The Bhuj Earthquake of 26.01.2001 -- Factfile

The Bhuj Earthquake of 26.01.2001 -- Factfile

There are basically two types of earthquakes, categorised as per the kind of activity involved in the earth's bowels. In most cases it occurs when the two earth plates rub against each others or collide or try to overlap. The other type of quake is called the intra-plate quake, like the one which Maharashtra in Latur, Killari and other areas.

The first major plate is called the Circum-Pacific Belt that starts from New Zealand, travels through the Indonesian archipelago, then through Japan and Korea ends in the Aleytian Islands connecting Russia with the Arctic. The Indian sub-continent plate is part of the second larger Asian plate called the Mediterranean-Alpine-Himalayan-Mayanmar table that starts from the Mediterranean and ends in the Anadamans. Bhuj is considered to belong to the active mobile second plate, though it falls slightly below it.

The Bhuj quake strictly speaking is neither because of the collision of the two plates, nor is it an intra-plate quake. What happens is the Indian sub-plate is sought to be thrust under the Tibetan plateau, which is why the sub-Himalayan line has high seismic volatiltiy and Bhuj falls in the southern fringe of this volatile activity, explained Dr V Subramanyan, the visiting faculty of IIT, Mumbai.

The Bhuj quake has beeen building for nearly a hundred and eighty years since the last quake there which occurred in 1819.

* Kutch falls in Seismic zone 5 of the seismic zones map of India (1972) currently being followed. Places situated in zone 5 have the probability of occurence of earthquakes of magnitude 7.0 and above.
* A severe earthquake of magnitude 8.0 occurred in 1819 at Bhuj and this gave rise to the famous Allah Bund which is a long rock-wall.
* Zone 5 occurs in pockets on Zone 4 starting from Kutch. It continues to the north through Quetta in the middle of the Sulaiman - Kirthar ranges and covers Kashmir, Himachal Pradesh, northern U.P., North Bihar, all the Northeastern states and Myanmar and ends up in the Andaman islands.
* According to geological studies, Kutch is bounded by one FAULT running east-west in the north and another FAULT running northeast-southwest, through the Little Rann and going along the northwestern coast of Kathiawar. Between these two FAULTS, Kutch has gone down in elevation and so is called a `Downthrown Block.'
* In contrast, Kathiawar, which is also bounded by two FAULTS in the northwest and southeast, has come up in elevation and is accordingly called a `Median Rise.'
* This earthquake has been felt by the entire country and seismologists like Dr D Subramanyan, project director and visiting faculty of the Department of Earth Sciences, IIT, Mumbai, that the 6.9 recorded by Indian observatories may not be correct and the figure of 7.9 as recorded by Foreign Observatories in China and by US satellites is closer to reality.