Understanding the mechanisms behind massive earthquakes to predict their magnitude and frequency requires conducting frequent measurements of seafloor movements with centimeter-level precision. However, with the currently available method, such observations call for traveling by ship to the target location, collecting data, and then returning--making it difficult to conduct measurements with sufficient frequency. Under these circumstances, Associate Professor Yusuke Yokota of #UTokyo_IIS throughout joint research with HAMA, Inc., has succeeded for the first time in the world in measuring the position of the seabed with centimeter-level precision using an unmanned aerial vehicle (UAV) that lands on the sea surface. This breakthrough technology is attracting attention for enabling more frequent and cost-effective measurements of seabed positions.

The Nankai Trough seafloor cable seismic observation network DONET is used for earthquake early warning and tsunami prediction. A thermometer is attached to each of these ocean bottom seismometers to measure the temperature near the seafloor. In this study, by investigating long-term ocean bottom temperature data, a research group of Yusuke Yokota (Associate Professor at #UTokyo_IIS), Tomohiro Inoue and Tatsuya Kubota (National Research Institute for Earth Science and Disaster Resilience) detected for the first time ocean waves fluctuating synchronously over an area of more than 100 km along the Nankai Trough. In oceanography, this may be a "Coastal Trapped Wave (CTW)" , and this is a rare observation case that shows the possibility of new oceanographic observations using the ocean bottom seismic observation network. The temperature change is very small, a phenomenon that cannot be detected by ocean bottom pressure gauges, and the signal is of a size that does not affect earthquake observations or slow slip observations in the Nankai Trough. In the future, if more accurate slow slip detection is implemented, it may become noise.

For the first time, researchers at #UTokyo_IIS, quickly and efficiently measure the seafloor down to the centimeter-level using an unmanned aerial vehicle

Researchers led by the Institute of Industrial Science, The University of Tokyo develop a novel method for measuring seafloor movement

Researchers from The University of Tokyo Institute of Industrial Science find that drones may be the next generation of communication bases to monitor the ocean and seafloor because of their high-speed positioning, stability, and efficiency.

Japanese researchers discover shallow slow slip seismic events using a combined Global Navigation Satellite System–Acoustic ranging combination technique in an interplate subduction zone prone to recurrent megathrust earthquakes