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Earthquake source processes - Imaging methods, numerical modeling and scaling (co-organized)
Convener: P. Martin Mai  | Co-Conveners: Henriette Sudhaus , Martin Vallée , Alice-Agnes Gabriel , Hideo Aochi 
 / Tue, 25 Apr, 08:30–12:00  / 13:30–15:00
 / Attendance Tue, 25 Apr, 17:30–19:00

Physics-based forward modeling, earthquake source imaging, laboratory experiments, and scaling relation linking source parameters help to understand the dynamic processes occurring during seismic ruptures. Furthermore, new approaches provided through numerical modeling of earthquakes can apprehend the physics of earthquake rupture, seismic wave propagation, fault zone evolution and seismic hazard assessment. However, numerous scientific challenges remain:

Which first-order physical processes control, at a given space-time scale, the macroscopic evolution of a dynamic rupture and thereby affect the resulting ground motion characteristics? Is the physics of fault rupture the same for large and small earthquakes? How could modern earthquake hazard assessment better account for source effects? Which aspects of the source rupture process need to be considered to further investigate local tsunami generation, triggering phenomena, induced seismicity and earthquake cycles?

Earthquake sources are imaged using a variety of seismic data and surface deformation measurements, such as GPS and InSAR, to learn about characteristics of active faults and fault systems. Since each data set has its strength and limitations in imaging specific source properties, a common approach is to combine different data sets into a single inversion. But how robust are these source models? And what are the resulting uncertainties?

Recent advances in numerical algorithms and increasing computational power enable unforeseen precision and details in physics-based earthquake simulation but also pose challenges in terms of fully exploiting modern supercomputing infrastructure, realistic parameterization of simulation ingredients and the analysis of large synthetic datasets.

Because of the abundance of small events, understanding whether earthquakes are self-similar down to very small ruptures is of practical importance for estimating hazard for natural earthquakes. Studies of earthquake scaling relations involve analysis of the Gutenberg-Richter distribution, seismic moment tensor (e.g. existence of non-DC focal mechanisms) as well as comparisons of static and dynamic source parameters such as stress drop and apparent stress. In spite of increased station coverage in recent years, observations of parameter scaling relationships vary widely.

This session aims at further understanding of source processes - from slow slip events and rupture dynamics to wave propagation and ground motion analysis - and earthquake scaling relationships over a wide range of magnitudes. It discusses advances in numerical and theoretical forward modeling of dynamic earthquake sources. It investigates whether variations in parameter scaling are regionally dependent. It explores whether observed differences in scaling relations are real, and if so, what physical mechanisms might account for such differences. This session is also dedicated to studies that aim at advancing earthquake source imaging techniques to obtain more robust rupture models that are desired to provide a better basis for interpretation of earthquakes with respect to the causative faults and the tectonic systems. We also welcome studies which further the state-of-the art in the related computational and numerical aspects.

Within this framework our session also provides a forum to discuss case studies on recent significant earthquakes.