COMET Webinar - Richard Walker - 30 July 2020 - 16:00 UK time
D.Juncu at leeds.ac.uk
Mon Jul 20 11:25:45 UTC 2020
The Centre for Observation and Modelling of Earthquakes, Volcanoes, and Tectonics (COMET) invites you to the next instalment of our webinar series, viewable from the home office.
Coming up next:
Prof. Richard Walker (University of Oxford)
Earthquakes of the Silk Road – reinterpreting the historic and prehistoric ruptures of central Asia.
The webinar will take place on Thursday the 30th of July 2020 at 16:00 UK time (GMT+1).
If you want to attend the webinar please register at https://us02web.zoom.us/webinar/register/WN_vXkdJVKATEei3qYdas84jQ
(After registering, you will receive a confirmation email containing information on how to join the webinar)
In contrast to plate boundaries, where earthquake hazard is usually confined to narrow zones around the edges of the oceans, active faulting within continental interiors is spread across very wide regions, and with intervals of hundreds, or even thousands of years between large earthquakes in any one area. The long recurrence intervals in continental interiors poses challenges for the identification of active faults, and means that we have only a very small database of well-studied examples for understanding the occurrence, style, and potential magnitudes in such settings. I will report on our effects to improve and enlarge the database of well-studied large magnitude continental interior earthquakes through a comprehensive mapping and forensic study of their ruptures, ancient and modern, across the interior of Asia. Our study encompasses a region spanning from Iran in the west, through the ex-soviet Central Asian republics, to China in the East. Our studies combine satellite image interpretation and field investigation to enable identification, mapping, and characterisation of active faults with unprecedented detail across sufficiently large regions. Earthquakes of the early to mid-20th century form an important bridge between the modern and historical eras as they allow direct comparison of early instrumental seismic data, historical documentary data, and the source parameters gleaned from study of the preserved surface ruptures. Many of our large late-historical examples are from the Tien Shan region of central Asia, as represented by the cluster of earthquakes in 1887, 1889, and 1911 in the vicinity of Almaty, Kazakhstan. These examples allow us to address the relationship between rupture length and amount of slip, and the potential for large earthquakes to occur due to complex rupture across multiple short faults. Many of the prominent faults of central Asia have no documented historical record of earthquakes near them, and yet display evidence in the landscape for rupture in the recent past. Forensic study of these faults is essential for determining the hazard posed to population centres across the region, and is important for establishing the level of completeness of the historical record. In Iran, for instance, the documented record of earthquakes extends for over a thousand years, and yet there are large regions without recorded events. Likewise, the Talas-Fergana and Dzhungarian strike-slip faults of the Tien Shan have been seismically quiet over historical times. Through palaeoseismic investigation of these major structures we are able to probe the upper limit of continental earthquake magnitude.
Daniel Juncu & Fabien Albino
COMET - Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics
COMET webinars on youtube<https://www.youtube.com/channel/UCtFDytX1hgjvlS4NH48M2oQ/videos>
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