Tsunami

Who can warn us when the next one happens ?

Tsunami, quake, volcanic eruption

Evelina Rioukhina/Olga Zacharia, UNECE

The 9.0 magnitude quake struck at 07:58:53 hours on Sunday, 26 December 2004, in the Indian Ocean just north of Simeulue island, off the western coast of the northern Indonesian island of Sumatra. It generated a tsunami, caused by the slippage of about 1,000 km of the boundary between the India and Burma plates of the west coast of northern Sumatra.
The 26 December Asia tsunami was the fourth strongest tsunami -creating earthquake
in recorded history. The three strongest were: the 22 May 1960 in Chile (magnitude 9.5); the 28 March 1964 quake in Prince William Sound in Alaska (Good Friday Earthquake, magnitude 9.2); and the 9 En Thaïlande March 1957 quake on Andreanof Island, Alaska (magnitude 9.1).

The 26 December Asia tsunami with a death toll of more than 283,000 (as of 25.01.2005) is the third deadliest disasters in history. The two others occurred in China: the deadliest earthquake ever recorded is believed to have occurred on 23 January 1556, in Shansi, killing 830,000 people, and the other one occurred on 22 July 27 1976, in Tangshan, with official death count of 255,000 (the estimated death count reached as high as 655,000).

Since the 26 December tsunami the Earth has been vibrating from the massive undersea earthquake, which was followed by numerous heavy aftershocks of a magnitude 6.6 along the plate of epicentre to near Andaman Island. The biggest of them, of a magnitude 7.3 and 7.1, off the Nicobar Islands, might have been powerful enough to create further tsunamis, but did not.
A tsunami is a natural phenomenon, generated by any disturbance that displaces vertically a large water mass from its equilibrium position. Earthquakes, landslides, volcanic eruptions, explosions, and even the impact of cosmic bodies, such as meteorites, can generate tsunamis. Tsunamis can savagely attach coastlines, causing devastating property damage and loss of life.
Tsunami is a Japanese word, translated as, "Harbour wave".
It is represented by two characters in Japanese, the character

	“Tsu” (pronounced “tsoo”) meaning harbour, and the character
	“Nami” (pronounced “nah-mee”) meaning wave.

Although the word “tsunami” comes from Japanese, its does not mean that this event always occurs somewhere in Asia or in some faraway oceans, like the Pacific Ocean or the Indian Ocean.

For example, in about 7000 B.C., the Storegga Slides were a major series of sudden underwater land movements in the North Atlantic Ocean spanning over the course of thousands of years.

Tsunamis usually emerge in the oceans, but they can be generated in the smaller seas as well. The Mediterranean area is particularly sensitive to tsunamis. The most significant past tsunamis near the European coast were:
1650 B.C. – Santorini (1650 B.C. or 1600 B.C. – this is still debated). The volcanic Greek island of Santorini erupted, causing a 100 m to 150 m high tsunami that devastated the northern coast of Crete, 70 km away.
365 A.D. – Greece. According to Pirazzoli et al. (1996) many coastal regions were affected by a crustal uplift represented by a series of coseismic uplift events (which are likely to have been associated with destructive tsunamis) which took place during a relatively short period of time between the mid-4th and 6th centuries A.D. The regions affected by the uplift at this time included several of the Ionian Isles, the eastern Gulf of Corinth, Antikythira Island and most of western Crete as well as parts of southern Turkey, Cyprus, Levant, Syria and Lebanon.
1693 – Sicily. One of the severest earthquakes and tsunamis took place on 11 January 1693 in eastern Sicily; tsunamis occurred at Catania and also at Augusta. Loss of life – 70,000.
1755 – Lisbon, Portugal. The heaviest earthquake and tsunami, caused the death of 60,000 to 70,000 people in Portugal, Spain and North Africa.
1783 – Calabria, where severe earthquakes and tsunamis took place on 5 and 6 February, resulting in a large number of victims and high flood levels.
1908 – Messina, Italy. On 28 December, a 7.2 magnitude quake struck Messina, producing a violent tsunami in the Straits of Messina, killing an estimated 70,000-100,000 people.
Some research has concluded that tsunamis can be generated even in inland lakes and scientists confirm tsunamis on Lake Tahoe (between 800 and 950 A.D., though still debated), on the Great Salt Lake in 1909, and in 1934 after the Hansel Valley Earthquake, magnitude of both 6.5 (or 6.0 debated) and 6.6; in 1959 on Hebgen Lake after 7.5 quake, and on Spirit Lake early during 18 May 1980 volcanic eruption (Mount St.Helens). (The question of whether a tsunami could in principle be generated in Lake Léman and what possible impact it might have perhaps deserves more detailed analysis and could be the subject of a future article).
When could the next tsunami happen?
In 2001 scientists predicted that a future eruption of the unstable Cumbre Vieja volcano in La Palma island of the Canary Islands could cause a giant undersea landslide, that could generate a “monster” tsunami, or more than a 100 m waves across the Atlantic, to devastate the coastlines in Europe (Portugal, Spain, France and parts of the UK), Africa (Western Sahara) and the Americas (coasts from Florida to Brazil). Later research showed that the threat was less than had originally been theorized. Eruptions on La Palma occurred in 1470, 1585, 1646, 1677, 1712, and in recent history in 1949 and 1971. Scientists expect the next volcanic eruption in the second half of the 21st century, although they fear that it may happen sooner.
Of course, this timeframe (±50 years or sooner!) is not significant in the life of our planet, but it does make a difference in the life of individuals. As was recently shown, in the event of a tsunami minutes, not hours, could make a difference in saving hundreds and hundreds of precious human lives. If only we could be warned in time…
This very recent tsunami raised again the belief in the “sixth” sense of the animals which has, in fact, been around for centuries. In 373 B.C., historians recorded that animals, including rats, snakes and weasels, deserted the Greek city of Helice in droves just days before a quake devastated the place. These phenomena were also documented during the Lisbon quake of 1755. Accounts of similar animal anticipation of disasters have surfaced across the years, but no serious or solid research has been undertaken so far. It was noted that during the 26 December 2004 tsunami, in the Yala National Park in Sri Lanka’s largest wildlife reserve (home to 200 Asian Elephants, crocodile, wild boar, water buffalo and the grey langur monkey, as well as Asia’s leopards) not a single animal corpse was found or even seen, whereas the highest number of tourists (all except 40 tourists who visited the reserve that day) perished or are missing. Apparently, all the animals sensed the disaster in advance and went uphill. Only now are they returning. At the Khao Lak resort in Thailand eight elephants used for tourist rides became agitated more than an hour before the tsunami came ashore. Crying or “trumpeting” they broke free of their chains and headed to a nearby hill lifting foreign tourists onto their backs, thus saving them from the tsunami. Some witnesses reports describe how one village in Sri Lanka and one tribe in Andaman Islands also escaped the killer wave following the animals instincts or their sense of disaster. If the earthquake or volcano eruption is of a sudden nature and, as some seismologists say, it is not possible to predict in advance the exact day of a potential disaster. Maybe, despite all scepticism, it will be worthwhile to pay deeper attention or to conduct solid research on this animal phenomenon.
Seismologists predict the eruption of Vesuvius during 2005-06 or sooner (!).
Recently being near the volcano, it was impressive to talk to the people living in Naples, or in smaller villages around the volcano (approx. 1 million people living in the area of potential risk in the event of the eruption). They are no longer waiting for the official warnings from seismologists and scientists. They are carefully watching… the stray dogs. They are carefully observing the animals’ behaviour. Today the strays are quiet, that means the disaster is not for today.