reply to post by Cerridwen
The Pacific Ocean is surrounded by what's known as the "ring of fire", the regions along major faults that have very frequent quake activity. Quite
honestly I wouldn't say that the recent activity in and on the edges of the Pacific has been anything out of the ordinary.
EDIT: whoever said there have been 3 quakes in the Pacific recently, might want to take a look at this map:
Source:
USGS
As my "source link" says, it's from the USGS (United States Geological Survey) and it's for 8 pm UTC today. I set up the map to show the Pacific
region. All those yellow squares are quakes in the past week but more than 24 hours ago, the blue squares are quakes less than 24 hours ago. I haven't
counted all the Pacific quakes there (need to exclude ones within the US, for example), but it's a lot more than 3.
And that is a pretty normal-looking map.
Just for rough comparison, here's a map from my archives that dates from June 2008. Give or take a few quakes, it's pretty much the same sort of
picture: quakes popping off round most of the Pacific Rim:
(Also from USGS but no longer available as a link because it's too long ago. But I link to the same map format below.)
It looks like this most of the time.
(End EDIT)
Here's a run-down of more-or-less what's been going on during the past week or so round the Pacific. I'll start in Sth America and work down and in
clockwise direction round the region.
Okay, down along the west side of Sth America, there are often quakes and in fact we can see a few there even up in the high 5 to mag 6 range every
month. The past week has been about average. Nothing huge by Sth American standards (biggest quake ever measured was in Chile in 1960 btw), and few
reports of serious damage.
Going across the Pacific from Chile, there have been a few smallish quakes in the sthn middle region. A bit over a week ago there was one near Easter
Island and one not far from Pitcairn. Not really common there but not super rare either. And they weren't large enough to be dangerous.
Moving around from there to the region off New Zealand, it's also very active. The Kermadec Islands had a magnitude 7.4 quake last week and some
decent sized aftershocks. That was the biggest quake for a while now -- bigger than the one in Turkey -- but luckily it was well away from any main,
inhabited islands and didn't harm anyone. Up and across to New Guinea,they've had a couple but again, nothing too bad and no reports of any serious
damage or losses.
Then over into Indonesia -- well, that's actually been relatively quiet in the last few weeks with only a couple of quakes getting near mag 6, but
most were down in the mag 5 range or even lower. However, a couple of volcanoes in Indonesia have been pretty active and erupting lately, such as
Merapi and Anak Krakatau, but on the other hand as that country has about half the world's active volcanoes (about 200 there!), it's normal that a few
of them are erupting to some extent. There are some links between volcanism there and quakes but it's not always a this-causes-that kind of thing,
more like a secondary effect, it seems.
Moving on from there up past Taiwan towards Japan, the past week has not been very busy, but once up to Japan itself, there were some quakes in the
Ryuku Islands (mag 5 range and no real drama), plus the ongoing aftershocks around Honshu from their massive quake back in March.
Okay, on up to the islands in the Alaskan region. These are always shaking and lately has been no different from usual. There was a mag 5.8 in the Fox
Islands (Aleutian Islands region) on Tuesday 10/25 then a mag 5.5 on Friday 10/28 not far from there, but for that part of the world it's nothing the
locals would even raise eyebrows much over, I think. They get ones in the magnitude 5 range every few weeks or so in that region on average.
Past Alaska and down past BC and Vancouver Island, it's been pretty peaceful offshore. Couple of teeny quakes that would barely be felt, just onshore
near Eureka and also some small ones down into California but again, nothing out of the ordinary.
California gets literally hundreds of quakes a week but most are so small they're barely noticed. Biggest quake in Cali lately was a mag 4.7 on Thurs
10/27, about 10 miles from Whitehawk. Didn't do any harm, as far as reports indicate. Was nothing exceptional, for sure.
Down in SoCal, it's business as usual. Lots of little quakes, many going right down the line towards Mexicali. Nothing that would spill anyone's
morning coffee, though.
There's been a mag 4.0 and also a 4.1 off the coast of Mexico in the past week, but both were on well-mapped fault lines and would have been barely
felt on land, if at all.
And that brings us back to Sth America.
So, for the ring of fire, a pretty average week. Would be nice if it would stay that way all the time, but it won't. A fair percentage of the biggest
quakes in the world occur in the places I've mentioned (excepting the mid-Pacific around Easter Island, where it's rare to have big ones). So, I guess
there'll be another mag 7 or bigger somewhere around that piece of our planet during the next month or so. Could go a bit longer or there could be a
couple close together. It's just averages. We usually get something like a dozen to 15 quakes in the mag 7 range each year worldwide, so that's the
rough odds.
For an idea of what it all looks like, try the
USGS Map of Latest Earthquakes in the
World. It's clickable and lets you get details on most quakes within a few minutes of when they happen. There is plenty of good info there.
Best regards,
Mike
edit on 29/10/11 by JustMike because: added maps, fixed links