Publication Date:
2020-11-26
Description:
Sirung is a frequently active volcano located in the remote parts of Western Timor (Indonesia). Sirung has a
crater with several hydrothermal features including a crater lake. We present a timeseries of satellite images
of the lake and chemical and isotope data from the hyperacid hydrothermal system. The fluids sampled in
the crater present the typical features of hyperacidic systems with high TDS, low pH and d34SHSO4 –d34SS0
among the highest for such lakes. The cations concentrations are predominantly controlled by the precipitation of alunite, jarosite, silica phases, native sulfur and pyrite which dominate the shallow portions of
the hydrothermal system. These minerals may control shallow sealing processes thought to trigger phreatic
eruptions elsewhere. Sparse Mg/Cl and SO4/Cl ratios and lake parameters derived from satellite images suggest gradual increase in heat and gas flux, most likely SO2-rich, prior to the 2012 phreatic eruption. An acidic
river was sampled 8 km far from the crater and is genetically linked with the fluids rising toward the active
crater. This river would therefore be a relevant target for future remote monitoring purposes. Finally, several wells and springs largely exceeded the World Health Organization toxicity limits in total arsenic and
fluoride.
Description:
Published
Description:
186-199
Description:
4V. Processi pre-eruttivi
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
