If I want to know something about earthquakes,
the first websites I go to are: the USGS Real Time Earthquakes Website or the IRIS
monitoring one.
As a continuation of my last post, this week we
are exploring seismicity and what countries do to prevent/mitigate the hazard.
Re: the first issue, the new 2014 US map of
seismicity (see image from USGS) shows the (obvious, in pink) ring of fire
portion on the West coast but also a central area in the middle of the plate.
I’d like to talk a bit more about this non-obvious one. This area, called
the New Madrid Zone was shaken
by a M8(!) in 1811. The reason for the activity is a very old intraplate rift
placed below the area (see image from http://showme.net).
Re: the second issue, I want to focus on a brand
new effort by the USGS: the ShakeAlert system, developed for the West coast using some
of the existing systems.
Today, the technology exists to detect
earthquakes, so quickly, that an alert can reach some areas before strong
shaking arrives. The purpose of an EEW (Earthquake Early Warning) system is to
identify and characterize an earthquake a few seconds after it begins,
calculate the likely intensity of ground shaking that will result, and deliver
warnings to people and infrastructure in harm’s way. Studies of earthquake early warning
methods in California have shown that the warning time would range from a few
seconds to a few tens of seconds, depending on the distance to the epicenter of
the earthquake.
A few seconds of warning might
make all the difference (enough to stop transit/elevators and to drop, cover, hold on).A brand new article worth reading: EOS the 'Big One'
All for now-
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