Jan 19 2010 - December roundup
Last month's progress and news within the GeoNet project.
The newly-completed seismic site at Waiomatatini Station near East Cape.
The newly-completed seismic site at Waiomatatini Station near East Cape.
Operations
- The tsunami gauge at Puysegur Point (PUYT) was installed. This required additional radios to be installed at Wednesday Peak in Southland.
- Seismic sites were installed north of Gisborne, one at Tauwharaparae (TWGZ) and another at Waiomatatini Station (WMGZ).
Earthquakes
- The most significant earthquake of the month occurred on December 9, magnitude 5.1, 30 km north-west of Otaki, 50 km deep. It was felt strongly in the south-west North Island.
- The preliminary locations of November's earthquakes are shown below.
Volcano Surveillance
Tuesday December 8 - Ruapehu Crater Lake sampling
The lake was sampled both for headspace gases and water in both the central vent and north vent areas. The lake surface appeared very calm and uniform and no upwellings were visible. Wind conditions were a bit dicey near the surface of the lake so after several failed attempts, the pilot decided to lighten the load and do the dunkings by himself. The lake was well a beautiful aquamarine colour. Temperatures measured were 21.5 °C in the central vent area and 21.3 °C in the north vent area, slightly down from the late October temperature.
There was a good flow at the lake outlet.
Wednesday December 9 - Gas flight over Ruapehu and Ngauruhoe
The wind speed was about 12.3 m/s with a clear sky. The wind speed was really high but stable. SO2 was barely detected on the Cospec and CO2, H2S and SO2 were barely detected on the interscan meter.
|
|
9/12/2009 |
21/10/2009 |
|---|---|---|
| SO2 emission (Cospec) | 9.4 | ND |
| SO2 emission (Flyspec) | ND | ND |
| CO2 emission (Contouring) | 202 | 405 |
| H2S emission (Contouring) | 0.1 | 0.5 |
| SO2 emission (Contouring) | 10.5 | 12.4 |
No gas was detected at Ngauruhoe.
Friday December 18 - Gas flight over White Island
Conditions were very good with a 15 knot wind and good results for all gases. The results were as follows:
|
|
18/12/2009 |
21/11/2009 |
|---|---|---|
| SO2 emission (Cospec) | 199 | 226 |
| SO2 emission (Flyspec) | 213 | 232 |
| CO2 emission (Contouring) | 2325 | 3031 |
| H2S emission (Contouring) | 3.3 | 2.8 |
| SO2 emission (Contouring) | 135 | 162 |
The results were very similar to the previous flight on 21 November – CO2 and SO2 were slightly down.
Reported Landslides
Tuesday December 1
- Minor slips reported on Paekakariki Hill Road and a larger one on SH 2 near Te Marua, where the southbound lane of SH 2 was blocked by a failure of a cut face at Twin Lakes.
Friday December 4
- A series of slips closed SH 1, the new northern gateway toll road north of Auckland. About three collapses of earthworks were reported near Puhoi. Other blockages were reported about 500 m south at Hungry Creek Road and about 1 km north of the Puhoi tunnels.
Sunday December 6
- SH 25 and 25A blocked by flooding and a number of small slips, Coromandel area, as a result of heavy rain.
Thursday December 10
- A slip on the Johnsonville line, Wellington, at about 6:25 am caused cancellation of two trains and delays of about half an hour for later morning services.
Felt earthquakes of November 2009.
Shallow earthquakes of November 2009.
Deep earthquakes of November 2009.
