Seminar “Triggering of earthquakes: a review” and “High precision prediction of catastrophic mechanical phenomena”

Seminar :

• Venue: OIST Lab1, C016
• Date/Time: July 15th / 10:00-12:00
  • Session 1: 10:00-11:00  “Triggering of earthquakes: a review”
  • Session 2: 11:00-12:00 “High precision prediction of catastrophic mechanical phenomena”

10:00-11:00   Prof. Takahiro Hatano (Earthquake Research Institute, University of Tokyo)

“Triggering of earthquakes: a review”

Abstract:  It is known that earthquakes can be triggered by extremely small perturbation such as tides or seismic waves from far field, although they only add shear strain as low as 10^-8 to earthquake faults. Interestingly, such sensitivity to small perturbation appears to be enhanced before major earthquakes like the 2004 Sumatra earthquake and the 2011 Tohoku earthquake. We discuss some potential physical mechanisms behind this phenomenon together with recent experimental results.

11:00-12:00   Prof. Tetsuo Yamaguchi (Department of Mechanical Engineering, Kyushu University)

“High precision prediction of catastrophic mechanical phenomena”

Abstract:  Monitoring and prediction of catastrophic mechanical phenomena, such as collapse of buildings, landslides and earthquakes, are very important for preventing disasters. However, in spite of many efforts, they are still considered to be essentially difficult or even impossible.

In this talk, we will show that the monitoring and prediction are possible with high accuracy. Based on the concept of critical slowing down which is well established in statistical physics, we study mechanical buckling, so called snap-through buckling, where an arch structure (bridges, dams and tunnels) collapses suddenly beyond a critical load [1]. We succeed in predicting the occurrence of collapse of our laboratory arches by monitoring the fundamental frequencies of the system which go to zero as the system approaches the critical load [2]. We will discuss how it works and also introduce our trials applying to laboratory earthquake experiments.

Reference:

[1] A. B. Pippard, Response and Stability, Cambridge University Press (1985).

[2] H. Ohtsubo, T. Yamaguchi, Y. Sawae, in preparation.

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Contact: Mathematical and theoretical physics unit,

shiho.saito@oist.jp