Date of Award
2024
Document Type
Open Access Master's Thesis
Degree Name
Master of Science in Geophysics (MS)
Administrative Home Department
Department of Geological and Mining Engineering and Sciences
Advisor 1
Greg Waite
Committee Member 1
Simon Carn
Committee Member 2
Chad Deering
Abstract
Large earthquakes of magnitude 7.0 or greater can alter volcanic emissions and even trigger eruptions at nearby volcanoes. The stress changes imparted by large earthquakes can cause otherwise stable conditions within the magmatic system to be disturbed, potentially inducing volcanic activity. The extent of the triggering potential is still unknown due to insufficient understanding of the mechanisms involved. We model static stress changes for 174 earthquake-volcano pairs from 2000-2023 at volcanoes within 500 km, computing changes in both the normal stress perpendicular to the direction of horizontal maximum stress and dilatational strain. We then use thermal satellite data to measure variability in volcanic activity that is promoted through movement of magma and magmatic gases. The cumulative radiative power from the MODVOLC and MIROVA databases was calculated over -1 to 1 year after each modeled earthquake. We summed the cumulative data for each volcano using a range of minimum thresholds for positive stress and strain, and negative stress and strain. In the composite data sets, we found positive departures from linear thermal power with normal stress increases, or unclamping, and volume increases approximately 7 months after an earthquake. Increases in thermal emission was evident 1-2 months after negative stress and strain. A possible triggering mechanism associated with unclamping and dilatation is magma decompression leading to bubble nucleation and less inhibited fluid ascent. Only 9 of 31 volcanoes with a normal stress increase showed an increase in thermal power at 7 months for the MIROVA database, while 6 of 10 volcanoes in MODVOLC showed an increase in thermal power. For 1-2 months following a negative normal stress change, only 2 of 7 MIROVA volcanoes showed an increase in power, and 2 of 2 volcanoes within the MODVOLC database showed the same trend. This could indicate that remote triggering is dependent on whether the volcano is in a critical state.
Recommended Citation
Zimmerman, Aimee, "Response of Open Volcanic Systems to Static Stress Changes", Open Access Master's Thesis, Michigan Technological University, 2024.