Multiple Magma Sources Beneath the Okmok Caldera as Inferred From Local Earthquake Tomography
نویسندگان
چکیده
Okmok volcano located on the northeastern part of Umnak Island is one most active volcanoes in Aleutian Arc. It was initially built as a large shield volcano, but 12,000 and 2,050 years ago, it experienced two caldera-forming eruptions that destroyed central volcano. The post-caldera have occurred mostly along inner perimeter caldera from cinder tuff cones. Here, we use local earthquake data Alaska Volcano Observatory (AVO) time period 2003 to 2017 build model with 3D distributions P S wave velocities Vp/Vs ratio. At depths more than 10 km, observe vertically aligned anomaly high ratio interpreted long-lived conduit likely responsible for evolution since its origin. Above this conduit, reveal representing main magma reservoir connected several shallow anomalies below centers recent caldera. One such represents Cone A, which source Okmok's historical eruptions. eruption 2008 fed by diapir formed then slowly ascended through ductile silica rich layer at 6 2 km. This interpretation consistent petrology studies modeling ground deformations.
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ژورنال
عنوان ژورنال: Journal Of Geophysical Research: Solid Earth
سال: 2022
ISSN: ['2169-9356', '2169-9313']
DOI: https://doi.org/10.1029/2022jb024656