Tsunami South India

2005-05-10T15:32:00.000+05:30

3 Dimensional View of Sethusamudram

Sedimentation in Palk Bay, Gulf of Mannar

2005-05-10T03:23:00.000+05:30

2001 Current Science paper by Chandramohan et al., click here to download.

Some Basic Facts on the First Tsunami Wave

2005-04-10T18:01:00.000+05:30

December 26th Earthquake onset time : 6.29 am IST

Tsunami Wave Arrival Time (WAT)1,
Wave Travel Time (WTT), Wave Speed

Chennai WAT 8.40 am WTT - 2 hrs 11 min (131 min)
Distance from Epicenter (DfE) – 2020 km
Wave Speed – 15.41985 km / min
925.19084 km / hr

Cuddalore WAT 8.00 am WTT - 1 hr 31 min (91 min)
DfE - 1990 km
Wave Speed - 21.86813 km/min
1312.08791 km/hr

Tuticorin WAT 9.57 am WTT - 3 hrs 28 min ( 208 min)
DfE – 2040 km
Wave Speed - 9.80769 km / min
588.46154 km/hr

Kochi WAT 11.10 am WTT - 4 hrs 41 min ( 281 min)
DfE - 2270 km
Wave Speed - 8.07829 km/min
484.69751 km/hr

1Data from Tide gauges maintained by Survey of India (at (Vishakapatnam Port Trust, Tuticorin Port Trust, Kochi Port Trust and Mormugao Port Trust) acquired and processed by the National Institute of Oceanography (NIO), Goa and posted at its website http://www.nio.org/jsp/tsunami.jsp

The website also has given the WAT data shared with it by the Survey of India for Cuddalore and Chennai.

Note: The NIO website has a map which shows the locations of the tide gauzes network maintained by the Survey of India. In it, Nagapattinam is marked as one among the various locations. However, no WAT data is presented for this location in the NIO website. Could it be due to the destruction and the loss of the tide guaze itself at Nagapattinam?

Also note: NIO had collected the data directly from the VPT, TPT, KPT and MPT and had processed the data by itself. However, it has not done the same for Chennai, Cuddalore and Nagapattinam. It had merely relied on the data shared with it by the Survey of India. Does this mean, that the gauzes at these ports had been destroyed by the tsunami and the SoI had only empirically observed facts to be shared with NIO? Could the lack of data at Nagapattinam mean, that even for sharing the empirically observed data, no port officials were available even for the Survey of India?

Epicenter Distance Map; Indian Ocean Tsunamigenic Areas; Hypothetical Indian Ocean Tsunami Animation by Las Alamos National Laboratory

2005-04-10T00:17:00.000+05:30

Distance from epicenters

Download the high resolution map of the distances of various South Indian/Sri Lankan towns from the epicenters of the Dec 26th and March 28th eartquakes.

Tsunamigenic Areas in Indian Ocean

(1) The Andaman sea

(2) Area about 400-500 kilometers SSW of Sri Lanka

(3) The Arabian Sea about 70-100 kilometers south of Pakistan Coast -- off Karachi and Baluchistan

Source: T. S. Murty , A. Bapat , “Tsunamis on the coastlines of India”, Science of Tsunami Hazards, Vol 17, No.3 (1999), p-167 to 172

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Animation of a hypothetical tsunami generated by a meteor falling in the Indian Ocean

This is a hypothetical animation of a tsunami generated by a meteor falling in the Indian Ocean 4000 km south of Cape Comorin. The cavity was 38 km wide and 4000 meters deep.

Note in this animation: The tsunami wave reaches Cape Comorin at 4 hours and embraces the southwest and the southeast coast of India and the coast of Sri Lanka, there after.

This animation can be downloaded from:
http://t14web.lanl.gov/Staff/clm/tsunami.mve/tsunami.htm . The file name is: INDIA.zip

This site contains numerous animations of tsunamis (as of June, 2001) performed so far using using the SWAN code described in the monograph "Numerical Modeling of Water Waves," by Dr. Charles L. Mader, published in 1988 by University of California Press. The site also says that, ‘A few calculations were performed using the full Navier-Stokes ZUNI or SOLA codes’.

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Distance of various cities/towns of South India and Sri Lanka from the Old and New Epicenters

2005-04-09T16:08:00.000+05:30

Epicenter of the 2004, 26th
December 9R Earthquake: 3.4 N 95.7 E

Epicenter of the 2005, 28th
March 8.7 R Earthquake: 2.093 N 97.016 E

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Distance of various cities/towns
of South India and Sri Lanka from
the Old and New Epicenters:

All distances shown in Kilometers

Red - Dec 26' 04 Black - March 28' 05

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Chennai

2020

2200

Kalpakkam Reactors

1990

2180

Kalpakkam DAE Quarters

2000

2180

Marakkanam

2000

2180

Pondicherry

1990

2180

Cuddalore

1990

2170

Thirumullaivayal

1960

2140

Tranquebar

1950

2130

Karaikal

1940

2120

Nagapattinam

1940

2120

Vedaranyam

1920

2100

Point Pedro

1860

2030

Mullaithivu

1770

1950

Trincomalee

1710

1870

Batticola

1630

1790

Hambatota

1640

1800

Galle

1740

1900

Kaluthura

1780

1940

Colombo

1800

1960

Male (Maldives)

2480

2630

Ernakulam

2270

2450

Kayankulam

2220

2390

Kollam

2210

2360

Thiruvanathapuram

2160

2320

Colachal

2110

2270

Cape Comorin

2080

2240

Kudankulam

2060

2220

Kulasekarapattinam

2040

2200

Thiruchendur

2030

2200

Tuticorin

2040

2200

Vembar

2020

2190

Rameshwaram

1930

2100

Dhanushkodi

1910

2090

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Credits and Sources

2005-04-08T10:23:00.000+05:30

History of Tsunamis that have hit South India

A very comprehensive compilation of all the available literaure on the tsunamis that have hit the South Indian Coastline has been made by Dr.Lareef Zubair of International Research Institute for climate prediction at Coumbia University, USA. It is available here.

Here is Dr.Zubair's blog.

Satellite Bathymetry data

Professor David T.Sandwell of Scripps Institute of Oceanography, La Jolla, CA, USA . The data can be accessed from here .

DEM creation free software

Mr.John Childs's BLACKART v 4.02 . Mr.Childs's web portal, from where the software can be downladed can be accessed from here.

DEM rendering 3 D GIS free software

Mr.Richard Horne's 3 DEM v.18.9.9. The web portal from where the software can be downloaded can be accessed from here .

Thanks to:

Mr.Richard B.Cathcart, who is a constant source of encouragement.

Technique used by me to measure the width of the continental shelf:

1. A map of the area was prepared using the commercial GIS software Mapinfo Professional v.7 using its World data set.

2. Sandwell's bathymetry map for the area was then aligned with this Mapinfo map, using the commercial image processing software Photoshop CS.

3. The 'Mapinfo aligned Sandwell bathymetry map' was then opened in Mapinfo Pro. Co-ordinates were then registered for the various locations.

4. The measuring tool available in the software was then used to measure the width of the continental shelf as presented in Sandwell's map.

5. The measured distance was then verified for its accuracy from the published data on the actual measurement of the width of the continental shelf. Only one study is available so far, for this area, and that is on the Mahabalipuram micro-region. The work is by G.Gaitan Vaz: "Relict coral reef and evidence of Pre-Holocene sea level stand off Mahabalipuram, Bay of Bengal" in CURRENT SCIENCE, Vol.71,No.3, 10 August 1996.

The value for the width of the Mahabalipuram continental shelf measured virtually and presented by me here, interestingly, coincides with the value generated by the field study by Dr.G.G.Vaz

2005-04-07T17:39:00.000+05:30

csmr

Reasons for attempting a morphological classification of the CSMRs

2005-04-07T01:20:00.000+05:30

Why should we attempt this classification in the first place?

The shape, structure and the alignment of the CSMRs seem to have played a great role in influencing the pattern in which the approaching tsunami waves (and also the waves generated by Tropical Cyclones) had been deflected on the shores.

Provisional morphological classification of the Continental Shelf Micro-Regions (CSMRs)

2005-04-07T00:16:00.000+05:30

From the last post, I now attempt at a classification of the continental shelf micro-regions (CSMRs) of South India and Sri Lanka based on their morphological characteristics.

I am able to discern 8 morphologically distinct CSMRs :

1. CSMR that is wide and jutting over its neighbouring MR and dips vertically at the shelf break : Palar estuary to Chennai stretch

2. CSMR that is relatively narrow and slopes gradually initially and dips vertically at the shelf break : Marakkanam to Palar estuary stretch

3. CSMR that dips steeply directly from the shoreline into the sea bed over a moderate distance : Poompuhar to Pondicherry stretch

4. CSMR that is moderately wide, flat and table top like initially and falls vertically at the shelf break later : Kodikkarai/Vedaranyam to Karaikal stretch, Point Pedro area, Tiruchendur to Cape Comorin stretch, Colachal to Ernakulam stretch

5. CSMR that is very wide, flat and table top like initially and falls vertically at the shelf break later : Cape Comorin to Colachal stretch

6. CSMR that is very narrow and flat initially and falls vertically at the shelf break later : Mullaitivu to Pottuvil stretch, South Srilanka coast, Galle to Puttalam stretch

7. CSMR that is moderately narrow and sloping intially and falls vertically at the shelf break later : Tuticorin to Tiruchendur stretch

8. CSMR that is flat, wide and table top like and does not have a shelf break zone : Northern end of Gulf of Mannar, Adam's Bridge ,Palk Bay and Palk Strait

Morphology of the Continental Shelf around South India and Sri Lanka

2005-04-06T18:24:00.000+05:30

Let us quickly summarise the notable features of the Continental Shelf (CS):

A) Comparison of Width

1. The CS of the east coast is much narrower than that of the west and the southern coasts of India.

2. The land mass of India and Sri Lanka are linked to each other in-continuum by the CS at northern portion of Gulf of Mannar (GOM), Adam's Bridge (AB), Palk Bay (PB) and Palk Strait (PS).

3. The CS around Sri Lanka in general is very narrow. However, the CS of the northern and north - western coast of Sri Lanka is broader.

4. The provisional measurements of the shelf break of CS above are as follows:

a) North eastern coast stretching from Palar estuary to Chennai - 40 to 50 km

b) CS adjoining Marakkanam - Palar Estuary stretch - ----------- 20 km

c) CS adjoining Poompuhar - Pondicherry ----------------------- 10 to 20 km

d) CS adjoining Vedaranyam - Karaikal -------------------------- 80 to 20 km

e) Point Pedro -------------------------------------------------- 40 km

f) Mullaitivu ---------------------------------------------------- less than 10 km

g) Trincomalee ------------------------------------------------- less than 3 km

f) Batticola ------------------------------------------------------ 5 km

g) Pottuvil --------------------------------------------------- 5 km

h) Galle - Colombo stretch--------------------------------------- 10 km

i) Tuticorin to Kudankulam -------------------------------------- 20 km

j) Cape Comorin to Colachal -------------------------------------- 120 to 160 km

k) Trivandrum --------------------------------------------------- 40 to 50 km

l) Kollam --------------------------------------------------------- 70 km

m) Ernakulam ---------------------------------------------------- 40 to 50 km

B) Alignment pattern of the CS in the various regions:

1. Palar to Chennai stretch is aligned in the N-S direction. It falls to 100 - 130 meters depth gradually over a distance of 40 to 50 km. From then on, the CS falls steeply to a depth of 2000 meters within a span of say 10 km.

2. Marakkanam to Palar estuary stretch is aligned in a NE-SW direction. The CS falls gradually for about 20 km at Marakkanam, then it dips suddenly to 1000 meters within a distance of 10 km, then the sea bed slopes gradually to 2000 meters over a distance of say 60 to 70 km.

3. Poompuhar to Pondicherry stretch is aligned in the N-S direction. The CS falls steeply from the shoreline to 1000 meters with in a spsn of say 10 km. However, the sea bed dips gradually from thereon, to reach a depth of 2000 meters in a span of 40 km.

4. The features of the Karaikal to Vedaranyam stretch is remarkably interesting. Here, the shoreline is aligned in the N-S direction. However, the CS is aligned in a NW - SE direction. CS at this stretch is like a flat table, whose brim is located at say 20 km from the Karaikal shoreline and at say 80 km from the Vedaranyam - Kodikkarai shoreline. The depth at which this CS is located is sub 20 meters. From this depth the CS taks a vertical dive to a depth of 2000 meters in a span of 5 to 10 km.

5. Point Pedro shoreline is aligned WNW - SE, whereas its CS is aligned NW - SE. The shape and depth of this region's CS is similar to the Karaikal - Vedaranyam CS stretch. It is flat and stretches to a distance of say 40 km. It also, like the previous region, falls from a depth of 20 m to 2000 m within a span of say 5 km.

6. Mullaitivu to Pottuvil shoreline is aligned NW-SE. The CS is also aligned similarly. The CS runs flat to east for about 5 to 10 km. From there it falls steeply to a depth of 2000 m within a span of 5 km.

7. The sea bed of Gulf of Mannar is step like.

8. The CS of the south coast of Sri Lanka is broader in the east ( say 10 to 30 km) (around Hambatota) and narrower in the west (say 5 km). The CS falls gradually over this distance initially, then dips to a depth of 3000 m, in a span of 20 km. There is no much difference between the alignment of the shoreline and the CS in this region.

9. The shoreline and the CS of the Galle - Colombo stretch is aligned in the S-N direction. The fall of the CS is gradual for a span of say 10 km, which falls steeply to 2000 meters at Galle, to 1000 m at Colombo within a span of 10 km.

10. The stretch between Colombo and Puttalam is simililar in all aspects except that the CS falls only to a depth of 500 m here.

11. The region of CS located north of Puttalam is the region that comprises of the northern portion of Gulf of Mannar, Adam's Bridge and Palk Bay. This CS is flat and tabletop like and its depth varies between say 5 to 100 meters. The CS keeps both the land masses of South India and Sri Lanka in continuum.

12. The shoreline and the CS between Tuticorin and Tiruchendur are aligned almost in the N-S direction. The CS falls gradually over a distance of 20 km initially, then dips steeply to a depth of 500 m with in a span of 5 km.

13. The shoreline between Tiruchendur and Cape Comerin is aligned in the ENE-WSW direction. However, the CS is aligned NE-SW direction. The CS is flat here, and stretches to a distance of say 20 to 60 km initially. It taks a dip to 500 meters then within a span of say 5 km.

14. The CS of Cape Comerin - Colachal stretch is flat and table top like. Up to a distance of 120 to 160 km, the sea depth is sub 100 meters. Beyond this distance, the CS falls steeply to a depth of 1000 meters within a span of 10 km.

15. The CS of the south western coast of South India that stretches between Colachal to Ernakulam is flat, and the CS break occurs at a distance of say 40 (Trivandrum and Ernakulam) to 70 km (Kollam) from the shoreline. The CS then dips steeply to a depth of (only) 500 meters, in a span of another 5 to 10 km.

2005-04-06T16:29:00.000+05:30

Another view with place names

2005-04-06T14:19:00.000+05:30

Sea Bed around Sri Lanka and South India

Tsunamis of South India

2005-04-05T00:02:00.000+05:30

Tsunamis have hit South Indian west and east coasts in the years 1881, 1883 and in 1941. The most recent and the most damaging tsunami is of course the tsunami of December 26, 2004.

To understand how the tsunami had interacted with these two coasts of South India, is the main purpose of this blog.

This we shall start with a 3 dimensional model of the sea bed around South India.