Aug 10 2009 - July roundup

Last month's progress and news within the GeoNet project.

Operations

Aerial reconnaissance of landslide damage was carried out after the July 15 Dusky Sound earthquake.

The White Island web camera was relocated due to the deterioration of its foundation.

No other contender: the most significant earthquake of the month occurred on July 15, magnitude 7.8, 100 km north-west of Tuatapere, 12 km deep. It was was widely felt in the South Island and up into the North Island.
The preliminary locations of June's earthquakes are shown below.

Three response activities have taken place this month:

On Monday June 29 a response was organised to assist the Waihi Village (Lake Taupo) residents and Taupo District Council determine whether or not earthquake swarm activity and recent rainfall had initiated or reactivated movement in the Hipaua Geothermal field:

GNS Science Report 2009/34 (2.31Mb)
Field investigations at Waihi Landslide, Taupo 30 June & 1 July 2009
A second response was undertaken to the Gisborne region to assess landslide damage after a rainstorm in late June. This response was delayed in order to allow time for roads to be repaired making travel around the region easier. The response involved undertaking an aerial reconnaissance of the region in a fixed-wing aircraft and this was followed up by ground reconnaissance activities. The purpose of the reconnaissance was to select an area where the acquisition of satellite imagery would allow analysis of landslides to assist with determining the rainfall threshold for initiation of landsliding.
A third response was initiated after the July 15 Dusky Sound earthquake. GNS Science staff were mobilised from Dunedin to undertake an initial aerial reconnaissance on July 16 to evaluate the landslide damage as a result of this earthquake.

SH 35 Gudgeons Rd, Te Araroa to Tikitiki - slip partially blocking road. Single lane open. (Still reduced to one lane on July 3).

SH 35 Busby's Hill, subsidence of the road - road closed.
SH 2 Rimutaka Hill blocked by major slip, 2.5 km before summit from Upper Hutt side.

Slip on SH 2 Rimutaka Hill blocking one lane in early morning, halfway down on the Featherston side.

SH 10 in the Far North was reported to be closed due to collapse of the road under a landslide after a truck nearly rolled off the road about 6 am. Minor slips were reported in the Far North district after a weekend of heavy rain and gales.

Major earthquake in Fiordland causes only minor landsliding, mainly between Dagg Sound and Puysegur Point.

Slip over the eastern portal of Mangaroa tunnel on the Wairarapa line was struck by the Masterton-bound passenger train at 6:20 pm, derailing it. Three hundred passengers were stranded in the tunnel for more than 2 hours until another locomotive pulled the last three carriages back to Upper Hutt. Trains were still not running beyond Upper Hutt on July 24.
A slip blocked SH 1 at Pukerua Bay about 5:30 pm. It re-opened to one lane at 8:00 pm.
Slips and gravel closed SH 58 between Pauatahanui and Haywards Hill, and the Paekakariki Hill was also closed by slips. Northbound traffic was forced to use the Akatarawa Road. Minor slips on roads in Wellington were also noted.

A train on the Paraparaumu line struck a slip after 8 am (near the south portal of Tawa No. 2 tunnel), and all rail services between Wellington and Porirua were cancelled, but trains were running normally between Paraparaumu and Porirua.

Felt earthquakes of
June 2009.

Shallow earthquakes of
June 2009.

Deep earthquakes of
June 2009.