In light of the research described in the section below, we have formed a collaboration with Kerry Sieh of Caltech and Massimo Cocco, Alessio Piatanesi, Carlo Giunchi, and Spina Concetti of INGV - Rome to model the next likely tsunami in the Indian Ocean. This NERC funded project involves the following steps:

Following the great 26 Dec.2004 Sumatra earthquake, we calculated the stress changes from it on the Sunda Trench immediately to the south and on the Sumatra Fault that runs down the middle of the island. We found that stresses had increased significantly on both structures and in a paper published in Nature on 17 March 2005 we warned that the seismic hazard had consequently increased in the area. On 28 March 2005 an M=8.7 earthquake occurred in the area of concern along the Sunda Trench although fortunately it did not trigger a large tsunami.

We have since recalculated the stresses from the two earthquakes and in a subsequent paper highlight the continued hazard along the Sumatra Fault as well as the increased hazard of a further earthquake and tsunami in the Mentawai Islands region, a portion of which has not experienced a large earthquake since 1797. We are now seeking funding from NERC to investigate stress interaction and the timing of future large earthquakes in a global catalog.

Aftershock hazard

The PRESAP project (EVG1-1999-00001) was led by the Geophysics Group and funded under Framework 5. It was designed to test the feasibility of making near real time Coulomb stress calculations in order to estimate the likely spatial distribution of aftershocks following moderate to large earthquakes in Europe. Although previous retrospective research had shown a clear causal link between stress changes and aftershocks, no one had investigated whether it would be possible to assess aftershock hazard in the hours to days following an earthquake. The aims of PRESAP were to determine whether this was both scientifically and technologically feasible.

The results and methodologies developed during the project were tested in a pseudo real time scenario in which data (disguised in location and time) were fed to participants in the time sequence in which it would have been available in reality. Only 4 hours and 25 minutes after the main shock, a Coulomb stress map was “released”; this release highlighted the danger of a particular fault that ruptured in a large magnitude event approximately 6.5 hours later. A subsequent release, 14 minutes before the large aftershock, increased the emphasis on this potential region of high hazard.

Click for some of our papers from this project ( pap1, pap2, pap3)

In 2002, we published a paper on Coulomb triggering and earthquake hazard along the East Anatolian Fault in Turkey. We identified two regions as being highly loaded and suggested that detailed paleoseismological work be carried out to investigate previous earthquakes along specific segments. In 2003, an M=6.4 earthquake occurred near the city of Bingol. This event was not, however, on the EAF but rather on a small conjugate fault. As our subsequent paper shows, the relationship between this earthquake and activity on the EAF is complex and has implications for commonly used methods of secular loading. This work was funded by NERC and a follow-up project currently underway is funded by an EC Intra-European Fellowship. In a related project, Emre Evren is presently doing Ph.D. research on earthquake hazard in the Istanbul area.