Search for and investigation of volcanoes with gravity surveys

0502952 - GFÚ 2019 RIV US eng C - Konferenční příspěvek (zahraniční konf.)
Mrlina, Jan
Search for and investigation of volcanoes with gravity surveys.
EAGE-HAGI 1st Asia Pacific Meeting on Near Surface Geoscience and Engineering. Proceedings. Red Hook: Curran, 2018, s. 324-328. ISBN 978-1-5108-6269-2.
[EAGE-HAGI Asia Pacific Meeting on Near Surface Geoscience and Engineering /1./. Yogyakarta (ID), 09.04.2018-13.04.2018]
Grant CEP: GA MŠMT LM2010008; GA MŠMT(CZ) LM2015079
Institucionální podpora: RVO:67985530
Klíčová slova: gravity survey * volcano monitoring * volcanic structure
Obor OECD: Volcanology

Geophysical methods, mainly gravimetry and magnetometry, can serve as suitable tools for location of unknown hidden volcanic structures that are not expressed by any typical topographic features. These may be e.g. diatremes and maars with eroded scoria cones or rims of tuff/tephra material, as well as lava flows. Gravity survey may reveal significant negative anomalies due to low density of the filling of volcanic vents, or positive anomalies over the bodies of compact lava accumulation. Magnetometry would rather show positive anomalies related to most of the volcanic structures due to high content of magnetic minerals in the volcanic rocks (except acid trachytes/phonolites/rhyolites). Geophysical surveys should therefore form part of any investigation of volcanic fields where some unknown volcanoes may still be expected. Gravity monitoring can reveal hidden mass and fluids movement in a volcano interior, and can therefore contribute to the hazard control at regions with active volcanoes.
Trvalý link: http://hdl.handle.net/11104/0294792