The mechanism of phreatomagmatic maar-diatreme eruption in the Lei-Hu-Ling volcanic area of northern Hainan Island, China: Insights from magnetotelluric and magnetic data
A maar-diatreme forms in response to the phreatomagmatic eruption caused by violent interaction between magma and externally derived water. Experimental work on phreatomagmatic eruptions has yielded considerable knowledge on maar-diatremes. However, the mechanism and process at natural scale remain...
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Published in | Journal of volcanology and geothermal research Vol. 427; p. 107566 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier B.V
01.07.2022
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Subjects | |
Online Access | Get full text |
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Summary: | A maar-diatreme forms in response to the phreatomagmatic eruption caused by violent interaction between magma and externally derived water. Experimental work on phreatomagmatic eruptions has yielded considerable knowledge on maar-diatremes. However, the mechanism and process at natural scale remain poorly understood, especially when surface deposits are present. This paper presents a magnetotelluric and magnetic study of the Late-Pleistocene maar-diatreme volcanoes in the Lei-Hu-Ling area of northern Hainan Island, China. The regional 3D electrical structures show shallow high resistivities below craters and a low resistivity layer overlying the deep high-resistivity basement. The local magnetic structure of maar Luo-Jing-Pan reveals a cylinder-like diatreme with high susceptibility. The shallow low-resistivity zone, which coincides with the Fushan depression controlled by the Changliu-Xiangou Fault, is associated with the accumulation of high-salinity fluids with high porosity. The considerable volume of water stored in the Fushan depression and the sedimentary basement ridges beneath maars could have enabled a high level of magma-water interaction. This indicates a fault-controlled type for the phreatomagmatic eruption in the Lei-Hu-Ling volcanic area. The explosion depth is at least 600 m for Ru-Huang-Ling and Luo-Jing-Pan maar-diatreme volcanoes, indicating deep phreatomagmatic eruptions with less contribution to surface deposits. In addition, the explosion energy of the Ru-Huang-Ling maar with a diameter of 1900 m is about 7–8 times that of Luo-Jing-Pan maar with a diameter of 900 m.
•Late-Pleistocene maar-diatremes of northern Hainan Island, China are delineated by a magnetotelluric and magnetic imaging.•Fushan depression provides a considerable volume of water for phreatomagmatic eruption.•The phreatomagmatic eruptions are of the fault-controlled type with explosion depth of at least 600 m. |
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ISSN: | 0377-0273 1872-6097 |
DOI: | 10.1016/j.jvolgeores.2022.107566 |