Related Experiment Video
Updated: Jun 20, 2026

Kinematic History of a Salient-recess Junction Explored through a Combined Approach of Field Data and Analog Sandbox Modeling
Published on: August 5, 2016
ScS-triggered slip on megathrust interfaces after the 2011 MW 9.0 Tohoku-Oki earthquake
Sunyoung Park1, Hiroo Kanamori2, Luis Rivera3
1Department of the Geophysical Sciences, The University of Chicago, Chicago, IL, USA.
None:
We report an extraordinary observation of ground motion in Japan after the moment magnitude (MW) 9.0 2011 Tohoku-Oki earthquake attributed to a multiplate-interface slip event triggered by shear wave that traveled to the Earth's core and back. The megathrust earthquake generated a strong ScS phase with a peak-to-peak amplitude exceeding 1 centimeter in Japan. Superposed on this waveform, an eastward steplike displacement of up to 5 to 6 millimeters was recorded in Global Navigation Satellite System (GNSS) data throughout Japan. This likely originated from slip on the megathrust interfaces triggered by the nearly simultaneous arrival of the ScS wave across Japan. Such an ScS triggering is a previously unrecognized source of seismic hazard, which can potentially (re)activate the mainshock area and the broader surrounding megathrust interfaces.
Related Concept Videos
Fault Types
For line-to-line faults occurring between phases B and C, the...
Shearing Strain
Elastic Strain Energy for Shearing Stresses
Stresses under Combined Loadings
The process begins by slicing the tube at critical points and analyzing the internal forces and stress components at these sections, focusing on the centroid. Normal stresses, generated by axial forces and bending moments, are either compressive or tensile and vary across the section from...
Shearing Stress
The average shearing stress can be calculated by dividing the shear by the area of the cross-section.
Stresses in a Shaft
Applying equilibrium conditions to the QR segment establishes that the internal shearing forces within the...