Tuesday, January 26, 2010

Jamaica, Haiti and Caribbean: Be prepared


Jamaica and the rest of the Caribbean need to heed the warnings and become better prepared for the potential of future earthquakes. The devastating earthquake of January 14, 1907 in Kingston buried my great-grandmother under a brick wall for 24 hours. She had been picking flowers in the back garden to take to a funeral when the earthquake struck. She was eventually rescued however it was a terrible ordeal. She said she could hear people on the street talking about wild animals that had gotten loose from a circus taking place nearby. She didn't know if her children were okay and her husband, my great-grandfather, was away in Mexico supervising the building of the railway from Veracruz across the Isthmus of Tehuantepec. Fortunately, the children were okay and great-grandma got rescued. This personal family story reminds me of how precarious life is and the devastating plight still going on for the people of Haiti.


The New York Times has an article today on the earthquake faults that run through the Caribbean, along with a history of quakes in the region including the two major quakes that hit Jamaica in 1692 and 1907. From the article:
The fault that ruptured violently on Jan. 12 had been building up strain since the last major earthquake in Port-au-Prince, 240 years ago. Dr. Calais and others had warned in 2008 that a quake could occur along that segment, part of what is called the Enriquillo-Plantain Garden fault zone, although they could not predict when.

But about 100 miles to the northeast is a long segment of a similar fault, the Septentrional, that has not had a quake in 800 years. Researchers have estimated that a rupture along that segment — and again, they have no idea when one might occur — could result in a magnitude 7.5 quake that could cause severe damage in the Dominican Republic’s second-largest city, Santiago, and the surrounding Cibao Valley, together home to several million people.

“You can imagine the strain that has accumulated there,” said Paul Mann, a senior research scientist at the University of Texas, referring to the Septentrional fault. “It’s been going on for longer and accumulating faster. Therefore it’s going to produce a stronger earthquake.”

The recent quake on the Enriquillo fault and the forecast for the Septentrional are bleak reminders that the Caribbean is an active seismic zone, one with many hazards. Major earthquakes have regularly devastated the region’s cities, including the Jamaican capital, Kingston, which was destroyed twice in three centuries. An eruption of Mount Pelée killed 30,000 people in Martinique in the Lesser Antilles in 1902, and it and other volcanoes are currently active along that island arc on the Caribbean’s north and eastern reaches. Earthquakes and landslides along the Puerto Rico Trench, an undersea fault zone, have the potential to cause tsunamis.

The Haitian quake itself might have added to the risks, researchers say. Dr. Calais and colleagues and a team including Ross Stein of the United States Geological Survey in Menlo Park, Calif., have each calculated the stress changes on the Enriquillo fault that occurred when a 30-mile segment, centered in Léogâne about 18 miles west of Port-au-Prince, gave way this month. Although the results are preliminary, the work shows that stresses have increased just west of the segment and just east, within three miles of Port-au-Prince.

“This earthquake has increased the risk on other segments of that fault and perhaps on other faults as well,” Dr. Calais said. “The numbers are well within the range of stress changes that have triggered earthquakes on other faults.” But he said the quake probably did not increase the likelihood of a major tremor on the Septentrional fault. . . .
Much of what is known about the seismic activity around Port-au-Prince has been gleaned from historical accounts of previous quakes. While far from precise, these accounts suggest a century-long, westward-marching sequence of quakes along the fault, beginning with one in 1751 in the Dominican Republic at the fault’s eastern end and including the 1770 earthquake that destroyed Port-au-Prince.

That raises the possibility that the Jan. 12 earthquake could be the beginning of a new sequence occurring over decades, with each successive quake redistributing stresses along the fault. “It’s certainly possible and it’s really something we’re very concerned about,” said Carol S. Prentice, a geologist with the geological survey in Menlo Park. Such sequences have been observed on other faults, including the North Anatolian in Turkey. Read whole article here.


From an article in the Jamaica Observer:

Jamaica shares the same fault line (a crack or break in the earth's surface) with Haiti, which suffered a devastating 7.0 magnitude earthquake on January 11.

This was disclosed by the Head of the Earthquake Unit of the University of the West Indies (UWI), Dr Lyndon Brown.

"The fault that created the quake in Haiti runs right across the western end of the Dominican Republic, through Haiti, cuts across the Caribbean Sea into Jamaica and continues more or less into different fault lines across Jamaica: one continuous fault line runs across from Haiti to Jamaica," Dr. Brown stated.

Article posted on Environmental News Network on Earthquakes and the Future of Haiti:

The aftershock sequence of the magnitude 7 earthquake that struck near Port-au-Prince, Haiti, on Jan. 12, 2010, will continue for months, if not years. The frequency of events will diminish with time, but damaging earthquakes will remain a threat. It is essential that the rebuilding effort in Haiti take into account the potential for, indeed the inevitability of, future strong earthquakes. Haiti is cut by two major plate boundary fault zones. Over the past three centuries, earthquakes comparable to or stronger than the recent one have struck Haiti at least four times, including those in 1751 and 1770 that destroyed Port-au-Prince. It is also not just Haiti that has this potential.

The geologic fault that caused the Port-au-Prince earthquake is part of a seismically active zone between the North American and Caribbean tectonic plates. The earthquake undoubtedly relieved some stress on the fault segment that ruptured during the event, but the extent of rupture along the fault is unclear at this time. In historic times, Haiti has experienced multiple large earthquakes, apparently on adjacent faults. Future quakes have to be anticipated. Read rest of article here.


Headline in the Jamaica Observer today: Earthquake Unit’s ordeal - Lack of funds continues to hobble operations:

Dr Lyndon Brown, research fellow and head of the Earthquake Unit, said they have had to put off replacing the analogue system they now use as the unit cannot afford the $5-million needed to acquire the digital system for at least three of its 12 stations across the island.

This digital system, Brown said, will generate maps within seconds of an earthquake indicating the magnitude of the tremor as well as the "intense shaking locations".

"With that system, ODPEM (Office of Disaster Preparedness and Emergency Management) would know right at the moment where the earthquake is and where there is the most intense shaking and so you could deploy your response agencies quite easily to these areas," he said.

Brown, who was addressing reporters and editors at yesterday's weekly Observer Monday Exchange at the newspaper's head office in Kingston, said he was hoping the budget for the digital system will be approved in April so as to prevent the loss of quality data.

"When an event happens, the problem with not having a digital system is we have to wait until someone calls to say 'did you feel the earthquake?' and if it is big enough we will feel it and we take the steps to see if we can come up with a solution to inform ODPEM," he said.

But with the digital system, he said, they would be automatically informed.

The Earthquake Unit's desire to digitise its network was first reported by the Sunday Observer in August 2004.

Yesterday, Information Minister Daryl Vaz told the Observer that consideration will have to be given to allocating funds to this system in light of the recent occurrences of earthquakes in the region.

"Based on what is happening now, obviously something like that would have to be priority and we will have to see what we can do," Vaz said.

Explaining that he was not familiar with this particular need of the unit, Vaz noted that if it has been on the table for the last five years it will definitely have to get priority attention.

Meanwhile, Brown said there is a proposal to get graduate students living on the University of the West Indies Mona campus -- where the Earthquake Unit is located -- to work with the unit, so in the event of an earthquake they would be close enough to get to the data.

With the January 12 magnitude 7 earthquake in Haiti which killed over 100,000 and left millions homeless still foremost in most people's mind, Brown said he is hoping that priority will finally be given to acquiring the digital system as well as the long list of items needed by the unit to carry out its functions.

The unit's function is very critical, given that Jamaica is situated in a very active zone which experiences over 200 tremors, nine of which are felt each year.

"I hope that we don't forget too easily or too quickly about earthquakes and forget to make this a priority," Brown said, adding that he hopes the unit will get the attention it deserves this financial year.

According to Brown, the unit has submitted a budget of $36 million, $2 million up from what was requested last year, but which was slashed to $22 million.

The unit is also trying to get a building of its own as the current space is too confined for research. The new building, he said, must be able to withstand structural damage in a major earthquake.

"This idea has been expressed to the university and the university had offered land on the campus that could be used," he said. However, that project is also being affected by a lack of funding.

Outside of small university research grants the unit receives the majority of its funding from the Government.

Included in the list of needs are a four-wheel drive vehicle, six or seven computers and two-way radios.

"Our computers are the most obsolete, sometimes you have to turn them off if you are running two programmes," Brown said.

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