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Report and images provided by Marco Liuzzo, Marcello Bitetto, Giancarlo Tamburello and Alessandro Aiuppa
The DECADE Initiative (Deep Earth Carbon Degassing) started in 2014 and was funded by the Deep Carbon Observatory (Pi, Aiuppa). The program has successfully continued with the installation of an automatic Multi-Component Gas Analyzer System (Multi-GAS) at Merapi volcano in Indonesia in September 2015 (see previous report at http://deepcarbon.net/feature/decade-installations-turrialba-and-po%C3%A1s#.UynFKIWPNbc).
Gunung Merapi (Merapi Volcano) is a stratovolcano and one of the most active of Indonesia. It is characterized by frequent Plinian and Subplinian eruptions and for the high incidence of pyroclastic flows, the most recent and dangerous of these being the eruption in 2010, which caused 353 deaths. The history of the volcano justifies particular attention in terms of monitoring and mitigation of risk, particularly in view of its proximity (less than 30 km) to the populated city of Yogyakarta (almost 2.5 million inhabitants) and for this reason was selected for the DECADE initiative.
The installation of the permanent Multi-GAS was completed at Merapi volcano during 16 and 18 September 2015. The field work was carried out by an international team of scientists in collaboration with colleagues from the Yogyakarta Volcanological Observatory BPPTKG (GMA Nandaka; A. B. Santoso; Kusdaryanto; R. Laksono; Y. Sulistyo; H. Humaida; N.Cholik), and the Istituto Nazionale di Geofisica e Vulcanologia - INGV and the Palermo University (M. Bitetto; M. Liuzzo; G. Tamburello).
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 BPPTKG Observatory. As in previous installations, three days were initially spent testing equipment and telemetry.
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 Moxa Embedded-PC Ethernet to servers at BPPTKG in Yogyakarta.
The first data acquired by the MultiGAS station on Merapi are shown in Fig 4. The average value of the CO2/SO2 ratio is approximately 12, which indicates a substantial dominance of the shallow hydrothermal system of the volcano. This condition also corresponds with the present low state of activity of Merapi volcano. It is possible to conjecture that significant variations of the CO2/SO2 ratio on Merapi plume will provide important information on the ongoing change of volcano activity.
Figure 1. Location of the MultiGAS monitoring station at Merapi volcano.
Figure 2. View of the top of Merapi volcano (showing Merbabu volcano in the background) and of the structure where the MultiGAS permanent station is located.
Figure 3. Work in progress during the installation of the Multigas station.
Figure 4. First days of CO2/SO2 ratios data measured by the permanent MultiGAS at Merapi Volcano from the installation on the 16 September 2015.