Three-dimensional seismic velocity structure of Mauna Loa and Kilauea volcanoes in Hawaii from local seismic tomography

TitleThree-dimensional seismic velocity structure of Mauna Loa and Kilauea volcanoes in Hawaii from local seismic tomography
Publication TypeJournal Article
Year of Publication2014
AuthorsLin G.Q, Shearer PM, Matoza RS, Okubo P.G, Amelung F.
JournalJournal of Geophysical Research-Solid Earth
Date Published2014/05
Type of ArticleArticle
ISBN Number2169-9313
Accession NumberWOS:000338009800023
Keywordsbeneath; california; crustal structure; deformation; east rift-zone; mantle; p-velocity; refraction measurements; relocation; south flank

We present a new three-dimensional seismic velocity model of the crustal and upper mantle structure for Mauna Loa and Kilauea volcanoes in Hawaii. Our model is derived from the first-arrival times of the compressional and shear waves from about 53,000 events on and near the Island of Hawaii between 1992 and 2009 recorded by the Hawaiian Volcano Observatory stations. The V-p model generally agrees with previous studies, showing high-velocity anomalies near the calderas and rift zones and low-velocity anomalies in the fault systems. The most significant difference from previous models is in V-p/V-s structure. The high-V-p and high-V-p/V-s anomalies below Mauna Loa caldera are interpreted as mafic magmatic cumulates. The observed low-V-p and high-V-p/V-s bodies in the Kaoiki seismic zone between 5 and 15 km depth are attributed to the underlying volcaniclastic sediments. The high-V-p and moderate- to low-V-p/V-s anomalies beneath Kilauea caldera can be explained by a combination of different mafic compositions, likely to be olivine-rich gabbro and dunite. The systematically low-V-p and low-V-p/V-s bodies in the southeast flank of Kilauea may be caused by the presence of volatiles. Another difference between this study and previous ones is the improved V-p model resolution in deeper layers, owing to the inclusion of events with large epicentral distances. The new velocity model is used to relocate the seismicity of Mauna Loa and Kilauea for improved absolute locations and ultimately to develop a high-precision earthquake catalog using waveform cross-correlation data.

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