Better together: seismometers and satellites for observing earthquakes in near- and far-field

Since a few decades earthquake seismology received a spectacular push through near-field observations of permanent surface displacement caused by earthquakes, made possible by new space-geodetic measurement techniques. The pattern of surface displacement is characteristic and allows to deduce many important properties of the causative earthquake. Before the availability of these new satellite observations and for more than a century, earthquake sources have been analyzed predominantly based on seismic waveforms, which most often are recorded in the far-field of earthquakes.

Near-field deformation and radiation of far-traveling seismic waves are different phenomena of earthquake rupture and their complementary information content is very beneficial in joint-data analyses of earthquakes. For finite-source analyses, this enables an imaging of lower magnitude earthquakes than before and/or to a higher degree of source complexity. Apart from gaining more information from more case studies, we can form new links to other observation techniques, e.g. to imaging with high-resolution seismic backprojection, for a better understanding of the rupture process. Furthermore, modern space-geodetic measurements enable the observation of slow ground motion to a very high precision. Based on these, a worldwide detection of slow-moving and seismically silent processes of the earthquake deformation cycle became possible.

In my presentation I show the progress in earthquake research achieved through the combination of seismological and geodetic data, made possible by an international group effort. The success is founded on open data sharing and method implementations in open software code during several research projects with a number of people. Among them are several German seismological research projects that have received significant funding by the German Research Foundation DFG.