This Research Topic is Volume II of a series. The previous volume can be found here: From Preparation to Faulting: Multidisciplinary Investigations on Earthquake Processes
What happens before an earthquake occurs?
What are the physical processes that take place in the Earth’s crust before the earthquake nucleates?
How can we observe, describe, and model them statistically, numerically, and physically in multiscales from samples in laboratory to tectonic plate of earth?
During the last few decades many efforts have been devoted to multidisciplinary studies in an attempt to answer these fundamental questions. Previously, the Institute of Physics of the Earth (IPE) model (dry) and Dilatancy Diffusion (DD) model (wet) were proposed for earthquake processes. Like Schrödinger's cat, earthquakes are unpredictable—according to the IPE model, yet they can be predictable—according to DD model. Recently, with advanced techniques, some scientists have declaimed that there are precursors to be used for earthquake forecasting, which offers new opportunities to study earthquake precursors.
The understanding of governing laws, from long-term tectonic loading and nucleation to rapid rupture propagation, is significant to earthquake forecasting and demands comprehension of the stress state and evolution, during the time of geophysical observations around seismically active areas. The evidence from multiscale experiments, multidisciplinary networks of monitoring systems, numerical modeling, and field investigations is key to advance our understanding of earthquake mechanics.
Earthquakes do not occur everywhere. Fault geometry and the physical properties of fault zones, geologic and tectonic settings, as well as crustal movement and the geodynamic environment play pivotal roles on seismic patterns. A variety of geophysical and geochemical observations, ranging from ground-related deformation patterns (GPS, SAR, etc.) to pre-earthquake changes (geochemical, electromagnetic, hydro-geological, geodetic, or thermodynamic), recorded by ground-based or satellite-based techniques may be related to stress variations in the lithosphere prior to an eventual large earthquake.
This Research Topic aims to provide state-of-the-art studies on processes of earthquakes via multidisciplinary approaches from geophysical, geochemical, geodetical, and geological backgrounds. Pre-earthquake observations, methods, and perspectives can provide a current view in the knowledge of processes preceding earthquake occurrence, which can possibly be employed to set up earthquake forecasting experiments, aiming to verify both in large or small test site areas.
Topics of interest include, but are not limited to:
• Geodynamic environment and its implications on fault activity
• Investigation of fault activity and description of fault geometry for earthquake cycles
• Extracting anomalous changes relevant to earthquake processes from observation systems
• Microseismicity detection and its contribution to the risk assessment of big earthquakes
• Model validation and statistical assessment of proposed physical-based precursors
• Time-dependent seismic hazard assessment based on space-time characterization of impending earthquakes
• Physics of seismic sources and source mechanisms
• Physical and numerical models of earthquake processes in different scales
• Case studies of recent and historical earthquakes