Researchers to Conduct Drilling Survey Related to 2011 Quake, Seek to Ascertain Mechanism Behind Giant Tsunami

The Yomiuri Shimbun

1:00 JST, March 12, 2024

A team of international researchers will begin a large drilling survey in September around the epicenter of the 2011 Great East Japan Earthquake, sources said.

Led by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), the team is aiming to determine the mechanism behind giant tsunami. About 50 researchers in fields including seismology and geology from Japan, the United States and seven other countries will dig through the seafloor off Miyagi Prefecture, where the boundary between plates significantly shifted 13 years ago.

The team will collect rocks and other materials in different strata, including those on the surface of the boundary.

It will be the first drilling survey in the area since 2012, the year after the devastating earthquake. The drilling will be conducted by the scientific drilling vessel Chikyu, whose name means Earth.

Operated by JAMSTEC, the Chikyu is a 210-meter-long, 56,752-ton world-class deep-sea drilling vessel.

A riser pipe with a drill will be lowered from the vessel to about 7,000 meters below the surface of the sea to drill 950 meters underground. Collected samples will be immediately analyzed using onboard equipment. Total operation costs for the three-month survey will be ¥3.9 billion.

Many of the victims of the magnitude-9 level quake, the most powerful temblor ever recorded in Japan, were swept away and killed by tsunami.

According to the Geospatial Information Authority of Japan, 561 square kilometers were inundated in Aomori, Iwate, Miyagi, Fukushima, Ibaraki and Chiba prefectures after the quake. This is equivalent to nine times the area of central Tokyo enclosed by the JR Yamanote Line.