Significance Of An Earthquake Early Warning System For Vulnerable Essential Facilities: The Example of A Potential Implementation in Costa Rica
Marino Protti, Director, Vulcanological and Seismological Observatory of Costa Rica National University (OVSICORI-UNA).
In developing countries, so many essential facilities are vulnerable to earthquakes that it is practically impossible to retrofit them all before the occurrence of another event. For this reason, a system that can warn the occupants of non-reinforced vulnerable structures a few seconds before the arrival of seismic waves could save many lives.
A mature seismic gap exists under and off the Nicoya peninsula on the Pacific coast of northwestern Costa Rica. This gap, the Nicoya seismic gap, is a subduction segment of the Middle American Trench where the Cocos plate subducts under the Caribbean plate. Large earthquakes have occurred in this segment in 1853, 1900 and 1950. The distribution of aftershocks of large earthquakes in the segments adjacent to the gap, during the 1990s, has made it possible to map its geographic location and estimate its size. Without significant slip since 1950, a convergence rate of around 88 mm/yr, and an area ranging from 5,000 to 10,000 km2, the Nicoya gap has the potential to generate an earthquake with moment magnitude above 7.5.
Costa Rica’s Central Valley, where the greatest concentration of population and infrastructure in the country is to be found, is located between 100 and 250 km from the potential rupture area of the Nicoya seismic gap. These distances are within the range of tested earthquake early-warning systems, making this region an excellent site for the operation of such a system. An early-warning system should not be seen as a substitute for a vulnerable structure reinforcement program; as a complement, however, it could prove invaluable.
[font=Arial, Helvetica, sans-serif]Many countries in Latin America have implemented programs for identifying and retrofitting seismically vulnerable essential facilities. Given the attendant costs, it is practically impossible to reinforce—or, alternatively, to demolish—all these structures before the next earthquake strikes. Costa Rica has a good seismic building code. Even so, the occurrence in the 1990s of several large-magnitude earthquakes weakened many structures, some of which might suffer significant structural damage or even collapse during the next major earthquake or its aftershocks. If we could rely on a system that, at the time an earthquake starts, could warn the occupants of these vulnerable buildings, we could reduce the number of the injured and possibly even save a considerable number of lives. Even a few seconds might be enough for the occupants to move towards more resistant areas of each building and, in some cases, to evacuate the structure altogether in an orderly manner. (This would obviously require that more resistant areas of buildings be identified in advance, disaster response plans be in place, and drills be executed.)[/font]
[font=Arial, Helvetica, sans-serif]Since, in Costa Rica, major earthquakes do not only affect the Pacific Northwest alone, the installation of more sensors along the entire coast would make it possible to warn the Central Valley of practically every event of significant magnitude occurring along the subduction zone.[/font]
[font=Arial, Helvetica, sans-serif]Tectonic Setting[/font]
[font=Arial, Helvetica, sans-serif]Central America’s tectonics are mainly controlled by the clash of the Cocos and Caribbean plates (see Figure 1). As a result of this clash, the Cocos oceanic plate is subducting under the Caribbean plate along the Middle America Trench at speeds that range from 70 mm/yr in front of Guatemala to little more than 90 mm/yr in front of the Osa peninsula [Protti, 1994, estimated from De Mets et al., 1990] (see Figure 2). It is along this plate boundary where most of the large-magnitude earthquakes occur in Costa Rica.[/font]
[font=Arial, Helvetica, sans-serif]In the southwestern boundary of the Caribbean plate, local tectonic strains have caused it to fracture and create a microplate, known as the Panama block, the boundaries of which have not yet been identified very clearly. The northern boundary of the Panama block with the Caribbean plate is a convergent margin known as the North Panama Deformed Belt [Silver et al., 1990], which ranges from the Caribbean coast of Colombia to Limon in Costa Rica (see Figures 1 and 2). It was at the western extreme point of this boundary that the Limon Earthquake of 1991 took place. Towards the Northwest, the boundary between the Panama block and the Caribbean plate is a diffuse zone of left-lateral strike-slip faulting that runs from Limon to the Middle America Trench through the central part of Costa Rica [Ponce and Case, 1987; Jacob and Pacheco, 1991; Güendel and Pacheco, 1992; Goes et al, 1993; Fan et al., 1993; Marshall et al., 1993; Fisher et al., 1994; Protti and Schwartz, 1994]. The Panama block therefore comprises the southern part of Costa Rica and all of Panama.[/font]
Tectonic location of Costa Rica.
[font=Arial, Helvetica, sans-serif]South of the Burica peninsula is the Panama fracture zone. This system of right-lateral strike-slip faulting is the boundary between the Cocos and Nazca plates. West of the Panama fracture zone is the Cocos Ridge, which subducts under the Osa peninsula. The Cocos Ridge is the scar caused on the Cocos plate by the Galapagos hotspot.[/font]
[font=Arial, Helvetica, sans-serif]This tectonic environment makes Costa Rica a very seismically active area, with seismic sources of different origins and depths that are spread throughout the entire country. Since April 1984, the Volcanological and Seismological Observatory of Costa Rica, National University (OVSICORI-UNA), has been recording activity from all these seismic sources and located more than 50,000 events in nearly 15 years.[/font]
Segementation of the subductions zone in front
of Costa Rica.
Link to remainder of article.
http://www.eird.org/ing/revista/No3_2001/Pagina8.htm
wil.
Marino Protti, Director, Vulcanological and Seismological Observatory of Costa Rica National University (OVSICORI-UNA).
In developing countries, so many essential facilities are vulnerable to earthquakes that it is practically impossible to retrofit them all before the occurrence of another event. For this reason, a system that can warn the occupants of non-reinforced vulnerable structures a few seconds before the arrival of seismic waves could save many lives.
A mature seismic gap exists under and off the Nicoya peninsula on the Pacific coast of northwestern Costa Rica. This gap, the Nicoya seismic gap, is a subduction segment of the Middle American Trench where the Cocos plate subducts under the Caribbean plate. Large earthquakes have occurred in this segment in 1853, 1900 and 1950. The distribution of aftershocks of large earthquakes in the segments adjacent to the gap, during the 1990s, has made it possible to map its geographic location and estimate its size. Without significant slip since 1950, a convergence rate of around 88 mm/yr, and an area ranging from 5,000 to 10,000 km2, the Nicoya gap has the potential to generate an earthquake with moment magnitude above 7.5.
Costa Rica’s Central Valley, where the greatest concentration of population and infrastructure in the country is to be found, is located between 100 and 250 km from the potential rupture area of the Nicoya seismic gap. These distances are within the range of tested earthquake early-warning systems, making this region an excellent site for the operation of such a system. An early-warning system should not be seen as a substitute for a vulnerable structure reinforcement program; as a complement, however, it could prove invaluable.
[font=Arial, Helvetica, sans-serif]Many countries in Latin America have implemented programs for identifying and retrofitting seismically vulnerable essential facilities. Given the attendant costs, it is practically impossible to reinforce—or, alternatively, to demolish—all these structures before the next earthquake strikes. Costa Rica has a good seismic building code. Even so, the occurrence in the 1990s of several large-magnitude earthquakes weakened many structures, some of which might suffer significant structural damage or even collapse during the next major earthquake or its aftershocks. If we could rely on a system that, at the time an earthquake starts, could warn the occupants of these vulnerable buildings, we could reduce the number of the injured and possibly even save a considerable number of lives. Even a few seconds might be enough for the occupants to move towards more resistant areas of each building and, in some cases, to evacuate the structure altogether in an orderly manner. (This would obviously require that more resistant areas of buildings be identified in advance, disaster response plans be in place, and drills be executed.)[/font]
[font=Arial, Helvetica, sans-serif]Since, in Costa Rica, major earthquakes do not only affect the Pacific Northwest alone, the installation of more sensors along the entire coast would make it possible to warn the Central Valley of practically every event of significant magnitude occurring along the subduction zone.[/font]
[font=Arial, Helvetica, sans-serif]Tectonic Setting[/font]
[font=Arial, Helvetica, sans-serif]Central America’s tectonics are mainly controlled by the clash of the Cocos and Caribbean plates (see Figure 1). As a result of this clash, the Cocos oceanic plate is subducting under the Caribbean plate along the Middle America Trench at speeds that range from 70 mm/yr in front of Guatemala to little more than 90 mm/yr in front of the Osa peninsula [Protti, 1994, estimated from De Mets et al., 1990] (see Figure 2). It is along this plate boundary where most of the large-magnitude earthquakes occur in Costa Rica.[/font]
[font=Arial, Helvetica, sans-serif]In the southwestern boundary of the Caribbean plate, local tectonic strains have caused it to fracture and create a microplate, known as the Panama block, the boundaries of which have not yet been identified very clearly. The northern boundary of the Panama block with the Caribbean plate is a convergent margin known as the North Panama Deformed Belt [Silver et al., 1990], which ranges from the Caribbean coast of Colombia to Limon in Costa Rica (see Figures 1 and 2). It was at the western extreme point of this boundary that the Limon Earthquake of 1991 took place. Towards the Northwest, the boundary between the Panama block and the Caribbean plate is a diffuse zone of left-lateral strike-slip faulting that runs from Limon to the Middle America Trench through the central part of Costa Rica [Ponce and Case, 1987; Jacob and Pacheco, 1991; Güendel and Pacheco, 1992; Goes et al, 1993; Fan et al., 1993; Marshall et al., 1993; Fisher et al., 1994; Protti and Schwartz, 1994]. The Panama block therefore comprises the southern part of Costa Rica and all of Panama.[/font]
Tectonic location of Costa Rica.
[font=Arial, Helvetica, sans-serif]South of the Burica peninsula is the Panama fracture zone. This system of right-lateral strike-slip faulting is the boundary between the Cocos and Nazca plates. West of the Panama fracture zone is the Cocos Ridge, which subducts under the Osa peninsula. The Cocos Ridge is the scar caused on the Cocos plate by the Galapagos hotspot.[/font]
[font=Arial, Helvetica, sans-serif]This tectonic environment makes Costa Rica a very seismically active area, with seismic sources of different origins and depths that are spread throughout the entire country. Since April 1984, the Volcanological and Seismological Observatory of Costa Rica, National University (OVSICORI-UNA), has been recording activity from all these seismic sources and located more than 50,000 events in nearly 15 years.[/font]
Segementation of the subductions zone in front
of Costa Rica.
Link to remainder of article.
http://www.eird.org/ing/revista/No3_2001/Pagina8.htm
wil.
Millennium Sportsbook * said:
I thought the tease was inappropriate and showed more grandstanding than professionalism. The article was more chicken little sky is falling than advice on how to insure yourself against a natural disaster in the Costa Rican area. I have the option to buy earthquake insurance, I do not. There are many other countries, many miles away from Costa Rica that would probably remain in business.
In no way am I trying to minimize the tragic loss of life, But you are talking about protecting businesses. I think if that disaster were to occur, I would have more concerns for the general populace, and donate immediately to help out. I already donate to children's homes in Costa Rica, and take care of people down there whenever posssible. In my humble opinion, I think it is out of line to give business advice on something with the ramifications of a natural disaster. I think saving lives would be first and foremost in everyone's eyes. I wonder how many Costa Rican sportsbook employees are thinking, to hell with the sportsbook/customer business, what about our families?
You write an article for input, you get mine for free...OF:digit:
This is a rare case where I COMPLETELY agree with Omnivorous Frog.
You could have accomplished this with a post that said:
Costa Rica is on a fault line, a disaster there would completely cripple the economy including the sports books located there.
End of story, and we wouldn't need all the pomp and circumstance to go with it.
You could have accomplished this with a post that said:
Costa Rica is on a fault line, a disaster there would completely cripple the economy including the sports books located there.
End of story, and we wouldn't need all the pomp and circumstance to go with it.
EveryGamblersDream said:
And to you too everygamblerswetdream! You must really have an important agenda and noteworthy life to dig this out from 3 weeks ago. Why don't you save your money for about 80 years so you can buy yourself an identity. You're one of the reasons why I have to count sheep each nite to fall asleep
i never had the chance to read this when it was 1st posted and i remember the build up. i appreciate that it was bumped up. i live on a faultline that connects to many others including the san andreas fault. i dont use a cr sportsbook but it doesnt matter. the tsunamis were a nightmare to see and helpless countrys have no prayer. im glad those of you in this area are prepared and i hope the big one doesnt come but the reality is they are as inevitable as another terrorist attack in america. i wish you all down there the best.
we had a quake very recently and when the rolling intensifies you have to wonder is this it? our most recent was centered 20 miles from my home and i live on a hill that is already weakened by scorched earth from out of control wildfires most of southern california suffered thru almost 2 years ago.the recent rains has eroded the hill and a bigger quake could send the whole hill down as it did in the L.A. area this winter.i was in vegas when the fires broke out and i never recieved such panicked calls from family and friends my entire life.all of san diego county burned and we lost an entire community. all available firefighters were in los angeles fighting up there.Millennium Sportsbook * said:
