Uranium-Series Isotopic Constraints on Recent Changes in the Eruptive Behaviour of Merapi Volcano, Java, Indonesia
Abstract
Merapi volcano (Central Java) is one of the most active and deadly volcanoes in Indonesia. The 2010 eruption was the volcano's largest eruption since 1872 and erupted much more violently than expected. Prior to 2010, volcanic activity at Merapi was characterised by several months of slow dome growth punctuated by gravitational dome failures, generating small-volume pyroclastic density currents (Merapi-type nuées ardentes). The unforeseen, large-magnitude events in 2010 were different in many respects: pyroclastic density currents travelled > 15 km beyond the summit causing widespread devastation in proximal areas on Merapi's south flank and ash emissions from sustained eruption columns resulted in ash fall tens of kilometres away from the volcano. The 2010 events have proved that Merapi's relatively small dome-forming activity can be interrupted at relatively short notice by larger explosive eruptions, which appear more common in the geological record. We present new geochemical and Uranium-series isotope data for the volcanic products of both the 2006 and 2010 eruptions at Merapi to investigate the driving forces behind this unusual explosive behaviour and their timescales. An improved knowledge of these processes and of changes in the pre-eruptive magma system has important implications for the assessment of hazards and risks from future eruptive activity at Merapi.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.V21E2537G
- Keywords:
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- 1036 GEOCHEMISTRY / Magma chamber processes;
- 1120 GEOCHRONOLOGY / Isotopic disequilibrium dating;
- 3618 MINERALOGY AND PETROLOGY / Magma chamber processes;
- 8488 VOLCANOLOGY / Volcanic hazards and risks