Dix­ie-Ann Dick­son

An earth­quake of 4.7 mag­ni­tude at a depth of 40km shook parts of north Trinidad on Sun­day. Act­ing di­rec­tor of the Seis­mic Re­search Cen­tre of the Uni­ver­si­ty of the West In­dies, Dr Joan Latch­man con­firmed the re­port yes­ter­day stat­ing that there was nei­ther dam­age nor in­jury. It was felt from Care­nage in the north­west, to Moru­ga on the south cen­tral coast, to Matu­ra on the north­east coast.

The quake oc­curred about 15 miles north­west of Port-of-Spain; 70 miles west south­west of Scar­bor­ough, To­ba­go; and 90 miles south of St George's Grena­da, at a depth of about 36.9 miles. But Latch­man not­ed that an earth­quake of 4.7 could bring a house down de­pend­ing on how far it was from the house. This one, she said, hap­pened away from the built-up ar­eas, so there was no dam­age. Mean­while, the Of­fice of Dis­as­ter Pre­pared­ness and Man­age­ment (ODPM) said in a re­lease yes­ter­day that the first re­spon­der agen­cies had been put on alert to ren­der as­sis­tance in the event of any af­ter­shocks. It said the Dis­as­ter Man­age­ment units with­in the var­i­ous mu­nic­i­pal cor­po­ra­tions would con­tin­ue to per­form dam­age as­sess­ments through­out the coun­try with as­sis­tance from the ODPM.

The ODPM said if cit­i­zens had been af­fect­ed, they should con­tact their mu­nic­i­pal cor­po­ra­tion or the ODPM at 800-6376. But Latch­man ex­plained that this re­cent earth­quake was part of a se­ries of earth­quakes that be­gan on Sep­tem­ber 29, 2006 that reg­is­tered a mag­ni­tude of 5.8-the high­est reg­is­tered on land in Trinidad-since they have been mon­i­tor­ing earth­quakes with their in­stru­ments. Re­count­ing that event, she said, on that same day and in the same gen­er­al area, the coun­try had 11 earth­quakes and the biggest af­ter­shock five hours lat­er with a mag­ni­tude of 5.3.

"The fol­low­ing day there were eight earth­quakes lo­cat­ed and on the third day, the num­ber dropped to four," Latch­man said. She fur­ther ex­plained that the num­ber of earth­quakes for this area fell off very rapid­ly un­til the in­ter­vals be­tween the earth­quakes got longer with one or two oc­cur­ring every month or two. Since that she said, the coun­try had an earth­quake on Feb­ru­ary 23rd, 2007 with a 4.7 mag­ni­tude. The oth­er one oc­curred on No­vem­ber 11, 2008 with a mag­ni­tude of 4.3 and the most re­cent on Sun­day De­cem­ber 27, 2010-a 4.7 mag­ni­tude.

She ex­plained that earth­quakes fol­low a cer­tain bal­ance or ra­tio and they ob­served that T&T did not ex­pe­ri­ence all the earth­quakes as ex­pect­ed. How­ev­er, Latch­man said, "We may still see an earth­quake larg­er than 4.7, but if its an af­ter­shock, it's not ex­pect­ed to be larg­er than 5.8 in mag­ni­tude." "This, how­ev­er, does not dis­count the pos­si­bil­i­ty that the ac­tiv­i­ty that we have seen in this area is all pre­cur­so­ry to some­thing big­ger than 5.8," she added.

She said since this is the first se­quence of earth­quakes they have in their data­base from a mon­i­tor­ing process since 1952, they had noth­ing with which to com­pare it in or­der to as­sess its de­vel­op­ment. "But the da­ta we have at this time sug­gests that we are see­ing af­ter­shocks," she said. How­ev­er, Latch­man ad­vised cit­i­zens to vis­it their Web site at www.uwi­seis­mic.com and take note of the rec­om­men­da­tions and try to im­ple­ment them.