Dense O cean floor N etwork system for E arthquakes and T
sunamis ( DONET)
Dense O cean floor N etwork system for E arthquakes and T
sunamis ( DONET)
Yoshiyuki KANEDA Yoshiyuki KANEDA DONET GROUPDONET GROUP
Department of Oceanfloor Network System Development for Earthquakes and TsunamisDepartment of Oceanfloor Network System Development for Earthquakes and Tsunamis
DONETDONETJapan Agency for Marine-Earth Science ant TechnologyJapan Agency for Marine-Earth Science ant Technology
JAMSTECJAMSTEC
Previous research in the Nankai trough
NANKAI TROUGH
KII peninsula
year age A B C
1605 KEICHO
1707 HOUEI
1854 ANSEI
1944 SYOWA
1946 SYOWA
Historical EQs. in the Nankai trough
A;Nankai EQ.B;Tonankai EQ.C;Tokai EQ.
?
PSP
Distribution of significant deep structures along the Nankai Trough
Tonankai
TokaiNankai
111 years
7days
103 years
97days
①①
②②
③③
103years
97days
TonankaiNankai③③
111 years7days
Tonankai +Tokai
Nankai②②Tonankai +Nankai
①①
The results of mega-thrust EQ. recurrencecycle simulation in the Nankai trough
Advanced Ocean Floor Cable System
Outline & Concept
Image
Ocean floor cable network system as MEXT project
Sensors
over20Seismometers
20 Pressure gauges
Outline of ocean floor cable system
Landing Station
Backbone cable system
Brunch unit
Sensor systemSeismometers,
Pressure gauge
・ Extendable Advanced Sensor System・ Replaceable Observatory Node
・ High Reliability Backbone Cable SystemSystem Concept
Seismometer
Pressure gauge
Other
Broadband seismometer
Strong motion accelerometer
Sensors
9
Seismometer evaluation based on the frequency bands
Case 1
Case 2 Case 3
Installations of Sensors
・ Speedy evaluation and notification for earthquakes and tsunamis.
・ Provide observed data such as ocean floor deformation derived from pressure gauges to improve the simulation and modeling researches about the mega- thrust earthquakes. (Data assimilation)
・ Understanding of the interaction between the crust and upper mantle around subduction zone.
Data Application
Maintenance systems of JAMSTECMaintenance systems of JAMSTEC
3000m Class ROV 「 HYPER-DOLPHIN 」
7000m class deep sea ROV「 KAIKO7000 」
Deep Sea Cruising AUV 「 URASHIMA 」
Technology developmentTechnology development
Cable extension system development
Network Array Planning
Advanced Ocean Floor Cable System
Network array planning
Kii PeninsulaTonankai Seisomogenic Zone
Nankai Seisomogenic Zone
sensor
node
Back bonecable
Advanced Ocean Floor Cable System
Image
The resolution test of hypocenter determination using oceanfloor network
Network Array Good resolution!!
▲: Land GPS and Pressure gauge
Resolution
・ Land GPS :horizontal; 1mmvertical; 3mm
・ Pressure gauges: 10mm
Ocean network system(36 pressure gauges)+ Land GPS
The checker board test for offshore geodetic data analyses
Land GPSModel
40 km square checker boardSlip rate : ±1m
Good resolution!!Around network array
Advanced Ocean Floor Cable System
Sensors 1) Multi seismometers for ・ Broad band phenomena ・ Strong Motion ・ Micro EQs.2) Precise pressure gauges for ・ Tsunami ・ Ocean floor deformation3) Data s t o rage function at the trouble
Under development* Precise ocean floor deformation monitoring system* Advanced in lined sensor cable system
Provide the estimated results before arriving seismic wave in populated area
Observe seismic wave by network
・ Magnitude・ Focal mechanism・ Asperity area
Synthetic waveform
Research on real time estimation of source elements using network data (regional analysis)
K-net
Ocean floor network
Tonankai Eq.
Analyze with theoretical data
Database
①
②
③
Gather data
④⑤
Construct source model and pre-estimate Tsunami waveform
Analyze③
Structure model by JAMSTEC
Data assimilation : using pressure gauge data as ocean floor deformation monitoring Keyword: Long term observatory
Improve the simulation model
Observation data
Data assimilation
Predict 2
Predict (n)
Time range for data assimilation
Optimization
time
Long-term predictusing predict (n)
time
Without improvement
Improvement
Improvement Simulation model
Network data flowNetwork data flow
Network
Land Station
JAMSTECData center
JMAOthers
analyses
analyses
Advanced Ocean Floor Cable System
Image
Sensors
・ over20 Seismometers・ 20 Pressure gauges
Project・ FY2006-FY2009 4 years
System Concept
・ Redundancy, Extension and advanced maintenance system using the looped cable system, junction boxes and the ROV/AUV etc.
・ Speedy evaluation and notification for earthquakes and tsunamis.
・ Provide observed data such as ocean floor deformation derived from pressure gauges to improve the simulation and modeling researches about the mega-thrust earthquakes.
・ Understanding of the interaction between the crust and upper mantle around subduction zone.
Data Application
Keywords: Landing both cable end, Node, Brunch unit
Park et al. (2002)
Philippine sea plateSeismogenic zone
Nankai trough
Target point
Future PlanFuture Plan
Borehole observatory will be connected with Ocean Floor Network System
Future Network for Geosciences
Now we are here!!
29
Future PlanFuture Plan
Buoy systems
AUV
Ocean floor network systems
Satellite systems
Aero systems
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