Seismotectonics Research Group
We integrate a wide range of approaches, including the observation and analysis of natural earthquakes and crustal deformation, geological investigations of fault zones that were active at depth in the past, laboratory experiments that reproduce frictional and failure processes in rocks, and numerical simulations that model earthquakes, to better understand the environments in which earthquakes occur and the processes that lead to their generation.
In recent years, we have actively applied machine learning techniques to develop methods for estimating subsurface fault geometries and to construct fundamental nationwide stress maps for Japan. We are also working to clarify fault deformation processes that span from brittle to ductile regimes. In addition, we have begun improving the efficiency of numerical simulations of earthquake generation, with a particular focus on the accumulation and release of strain energy along plate boundaries.
Through these efforts, we aim to establish physics‑based techniques for forecasting the magnitude and timing of earthquakes.
Research approach of our group to elucidate the physical and mechanical properties of seismogenic zone and the generation processes of large earthquakes.
Member
- Takahiko Uchide (Leader, Group)
- Miki Takahashi (Senior Researcher)
- Haruo Horikawa (Senior Researcher)
- Yumi Urata (Senior Researcher)
- Takahiro Shiina (Senior Researcher)
- Kiyokazu Ohashi (Senior Researcher)
- Akemi Noda (Senior Researcher)
- Yukiko Kita (Research Assistant)
- Reiken Matsushita (Technical Staff)
I aim to advance our understanding of the physics of earthquake generation and to clarify the tectonic setting and environment in which earthquakes occur, using the characteristics of earthquakes as clues. In particular, I have conducted research on stress fields using focal mechanism solutions of numerous small earthquakes, on the complexity of rupture processes inferred from source spectra of small earthquakes, and on the similarities in rupture growth processes across different earthquake magnitudes. To analyze large volumes of seismic waveform data, I also utilize machine learning techniques.
In order to understand earthquake generation mechanisms, I am measuring the deformation and physical properties of rocks under the high-temperatures and high-pressures in the laboratory. My research interests focus on the frictional behaviors of materials in brittle-plastic transition regions and effects of pore fluid pressure on the frictional behaviors.
I conduct research aimed at inferring the location and geometry of seismogenic faults, using aftershocks and/or microearthquakes. In addition to developing methods for fault estimation, I also work on improving the accuracy of determining the locations of these microearthquakes, which serve as essential data for the analysis.
I am interested in the physical mechanism of large earthquakes. I work on numerical modeling and simulations using data of a rock friction experiment and of seismological and geodetic observation.
I am investigating crustal structures and the structural factors related to generation of inland earthquakes through analyses of seismic waveform data. My aim is to improve constraints on the potential areas of earthquake occurrences and thier fault sizes by understanding mechanisms of earthquake generation.
To understand the physico-chemical processes occurring within fault zones during and after earthquakes, I conduct geological surveys of exhumed seismogenic fault zones and perform laboratory analyses of fault rocks. I also carry out deformation experiments to elucidate the mechanical properties of faults to develop mechanical models of inland faults that incorporate changes over seismic to geological timescales.
I investigate earthquake generation mechanisms through inversion analyses of crustal deformation data. My research focuses on the relationship between strain accumulation prior to earthquakes and strain release during seismic events. Based on these analyses, I quantify changes in elastic strain energy within the crust and develop methods to evaluate earthquake generation potential from the perspective of energy balance.
In order to clarify the physical properties of rocks, I synthesize model materials that simplify the earth's crust to the limit and conduct mechanical experiments. In particular, I focus on the effect of fluids on the strength of rock flow.
My field of study is system information processing, currently with an emphasis on machine learning and advanced signal processing. I analyze earthquakes down to the smallest detectable magnitudes using temporary observation data and Hi-net seismic data. This work contributes to the development of seismotectonic maps.