DESTRESS supporting the Pohang investigations
On 20 March 2019, the independent expert commission will release its report concerning the Pohang earthquake and its potential link to the nearby geothermal project. The event of magnitude 5.4 occurred on 15 November 2017, injuring about 80 people and causing damage to numerous buildings.
In August 2017, DESTRESS conducted a first soft stimulation treatment at the Pohang geothermal site. Experts from GFZ, GES, KICT, KIGAM, NexGEO, SNU, TNO, and UoG were involved. This treatment did not induce any seismic activity larger than magnitude 2.0. DESTRESS supported the seismic monitoring by the deployment of instruments. The project collected important data and has been given access to further information thanks to the partnership with the local site owner, NexGEO. However, the dataset available to DESTRESS is incomplete and less extensive than that to which the expert commission has been granted access.
DESTRESS has conducted various analyses scrutinising seismic, hydraulic, geophysical, and geochemical data in the area concerned. The results were made available to the expert commission. In November 2018, DESTRESS partners met for a workshop (see this news item summarizing the main findings) to discuss preliminary results of the work performed. At the recent annual meeting in Strasbourg, further findings were discussed. The focus laid on the potential for a triggered event. In case of triggered events, even small human activities can potentially accelerate the failure of a naturally pre-stressed fault inducing large earthquakes. However, especially, the two months gap between last injection activities and the damaging earthquake raises questions. The DESTRESS working groups provided potential explanations including diffusion processes or slow chemical reactions. DESTRESS partners are committed to continue to work on this highly unprecedented event. All elaborations will be published in a special issue in Geothermics. In addition, DESTRESS plans to release a report on lessons learned, summarising the main findings on which to base future deep geothermal projects. In the meantime, an overview of existing publications and contributions of DESTRESS partners linked to the Pohang earthquake is available in the result section.