The Department of Geography is delighted to announce a series of upcoming lectures from current members of staff, showcasing some of the exciting research that is happening within the department. The talks will last approximately 1 hour, with time for questions and discussion, and will be delivered online. They will also be recorded, so if you can’t make the live event, you can catch up at your leisure.
Scheduled speakers for 2021/22:
16 June 2021: Dr Noam Leshem, on journeys through No Man’s Land
3 November 2021: Prof Erin McClymont, on how Antarctic sea ice ecosystems respond to climate change
28 April 2022: Dr Simon Engelhart, on evidence for earthquakes and sea-level change in the northwestern USA
November 2022: Prof Louise Amoore, on how algorithms shape our lives
Full details will be posted in due course on the website and on our department Twitter pages and alumni Facebook and LinkedIn pages.
We look forward to seeing you online!
An Evening with Dr Simon Engelhart
Searching for the largest earthquakes in North America
Thursday 28 April 2022 7pm (BST)
Subduction zones are the source of the largest earthquakes on Earth and commonly produce high tsunami that devastate coastal environments and populations. The instrumental record provides accurate information on parameters such as magnitude and shaking intensity, with additional lower resolution data often available via historical records. However, the instrumental and historical records are almost always too short, typically less than a hundred years, to provide useful information on recurrence intervals or to answer questions on variability in magnitude between events, including the existence of patterns or cycles. One solution to this is to develop reconstructions of past earthquake and tsunami from geological records that can extend the record to millennial timescales. The importance of such palaeoseismic records has been highlighted in recent years by unexpected M8.5+ subduction zones earthquakes in places where hazards was previously underestimated. As such, palaeoseismic records that span beyond the instrumental/historical era remain the best way to quantify variations in the size of past earthquakes and to assess the variability of recurrence intervals. Earthquake-induced changes in land-level at coastal locations can be measured using sedimentary or coral archives that record changes in environment due to subsidence or uplift and from deep sea and lake records that retain evidence of high intensity shaking. Tsunami can be reconstructed from the deposition of anomalous sand sheets in typically low energy, fine grained environments.
In this talk, I will provide the background to using geological archives to document pre-instrumental/historical earthquakes at global subduction zones. Building from this introduction, I will then discuss how work that has been ongoing in the Geography department at Durham since the early 1990s has improved our understanding of subduction zone earthquakes along the west coast of the United States and Canada at the Cascadia and Alaska-Aleutian subduction zones.