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グルノーブル・アルプ大Scoquet教授の特別セミナー(9月7日)

Seminar by Prof. Anne Socquet (Univ. Grenoble Alpes)

セミナー等

SEMINARS

更新日:2023.09.07

Updated: 2023.09.07

フランスのグルノーブル・アルプ大学(Univ. Grenoble Alpes, IS Terre, France)のAnne Scoquet教授が、9月7日に防災研、9月8日に吉田の地球物理学教室を訪問されます。
9月7日午後3時からハイブリッド形式(対面は防災研E232D)でセミナーを開催しますので、皆様、ご参加いただけますようお願いします。詳細な情報は以下のとおりです。

Prof. Anne Socqet (University Grenoble Alpes, France) visits the DPRI and School of Geophysics, Kyoto Univ. on Sep. 7 and 8, respectively.
We invite you to her seminar starting at 3 PM on September 7. We are looking forward to seeing you at the seminar.

Speaker: Prof. Anne Socquet (Univ. Grenoble Alpes)
Date and Time: PM3:00-4:30, September 7 (Thursday)
Venue (Hybrid): E232D, Main Building of Uji Campus, Kyoto University

Title:
Loading and release along the central Andes subduction : from slip budget to earthquake nucleation, rupture and induced relaxation
Abstract:
In this talk I will present a synthesis of the analysis of the deformation field in the Central Andes (12 to 24°S) as constrained by GNSS and InSAR, and interpret it in terms of buildup and release of elastic strain along the subduction megathrust.
15 years of GNSS observations in Chile and Peru are used to constrain the interseismic deformation field. The interseismic loading show an along strike segmentation that can be compared with the seismic segmentation.
Considering uncertainties on the data and models, we discuss the implication of our coupling estimates with the size and timing of large megathrust earthquakes. We then investigate the link between seismic and aseismic slip. We perform a systematic search for small slow slip event using a template matching method. We find 33 SSEs with durations from 9 to 40 days and magnitudes from Mw~5.6 to 6.2. The majority of SSEs occur in regions of intermediate geodetic coupling or where plate-geometrical complexities are observed.
We then focus on the seismic and aseismic processes that occurred before and during the 2014 M8.3 Iquique sequence. We find that an 8-month mostly aseismic slow slip event preceded the main shock, that was followed by a series of foreshocks eventually leading to the main rupture. We also investigate the details of the early afterslip and the processes leading to the largest Mw7.6 aftershock that appears to be preceded by an increase in seismicity driven by the afterslip.
The post-seismic relaxation following the 2014 Iquique earthquake is then studied and modelled using a finite element framework with a realistic geometry and a visco-elastic rheology. The temporal evolution of the post-seismic deformation constrains the amount of afterslip versus viscoelastic relaxation, as well as the geometry and the rheology of the mantle wedge. A weak body is needed below the Altiplano with a Burgers rheology and a Kelvin viscosity of 10^18Pa.s.

Prof. Anne Socqet (University Grenoble Alpes, France) visits the DPRI and School of Geophysics, Kyoto Univ. on Sep. 7 and 8, respectively.
We invite you to her seminar starting at 3 PM on September 7. We are looking forward to seeing you at the seminar.

Speaker: Prof. Anne Socquet (Univ. Grenoble Alpes)
Date and Time: PM3:00-4:30, September 7 (Thursday)
Venue (Hybrid): E232D, Main Building of Uji Campus, Kyoto University

Title:
Loading and release along the central Andes subduction : from slip budget to earthquake nucleation, rupture and induced relaxation
Abstract:
In this talk I will present a synthesis of the analysis of the deformation field in the Central Andes (12 to 24°S) as constrained by GNSS and InSAR, and interpret it in terms of buildup and release of elastic strain along the subduction megathrust.
15 years of GNSS observations in Chile and Peru are used to constrain the interseismic deformation field. The interseismic loading show an along strike segmentation that can be compared with the seismic segmentation.
Considering uncertainties on the data and models, we discuss the implication of our coupling estimates with the size and timing of large megathrust earthquakes. We then investigate the link between seismic and aseismic slip. We perform a systematic search for small slow slip event using a template matching method. We find 33 SSEs with durations from 9 to 40 days and magnitudes from Mw~5.6 to 6.2. The majority of SSEs occur in regions of intermediate geodetic coupling or where plate-geometrical complexities are observed.
We then focus on the seismic and aseismic processes that occurred before and during the 2014 M8.3 Iquique sequence. We find that an 8-month mostly aseismic slow slip event preceded the main shock, that was followed by a series of foreshocks eventually leading to the main rupture. We also investigate the details of the early afterslip and the processes leading to the largest Mw7.6 aftershock that appears to be preceded by an increase in seismicity driven by the afterslip.
The post-seismic relaxation following the 2014 Iquique earthquake is then studied and modelled using a finite element framework with a realistic geometry and a visco-elastic rheology. The temporal evolution of the post-seismic deformation constrains the amount of afterslip versus viscoelastic relaxation, as well as the geometry and the rheology of the mantle wedge. A weak body is needed below the Altiplano with a Burgers rheology and a Kelvin viscosity of 10^18Pa.s.

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