Collaborative Research: Catching the quake: Investigating samples from the JFAST expedition for evidence of the 2011 Tohoku Earthquake

Lead PI: Heather Savage, Pratigya Polissar

Unit Affiliation: Seismology, Geology and Tectonophysics, Lamont-Doherty Earth Observatory (LDEO)

May 2013 - April 2016
Asia ; Pacific Ocean ; Japan
Project Type: Research

DESCRIPTION: This proposal seeks to understand how shallow slip occurred during the Tohoku earthquake by determining the frictional strength of the fault before the rupture initiated and during slip. Using samples collected from the fault during IODP exp 341 (JFast), the PI's will undertake:

1) Organic thermal maturity measurements to identify the rupture plane and quantify the frictional temperature anomaly induced by coseismic slip.

2) Microstructure observations to identify and characterize the fault that hosted the earthquake, including the identification of textures that indicate frictional weakening.

3) Friction measurements to constrain the steady-state frictional stress of the faults.

These results are crucial for understanding tsunami genesis in shallow subduction zones and will provide critical information for tsunami prediction and hazard mitigation. Importantly, only direct observation and measurement of the fault physical properties can determine these parameters.