Real Time Observation of Tsunami, Wave and Tide by GPS Buoy'

1
Real Time Observation of Tsunami, Wave and Tide
by GPS Buoy.

• Yukihiro TERADA
• Kochi National College of Technology
• Teruyuki KATO
• Earthq. Res. Inst., Univ. Tokyo
• Toshihiko NAGAI ,
• Port and Airport Res. Inst.
• Shunichi KOSHIMURA
• Grad. Sch. Eng., Tohoku Univ.
• Yoshiki SUKEYASU and Hidetoshi MIYAKE
• Hitachi Zosen Corp.

2
Tsunami sensors

• Tide gauge
• Super sonic sensors
• Pressure sensors
• Satellite altimetry
• GPS buoy

3
Outline

• Concept of GPS buoy
• History of developing GPS buoy
• Recent progress
• Summary

4
Requirements for tsunami sensorfor disaster
mitigation

• Early detection of Tsunami before its arrival.
• Real-time transmission of data to local people.
• Accurate determination of sea surface heights.
• Long-term sustainability of the system.
• Cost effectiveness for multiple deployments.

GPS buoy would be an answer.
5
Basic concept
6
Important specifications of GPS buoy for
monitoring tsunami

• Real-time detection of SSH using RTK GPS.
• 2-3cm accuracy in estimating SSH.
• High-rate (up to 20Hz) sampling of data.
• Real-time transmission of data using radio.
• Real-time dissemination of results through. web
  page.

7
History of Development

• 12-years of history since 1996
• First experiment in Sagami Bay in 1997
• Second experiment in March 1999
• using dual buoys for 10 days
• Third experiment off Ofunato
• Jan. 2001 to Jan. 2004
• Successful detection of tsunami
• 2001Peru and 2003Tokachi eqs.
• Fourth phase since April 2004
• Successful detection of tsunami
• 2004 Off-Kii Pen. Earthquake
• National project began in 2006

8
Proto-type GPS buoy first experiment -
January 1997
9
History of Development

• 12-years of history since 1996
• First experiment in Sagami Bay in 1997
• Second experiment in March 1999
• using dual buoys for 10 days
• Third experiment off Ofunato
• Jan. 2001 to Jan. 2004
• Successful detection of tsunami
• 2001Peru and 2003Tokachi eqs.
• Fourth phase since April 2004
• Successful detection of tsunami
• 2004 Off-Kii Pen. Earthquake
• National project began in 2006

10
Second phase experiment (March 18-26, 1999)
Experiment of two buoy system using a spur type
buoy
11
(No Transcript)
12
GPS buoy ? Well type tide gauge
Tide Gauge using GPS buoy
March, 1999
330
13
History of Development

• 12-years of history since 1996
• First experiment in Sagami Bay in 1997
• Second experiment in March 1999
• using dual buoys for 10 days
• Third experiment off Ofunato
• Jan. 2001 to Jan. 2004
• Successful detection of tsunami
• 2001Peru and 2003Tokachi eqs.
• Fourth phase since April 2004
• Successful detection of tsunami
• 2004 Off-Kii Pen. Earthquake
• National project began in 2006

14
GPS buoy established off Ofunato, northeastern
Japan
2003Tokachi
f2.8m H8.2m W12ton Water depth50m
15
The third experiment in Ofunato, northern Japan
2001-2004
16
Original 1Hz data
17
Peru Earthquake JST25/06/2001
GPS Buoy
Tide Gauge
18
(No Transcript)
19
Tsunami record due to Sept. 26, 2003, Tokachi
Earthquake
(60 sec. moving average)
GPS Buoy
GPS?????
Tide gauge
20
History of Development

• 12-years of history since 1996
• First experiment in Sagami Bay in 1997
• Second experiment in March 1999
• using dual buoys for 10 days
• Third experiment off Ofunato
• Jan. 2001 to Jan. 2004
• Successful detection of tsunami
• 2001Peru and 2003Tokachi eqs.
• Fourth phase since April 2004
• Successful detection of tsunami
• 2004 Off-Kii Pen. Earthquake
• National project began in 2006

21
Fourth phase of GPS buoy
Apr. 2004-Mar. 2006 Apr. 2008- in offshore
Muroto, southwestern Japan
22
Southwestern Japan
Kobe
Kii Pen.
Shikoku
23
GPS Tsunami Observation System at Muroto,
Southwestern Japan
24
Real-time monitor of Tsunami
Tsunami due to Sept. 5, 2004, Off-Kii-Pen. Eq.
High freq.
Low freq.
Height 10cm
http//www.tsunamigps.com/
25
(No Transcript)
26
Comparison Tide gauge, Simulation and GPS buoy
Tide gauge Simulation
Height (m)
GPS Tsunami Meter
Time (06/09/2005, Hrmin)
27
June 20, 2004, Typhoon No.6
28
??6? ??16?6?21? ?????
???????????
29
Observation Station
Pressure, Wind (Direction, Velocity) June 21,
2004,Typhoon No.6
West
??
Wind velocity (m/s) Direction (deg.)
Pressure (hPa)
East
967hPa
30m/s
Time
30
Wave Measurement
Height (m)
????
Time
June 21, 2004, Typhoon (Maximum Height 18m)
Height (m)
????
Time
June 23, 2004 (Maximum Height 2m)
31
Typhoon in 2004 Aug. Sep. Oct.
GPS Buoy
32
Lessons learned from a series of GPS buoy
experiments

• GPS buoy is capable of detecting tsunami with 2-3
  cm accuracy to at least 13km distance (about
  10min lead time).
• Real-time monitor of sea surface variability is
  possible.
• Tsunami can be segregated from wind waves by
  simple filtering technique and in near real-time
  manner.
• Reliable buoy can survive even after the passage
  of big typhoons.
• Deployments of GPS buoy to deeper and farther
  open ocean is a challenge.
• Combination with numerical simulation is
  essential for forecasting tsunami at the coast
  Monitor and Forecast.

33
Crash and lost by a ferry boat in March 2006
scratch
34
and we recovered
REF03 50km
REF02 10km
REF01 13km
GPS Buoy (Example) Lat. 3315'55.2012?N Lon.
13402'15.5496?E EHT 45.090m
35
Recent progress

• Improvements of data reliability by reducing
  signal mis-fix, data loss, etc.
• Use of multiple analyses system
• Dual radio transmission for redundancy
• Application to wind wave monitoring and other
  oceanographical observations
• Various sensors installed on the buoy
• Monitoring sea surface by photo
• Dissemination of wave height by FM radio
• Combination with numerical tsunami modeling for
  coastal disaster reduction

36
Cases of data trouble

• Low satellite number (4 or less) and high DOP
• Radio transmission problem
• Signal pass problem
• Parallel operation of multiple softwares
• Addition of GLONASS and GALILEO in future

37
PVD (Point precise Variance Detection Method)
Ocean Platforms Workshop Poster Session
(UTC2001-11-05)
(??????)
38
Recent progress

• Improvements of data reliability by reducing
  signal mis-fix, data loss, etc.
• Use of multiple analyses system
• Dual radio transmission for redundancy
• Application to wind wave monitoring and other
  oceanographical observations
• Various sensors installed on the buoy
• Monitoring sea surface by photo
• Dissemination of wave height by FM radio
• Combination with numerical tsunami modeling for
  coastal disaster reduction

39
Monitoring the ocean by photo
Since August 2008
Transmit the photo every 5 minutes
40
Nationwide Tsunami/Wave Monitoring Network
2006
48 14 6
Since 2006
41
(No Transcript)
42
Summary

• GPS buoy will be a powerful tool for monitoring
  sea surface including tsunami.
• Appropriate design and installation is important
  for long-term sustainability.
• Combination with numerical simulation is
  necessary for precise forecast of tsunami.
• Nationwide offshore tsunami wave monitoring
  system is now under construction.

43
Future challenges

• Improvements of accuracy for longer baseline
  (1cm/1000km)
• Data transmission through comm. satellite
  (currently too expensive)
• Wider application for ocean monitoring (ocean
  current, meteorological conditions etc.)

44
Thank you
45
Thank you
46
Thank you
47
Thank you