The Japan Trench Fast Drilling Project and the unprecedented drilling depth

Right now my advisor, Christie Rowe, is located at the orange dot in the above picture. What are a bunch of earth scientists doing on a boat off the coast of Japan? They’re drilling with the goal of piercing part of the fault that slipped during the Tohoku earthquake (M9) of 2011. That earthquake had a fault slip of approximately 50 m (Lay et al. 2011) that caused a devastating tsunami. The Japan Trench Fast Drilling Project, or JFAST hopes to drill into the fault at the plate boundary.

The drill site is located at a water depth of 6910 m and the researchers hope to drill 1000 m below the sea floor. These depth goals put the Chikyu research vessel on record setting waters. The awesome thing is that GPS transponders on the sea floor at the drill site allow the Chikyu to be positioned within 3 cm accuracy above the drill site. Science rules.

The drilling has two main goals. First, the recovery of fault rock samples. Check out this blog post by Christie Rowe for why we care about fault rocks. The fault rock core will provide insights into the nature of seismogenic earthquakes, which can be compared with what we know about ancient fault rocks exposed in the field. Second, the fault will be instrumented to record the residual heat, fault permeability, and fluid/rock chemical properties. The residual heat will be used to gain insight into the frictional strength of the rock.

Follow along with developments here: http://www.jamstec.go.jp/chikyu/exp343/e/report.html. The researchers are required to blog.