Ini saya copas artikel di yahoo news:
http://news.yahoo.com/big-earthquakes-might-calm-earth-170627634.html
katanya hasil penelitian memperlihatkan bahwa gempa di Aceh itu sebagai akhir
dari rentetan gempa, dan mereka meng-interpretasikan bahwa justru gempa Aceh
itu adalah gempa yang menetralisir. jadi mungkin maksudnya sudah stabil
sesudah gempa Aceh tersebut. cuma ngak disebutkan bahwa gempa di Aceh itu
masih ada gempa yang cukup besar seperti yang di Pangadaran dan beberapa lagi.
memeng tidak sebesar yang di Aceh.
jadi apakah yang sekarang terjadi ini akan berentetatn lagi seperti "baiasnya"?
ada yang ikut annual meeting ini ngak?
fbs
Big Earthquakes Might Calm the EarthBy Becky Oskin, OurAmazingPlanet Staff
Writer | LiveScience.com – Fri, Apr 19, 2013
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A map of the earthquakes triggered …
The biggest earthquakes make the Earth ring like a bell. But doearthquakes that
rock the world increase the risk of new temblors?
Not by much, according to two reports presented today (April 19) at the
Seismological Society of America's annual meeting in Salt Lake City. In fact,
one recent quake near Sumatra, Indonesia, seemed to actually quiet global
earthquakes.
The April 11, 2012, Indian Ocean earthquake was the largest strike-slip
shake-up ever recorded. A strike-slip fault moves horizontally, as California's
San Andreas Fault does. The magnitude-8.6 quake triggered earthquakes
worldwidefor up to six days, said Fred Pollitz, a geophysicist at the U.S.
Geological Survey's (USGS) Menlo Park, Calif., office.
But once the triggered quakes stopped, Pollitz was surprised to find a sharp
drop in moderate earthquakes for more than three months. Seismic monitors
detected no earthquakes bigger than magnitude 6.5 for 95 days. Normally, quakes
of this size hit every 10 days, Pollitz said.
"That is quite a rare occurrence," he told OurAmazingPlanet. "The chance of
that happening is about 1 in 10,000."
Energetic earthquake
Pollitz thinks the Indian Ocean earthquake's unusually energetic seismic waves,
which traveled shallowly through Earth's crust for long distances, could have
shifted stresses on faraway faults, delaying earthquakes.
"Usually, these dynamic seismic waves only increase the chance of an earthquake
at any distance," Pollitz said. "We've documented, for the first time, that
they can also decrease the chance of an earthquake."
Because it doesn't necessarily take a massive earthquake to trigger new shocks
— the 2002 Denali, Alaska, earthquake, a magnitude 7.9, set off quakes
throughout the northwestern United States — Pollitz wants to comb through past
earthquake records in hopes of finding more quiet periods.
"We need to go back and look at these other earthquakes and see if this is a
general pattern of a temporary increase and a longer-term decrease," Pollitz
said.
Global risk
Although the Indian Ocean earthquake may have had a rare calming effect after
some time had passed, it did immediately spark a global furry of quakes, as
many massive earthquakes often do.Tom Parsons, a USGS geophysicist also at
Menlo Park, wants to know how often dangerously large temblors follow strong
earthquakes. [Stunning Map Reveals World's Earthquakes Since 1898]
"Every time we have a magnitude 7 or something larger, should the whole rest of
the planet be concerned about the increase in hazard?" Parsons told
OurAmazingPlanet.
Parsons analyzed hundreds of earthquakes of at least magnitude 7.0 in the past
30 years. Only 24 of the 260 big earthquakes triggered large earthquakes
globally.
The risk of earthquakes bigger than magnitude 5.0 translates to 1 or 2 percent
in the hours following a large earthquake, the study found. Parsons and other
scientists are looking into why some large earthquakes seem to trigger other
temblors and other don't.
"That is far less frequent than anticipated," Parsons said. "It's still in the
range of random chance, but it's not a zero chance."
These aftershocks were delayed by up to nine hours compared to their smaller
magntiude-2 and magntiude-3 counterparts, which may rupture as soon as 45
minutes after the first big quake.
From: "[email protected]" <[email protected]>
To: [email protected]; Forum Himpunan Ahli Geofisika Indonesia
<[email protected]>
Sent: Sunday, April 21, 2013 3:25 AM
Subject: Re: [iagi-net] Gempa bumi di China...Re: Gempa bumi Pakistan - Iran
Gempa Cina melanda jalur padat penduduk, sudah 156 orang meninggal.
Sent from my BlackBerry®
powered by Sinyal Kuat INDOSAT
________________________________
From: [email protected]
Sender: <[email protected]>
Date: Sun, 21 Apr 2013 07:57:34 +0000
To: <[email protected]>; Forum Himpunan Ahli Geofisika
Indonesia<[email protected]>
ReplyTo: [email protected]
Subject: Re: [iagi-net] Gempa bumi di China...Re: Gempa bumi Pakistan - Iran
Mungkin banyak yg peduli dgn Gempa China, aku pun berusaha cari info juga,
hanya jangan lupa ada gempa (vulkanik ?) juga loh di Dieng. Kawah (aku lupa
namanya) mengeluarkan asap putih tebal, status Siaga-1 (??).
Salam,
Nuning
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________________________________
From: Franciscus B Sinartio <[email protected]>
Sender: <[email protected]>
Date: Sun, 21 Apr 2013 00:49:56 -0700 (PDT)
To: [email protected]<[email protected]>; Forum Himpunan Ahli Geofisika
Indonesia<[email protected]>
ReplyTo: [email protected]
Subject: Re: [iagi-net] Gempa bumi di China...Re: Gempa bumi Pakistan - Iran
Pak Luthfi,
mudah2an bukan kita berdua saja di milis ini yang perduli tentang hal ini.
saya harap mereka semua lagi sibuk men-plot semua gempa2 itu dan membuat
analisa nya.
saya sendiri mau berbuat lebih banyak cuma expertise saya belum begitu banyak
dalam hal ini, saya sekedar pengamat.
tetapi saya akan berusaha google gempa2 tsb, dan cari coordinat epicenter nya
dan kedalamnya. lalu coba plot di googleearth.
salam,
frank
________________________________
From: "[email protected]" <[email protected]>
To: [email protected]; Forum Himpunan Ahli Geofisika Indonesia
<[email protected]>
Sent: Sunday, April 21, 2013 2:40 AM
Subject: Re: [iagi-net] Gempa bumi di China...Re: Gempa bumi Pakistan - Iran
Disamping di Cina magnitude 7,4 SR . Di P. Saumlaki, Maluku magnitude 6,. SR
dan di Jawa Tengah 4,7 SR. Kan setelah rentetan gempa Iran-Pakistan berlanjut
ke Indonesia, bahkan Cina. Siapkah kita menghadapi bencana gempa ???
Sent from my BlackBerry®
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________________________________
From: Franciscus B Sinartio <[email protected]>
Sender: <[email protected]>
Date: Sun, 21 Apr 2013 00:18:32 -0700 (PDT)
To: iagi<[email protected]>; Forum Himpunan Ahli Geofisika
Indonesia<[email protected]>
ReplyTo: [email protected]
Subject: [iagi-net] Gempa bumi di China...Re: Gempa bumi Pakistan - Iran
Ini ada gempa yang besar lagi di region yang berdekatan. di China.
fbs
________________________________
From: Franciscus B Sinartio <[email protected]>
To: iagi <[email protected]>; Forum Himpunan Ahli Geofisika Indonesia
<[email protected]>
Sent: Tuesday, April 16, 2013 7:06 AM
Subject: Gempa bumi Pakistan - Iran
Ada yang punya berita tentang gempa bumi di Iran-Pakistan sejam yang lalu?
tambahan info gempa yang cukup besar di kashmir october 2004 (ini ada
hubungannnya dengan benturan australian plate dan asian plate (yang membentuk
himalaya itu, sorry kalau nama plate nya salah).
lalu kemudian kita semua tahu desember 2006 gempa besar di offshore aceh.
sampai sekarang belum ada yang kaji apakah ada hubungannya atau seperti itulah.
sekarang ada gempa yang lebih besar di daerah yang sama. di Pakistan.
fbs
