Page 7 - LabMedya - ENG - 11

www.labmedya.com | SPECIAL EDITION 11

YOUR DAILY DOSE OF SCIENCE 7

WHY DIDN’T THE EARTHQUAKE IN

RUSSIA TRIGGER A MASSIVE TSUNAMI?

Tsunami warnings were However, as of this writing, In Kamchatka and occurred to the trench—
issued along the Pacific many countries that were surrounding areas, some usually emerge one or two
coasts, but the expected in the path of potential localized damage did hours after the tsunami
devastation did not occur. destruction did not occur. The eastern Russian appears.
Here’s the geological experience the expected city of Petropavlovsk-
explanation for why. wall of water. The waves Kamchatsky was shaken Modern tsunamis like
that reached Japan and severely, with some today’s are monitored
The 8.8-magnitude Hawaii slightly exceeded buildings sustaining in real-time using deep-
earthquake that struck 1.2 meters, prompting damage. In Severo-Kurilsk, ocean pressure sensors.
off the coast of Russia’s authorities to downgrade a town in the Kuril Islands Still, Melgar notes that
Kamchatka Peninsula tsunami alerts and cancel just south of Kamchatka, “the sensor network is
sparked deep concern some evacuation orders. tsunami waves reached up sparse, so it doesn’t always
among scientists. This A tourist in Hawaii told the to five meters, damaging capture the full complexity
region, located at a BBC, “The disaster we were homes and sections of the of wave energy moving
convergence where the expecting didn’t happen.” port. across the basin.”
Pacific plate subducts In California, water levels
beneath a branch of rose to about 2.5 meters, Each country has slightly The final height of a
the North American but no significant damage different procedures for tsunami as it reaches the
plate and lies close to was reported. issuing tsunami warnings. shore is also affected
the Eurasian plate, is Generally, however, if a by the shape and depth
known for its potential Why didn’t this massive dangerous tsunami is of the seafloor (known
to generate widespread undersea earthquake anticipated, evacuation as bathymetry), as
and destructive tsunamis. produce a larger tsunami? orders are given for well as the coastline’s
In fact, a 9.0-magnitude affected coastal regions. geography. Stephen Hicks,
earthquake in 1952 wiped The short answer: the Initial predictions often a seismologist at University Geological Survey, a 9.1
out a nearby Russian town fault that ruptured during include wave height College London, says, quake releases nearly
and caused major damage the earthquake produced estimates, but these early “Geographic features like three times more energy
in Hawaii. exactly the tsunami it was figures are subject to bays can amplify wave than an 8.8.
capable of generating. uncertainty. heights, while waves can
At 11:24 a.m. local time While our instincts may also be diffracted around Judith Hubbard, an
on Wednesday (7:24 p.m. have led us to expect more Independent earthquake islands.” earthquake expert at
EDT on Tuesday), when the destruction, the resulting scientist Amilcar Carrera- Cornell University, explains:
seafloor off Kamchatka tsunami matched the Cevallos explains that Today’s earthquake might “The 2004 and 2011 events
suddenly shifted, it seemed geophysical potential of “tsunami energy does naturally be compared to were significantly larger
likely that a dangerous the fault. not radiate symmetrically the 2011 magnitude 9.1 than this one.” As a result,
tsunami was on its way. across the ocean.” Faults quake off Japan, which they were much more
Scientists predicted that According to Diego don’t break in neat, produced 130-foot-high capable of displacing vast
many countries around Melgar, an earthquake linear lines, and seafloor waves and claimed over volumes of ocean water.
the Pacific Rim would be and tsunami expert at the movements aren’t always 15,000 lives. The 2004
affected. Millions of people University of Oregon, “The smooth or unidirectional. magnitude 9.1 quake Still, not knowing the
were evacuated from very fact that a tsunami This leads to variations and tsunami in the Indian exact wave height at
coastal areas of Japan, warning was issued is a in wave intensity across Ocean, which killed more every Pacific coastline in
and residents in Hawaii success story in itself.” A different regions. than 280,000 people, also advance is a secondary
were instructed to move tsunami doesn’t need to comes to mind. concern. What truly
to higher ground. Similar consist of towering waves Diego Melgar adds, “Initial matters is that tsunami
warnings were issued in to cause devastation; even warnings are based solely However, today’s warnings were issued
Central and South America. relatively modest waves on the estimated size and 8.8-magnitude quake quickly and that people
As the first small tsunami can easily sweep away location of the quake, may not be as powerful were told when to expect
wave appeared off Japan’s people and structures. The but that’s not enough to as it seems. Earthquake waves at their location.
Hokkaido island, there fact that casualties have determine how much water magnitude is not measured As Hubbard notes, “The
were fears that waves remained low is largely due is displaced or where the on a linear scale; each current strategy of
could reach up to three to effective warnings and waves will concentrate.” increase in magnitude preventative evacuation
meters in height. timely evacuations. More detailed insights— represents a dramatic does a great job at saving
such as the extent of rise in energy release. lives.”
fault slip and how close it According to the U.S.