DECADE Installation of a Multi-GAS Instrument at White Island Volcano, New Zealand

DECADE Installation of a Multi-GAS instrument at White Island Volcano, New Zealand

Report and images provided by Marco Liuzzo, Gaetano Giudice and Alessandro Aiuppa

The DECADE Initiative (Deep Earth Carbon Degassing) was set up in 2014, funded by the Deep Carbon Observatory (Pi, Aiuppa). The completion of the second year of the program has seen the sixth installation of an automatic Multi-Component Gas Analyzer System (Multi-GAS) at White Island volcano in New Zealand in December 2015 (see previous report at http://deepcarbon.net/feature/decade-installations-turrialba-and-po %C3%A1s#.UynFKIWPNbc).

Whakaari Volcano (White Island Volcano) is one of the most active volcanoes of New Zealand. It is situated in the Bay of Plenty, about 50 km from the North Island coast. This Andesitic-to-dacitic stratovolcano shows an almost continuous degassing activity from the fumarolic field and the acidic lake at the base of the crater. Historical records indicate that eruptions have usually been moderate phreatomagmatic and strombolian- like. However, in 1914, a more serious and tragic event resulted in the collapse of the southeast part of the crater wall, producing a debris avalanche that killed workers in the nearby sulfur mine, which was subsequently abandoned.

The installation of the permanent Multi-GAS was completed at White Island volcano during 3 December 2015. The fieldwork was carried out by an international team of scientists in collaboration with colleagues from the GNS Science - New Zealand - (B. Christenson and A. Mazot, and a team of technicians ), and the Istituto Nazionale di Geofisica e Vulcanologia - INGV (M. Liuzzo; G. Giudice). Figure 1. Location of the MultiGAS monitoring station at White Island volcano – New Zealand.

The Multi-GAS instrument, including radio transmitters and case, were assembled and calibrated at UniPa-INGV, Italy, while auxiliary hardware (solar panels, batteries, masts, etc.) was provided by GNS Science - Wairakei Research Centre, Taupo. As in previous installations, three days were initially spent testing equipment and telemetry.

In agreement with the team of the GNS Science of Taupo, the MultiGAS station was installed on the north-northwestern rim of the White Island Volcano at an altitude of 280 m a.s.l .(Figs. 1-2).

Figure 2. Photos of the MultiGAS permanent station located at the White Island volcano. Figure 3. Work in progress during the installation of the Multigas station.

Following the installation of the Multi-GAS (Fig. 3), it was necessary to configure the MultiGAS in order to complete automatic procedures of data acquisition. Transmission was monitored over a period of days to ensure correct functioning. Data are now able to be transmitted at regular intervals via Ethernet to servers at GNS in Wellington.

The first data acquired by the MultiGAS station on White Island are shown in Fig 4. The average value of the CO2/SO2 ratio is approximately 4. This corresponds with the expected value for White Island in its present state of low volcanic activity. Indeed, the first measurements show very modest variability from the average, suggesting, therefore, that any future significant variations of the CO2/SO2 plume ratio will provide important points of reference in any ongoing change of volcano activity. Figure 4. First measurements of CO2/SO2 ratios from the permanent MultiGAS data at White Island Volcano since) the installation on the 03 December 2015; broken red line is the CO2/SO2 average.