After the disastrous tsunami of 2004, researchers have been digging into the past to document all cases of possible tsunamis which happened in the past. We were alerted to the possibility of a tsunami after reading the description of 'the great storm of the 16th, 17th and 18th April, 1847' as described by William Logan in his Malabar Manual.
'The storm originated somewhere beyond the southern islands of the Laccadive group. It swept over islands of Kalpeni and Androth, and did some damage to Kavarathi, but Agathi was apparently beyond the circle of its violence'. ... Kalpeni was also partially submerged by a wave, and the drinking water of the people in wells was spoilt and their stores of food and their houses destroyed. ...it was estimated that from three hundred to four hundred people only had perished in the storm or of famine afterwards and that the others had left the island'.
Of a population of over two thousand five hundred in Androth, nine hundred only remained, the rest having either perished in the storm or dispersed. Two boats with ninety-six males and a number of females belonging to Agatti were caught in the storm and heard of no more.
The tsunami did not spare the Malabar coast either. As Logan reports, The storm wave dashed on the coast in a very unexpected manner and its effects were felt from Cannanore to Chetwai. The wave destroyed the Cannanore Custom house, it came in so suddenly that the officials had hardly time to escape by the rear as the sea swept in at the front. Graphic description of a typical tsunami wave, as those who have watched on TV the visuals of the waves hitting Phuket on 26th December 2004 would recall.
Further south the waves damaged the mouth of the Kotta (Moorad, Vatakara) river and destroyed the Palliyad dam and the cultivation above it over two miles from the mouth of the river. The floods from inland breached the new work on the Conolly canal at Calicut. At Parappanangadi and Tanur private persons suffered much loss from the sudden rise of the sea.
The tsunami altered the topography permanently in Chavakkad, where, Logan records, the sea forced a new and deep opening into the Chavakkad backwater and broke with much strength on the Ennamakkal dam....
The description leaves no room to doubt that it was indeed a tsunami . Considering the lack of proper communication those days, it is likely that the damage - particularly in terms of loss of lives and destruction of property - was much more widespread but was not properly documented.
But is there a record of this tsunami in the annals of tsunami research? We find that there indeed was an earthquake of an estimated magnitude of 7.5 – 7.9 on the Richter scale in 1847 which was followed by a tsunami in the Indian Ocean, but its impact is not known. But the date recorded was 31 October 1847 and the destruction was centred around Great Nicobar Island. An earthquake is also recorded in Zennkoji, Japan on the 8th May 1847, killing nearly 10,000 people. But, no event has been recorded on the dates mentioned by Logan - 16th, 17th and 18th April. Most probably, this event escaped the notice of the researchers, although it is also possible that Logan, writing 30 years after the event, got his dates wrong. As the 2004 tsunami showed us, Calicut is not totally tsunami-proof. It was explained that in 2004, Malabar coast was saved by the protection offered by the Lakshadweep Islands. But, what if these islands are also hit, as seems to have happened in 1847?