Northern Chile earthquake (31.570°S, 71.654°W, depth 25 km) occurred at 2254:33 UTC and generated a tsunami that was observed all over the Pacific region and caused damage locally.  According to news reports, more than 1 million persons immediately evacuated in Chile.  The Pacific Tsunami Warning Center (PTWC) issued its 1st advisory information at 2300 UTC, and continued issuing threat information messages for the next 24 hours with the Final message issued at 2305 UTC on September 17.  A 4.75 m high tsunami wave was measured on the Coquimbo, Chile sea level gauge, and 1-2 m high waves were measured elsewhere in Chile.