Dr. Breanyn MacInnes
Current Research Projects
Past Research Projects
Current Graduate Students
Finished Graduate Students
My long-term research goal is to understand the effect of geologic catastrophes (such as earthquakes, tsunamis, and volcanic eruptions) on short-term and long-term coastal landscape evolution and maritime cultures, with a focus on island coastlines.
Coastal Geomorphology and Landscape Evolution: I am especially interested in studying how coastal landforms preserve the history of past events and how geological, marine and anthropogenic factors control the geomorphology of a coast. So far, the focus of my research is on geologic catastrophes, such as tsunamis, volcanic eruptions and coseismic land-level change. One major aim of my research is determining how tsunamis alter coastal landforms (such as beach ridge plains, Holocene marine terraces, coastal marshes, etc.) in a way that can be preserved and recognized.
Tsunami Geology/Paleoseismology: Studying paleotsunami deposits can help to estimate how often earthquakes occur along different subduction zones. I am trained to recognize tsunami deposits in settings around the north Pacific and I calculate recurrence intervals using tephrochronology and radiocarbon dating.
Geoarchaeology: I am interested in how maritime cultures (those reliant on boats and coastal resources) respond, mitigate, and reduce risk to geologic catastrophes. In particular, I work to to determine (1) if people occupied the islands during major events (or conversely, how often did major events occur while people occupied certain islands), (2) how, if at all, records of those events are preserved in archaeological settings, and (3) what effect geologic catastrophes have on local flora and fauna. I also work with archaeologists to help reconstruct Holocene landscape evolution.
Subduction-zone processes: I use tsunami models and onshore observations of tsunami (post-tsunami surveys, paleotsunami deposits, or historical records) to understand more about earthquake rupture processes. Variations in the runup of a tsunami onshore are effected by the amount and distribution of slip during an earthquake. Via tsunami computer models, I can use tsunami observations, or paleotsunami deposits, to determine patterns of slip during an earthquake.
Neotectonics: Marine terraces and other indicators of vertical displacement were my first love. Sea-level is a fantastic horizontal datum to understand active tectonics in the Quaternary. Coastal features can be used in all sorts of ways to recognize recent or ongoing horizontal and vertical displacement. My research interests include Holocene and Quaternary marine terraces, fault scarps and offsets, sag ponds, and any other aspect of tectonic geomorphology observable in coastal settings.
Sediment transport and erosion: I use sediment transport equations to understand how tsunamis erode, transport and deposit sediment. Sediment grain size and grain-size distribution can reflect characteristics of the flow of a tsunami wave. I also am interested in how sediment transport results in bedforms and other sedimentary structures.
Tephrochronology: Tephra makes telling time easier. I correlate tephra between excavations using description and chemical analyses. One tephra from a known eruption found in multiple excavations means I can draw a timeline between these excavations without having to obtain radiocarbon dates from each place.