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Assessing Volcanic Hazard and Exposure at Obscure Volcanic Fields: A Case Study from the Bolaven Volcanic Field, Laos
  • Andrea Verolino
Andrea Verolino
Earth Observatory of Singapore

Corresponding Author:[email protected]

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Abstract

South-east Asia is one of the most volcanically active places on Earth, with the majority of the volcanoes located in Indonesia and in the Philippines. Indochina (Myanmar, Cambodia, Laos, Thailand and Vietnam) also hosts a certain number of volcanoes that for several reasons (post-World War II conflicts, little accessibility due to dense vegetation, no significant historical activity recorded), have been little studied so far. Some of these volcanoes show evidence of recent (Quaternary) activity, therefore, a systematic assessment of the threat these volcanoes may pose to resident populations is needed in the region. A recent study on the inferred location of the Australasian meteorite impact (the largest known young meteorite on Earth) provided an unprecedented amount of data for the Bolaven Volcanic Field in Laos, in terms of geological mapping, location of vents, and over 30 absolute ages of lava flows and vents. On this basis, besides additional data obtained for this work, we used the Bolaven Volcanic Field as a case study, to assess the potential exposure of populations and infrastructure to lava flows in case of an eruption in the field. Key results suggest that an overall area of ~5500 km2 is potentially exposed to lava flows in case of eruption, including over 2000 km of roads, 400 km of power lines, two power stations and two dams, and over 500 km2 of agricultural lands, with the potential to affect about 300,000 people living in this area, and their main businesses (hydropower and coffee production). In addition, the abundance of water in this region may lead to life-threatening explosions from phreatomagmatic eruptions. Finally, based on the data available we provide a maximum estimate of the past eruption frequency of the field, which is approximately 10,400 years. Our study provides a number of techniques and approaches (remote sensing of potential sources and past flows, lava flow simulations and open-access exposure data) that can be used to assess hazards and exposure at other understudied volcanoes.