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Location and size of the shallow magma reservoir beneath Kīlauea caldera, constraints from near‐source V p / V s ratios
Author(s) -
Lin Guoqing,
Amelung Falk,
Shearer Peter M.,
Okubo Paul G.
Publication year - 2015
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 - 10.1002/2015gl065802
Subject(s) - geology , caldera , seismology , impact crater , magma , volcano , lava , hypocenter , rift zone , rift , petrology , induced seismicity , tectonics , physics , astronomy
We present high‐resolution compressional wave to shear wave velocity ratios ( V p / V s ) beneath Kīlauea's summit caldera by applying an in situ estimation method using waveform cross‐correlation data for three similar earthquake clusters. We observe high V p / V s ratios (1.832 and 1.852) for two event clusters surrounded by the low background V p / V s value of 1.412 at ∼2.1 km depth below the surface. These high and low V p / V s ratios can be explained by melt‐ and CO 2 ‐filled cracks, respectively, based on a theoretical crack model. The event cluster with the highest V p / V s ratio consists of long‐period events that followed the 1997 East Rift Zone eruption, indicating their association with fluid and magma movement. The depths of the two clusters with high V p / V s ratios are consistent with the magma reservoir location inferred from geodetic observations. Their locations east and north of Halema‘uma‘u crater suggest a horizontal extent of a few kilometers for the reservoir.