JAMSTEC

Contact Us

Japanese


DONET

News

2012.08.03 update
[First anniversary for DONET implementation]


At 31 July, 2011, JAMSTEC constructed DONET system and data transfer of all twenty stations to JAMSTEC started. We has implemented DONET system smoothly well for one year. DONET data is ordinarily sent to Japan Meteorological Agency (JMA) and National Research Institute for Earth Science and Disaster Prevention, especially, pressure gauge sensor is already used for JMA's tsunami alert. Since there are much data from all stations with six sensors and much devises playing a role of the interface, there are some issues to be resolved as failure of sensor lock system for a broadband sensor and unstableness of a high resolution thermometer. The total system, however, is working well and there are no fatal errors at this moment.

DONET has recorded many events during one year from huge events, like the 2011 off Tohoku earthquake (M9, Figure 1) and the 2012 off the west coast of northern Sumatra earthquake (M8.6, Figure 2) to small events occurred around deformation front area of the Nankai Trough. Some tsunamis were also recorded by DONET. The tsunami height of the off Tohoku earthquake was approximately 20 to 30 centimeters and DONET also observed tsunami amplification accompanied with tsunami propagation to shallow region (Figure 3). In addition, micro tsunami excited by 2010 off the eastern coast of the Chichijima earthquake (M7.4) was also detected and the height was only eight millimeters (Figure 4).

Japan is still faced with severe disaster by the off Tohoku earthquake, and many people, that are not only scientists and bureaucrats but general, pay much attention to next Tonankai/Nankai earthquake. Now, we are constructing database system to check equipment and the data, and to open them to general. We are carefully implementing and resolving some issues and hope that DONET contributes for disaster prevention of future huge Tonankai/Nankai events and breakthrough of broad science in the world.

Figure 1 DONET records without filtering of 2011 off Tohoku earthquake (Strong motion sensor with sampling rate of 200 Hz).

Figure 1 DONET records without filtering of 2011 off Tohoku earthquake (Strong motion sensor with sampling rate of 200 Hz).

Figure 2 DONET records without filtering of 2012 off the west coast of northern Sumatra earthquake (Broadband seismometer with sampling rate of 20 Hz).

Figure 2 DONET records without filtering of 2012 off the west coast of northern Sumatra earthquake (Broadband seismometer with sampling rate of 20 Hz).

Figure 3 Tsunami records obtained by DONET stations of 2011 off Tohoku earthquake. All traces are filtered by 10,000 – 100 seconds.

Figure 3 Tsunami records obtained by DONET stations of 2011 off Tohoku earthquake. All traces are filtered by 10,000 100 seconds.

Figure 4 Tsunami records obtained by DONET stations of 2010 off the eastern coast of the Chichijima earthquake. All traces are filtered by 1,000 – 100 seconds.

Figure 4 Tsunami records obtained by DONET stations of 2010 off the eastern coast of the Chichijima earthquake. All traces are filtered by 1,000 100 seconds.