Wanganui Basin Aftershock

An aftershock of yesterday’s fifth magnitude earthquake in the Wanganui Basin struck just before four o’clock this afternoon.

Thursday 10th December 2009

A magnitude 4.1 undersea earthquake struck the Wanganui Basin at 3:54 NZDT this afternoon. The quake was located 40 km west of Levin (40 km north-west of Otaki, 80 km north of Wellington) at a depth of 40 km. The quake was felt from Wanganui to Wellington.

Today’s quake is an aftershock of the magnitude 5.1 event at 11:09 a.m. yesterday. That earthquake occurred in the same location but 10 km deeper in the descending part of the Pacific Plate. GeoNet reports that the location and size is not unusual. A similar earthquake of magnitude 5.0 struck nearby on the evening of Saturday the 7th of December 2002.

Yesterday’s earthquake has attracted more than 1200 felt reports from the public and was felt strongly at Wanganui, Marton, on the Kapiti Coast and in Wellington. Being classified as “strong” indicates that small objects were shifted or overturned, crockery and glassware might have been broken, and doors were seen to swing open and shut.

[Compiled from data provided by the GeoNet project and its sponsors EQC, GNS Science and FRST.]

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