Ruapehu volcano (North Island, New Zealand): crater lake temperature is rising again
Wed, 4 Nov 2020, 09:3609:36 AM | BY: MARTIN
GeoNet reported that the activity at Crater Lake (Te Wai ā-moe) is characterized by a heating-cooling cycle. In late September the lake had cooled to around 12 °C marking the low point of the cycle. Since mid-October the lake has been warming slowly and has now reached 22 °C.
Ruapehu volcano today (image: GeoNet webcam)
Chemical analysis of lake water collected on 9 October showed no significant changes in the makeup of the lake waters since the previous sample collected on 9 August. The pH remains at 0.8, having ranged between 0.7 and 0.9 over the last 6 years. Other key chemical indicators such as the respective water concentrations in Mg (magnesium) and Cl (chloride) can be used to track whether the uprising fluids travel through new fractures or in the proximity of magma.
These observations say that underlying vent areas are open to volcanic gases and geothermal fluids entering the lake and reacting with rock in the vents.
The level of volcanic tremor intensity has been variable but has remained weak during the past three months, and small earthquakes continue to be detected near the volcano.
Both the Volcanic Alert Level (level 1) and Aviation Code (Green) remain unchanged.
Source: GeoNet New Zealand volcano activity update 4 November 2020
Thu, 22 Oct 2020, 07:54
GeoNet observatory reported that the activity at Crater Lake (Te Wai ā-moe) is often dominated by a heating-cooling cycle. In the most recent cycle, the lake temperature reached a high of 41°C in April and then cooled steadily to 12 °C by late September. Over the last two weeks, the lake has warmed slightly to 15 °C, which is a normal observation. ... Read all
Tue, 11 Aug 2020, 08:58
GeoNet observatory reported that since April 2020, lake temperature has decreased from a high of 42°C to around 22-23 °C. This lower lake temperature is normal for Crater Lake. To keep the lake at this temperature, low-level heat must continue to flow into the lake. This indicates that the underlying vent area is open to volcanic gases and hydrothermal fluids. Other signs that point to this open vent are visible upwellings and sulphur slicks on the lake surface. ... Read all