Seismotectonics Research Group

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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.

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)

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.

Miki Takahashi (Senior Researcher)

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.

Haruo Horikawa (Senior Researcher)

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.

Norio Shigematsu (Senior Researcher)

I am studying on inland-earthquake generation processes based on the investigation of geological survey of exhumed past hypocentral regions. I will use this information to investigate the processes of deformation of rocks in the laboratory at high pressures and high temperatures to improve accuracy of forecasting a large earthquake occurrence.

Yumi Urata (Senior Researcher)

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.

Takahiro Shiina (Senior Researcher)

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.

Kiyokazu Ohashi (Senior Researcher)

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.

Kodai Sagae (AIST Postdoctoral Researcher)

I develop machine-learning–based methods for the automatic detection and source localization of tectonic tremors. Using the resulting tremor catalog, I investigate the spatiotemporal evolution of tremors and earthquakes to better understand the underlying physical processes.

Admore Mpuang (AIST Postdoctoral Researcher)

To better understand the generation processes of crustal earthquakes, I investigate crustal velocity structure, underground faults and stress states through seismic waveform modelling and seismicity analysis. I apply both traditional seismic methods and machine-learning techniques to reveal the regional tectonics and geodynamic processes driving earthquake generation.

Yukiko Kita (Research Assistant)

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.

Ryousei Omori (Research Assistant)

I am conducting research to determine the frictional strength of weathered volcanic ash soils that from sliding cliffs.

Reiken Matsushita (Technical Staff)

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.

Hiroshi Terunuma (Technical Staff)

Assistant work for the geological studies at the seismotectonics research group.