Panama 'at higher risk from quake than thought'
[SANTIAGO] Panama's earthquake hazard is far greater than assumed, according to a study that officials have said is raising undue alarm.
Contrary to earlier findings, researchers found that the two fault lines in central Panama — Limon and Pedro Miguel — are active and prone to large earthquakes.
The Pedro Miguel fault runs between two of the locks on the Panama Canal, which is undergoing a major widening project.
Panama City may also be at particular risk as it is near the two fault lines and its construction codes do not take into account the full extent of the risk, the paper, published in the December issue of the Bulletin of the Seismological Society of America, said.
The damage would be compounded if both faults slipped simultaneously, the paper said.
"We have evidence that they both ruptured together in 1621, producing a 3-metre displacement, which we estimate would have been of a magnitude of seven — a major quake," Eldon Gath, one of the authors of the study, told SciDev.Net.
If the strain accumulated since 1621 was released today, the earthquake's magnitude would be about 6.7, Garth added — strong enough to cause widespread destruction.
He said that, since the last earthquake on this fault happened almost 400 years ago, the next one is expected soon — but could happen any time in the next 100–200 years.
But the paper's final conclusions, which question the preparedness of Panama's buildings, have angered the Panama Canal Authority (PCA), which operates and maintains the canal — and which commissioned the study as part of the widening project.
"The journal article … provides an erroneous, alarmist and editorialised analysis of the sound research that has been conducted regarding the risk of earthquakes around the canal and Panama City," it said in an open letter to New Scientist.
The authority said it was aware of the risks.
Luis Alfaro, vice president of engineering for the authority, told SciDev.Net: "We do not object to the paper's technical findings but there are no grounds for raising alarm".
He said that information from the study was being used in the design of the new facilities in the canal and that Panama City's building codes are being revised to incorporate the new findings.
Lloyd Cluff, a member of the Seismic Advisory Board of the PCA, said: "The paper gives compelling evidence for repeated displacements releasing large earthquakes along the two faults".
He cautioned that making buildings safer takes a long time.