← Back to Sessions

Probing Magma Storage and Transport Beneath Pāhala, Hawaiʻi

Description: 

Deep (> 20 km below sea level) earthquakes occur along mantle fault zones beneath the southern coast of the Island of Hawaiʻi, near the active volcanic centers of Kīlauea, Mauna Loa, and Kamaʻehuakanaloa (formerly Lōʻihi). Previously, long-period tremor and a recent ten-fold increase in seismicity at these depths since 2019 centered beneath the town of Pāhala have been observed. We hypothesize that magma transport processes trigger some of the deep seismicity along these mantle faults. These may potentially provide pathways for magma to the summit storage systems of these volcanoes via sub-horizontal mantle fault zones. Detailed seismicity studies in this region have relied on 1-D velocity models; construction of local 3-D velocity models to better understand relationships between magma storage and earthquake processes has been precluded by the scarcity of seismic instruments deployed in this region. In summer 2022, we conducted a three-month deployment of 80 continuously recording three-component seismic nodes extending from the epicentral region of the Pāhala swarm towards Kīlauea’s summit. This included a dense line of nodes to enhance imaging of geologic structures embedded within a sparser grid designed for precise earthquake detection and location. We use a machine-learning based workflow to detect and locate earthquakes with this novel dataset. The earthquake dataset complements imaging from receiver functions and is used for body wave tomography, which together provide improved constraints on crustal and upper mantle structures in the region. The combined interpretation of these datasets will shed light on the magmatic structure and processes that have contributed to the dramatic increase in seismicity since 2019.

Session: Seismoacoustic, Geodetic and Other Geophysical Investigations of Active Volcanoes - I

Type: Oral

Date: 5/3/2024

Presentation Time: 08:15 AM (local time)

Presenting Author: Helen

Student Presenter: No

Invited Presentation: 

Authors