Mar 15 2010 - February roundup
Last month's progress and news within the GeoNet project.
Mount Quoin GPS station in the Tararua Ranges.
Operations
Mount Quoin GPS station in the Tararua Ranges.
- A new continuous GPS site Mount Quoin (MTQN) in the southern Tararua Ranges, north of Wellington, was made operational.
- New seismic stations were made operational for the Taranaki volcano-seismic network at Lake Rotokare (LREZ) and Palmer Road (PREZ).
- A new borehole seismic station was made operational for the Auckland volcano-seismic network at East Tamaki Reservoir (ETAZ).
- A new tsunami gauge Dunedin (OTAT) was installed on the wharf at Port Chalmers.
- The tsunami gauge sensors on Chatham Island (CHIT) were replaced, both because they were faulty and because the wharf has been re-built, requiring the cables to be re-located.
Borehole installation work at East Tamaki Reservoir, Auckland.
Tsunami
Borehole installation work at East Tamaki Reservoir, Auckland.
A tsunami warning for New Zealand was issued by the Ministry of Civil Defence and Emergency Management on February 27 in response to the magnitude 8.8 South America earthquake south-west of Santiago, Chile. GeoNet tsunami gauges detected waves of one metre at Gisborne and Chatham Island.
Earthquakes
- The most significant earthquake of the month occurred on February 13, magnitude 5.0, near Paraparaumu but 60 km deep.
- The preliminary locations of January's earthquakes are shown below.
Volcano Surveillance
Thursday February 4 - Soil gas survey at Ngauruhoe Volcano
The mean CO2 flux (23.6 t/day for an area of 46,600 m2) is comparable with the CO2 flux calculated in 2008 (20.2 t/day for an area of 45,150 m2). The results for the two surveys are summarised below:
|
04/02/2010 |
10/04/2008 | |
|---|---|---|
| Average | 416 | 249 |
| Sum - All Sites | 64150 | 36036 |
| Maximum | 4805 | 1792 |
Tuesday February 23 - Soil gas survey at White Island
40 sites had decreased in flux while 11 had increased. The overall gas flux was lower from the previous measurement. The highest CO2 fluxes are still focused in the north-west of the crater.
|
23/02/2010 |
13/11/2009 | |
|---|---|---|
| Average | 349 | 555 |
| Sum - All Sites | 17788 | 27770 |
| Maximum | 7036 | 3994 |
| Sites Increased | 11 | 22 |
| Sites Decreased | 40 | 29 |
Tuesday February 23 - Monitoring survey at White Island
The crater lake level has fallen about 1 - 1.5 m. There were several convection cells/gas upwelling to be seen. The nearer ones appeared less vigorous than when last observed. However a moderate gas flux continues through the lake.
On the main crater floor there are several new mud pots. The spa and stream flows appear about the same. The usual levelling suvey was conducted.
Reported Landslides
Thursday February 4
- A further rock-fall occurred at Totara Reserve on the Pohangina River north of Ashhurst in the Manawatu. A smaller rock-fall at the same site in 2006 killed three children.
Felt earthquakes of January 2010.
Shallow earthquakes of January 2010.
Deep earthquakes of January 2010.
