Japanese earthquake researchers have begun setting up a large-scale underwater network of seismographs and tsunami recorders in the Pacific Ocean along the country's eastern seaboard.

The National Research Institute for Earth Science and Disaster Prevention plans to complete the national project in about 2 years.

A vessel began placing instruments in seas off Chiba Prefecture, near Tokyo, on Tuesday.

The instruments are seismographs and recorders that detect tsunamis by observing changes in water pressure.

They are contained in metal tubes that are being installed at 150 locations on the seabed on both sides of the Japan Trench. The deep sea trench runs off the coast of eastern Japan from Chiba Prefecture to the northernmost island of Hokkaido. Observation data will be sent via a 5,700-kilometer underwater cable.

If a quake occurs near the Japan Trench, the seismographs will help the Meteorological Agency issue earthquake warnings by several tens of seconds earlier than now. The tsunami recorders are also likely to detect tsunamis faster than instruments at coastal observation posts.

A researcher from the institute says a huge earthquake is highly likely to occur in the region around the Japan Trench, where the March 2011 quake and tsunami took place. He says he hopes the improved data-gathering will help save lives and reduce damage.

Jul. 9, 2013 - Updated 10:20 UTC