The IRSN unit specialized in seismic risk assessment (BERSSIN - Seismic Risk and Facility Safety Assessment Unit) has organized a workshop on earthquake surface ruptures on December 8-9, 2016, in collaboration with the Instituto Nazionale di Geofisica e Vulcanologia
(INGV), the US Geological Survey
(USGS) and the California Geological Survey
(CGS). The workshop, held in Menlo Park, near San Francisco, USA, has been attended by a hundred geologists and engineers from all over the world.
Funded by the Pacific Earthquake Engineering Research Center
(PEER) and the Pacific Gas and Electric Company
(PG&E), the workshop had three goals:
- make practitioners (engineers and consultants) and geologists with data aware of the advantages of setting up a unified, worldwide database for improved estimation of the surface rupture hazard;
- define the structure of this database;
- broaden collaborations and sources of funding to ensure the success of the project.
Surface rupture analysis is an important part of assessing the risks induced by active faults for the safety of industrial facilities located nearby. The seismic hazard involves two main phenomena: vibratory ground motion, and ground surface displacement along the fault, which can produce a scarp. A great deal of work has been done in the past twenty years on characterizing the first of these phenomena, in particular by amassing a very large quantity of recordings to study seismic wave propagation in the earth's crust. The data acquired to describe surface displacement, however, is still scarce and fragmented, resulting in a high degree of uncertainty in the related risk assessments.
The workshop has brought together geology and earthquake specialists concerned by these issues. The first lessons drawn from the workshop have been announced the following week at the American Geological Union
(AGU) Fall Meeting, during a special session entitled "Towards a unified and worldwide database of earthquake surface ruptures".