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Spatiotemporal Variations of Focal Mechanism and In Situ V p / V s Ratio During the 2018 Kīlauea Eruption
Author(s) -
Lin Guoqing,
Shearer Peter M.
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2021gl094636
Subject(s) - geology , seismology , focal mechanism , rift , caldera , rift zone , flank , volcano , summit , mantle (geology) , fault (geology) , geophysics , tectonics , cartography , sociology , anthropology , geography
We examine the spatiotemporal variations in seismic parameters corresponding to the 2018 Kīlauea eruption. We find that the summit area had mainly strike‐slip focal solutions prior to the eruption, whereas normal‐faulting was the predominant feature during the eruption, partially due to the collapse events. In contrast, the majority of the earthquakes in the central south flank had normal‐faulting solutions before December 2017, in agreement with the normal‐faulting of the Hilina Fault System, while there are more reverse solutions during the eruption. We also observe temporal variations in the estimated in situ V p / V s ratios corresponding to the eruption, with increases in the summit and decreases in the East Rift Zone. The sustained low V p / V s ratios below 4 km depth under the summit caldera may suggest persistent ascent of volatiles from the mantle. The low V p / V s values in the East Rift Zone are probably associated with increased degassing.