Tonga Microplate Earthquakes

A burst of moderately strong earthquake activity rippled along the plate boundary between Tonga and the Kermadec Islands last night and has continued this morning.

Tuesday 23rd February 2010

A series of shallow earthquakes commenced south of Tonga at 6:09 p.m. New Zealand time last night, when a magnitude 5.7 earthquake struck 150 km east-south-east of the Tongan capital Nuku’Alofa at a depth of 35 km.

A magnitude 6.0 earthquake followed at 8:01 p.m. New Zealand time. This quake was located 295 km south-south-west of Nuku’Alofa at a depth of 35 km. An aftershock of magnitude 5.2 struck 24 minutes later.

Activity continued drifting southward along the edge of the Tonga Microplate with a magnitude 5.3 quake 300 km south-south-west of Nuku’Alofa at 9:42 p.m., a magnitude 5.0 event located 310 km south of Nuku’Alofa at 7:44 this morning, and a magnitude 5.1 earthquake 340 km south of Nuku’Alofa at 8:49 a.m.

A magnitude 5.2 earthquake was recorded 270 km north-north-east of Raoul Island (1350 km north-east of Auckland) at five minutes after midnight.

All of the earthquakes have been shallow events at depths between 13 and 35 km.

On the 13th of February, a magnitude 6.3 earthquake struck closer to the Tongan capital. This quake was located 95 km south-south-east of Nuku’Alofa at a depth of 10 km.

[Compiled from data supplied by the U.S. Geological Survey and its contributing agencies.]

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