The Alaska Peninsula, a region known for its seismic activity, has captured the attention of scientists as a key area to study fundamental questions about subduction processes. Subduction, where one tectonic plate moves beneath another, can lead to large magnitude earthquakes. The Alaska Peninsula has a history of such events, making it an ideal location to explore the relationship between different geological features of the overriding and subducting plates and these earthquakes. Recent community seismic experiments have provided high-quality data from this region. This project will allow researchers to utilize this data to better understand the structure of the Earth's plates in this region. This will in turn allow testing hypotheses related to how structures in the overriding plate may influence earthquake processes. This research not only benefits Alaska but contributes to a global understanding of earthquake processes, ultimately helping us better prepare for and mitigate earthquake hazards at subduction zones. This is a collaborative project with Shawn Wei at MSU.

The subterranean plumbing system beneath volcanoes is still not well understood. Recent advances in the understanding of crustal magmatic storage reveal them as complex, multi-layered systems consisting of both melt and crystal mush. However, it remains unclear how magma is stored and transported from the Earth’s mantle through the crust at volcanic arcs. A volcanic arc is a chain of volcanoes located above a subducting tectonic plate, i.e., a plate diving underneath another. Magmatic systems at arc volcanoes are a critical link between the subducting slab and the shallow magma reservoirs that feed volcanic eruptions. However, many established methods of constraining depth of magma storage have relatively low resolution in the mid-to-deep crust. Receiver functions are a technique of seismic imaging relatively underutilized in volcanic settings. They have recently shown promise in their ability to image magma storage in the deep crust. Here, we apply this technique to image the magmatic system beneath volcanoes in the Aleutian Island arc, in Alaska. This study also contributes to developing an imaging technique that can be applied to other volcanoes around the Globe.

Since August 2019 the Pāhala region has been experiencing an elevated swarm of deep seismicity (> 20 km depth). It is currently one of the most seismically active regions on the Big Island of Hawaiʻi, and it is of continued concern to residents and emergency managers in the region. The increase of the rate of seismicity since has renewed scientific interest in implications for deep magma supply. While the ongoing seismic swarm is well characterized by the HVO seismic network, independent seismic velocity constraints can provide additional information on the potential presence of magmatic storage or transport at depth in this region. To address this gap, we will calculate a seismic receiver function profile along a transect within the current Pāhala swarm.

We hosted a 2-day workshop, with a half-day early career pre-workshop meeting at the University of Hawaiʻi at Mānoa from March 16 - March 18, 2022. This was a GeoPRISMS Funded synthesis workshop focused on the following questions: (1) What are the relationships between fault zone rheology and deformation and how are they constrained across a range of temporal and spatial scales in the field and lab? (2) How does the rheology of the crust and mantle influence and/or record deformation at plate boundaries? (3) What feedbacks exist between larger scale lithospheric processes, fault zone rheology, and surface processes? More information can be found at the workshop website.

Crustal magmatic structure beneath volcanoes is difficult to seismically image, particularly in the mid- to deep-crust. Receiver functions provide an opportunity to observe low velocity regions likely associated with partial melt/mush, elevated temperatures, or altered material within the crust at these depths without the need for a high-density, large-aperture broadband seismic array. Our results at Cleveland Volcano in the central Aleutian island arc, one of the more active volcanoes in the region, shows evidence for an extensive crustal magma body, extending to depths greater than 10 km, likely indicating a transcrustal magmatic storage region at this open system volcano.