Some Basic Facts on the First Tsunami Wave

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?