New seismograph can take the pressure

The Yomiuri Shimbun

Japanese researchers have developed a seismograph container able to withstand extremely high pressure, allowing it to be used in the deepest parts of the ocean.

The group from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) and others produced the container to withstand environments where atmospheric pressure exceeds 1,000 atm. Such environments include the Mariana Trench, the world's deepest, which reaches 10,920 meters.

The product is expected to enable researchers to monitor the entire Japan Trench, where massive tsunami-causing quakes have originated in the past.

Sea-bottom seismographs are usually recovered after weights attached to them are released by sending signals from a ship. The containers need to be both light and pressure resistant, with present models able to withstand 600 atm, about 6,000 meters deep.

The researchers chose to make the container out of ceramic instead of glass. This made it possible to nearly double its strength while keeping its weight at about 20 kilograms, similar to conventional containers.

The Japan Trench was created off the Sanriku coast in Iwate Prefecture when the oceanic Pacific plate subducted beneath the continental Eurasian plate.