Last week summer called by for a couple of days and the team visited White Island (Whakaari), completed a gas flight around Ruapehu and visited the Crater Lake at Mt Ruapehu.

Ruapehu

As part of the monitoring at Mt Ruapehu we attempt to sample the Crater Lake about once a month. This allows us to collect water and gas samples and confirm the temperatures from the data logger probe in the lake. The lake was successfully sampled last Saturday. The lake appeared a uniform grey colour as it has on past samplings. This indicates there is some convection (mixing) occurring in the lake as the gases and hot fluids enter it. The lake was overflowing, which is normal for the lake and varies little. The temperature of the Crater Lake is currently around 21 °C and is slowly cooling. A gas flight was also completed on the 24th. The results from this flight indicate low-moderate amounts of volcanic gas continue to come through the lake. The Volcanic Alert Level for Ruapehu remains at Level 1 (minor volcanic unrest).

White Island (Whakaari)

Meanwhile a visit was also made to White Island on the 27th. We visit the island to make many measurements, this trip was to collect gas and water samples, observe the activity from the active crater and make a soil gas survey. The gas chemists collect gas from the hottest accessibly fumaroles (steam vents). Fumarole #1 is currently the hottest and the team measured 191 °C while sampling it. Basically the same temperature as the previous trip. The activity from the vent in the active crater was also unchanged. The crater floor remains ‘dry’, only a few small ponds and springs are present. The crater lake has not reformed since the eruptions in April and September last year. The soil gas survey measures the CO2 gas leaking from the Main Carter floor. We make measurements at 61 sites. There has been an increase from the measurements in November 2016, some of this is related to the dryer conditions on the island. The Volcanic Alert Level for White Island remains at Level 1 (minor volcanic unrest).