Title: Associate Professor
Country/Region: Canada
Period: 2025/5/20 - 2025/10/17
Theme: Advancing the Understanding of the Nucleation Process of the Noto Earthquake
Host: Aitaro KATO
Introduction: Dr. Miao Zhang is an Associate Professor at Dalhousie University, Canada. Before joining Dalhousie in 2019, he received his Ph.D. from the University of Science and Technology of China in 2015, followed by postdoctoral training at Los Alamos National Laboratory and Stanford University. His research interests include all types of seismic events and their occurrence mechanisms, both on land and at sea—ranging from tectonic and volcanic earthquakes to induced earthquakes and man-made explosions. He is also passionate about developing open-source software packages for earthquake monitoring and seismic analysis. During his stay at the ERI, he will work with Prof. Aitaro Kato to characterize and understand the mechanisms of foreshocks of large earthquakes.
Research Report:
Research Report:
I visited for five months (May–October 2025) to collaborate with Prof. Aitaro Kato on the characterization of focal mechanisms for small foreshocks preceding the 2024 Noto Mw 7.5 mainshock. On January 1, 2024, a Mw 7.5 earthquake struck the northern Noto Peninsula in Japan. Prior to the mainshock, an intense seismic swarm persisted for over three years—driven by fluid propagation and accumulation—and culminated in two large foreshocks: the Mj 5.4 event in 2022 and the Mj 6.5 event in 2023. High-resolution earthquake catalogs are essential for elucidating earthquake nucleation processes, but they offer only a limited view of detailed faulting mechanisms, fault structures, and spatiotemporal stress changes. In contrast, focal-mechanism solutions for small earthquakes (e.g., M < 3)—which are difficult to obtain using traditional methods when station coverage is limited—provide valuable qualitative constraints on fault orientations and evolving stress fields. During my visit, I focused on the period from January 2020 to March 2024, utilizing a newly developed cross-correlation-based double-ratio focal-mechanism inversion method and 135 F-net focal mechanisms as templates, and determined focal mechanisms for more than 1,000 M > 2 earthquakes. The detailed variations in focal mechanisms delineate the dipping angles of fine fault structures and the spatiotemporal evolution of stress. Most interestingly, we found reversed normal-faulting earthquakes following large events. I presented this work at the Slow-to-Fast Earthquake Workshop in Kochi. In addition, I participated in the geological field trip and the ERI-SESS & PKU Joint Seminar organized by the ERI International Office. I also gave a seminar at ERI and attended many excellent seminars. I discussed research ideas with several ERI researchers and others beyond the institute, exploring possibilities for future collaboration. Finally, I would like to express my sincere gratitude to my host, Prof. Aitaro Kato, for his research support, and to the ERI International Office team for their assistance with logistical and administrative matters.
I visited for five months (May–October 2025) to collaborate with Prof. Aitaro Kato on the characterization of focal mechanisms for small foreshocks preceding the 2024 Noto Mw 7.5 mainshock. On January 1, 2024, a Mw 7.5 earthquake struck the northern Noto Peninsula in Japan. Prior to the mainshock, an intense seismic swarm persisted for over three years—driven by fluid propagation and accumulation—and culminated in two large foreshocks: the Mj 5.4 event in 2022 and the Mj 6.5 event in 2023. High-resolution earthquake catalogs are essential for elucidating earthquake nucleation processes, but they offer only a limited view of detailed faulting mechanisms, fault structures, and spatiotemporal stress changes. In contrast, focal-mechanism solutions for small earthquakes (e.g., M < 3)—which are difficult to obtain using traditional methods when station coverage is limited—provide valuable qualitative constraints on fault orientations and evolving stress fields. During my visit, I focused on the period from January 2020 to March 2024, utilizing a newly developed cross-correlation-based double-ratio focal-mechanism inversion method and 135 F-net focal mechanisms as templates, and determined focal mechanisms for more than 1,000 M > 2 earthquakes. The detailed variations in focal mechanisms delineate the dipping angles of fine fault structures and the spatiotemporal evolution of stress. Most interestingly, we found reversed normal-faulting earthquakes following large events. I presented this work at the Slow-to-Fast Earthquake Workshop in Kochi. In addition, I participated in the geological field trip and the ERI-SESS & PKU Joint Seminar organized by the ERI International Office. I also gave a seminar at ERI and attended many excellent seminars. I discussed research ideas with several ERI researchers and others beyond the institute, exploring possibilities for future collaboration. Finally, I would like to express my sincere gratitude to my host, Prof. Aitaro Kato, for his research support, and to the ERI International Office team for their assistance with logistical and administrative matters.