Number
of OBSs
(Hachijojima-Torishima) 1
(Hachijojima-Torishima) 2
Click the Area name, you can move to each cruise page.
The earthquakes occurred underneath the ocean bottom can be observed on land, but the size of detectable earthquakes has the limit and focal distribution cannot know accurately.
Observations by the ocean bottom seismograph (OBS) allow to detect the microearthquakes occurred underneath the sea floor and obtain the accurate focal distribution.
Survey Specification
Ocean Bottom Seismograph (OBS) :
Maximum Depth : 6000m
Sensor : Three-component Geophone & Hydrophone
[One vertical and two horizontal components, Natural frequency:4.5Hz, Sensitivity:0.69V/inch/s(OPEN)]
Recording System : Sampling continuously (Timer control is possible for start time.)
Recording Media : DAT(digital audiotape) or Hard Disk
Sampling Rate : 100Hz
Power : Rechargeable lithium-ion or alkali battery
Accoustic Communication & Release System: Transponder,Transducer, Forced electrochemical errosion
Attached Parts : Weight, Flush light, Radio beacon
Pressure Resistant Container : 17 inch glass sphere
| Earthquake Observations | ||||
|---|---|---|---|---|
| Year | Survey Area |
The Number of OBSs |
Period (Cruise ID) | |
| 2001 | Nankai Trough / Off Kumano | 24 | deploy | Nov.4.-Dec.3.2001 (KR01-14) |
| retrieve | Feb.4.-Feb.13.2002 (KY02-02) | |||
| 2003 | Off Kii Peninsula / Nankai Trough | 30 | deploy | Mar.8.-Mar.15.2003 (KY03-03) |
| retrieve | May.23.-May.30.2003 (KY03-05) | |||
| 2004 | Off Kochi / Nankai Trough | 27 | deploy | Mar.8.-Mar.16.2004 (KY04-03) |
| retrieve | May.23.-May.30.2004 (KY04-05) | |||
| 2005 | Off Shima Peninsula / Nankai Trough | 28 | deploy | Mar.12.-Mar.18.2005 (KY05-03) |
| retrieve | Jun.3.-Jun.10.2005 (NT05-07) | |||
| 2006 | Northern Izu-Bonin (Hachijojima-Torishima) 1 |
36 | deploy | Apr.19.-Apr.28.2006 (KY06-05) |
| retrieve | July.18.-Jul.30.2006 (KY06-08) | |||
| 2006 | Northern Izu-Bonin (Hachijojima-Torishima) 2 |
3 | deploy | July.18.-Jul.30.2006 (KY06-08) |
| retrieve | Sep.30.-Oct.25.2006 (KR06-13) | |||
| 2008 | Off Kii Peninsula / Nankai Trough | 39 | deploy | Jul.24.-Jul.31.2008 (KY08-06) |
| retrieve | Dec.8.-Dec.13.2008 (KY08-11) | |||
| 2008 | Hyuganada / Nankai Trough | 160 | deploy | Dec.7.-Dec.26.2008 (KR08-16) |
| retrieve | Jan.14.-Jan.28.2009 (KY09-E01) | |||
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Click the Area name, you can move to each cruise page.
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