Dec 15 2009 - November roundup

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

Operations
The Lily tiltmeter enters the inky blackness of the Chateau Observatory borehole.

The Lily tiltmeter enters the inky blackness of the Chateau Observatory borehole.

  • Three new continuous GPS sites were installed in Marlborough: Mahakipawa Hill (MAHA), Okoha (OKOH) and Wither Hills (WITH).
  • The borehole seismic sensor at Chateau Observatory (COVZ) was commissioned and a tilt-meter was installed in the same well. The meter is an Applied Geomechanics Lily meter and is capable of measuring tilt to 5 nanoradians. The installation will be used to determine the appropriateness of tilt as a volcano monitoring tool for Ruapehu.
  • A new seismic site was completed at Galatos Road (GRRZ), near Atiamuri between Taupo and Rotorua.

Website

  • GeoNet earthquake alerts, volcanic alert bulletins and news articles can now be followed on Twitter.
  • For researchers, annual summaries of finalised earthquake hypocentres and phases are available from our FTP site.

Earthquakes

  • The most significant earthquake of the month occurred on November 19, magnitude 5.1, 10 km south of Palmerston North, 40 km deep. It was felt throughout the lower North Island.
  • The preliminary locations of October's earthquakes are shown below.

Volcano Surveillance

Friday November 13 - Soil gas survey at White Island

29 sites had decreased in flux while 22 had increased. The overall gas flux was lower than the previous measurement. The higher CO2 fluxes are still focused in the north-west of the crater. The fumaroles and some springs, including the lake, were also sampled during the visit. The lake was easy to access as the level was slightly higher than when sampled in August. The temperature was 56.5 °C compared with 56.0 °C in August.

Friday November 20 - Completion of 3-monthly monitoring survey at White Island

The usual levelling suvey was conducted and the balance of fumaroles and springs were sampled.

Saturday November 21 - Gas flight over White Island

Flying conditions were good but quite windy. The wind speed was about 13.5 m/s. The SO2 flux increased and CO2 flux is much higher than for the last survey.

White Island Gas
(Method)

21/11/2009
(T/day)

14/10/2009
(T/day)

SO2 emission (Cospec) 226 197
SO2 emission (Flyspec) 232 265
CO2 emission (Contouring) 3031 1141
H2S emission (Contouring) 2.8 2.4
SO2 emission (Contouring) 162 87

Reported Landslides

Wednesday November 4

  • Slip reported at the Ashhurst end of Manawatu Gorge, affecting both lanes but road still open.

Monday November 16

  • On-going problems with subsidence of SH 1 at Pine Hill, Dunedin over the last 3 years were reported to have got worse, with 6 mm subsidence in the last month affecting a 100 m section of highway near the Bank Street intersection.

Monday November 30

  • A slip was reported on SH 3 near Symes Road, Kai Iwi, Wanganui.
Felt earthquakes of October 2009.

Felt earthquakes of
October 2009.

Shallow earthquakes of October 2009.

Shallow earthquakes of
October 2009.

Deep earthquakes of October 2009.

Deep earthquakes of
October 2009.