Graduation Year

2020

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Geology

Major Professor

Timothy H. Dixon, Ph.D.

Co-Major Professor

Rocco Malservisi, Ph.D.

Committee Member

Charles B. Connor, Ph.D.

Committee Member

Jochen Braunmiller, Ph.D.

Committee Member

Rowena B. Lohman, Ph.D.

Keywords

Data inversion, Digital elevation model, Gravity anomaly, Interferometric synthetic aperture radar, Numerical modeling, Surface deformation, volcano, induced seismicity

Abstract

I use geophysical and geodetic data to study dynamics of the Earth System, including volcanoes and induced seismicity, aiming to improve related hazard assessment at different time and space scales. My dissertation consists of the following three projects: 1) Geophysical model for the origin of volcano vent clusters (Deng et al., 2017). We developed a conceptual model to simulate long-term magma transport to explain the origin of volcanic vent clusters in Quaternary Colorado Plateau volcanic fields. We used density contrast inverted from gravity data to constrain the magma transport model. The development of vent clusters appears to be influenced by large-scale lithologic variation in the Proterozoic crust. 2) High-resolution DEM generation combining multiple remote-sensing data sets (Deng et al., 2019). As the first study (as far as we are aware) to combine satellite radar, ground-based radar, ground-based photography, and freely available global digital elevation models (DEMs), we have generated and released a high-resolution (10-m) DEM without data gaps for Nevado del Ruiz volcano, Colombia. The simulated inundation zones from volcano flow models using our new 10-m DEM show significant differences with respect to a global 30-m DEM. 3) Surface deformation and induced seismicity due to fluid injection and oil and gas extraction (Deng et al., 2020). We found that the recent increasing number of earthquakes in western Texas is likely related to the increasing fluid injection rate. We have observed surface deformation due to fluid injection and oil/gas extraction using satellite data. Numerical models of the physical process were used to quantitatively assess the relation between induced seismicity and fluid injection/extraction. The result suggests that pore pressure change due to fluid injection is likely the main contributor to the elevated earthquakes.

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