On 4 April, 2010, the El Mayor-Cucapah earthquake occurred in NW Baja California, Mexico. It was magnitude 7.2 strike-slip event, and the (surface) ruptures were distributed over a set of faults in the area, among them the Laguna Salada Fault. The epicentral area was under surveillance by a technique similar to DInSAR – Uninhabited Aerial
Vehicle Synthetic Aperture Radar (UAVSAR). Comparison of images from before and after the M7.2 earthquake revealed that slip occurred not only in the epicentral area and at the Laguna Salada Fault, but also on faults to the north. These findings were recently published by Donnellan et al. (2014). more
The SSA2014 annual meeting took place in Anchorage, Alaska from 29 April – 2 May. Currently the post-meeting excursion on the effects of the Great Alaska Earthquake of 1964 is taking place, and we placed our paleoseismicity-spy Gösta Hoffmann in the group. We hope that no one realizes that he’s a desert geologist and absolutely in the wrong place, but he promised to not wear his Teva sandals in order not be identified. Gösta is Associate Professor at the German University of Technology in Oman (GUtech) and works on coastal change and tsunamis, and particularly on tsunamis in the Arabian Sea. Here is his report from Alaska: more
The Friends of the Pleistocene went on a fieldtrip few days ago to study the 4D Architecture of an Oblique Rift Margin in Baja California, NW Mexico. The tour focussed on the paleoseismology of the Borrega and Laguna Salada Faults, especially on the 1982 and 2010 surface ruptures, and took place fom 27 February to 2 March, 2014. You can download the detailed field guide and the road log here. more
On 27 March, 1964, an earthquake of magnitude 9.2 occurred offshore Alaska (Plafker, 1965) and caused a Pacific-wide tsunami. This quake was the second most powerful that was ever recorded and is also referred to as the Great Alaska Earthquake. The USGS has now released a report on a comparable tsunami scenario. The SAFRR (Science Application for Risk Reduction) Tsunami Scenario deals with a tsunami caused by a major quake off Alaska and investigates the possible impact at the coast of California. more
BSSA’s most recent issue is full of paleoseismological work. The April 2013 issue contains a number of papers dealing with old earthquakes in Turkey, California, Argentina, and Jamaica. Also, there’s info on earthquake catalogues in South America and China. A study on seismic sources in the Lower Rhine Embayment, (W Germany, Belgium, The Netherlands) is especially interesting for me, because it’s right in my backyard. Plus, there are some basic studies on the reliability of paleoseismological investigation and problems in earthquake geology. more
Jim McCalpin will teach his 13th Field Course in Neotectonics and Paleoseismology from May 22-31, 2013 in Crestone, Colorado, USA. This is a “9-day summer Field Course, offered by the Crestone Science Center, which teaches the latest field techniques, but also contains evening lectures covering the entire field of Paleoseismology.” more
We’ve seen several magnitude 6 earthquakes last week. On 28 Januar, a shallow M6.1 strike-slip event occurred in eastern Kazakhstan. A little surprise only, we knew about thrust mechanisms in this area, but of course some strike-slip movements do not change the big picture. Would be interesting to check for surface ruptures. This is, by the way, the study area of our friend and colleague Angela Landgraf. Maybe we can convince her to write something about the paleoseismological background of that area? more
The RealClimate blog network published two long articles on the state of the art of sea level rise estimations. Part 1 was written by Stefan Rahmstorf on 9 Jan, part 2 was posted today. What will we need to prepare for until the end of the century? more
The Sparta Fault in Greece is marked by one of the most impressive mountain fronts I’ve ever seen. A huge (yes, huge!) fault scarp has developed, traceable for kilometers; the fault itself is more than 60 km long. Ancient Sparta has been devastated by the last known major (M>7) earthquake that happened at this fault in 464 BC. Now, Papanikolaou et al. have published new data on this fault. They examined how paramaters like throw, segmentation, and catchments vary along strike and created a new seismic hazard map, showing a site-specific long-term recurrence interval of ~1.8 ka (+/- 450 a). more
Two really strong earthquakes happened yesterday at the Mid-Atlantic Ridge in the Jan Mayen Islands area. The first one had a magnitude of M6.6, the second one, around ten minutes later, had M5.3. Moment tensor solutions show clear strike slip along a transform fault west of the ridge. The seismicity map shows that events like yesterday’s don’t come as a suprise: more
