
Chile,
one of the most seismically active countries in the world, has been
struck by three major earthquakes of magnitude 8 or greater in the past
five years. The first, in February 2010,
killed 525 people, including those who died in the tsunami it spawned.
But only 11 people have so far been reported killed in the latest, which struck on Wednesday.
Why is the toll so much lower this time?
The latest earthquake was not as powerful.
Though
the earthquake on Wednesday was quite strong, at magnitude 8.3, it
released only about a third of the energy of the magnitude 8.8 quake in
2010, one of the strongest recorded in modern times. (Magnitude is
measured on a logarithmic scale.)
It affected a more focused area.
The
2010 quake struck off the central coast and directly affected large
cities and populous areas, including resort areas crowded with
vacationers. At least one-third of the country’s coastline suffered
significant damage from the tsunami it created, and more minor damage
was reported as far away as San Diego and Tokyo. Almost all of Chile
lost power. By contrast, the latest quake and its tsunami have mainly
affected a single, less densely populated region, Coquimbo.
Coastal residents were better prepared.
Since
the 2010 quake, there have been many earthquake drills and dry runs,
and evacuation routes have been clearly marked up and down the coast. As
a result, though the latest quake’s tsunami did extensive physical
damage in several coastal cities and ports, very few people were in
harm’s way when the waves hit. In 2014, when a magnitude-8.2 quake struck off northern Chile, Coastal areas were evacuated quickly and efficiently.
Warnings were issued promptly.
In 2010, no tsunami alert was issued,
and national leaders prematurely told the public that they could return
to their homes. Residents in coastal areas knew to head for higher
ground, but many visitors did not. Since then, the government has issued
immediate preventive tsunami warnings and has been much more cautious
about sounding the all-clear, as seen in the 2014 quake and again this
week.
Strong building codes are enforced.
In poorer, developing countries like Haiti or Nepal,
major quakes are often devastatingly deadly, with thousands of people
killed by collapsing buildings, bridges and dams. It used to be that way
in Chile, too, but decades of prosperity have raised construction
standards, and the country has learned through hard experience to set
and enforce stringent building and safety codes along the lines of those
used in California. Because of this, Chile’s modern buildings tend to
fare well in quakes, though historic structures and those in rural areas
may still be vulnerable.
Emergency response has been improved.
Since
2010, the National Seismic Center in Chile has been operating around
the clock, as have many of the regional offices of the government’s
national emergency bureau. More robust sea-level monitoring systems and
better procedures to help coordinate the efforts of public and private
agencies have also made a difference.
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