Goals and Mission: Within the GFZ, Section 2.4 provides core seismological competence and infra-structure. A reliable assessment of the earthquake hazard requires a fundamental understanding of the underlying geodynamic processes. We examine these on a lithospheric scale by application and development of seismological methods for imaging the upper mantle and crust. We also locate and characterise seismicity on a local and regional scale as a marker of stress and deformation processes.
We run a program, GEOFON, with which we seek to facilitate cooperation in seismological research and earthquake and tsunami hazard mitigation by operating a global network of stations, by providing rapid transnational access to seismological data and source parameters of large earthquakes, by keeping these data accessible in the long term and by developing and distributing communication and processing software. Mitigation of the effects of major earthquakes by early warning from tsunamis and the provision of prompt information for governmental agencies, NGOs, the media and the general public requires rapid determination of earthquake parameters. We develop methods for the fast automatic location and determination of magnitude and other parameters (moment tensor, rupture propagation), and provide a bulletin for all major earthquakes.
Competence, research focus, services: Seismology allows imaging the interior of the Earth with a resolution unmatched by any other method. For example, long term seismological records and data from dense temporary deployments have allowed seismologists to map the variation of lithospheric thickness below the continents. Tomographic images of the Earth's interior provide a snapshot of the convective system of the mantle and how it interacts with the processes visible at the surface; these are the prime means by which we can gauge the quality of geodynamic models. Measurements of shear wave splitting have allowed seismologists to map the lithospheric and asthenospheric strain fields, and seismological observations have provided detailed maps of Moho depths. We are learning from observations of small and moderate earthquakes how deformation is distributed at plate margins, and have inferred frictional properties of subduction megathrusts using seismicity patterns. Progress in seismology depends critically on the quantity and quality of available data. The seismologists of the section are all involved in the acquisition of data by running a permanent global network of stations, by installing long term observatories, and by carrying out temporary seismological experiments involving the deployment of dense arrays of broadband seismometers, often in joint projects with external partners, nationally and internationally, or as components of integrated projects with other groups at the GFZ. However, we do not only draw on the data from these experiments but in equal measure make use of available data from permanent global and regional networks. By openly distributing data from our permanent network and developing and providing open source processing software we support seismological research worldwide, and contribute to the spirit of open data exchange in seismology. Building on a solid understanding of the physics of wave propagation, scientists of the group are engaged in the development of computational tools for the efficient analysis of seismic data, and are interpreting their observations in terms of their geodynamic and seismo-tectonic implications.