Aseismic mid-crustal magma reservoir at Cleveland Volcano imaged through novel receiver function analyses.

ABSTRACT: Processes related to eruptions at arc volcanoes are linked by structures that transect the entire crust. Imaging the mid- to lower-crustal portions (here, ~5-15?km and?>15?km respectively) of these magmatic systems where intermediate storage may occur has been a longstanding challenge. Tomography, local seismic source studies, geodetic, and geochemical constraints, are typically most sensitive to shallow (<5?km) storage and/or have insufficient resolution at these depths. Geophysical methods are even further limited at frequently-erupting volcanoes where well-developed trans-crustal magmatic systems are likely to exist, due to a lack of deep seismicity. Here we show direct evidence for mid-crustal magma storage beneath the frequently erupting Cleveland volcano, Alaska, using a novel application of seismic receiver functions. We use P-s scattered waves from the Moho as virtual sources to investigate S-wave velocities between the Moho and the surface. Our forward modeling approach allows us to provide direct constraints on the geometry of low velocity regions beneath volcanoes despite having a comparatively sparse seismic network. Our results show clear evidence of mid-crustal magma storage beneath the depths of located volcanic seismicity. Future work using similar approaches will enable an unprecedented comparative examination of magmatic systems beneath sparsely instrumented volcanoes globally.

SUBMITTER: Janiszewski HA 

PROVIDER: S-EPMC7000785 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature