Quake waves went around world twice
Pastor Dale Morgan
Quake waves went around world twice*
From correspondents in Tokyo
May 16, 2008 06:56pm
Article from: Agence France-Presse
THE devastating earthquake in southwest China was so powerful that its
seismic waves travelled around the globe - twice, a Japanese observatory
said today.
The Matsushiro Seismological Observatory, north of Tokyo, detected
surface quake waves at 3.41pm Japanese time (1641 AEST) on Monday, some
13 minutes after the 7.9-magnitude quake struck in China's Sichuan province.
Seismological equipment in an underground tunnel showed the same kind of
low-frequency waves 90 minutes later at 6.10pm and again at 8.40pm,
according to the observatory.
This shows the waves from the quake went round the globe twice,
travelling eastward from the epicentre to Japan, crossing the Pacific to
the Americas and the Atlantic Ocean to Africa before coming back to
Asia, it said.
Westbound waves were also observed, it added.
"The circling of waves was observed as the quake was so intense,''
Matsushiro observatory chief Naoya Mikami said.
A huge fault, or a break in the Earth crust, caused the earthquake,
sending strong seismic waves, he said, adding that usually only surface
waves from a quake of about magnitude 8.0 or stronger go around the
globe more than once.
Surface waves, which cannot be felt by humans, travel more slowly and
last longer than waves that go through the interior of the Earth.