| Ocean Floor Networks in Japan – Towards Disaster Mitigation on Earthquakes and Tsunamis
日本的海底觀測網-以地震海嘯減災為目標
Based on lessons learned from 2011 East Japan Earthquake/Tsunami, we recognized the importance of real time monitoring of these natural hazards. Therefore, as real time monitoring system, DONET1 (Dense Ocean floor Network for Earthquakes and Tsunamis) was deployed and DONET2 is being developed around the Nankai trough southwestern Japan. Furthermore, DONET1 and DONET2 with multi kinds of sensors such as broadband seismometers and precise pressure gauges will be expected to monitor slow events such as low frequency tremors and slow earthquakes for the estimation of seismic stage which is the inter-seismic or pre-seismic stage based on slow event simulation researches. Not only slow events, but also the change of micro seismicity will be significant for the estimation of seismic stage.
Furthermore, advanced simulations such as the recurrence cycle of mega thrust earthquakes, tsunami inundation and seismic response on buildings /city are very important for future disaster mitigation programs and related measures. Now, we are developing to the Tsunami estimation system with the integration of real time monitoring data and tsunami simulation database. If this system is practical, it is very powerful for the estimation of damages by tsunamis and evacuation and rescue.
Finally, Around off Tohoku seismogenic zone, New Inline cable systems are under construction, so Japanese government are preparing and constructing ocean floor networks for Disaster mitigation and Predictive researches steady.
從2011年東日本地震/海嘯的經驗中，我們認清了這些天然危害即時監測的重要性。因此，作為即時監測系統的DONET1以及開發中的DONET2都將被佈署在日本西南的南海海槽附近。在這兩組系統中裝載了不同種類的感應器，例如寬頻地震儀與精密水壓計，它們被預期用來監測緩慢事件，例如低頻微震與慢性地震，這些從慢性地震的模擬研究成果歸納，屬於地震與地震之間、或地震前會發生的現象，可作為地震發生階段的估計。不只是慢性地震，微地震的改變對於地震階段的估計也有重大意義。
此外，進一步的模擬，像是巨大逆衝地震的再現週期、海嘯氾濫、與建築/城市的地震反應，對未來減災計畫與評量都相當重要。目前，我們正整合即時監測資料與海嘯模擬資料庫來發展一套海嘯評估系統，如果此系統確實實用，它在海嘯災損評估、疏散與救援的用途將會很強大。
最後，大約在東日本地震帶之外，新的(Inline)電纜系統正在興建，這也說明日本政府正在為減災準備和建構海床監測網路，相關預報研究也正在紮實地進行中。 |
