Earthquakes Near Gisborne

A burst of earthquake activity has occurred off-shore near Gisborne today.

Monday 31st January 2011

A burst of earthquake activity centred 30 km south of Gisborne has shaken residents of Gisborne and northern Hawke’s Bay today. GeoNet has reported five events with magnitudes between 3.3 and 4.2 since the sequence began at 6:49 this morning.

The earthquakes are occurring at depths of 25 to 30 km on the interface between the Australian and Pacific tectonic plates off the coast north of Mahia Peninsula. They are centred about 10 km offshore south-east of Bartletts. GeoNet describes the epicentre for the earthquakes as 30 km south of Gisborne, 30 km south of Manutuke, 30 km north-east of Nuhaka.

The activity began at 6:49 this morning when a magnitude 3.8 earthquake struck at a depth of 25km. A burst of activity followed after midday with a magnitude 4.2 quake at a depth of 25 km at 12:39 p.m. and another magnitude 4.2 event at 25 km at 12:53 p.m. These were followed by a magnitude 3.3 quake at 1:01 p.m., also at a depth of 25km.

At 2:00 p.m. a magnitude 4.1 earthquake struck at a depth of 30 km.

GeoNet’s seismograph network 31 January 2011

This snapshot of GeoNet’s seismograph network shows the traces of the Gisborne quakes recorded since midday. [click for larger view]

Kokohu Road seismograph 31 January 2011

GeoNet’s Kokohu Road seismograph, located near Nuhaka, shows the traces of today’s five nearby events. [click for larger view]

In March last year a slow-slip earthquake event was detected near Bartletts.

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

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