study says quakes in excess of 9.0 are possible
By the A.M. Costa Rica staff
Just how strong can an earthquake get? That is a question that
has puzzled researchers, and they were surprised when an undersea quake
March 11, 2011, registered a magnitude of 9.0. The earthquake was off
the Oshika Peninsula of Tōhoku in Japan.
The Seismological Society of America said that a new study suggests the
possibility of quakes 9.0 and even greater along the Ring of Fire that
includes western Costa Rica.
Earthquake magnitudes are expressed in base-10 exponential numbers like
the velocity of the Starship Enterprise. So every increase in a whole
number means a quake 10 times stronger. A 9.0 quake is 10 times
stronger than an 8.0.
This study, published online by the Bulletin of the Seismological
Society of America, calculates the "probable maximum earthquake
magnitude within a time period of interest," estimating the probable
magnitude of subduction zone earthquakes for various time periods,
including 250, 500 and 10,000 years, said the society.
The study's results indicated most of the subduction zones can generate
magnitude 8.5 or greater over a 250-year period, M 8.8 or greater
years and M 9.0 or greater over 10,000 years. Said the society in a
summary of the study:
"The instrumental and historical earthquake record is brief,
complicating any attempt to confirm recurrence rates and estimate with
confidence the maximum magnitude of an earthquake in a given period.
The authors validated their methodology by comparing their findings to
the seismic history of the Cascadia subduction zone, revealed through
deposits of marine sediment along the Pacific Northwest coast. While
some subduction zones have experienced large events during recent
history, the Cascadia subduction zone has remained quiet. Turbidite
[sedimentary] and onshore paleoseismic studies have documented a rich
seismic history, identifying 40 large events over the past 10,000 years.
Some of the participants in the study work for companies that insure
Many of Costa Rica's major quakes are a product of the Coco tectonic
plate pushing under the lighter Caribbean plate. The visible junction
of the plates is off the Pacific coast. The Nicoya earthquake
2012, had a magnitude of 7.5. The quake did significant damage in the
community of Nicoya. An April 22, 1991, quake in Limón was
measured at 7.8.
pair accompanied a very expensive tire
By the A.M. Costa Rica staff
While some expats complain about the time and effort needed to obtain a
firearms carry permit, two men with such permissions were detained
Tuesday night in the company of $4.1 million.
The Fuerza Pública said that the two men, identified by the last
names of Vega and Ortiz, were fully licensed to carry weapons. Neither
has a criminal record, said officers. The money in U.S. currency was
neatly stacked in a spare tire in the back of the pickup in which
the men were riding.
Officials are presuming that the money represents proceeds of drug
sales, perhaps in the United States, that was being transported back to
the headquarters of a Columbian cartel.
Police officers stopped the vehicle and the two men at a checkpoint
in Montes de Oro, Puntarenas. An officer became suspicious
because the spare tire was not inflated, officials said. The tire also
was from a trailer and not the size for the pickup, they added.
Ministerio de Gobernación,
y Seguridad Pública/Alonso Álvarez
Police officer counts some of the U.S.