Two main periods have been observed after analyzing the Deep-ocean Assessment and Reporting of Tsunamis (DART) data: 14 min and 26 min (Makela et al., 2011).
The Deep-ocean Assessment and Reporting of Tsunamis (DART) system, operated by the Pacific Marine Environmental Laboratory (PMEL) of the National Oceanic and Atmospheric Administration NOAAalsoalso utilizes Paros pressure gauges for the early monitoring of offshore tsunamis over the quasi-global ocean (González et al., 2005).
The National Oceanic and Atmospheric Administration NOAAA) employs the Deep-ocean Assessment and Reporting of Tsunamis (DART) real-time monitoring system to develop effective tsunami forecasting methods and tools (Titov et al. 2005; Tang et al. 2009).
Triangles, diamonds and squares indicate the locations of coastal (tide or wave) gauges, offshore GPS wave gauges and ocean-bottom tsunami sensors or DART (Deep-ocean Assessment and Reporting of Tsunamis) systems, respectively.
Eight large earthquakes (M w 7.5 8.6) from 2007 to 2015 were tsunamigenic as detected by the ocean-bottom pressure observations of the Deep-ocean Assessment and Reporting of Tsunamis (DART) system (e.g., Mungov et al. 2013) (Fig. 2).
Details of the tsunami model, earthquake fault parameters, and incorporation of data from buoys of Deep-ocean Assessment and Reporting of Tsunamis (DART) are presented in Appendix 2. Fig. 4 Band-pass filtered tide gauge record from Chichijima Island showing observed tsunami waveforms (dark blue) and computed tsunami waveforms (light blue).
These large tsunamis were clearly observed at offshore tsunami observation stations around Japan, such as cabled ocean-bottom pressure gauges (OBPGs) (e.g., Meteorological Research Institute, 1980) and GPS buoys (e.g., Kato et al., 2005), as well as by the worldwide Deep-ocean Assessment and Reporting of Tsunamis (DART) buoy systems (e.g., Titov et al., 2005).
The giant tsunamis generated by the 2011 Tohoku and the 2010 Chilean earthquakes were recorded by basin-wide OBP gauges operated by the Deep-Ocean Assessment and Reporting of Tsunamis (DART) system (González et al., 1998), and by the seafloor cable system of the Japan Agency for Marine-Earth Science and Technology (JAM-STEC) (Momma et al., 1997; Hirata et al., 2002).
Tsunamis in the open ocean can potentially be detected both by buoys of the U.S. Deep-ocean Assessment and Reporting of Tsunamis (DART) array (e.g., González et al., 2005) and by altimeters installed on satellites (e.g., Okal et al., 1999; Gower, 2005).
The Deep-ocean Assessment and Reporting of Tsunamis (DART), developed by NOAA National Oceanic and Atmospheric Administrationn) of the USA, records water levels using bottom pressure gauges, and sends signals to a surface buoy via acoustic telemetry in the ocean, then via satellites to a land station in real time [50].
This network, called Deep Assessment and Reporting of Tsunamis, is composed of two parts: a sea floor sensor and a buoy that relays tsunami information to warning centers on the ground by satellite communication.
