30 June 2011
28 June 2011
An Earthquake Is Coming
Seattle is in a very earthquake prone region. It took some getting used to. I don't like the ground to move!
For the first 10 years i lived in Seattle we had an earthquake every 13.5 months (by my calculations). For the second ten years i've been here we've had exactly ZERO earthquakes. Or so it seems. Right now we know an earthquake is coming. It's expected on October 29th. No, i know it's impossible to predict earthquakes, but something interesting has been happening. Let me explain.
The first two years i was in Washington there were no earthquakes. Since then there have been eight. I graphed them here:
(bubbles are magnitude, height is time since previous quake in days)
Nine earthquakes in less than 8 years and then nothing for over 11 years? Well, it's possible, and THE BIG ONE could still happen any day. (I'm involved with HAM radio neighborhood emergency training for just that possibility.)
But it turns out that in fact, we HAVE had earthquakes since 2001, seven or eight of them, all around 7.0 on the Richter scale. But instead of lasting for 17 seconds or 52 or 31 or even 138 seconds, they've lasted for 28 days! The plates still slip, the same amount of energy is released, but over a much longer period of time.
Because the energy is spread out over such a long time, they were called Silent Earthquakes when the were first discovered (here in Washington) in 2003, which soon after changed to Slow Earthquakes when the reasons were discovered. Now they are officially called ETS events, Episodic Tremor and Slip, but i like the term Slow Earthquake better. They have since found them in Hawaii, Indonesia and a number of other places around the world. Central Washington University has a nice detailed explanation.
So yes, i know this all sounds like i made it up, it's just so strange. And wait... it gets weirder! Most amazing of all, they come at regular intervals, every 14 months reasonably dependably. They are predictable! With some data from The University of Washington and The Pacific Northwest Seismograph Network i made some charts and calculated averages.
You can see the regularity of the events (the 2008 ETS had a long tail, it seemed to end on time, but then there were continuing effects for a couple of months). So using that average, 13.7 months, i came up with a date of October 29th for the start of the next Slow Earthquake. Just this week the PNSN added a prediction of late October to their ETS page [fixed dead link 2013]-- so i guess i came close. I made a calender graph of when the seven well documented ETS events have happened, and used some mathematical modeling to estimate previous, and future events.
The PNSN ETS page, http://www.pnsn.org/NEWS/PRESS_RELEASES/TREMOR_05.html, [fixed dead link 2013]- has all the data on previous Tremors and usually has day to day updates on events when they happen. So keep an eye on it, and be ready for a silent earthquake on Halloween!
For the first 10 years i lived in Seattle we had an earthquake every 13.5 months (by my calculations). For the second ten years i've been here we've had exactly ZERO earthquakes. Or so it seems. Right now we know an earthquake is coming. It's expected on October 29th. No, i know it's impossible to predict earthquakes, but something interesting has been happening. Let me explain.
The first two years i was in Washington there were no earthquakes. Since then there have been eight. I graphed them here:
- Thu 25 Mar 1993 13:34, magnitude 5.6 in Scott Mills OR (far away)
A small earthquake (here). I didn't feel it although many people did. I was at a fast food restaurant in Factoria.
- Sat 28 Jan 1995 19:11 5.0 at Robinson Point in Puget Sound (very close!)
It was cold and rainy and i was just out of the shower and making mac & cheese. It scared the heck out of me!! It was my first earthquake, so maybe my memory is exaggerated, but it seemed huge.
- Thu 02 May 1996 21:04 5.3 near Duvall (close by)
A little less scary but still disturbing. I was at home listening to baseball on the radio - the announcer left the booth and there was dead air.
- Sun 09 Feb 1997 20:26 3.5 under Seattle (very close)
I felt it, but it was quite small.
- Mon 23 Jun 1997 12:13 4.9 near Bremerton (near by)
I was at work at PSC. I was in the bathroom. When i got back to my desk everyone was freaked out about the quake, but i hadn't felt it.
- Tue 03 Nov 1998 02:40 3.1 near Bremerton (close by)
It was in the middle of the night and i didn't wake up.
- Fri 02 Jul 1999 18:43 5.8 Satsop (not close)
I don't remember this, maybe i didn't feel it.
- Wed 28 Feb 2001 10:54 6.8 near Olympia (not close)
This was very big in Olympia, but only 4.2 in Seattle. Still, it was the biggest i've felt. My computer monitor fell in my lap, i ran out of the apartment, thought better of crossing the skybridge and got out of the 100 year old brick building.
- Incidentally, i was in another earthquake, although not in Seattle
Mon 10 Jan 2000 22:27 magnitude 2.8 Trapani, Italy
Very surreal. I was in a hostel in Sicily in even though it wasn't strong, it was long, and we were right on top of it. I took it in stride, but the other people in the hostel, especially the Moroccan students Josef & Rashid in the next room were very scared!
Nine earthquakes in less than 8 years and then nothing for over 11 years? Well, it's possible, and THE BIG ONE could still happen any day. (I'm involved with HAM radio neighborhood emergency training for just that possibility.)
But it turns out that in fact, we HAVE had earthquakes since 2001, seven or eight of them, all around 7.0 on the Richter scale. But instead of lasting for 17 seconds or 52 or 31 or even 138 seconds, they've lasted for 28 days! The plates still slip, the same amount of energy is released, but over a much longer period of time.
Because the energy is spread out over such a long time, they were called Silent Earthquakes when the were first discovered (here in Washington) in 2003, which soon after changed to Slow Earthquakes when the reasons were discovered. Now they are officially called ETS events, Episodic Tremor and Slip, but i like the term Slow Earthquake better. They have since found them in Hawaii, Indonesia and a number of other places around the world. Central Washington University has a nice detailed explanation.
So yes, i know this all sounds like i made it up, it's just so strange. And wait... it gets weirder! Most amazing of all, they come at regular intervals, every 14 months reasonably dependably. They are predictable! With some data from The University of Washington and The Pacific Northwest Seismograph Network i made some charts and calculated averages.
22 June 2011
Stairway
How can Stairway to Heaven be the best song ever when it isn't even the THIRD best song on it's own album?
Seriously, The Runes Album has at least 3 songs that are clearly better:
Rock & Roll
Bron-Y-R Stomp
and especially
Misty Mountain Hop
Seriously, The Runes Album has at least 3 songs that are clearly better:
Rock & Roll
Bron-Y-R Stomp
and especially
Misty Mountain Hop
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