Tsunami Warning SystemsTsunami Warning Systems Efficient use of Tide Gauge Efficient use of Tide Gauge

StationsStations

I.V. FineI.V. Fine1,21,2, , F.E. StephensonF.E. Stephenson33, , A.B. RabinovichA.B. Rabinovich1,41,4 and R.E. Thomson and R.E. Thomson11

1 Institute of Ocean Sciences, Sidney, B.C. Canada2 Heat and Mass Transfer Institute, Minsk, Belarus 3 Canadian Hydrographic Service, Sidney, B.C. Canada 4 P.P. Shirshov Institute of Oceanology, Moscow, Russia

The Sumatra-Andaman Tsunami of The Sumatra-Andaman Tsunami of December 26, 2004 (MDecember 26, 2004 (Mww = 9.3) = 9.3)

Phi Phi Island (Photos by J.T. and Carolina Malatesta)

As a result of the Sumatra-As a result of the Sumatra-Andaman Tsunami …Andaman Tsunami …

There has been a strong international commitment to install or upgrade many tide stations and seismic stations.

This is an excellent start, but what can we learn from past experiences?

What will this new network of tide What will this new network of tide gauges look like in 30-40 years?gauges look like in 30-40 years?

What does past experience teach us?

Canadian Arctic GLOSS program in the Indian Ocean

In all probability…In all probability…

“Disaster response” funding will be used to install many instruments and related communication systems

Many nations / agencies will lack the means or the commitments to maintain these networks in the long-term

The ability of these networks to provide effective tsunami warning will decrease

An alternate strategyAn alternate strategy

Before installing new coastal stations and offshore buoys, try to assess the hazards and the warning requirements

Plan the network of stations to provide the required warning times

Implement a network which is sustainable

Tsunami Detection and WarningTsunami Detection and Warning

For an arbitrary tsunami source location, we can estimate a safe warning time (T) -- for any specified coastal site and known warning station – as the time delay between the arrival time at the station and the coastal site

Source

Station

Coastal Site TC

Source

Station

Coastal Site TC

Tsunami sources in the Indian OceanTsunami sources in the Indian Ocean (416 AD-2005)(416 AD-2005)

Most of tsunami source regions in the Indian Ocean are along the Sunda Trench subduction zone (along Burma, Andaman and Nicobar islands, Sumatra and Java). However, there are sources (e.g. 1945) in the NW part of the ocean (Murray Ridge)

(courtesy of V.K. Gusiakov [2005])

1945

2004

1797

1861

General seismicity of the Indian Ocean General seismicity of the Indian Ocean 416 AD - 2005416 AD - 2005

(courtesy of V.K. Gusiakov [2005])

The main seismic area is the extensive subduction zone near the NE margin of the Indian Ocean. However, there are also other zones: the SW, Central, Carlsberg and Murrey ridges

Tsunami Detection and WarningTsunami Detection and Warning

For an arbitrary tsunami source location, we can estimate a safe warning time (T) -- for any specified coastal site and known warning station – as the time delay between the arrival time at the station and the coastal site

Source

Station

Coastal Site TC

Source

Station

Coastal Site TC

Delay (minutes) between a “Nicobar” warning Delay (minutes) between a “Nicobar” warning station and the City of Vishakhapatnam station and the City of Vishakhapatnam

A “Nicobar” site would provide an optimal warning time (> 2 hours) for a tsunami source located in the SE Indian Ocean (similar to the Dec. 26, 2004 earthquake). However, such a site would not be optimal for tsunami sources located in the West Indian Ocean.

60E 65E 70E 75E 80E 85E 90E 95E 100E0N

5N

10N

15N

20N

25N

Nikobar

Vishakhapatnam

-240

-180

-120

-60

-30

0

60

120

180

240

Delay (minutes) between an “Andaman” warning Delay (minutes) between an “Andaman” warning station and the City of Vishakhapatnamstation and the City of Vishakhapatnam

An “Andaman” site would provide a less optimal warning time (about 1.5 hrs) for sources in the SE Indian Ocean compared with a “Nicobar” site, but would improve warning time (> 2 hrs) for sources in the eastern part of the Indian Ocean.

60E 65E 70E 75E 80E 85E 90E 95E 100E0N

5N

10N

15N

20N

25N

Andaman

Vishakhapatnam

-240

-180

-120

-60

-30

0

60

120

180

240

Delay (minutes) between a “Minicoy” warning Delay (minutes) between a “Minicoy” warning station and the City of Vishakhapatnamstation and the City of Vishakhapatnam

A “Minicoy” site would provide excellent warning time (2-4 hrs) for sources in the West Indian Ocean but poor warning for sources in the SE Indian Ocean (such as the Dec. 26, 2004 earthquake).

60E 65E 70E 75E 80E 85E 90E 95E 100E0N

5N

10N

15N

20N

25N

Minicoy

Vishakhapatnam

-300

-240

-180

-120

-60

-30

0

60

120

180

240

Delay (minutes) for Vishakhapatnam for Delay (minutes) for Vishakhapatnam for all three warning stations combinedall three warning stations combined

Simultaneous operation of all three warning stations would remarkably improve the safety (time delay) for Vishakhapatnam. Distant waves, excluding those that came from the south, would be recorded 2-4 hours prior to the arrival of the waves.

60E 65E 70E 75E 80E 85E 90E 95E 100E0N

5N

10N

15N

20N

25N

Minicoy

Vishakhapatnam

-300

-240

-180

-120

-60

-30

0

60

120

180

240

Andaman

Nikobar

Delay (minutes) between a “Nikobar” warning Delay (minutes) between a “Nikobar” warning station and Phuket (Thailand) station and Phuket (Thailand)

A “Nicobar” site would provide an optimal warning time (> 1.5 hours) for a tsunami source located off the western coast of Sumatra (similar to the Dec. 26, 2004 earthquake) and for West, North, and SE Indian Ocean. However, such a site would not be useful for tsunami sources located between the Nicobar/Andaman Islands and the maincoast (in the Strait of Malacca)

80E 85E 90E 95E 100E0N

5N

10N

15N

20N

25N

NikobarPhuket

-240

-180

-120

-60

-30

0

60

120

180

240

Delay (minutes) between an “Andaman” Delay (minutes) between an “Andaman” warning station and Phuket (Thailand)warning station and Phuket (Thailand)

An “Andaman” site will provide better warning time (> 2.0 hours) than a “Nicobar” site for a tsunami source located in the northern part of the Andaman Sea, but will be much less useful for a wave source near Sumatra (similar to the Dec. 26, 2004 earthquake). Such a site would also not be useful for tsunami sources located between the Nicobar/Andaman Islands and the coast of Thailand (in the Strait of Malacca)

80E 85E 90E 95E 100E0N

5N

10N

15N

20N

25N

Andaman

Phuket

-240

-180

-120

-60

-30

0

60

120

180

240

Delay (minutes) between an “open ocean” Delay (minutes) between an “open ocean” warning station and Phuket (Thailand)warning station and Phuket (Thailand)

80E 85E 90E 95E 100E0N

5N

10N

15N

20N

25N

BouyPhuket

-240

-180

-120

-60

-30

0

60

120

180

240

An “open ocean” station deployed in the Strait of Malacca between Nicobar Islands and Phuket would significantly improve the situation for sources located between the Nicobar/ Andaman Islands and the mainland coast (Malacca Peninsula). It would provide warning times > 1 hour.

BC project

-132

50

Victoria

Bamfield

Bella Bella

Langara

Cape St. James

Neptune-2

Winter Harbour

Neptune-1

Tofino

X= 0.00 Y= 0.00 Z= 0

BC project

-132

50

Victoria

Bamfield

Bella Bella

Langara

Cape St. James

Neptune-2

Winter Harbour

Neptune-1

Tofino

X= 0.00 Y= 0.00 Z= 0

BC project

-132

50

Victoria

Bamfield

Bella Bella

Langara

Cape St. James

Neptune-2

Winter Harbour

Neptune-1

Tofino

X= 0.00 Y= 0.00 Z= 0

Some examples for ChileSome examples for Chilechile project

-70-80

-20

-30

-40

Valparaiso

Antofagasta

Arica

Callao

Puerto Montt

San Felix

Station-2

Juan Fernandez

DART 32401

Talcahuano

X= -76.41 Y=-20.12 Z= 4725chile project

-70-80

-20

-30

-40

Valparaiso

Antofagasta

Arica

Callao

Puerto Montt

San Felix

Station-2

Juan Fernandez

DART 32401

Talcahuano

X= -70.78 Y=-18.50 Z= 862

Several scenarios for ValparaisoSeveral scenarios for Valparaisochile project

-70-80

-20

-30

-40

Valparaiso

Antofagasta

Arica

Talcahuano

Callao

Puerto Montt

Mobile

San Felix

Station-2

Juan Fernandez

DART 32401

X= 0.00 Y= 0.00 Z= 0 chile project

-70-80

-20

-30

-40

Valparaiso

Antofagasta

Arica

Talcahuano

Callao

Puerto Montt

San Felix

Station-2

Juan Fernandez

Mobile

DART 32401

X= -77.76 Y=-44.75 Z= 3036

ConclusionsConclusions

Modeling can be used to provide useful information on safe warning times

This supports decision making about the optimum placement of gauges

The effect of inoperative stations can be immediately accessed

Time delays for data transmission can also be modeled