Hydrothermal system in the Volcano by magnetotellurics

Presenter: Huei-Guo Jhou

Date: 2015/10/15

Abstract

The report is to study the magnetotelluric geophysical exploration on the volcano for a long-period magnetotelluric and audio-magnetotelluric. A long-period magnetotelluric experiment was conducted in early 2009 in western Nicaragua to study the electrical resistivity and thus fluid/melt distribution at the Central American continental margin where the Cocos plate subducts beneath the Caribbean plate. The major remaining conductive structure is now quasi directly beneath the volcanic chain and interpreted as a deep-seated magma deposit. Conductivity in the backarc is also relatively high and may either be caused by still existing partial melts beneath the Paleocene to Miocene volcanic arcs or by related metallic deposits in the aureoles of hydrothermal alteration. Audio-magnetotellurics (AMT) surveys were conducted in the Tatun Volcano Group in northern Taiwan. Reveal the spatial distribution of resistivity, which is highly sensitive to fluids and hydrothermal alteration. By combining the obtained resistivity structure with other geophysical and geochemical evidence, the following hydrothermal system was inferred.

 

Reference

Brasse, H., et al. (2015). "Deep-crustal magma reservoirs beneath the Nicaraguan volcanic arc, revealed by 2-D and semi 3-D inversion of magnetotelluric data." Physics of the Earth and Planetary Interiors.

 

Komori, S., et al. (2014). "Hydrothermal system in the Tatun Volcano Group, northern Taiwan, inferred from crustal resistivity structure by audio-magnetotellurics." Progress in Earth and Planetary Science 1(1): 1-14.