Increased Quake Activity, South-west Pacific

Two earthquakes in the Kermadec Islands overnight were the latest in a series of moderately strong quakes to have struck the south-west Pacific on Sunday.

The burst of activity in the south-west Pacific commenced with a quake near Vanuatu on August 16th, and activity has increased following Thursday’s magnitude 8.0 quake off the coast of Peru. There have been 25 earthquakes of magnitude 4 or greater near the Mariana Islands, Papua New Guinea, the Solomon Islands, Vanuatu, the Loyalty Islands, Fiji, the Kermadec Islands, and here in New Zealand during the past week.

Two 5th magnitude quakes struck the Rota Region of the northern Mariana Islands on August 15th and 17th. A magnitude 4.7 quake struck near Bougainville, Papua New Guinea on August 15th and a magnitude 5.2 tremor occurred to the north-west on the 19th.

The six earthquakes reported in the Solomon Islands began with magnitude 5.3, 6.7 and 4.9 events on August 16th, continued with magnitude 4.8 and 5.0 quakes on the 17th, and ended with a magnitude 5.3 tremor on the 19th. The magnitude 5.0 quake near Vanuatu on August 14th was followed by a magnitude 4.4 earthquake on the 17th and a magnitude 5.6 quake early this morning.

The Loyalty Islands have experienced a magnitude 4.8 quake on the 17th, and magnitude 6.0 and 5.1 quakes on the 19th. The two 4th magnitude quakes near Fiji occurred on August 15th and 17th.

Closer to home, four magnitude 5 events have been recorded in the Kermadec Islands since early on August 18th. A magnitude 5.0 quake struck at a depth of 35 km, 130 km south of L’Esperance Rock (760 km north-east of Auckland) at 4:45 a.m. on August 18th. A magnitude 5.4 quake was recorded 50 km ENE of Raoul Island at a depth of 46 km just before 1 o’clock the following morning. This morning’s quakes were a 50 km-deep magnitude 5.1 quake 270 km south of L’Esperance Rock (680 km ENE of Auckland) at 1:31 a.m. and a magnitude 5.4 event located 85 km east of L’Esperance Rock (900 km north-east of Auckland) at a depth of 41 km at 4:45 a.m.

Geonet has reported three 4th magnitude events within New Zealand during the past seven days. A magnitude 4.1 quake struck 30 km east of Taihape at a depth of 50 km on Wednesday August 15th 2007. The following day a magnitude 4.9 quake occurred 40 km north of Nelson at a depth of 150 km, and a magnitude 4.4 event was recorded 50 km north-west of Wellington at a depth of 60 km.

[Compiled from data supplied by the US Geological Survey and its contributing agencies, and the Geonet project and its sponsors EQC, GNS Science and FRST.]

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