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Fault Slip Behavior
Fault Slip Behavior
Slip on faults happens in a variety of ways over a variety of timescales. Slip can happen quickly during an earthquake, more slowly during transient events such as postseismic slip or slow slip events, or not at all if a fault is frictionally locked and accumulating strain towards the next earthquake. I'm interested in characterizing the various kinds of slip, understanding the processes responsible for the slip behavior, and investigating how different slip behaviors can influence each other and overall earthquake hazard. Current projects in Alaska focus on the Shumagin and Semidi segments of the subduction zone, the Fairweather, Queen Charlotte, and Denali faults, and the flat slab region of the subduction zone.
Figure at right: Interseismic locking (coupling) on the subduction zone with the slip areas of major earthquakes along the Alaska Peninsula including the 2020 M7.8 Shumagin and 2021 M8.2 Chignik earthquakes. From Elliott et al. (2022).
Tectonic Plate Kinematics
Tectonic Plate Kinematics
Expanded networks of seismic and geodetic instrumentation have shown that the traditional view of large tectonic plates only deforming along their boundary edges is too simple. Boundary zones can be very broad and can include a number of smaller plates or blocks and distributed deformation regions. Understanding how plates move and how relative motion between plates is accommodated improves our knowledge of the Earth system and informs earthquake hazard estimates. My current projects focus on the northern Pacific margin (western Canada, Alaska, and eastern Russia) and the southern East Africa Rift system.
Expanded networks of seismic and geodetic instrumentation have shown that the traditional view of large tectonic plates only deforming along their boundary edges is too simple. Boundary zones can be very broad and can include a number of smaller plates or blocks and distributed deformation regions. Understanding how plates move and how relative motion between plates is accommodated improves our knowledge of the Earth system and informs earthquake hazard estimates. My current projects focus on the northern Pacific margin (western Canada, Alaska, and eastern Russia) and the southern East Africa Rift system.
Predictions of tectonic block motion in Alaska and western Canada. From Elliott and Freymueller (2020).
Cryospheric and Hydrologic Change
Cryospheric and Hydrologic Change
Glaciers can experience large dynamic changes due to retreat and thinning, which can influence hazards such as outburst floods and sea level rise. Changes in surface ice or water loads can cause significant vertical motion which can impact interpretation of other deformation signals and sea level rise and may alter stress states on faults. I am interested in characterizing cryospheric and hydrologic changes, investigating the processes behind the changes, and exploring how non-tectonic and tectonic processes may be interrelated. Current and recent projects include observing tidewater glacier changes in southeast Alaska with satellite data, digitizing historic photos of glaciers, and evaluating glacial isostatic adjustment in Alaska.
Uplift rates observed at GNSS sites in southeast Alaska.
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