6.9 Quake Just Slammed California

Made the reply above but also wanted to bump the discussion for those who may have missed reading the thread yesterday. This is not an over and out situation so move along kind of thing imho.

Thank you to each contributor in this thread. Hopefully all will be calm and no updates will be needed but probably not.

reply to post by antar


I was a kid in the area when St. Helens blew. I remember my family scrambling to get face masks as the ash came piling in. It was an exceptional event indeed. The joke when I was a double science major in college was that, for all the geology I was taking, I should've been a triple science major. Suffice it to say that I've been aware of the seismic potential of the area for decades. Really the only thing that one can do is make sure that one has an earthquake kit. I store large bottles of water, have cans of sterno, flashlights/camplights, and keep a decent supply of canned foods at all times. We'll rotate out the water and canned foods through natural consumption for the most part so that expiry dates are ok on both. The only way that it has affected my life choices is that I refuse to work in the downtown areas because of the combination of the geology of the areas and due to not all of the buildings being built to withstand a megathrust. That's all one can really do because when it happens, it's going to happen. It's just the way it is.

I remember being a kid and seeing this footage of a man almost getting caught in the St. Helen's blast.



It was what started my real awareness of the seriousness of natural disasters and the need to be prepared for the reality as much as you can without getting completely batty about it.

I hope the faults don't let go yet. I have two uncles, their families, and the family of a second cousin out there.

no big deal SO FAR

Looks like I'm the first to post about the new quake off-shore Oregon.

Hmmmmmm....


5.1mag 10km deep

USGS link


It's quite a ways out on the Juan de Fuca plate, but so long as they don't re-position it, it's still East of the Atlantic plate. I would assume they are going to also call this a strike-slip, associated with the spreading plates, vs the subduction zone. At this point however, I don't care so much WHAT the mechanism is...I just don't like seeing it there.

Granted, this area is no stranger to this size of quake but I think it would be a stretch to say that it ISN'T associated with the 6.9 quake two days ago. Hopefully this will be it, but I still wouldn't be at all surprised to see another one or two is this range, up to the 6's at the far North end of the Juan De Fuca plate, or in the Queen Charlotte fault system along Vancouver Island.

ETA: I have to add this this date will forever be etched into my memory. I will never forget watching (live) the tsunamis wash over the cites, carrying people away before our eyes. I'll never forget watching the first P waves roll over GEE and KNOWING without a doubt that thousands of people were about to die. May they rest in peace and I also pray that a fix to the on-going fukashima disaster is found.

reply to post by WhiteAlice


Hum sounds like you have given this considerable thought, it was good to get to know you a bit more too in the way you think and such. It is rarely for oneself that we get concerns. The reality is so much larger than anyone can imagine unless like yourself you have had a taste of that type of reality. One thing I would like to add or ask is how the population has changed since your first experience and how you see that affecting evacs in the future? Also you said as a youngster your family had masks and a route out of harms way, do you also have this level of togetherness and a safe route away from the ash as an adult? Sorry if this seems like 20 questions it is not meant to be I really feel like you have a different more grounded sense about the past, present and future.

reply to post by westcoast


I am with you my friend, was with you during the event if you remember, here, it was and is always will be with me as well.

Keep watch over us because most of us are kept turning our heads this way and that so much this day and age its hard to know what is coming down the pike or truly relevant.

reply to post by antar


The first question I can't entirely answer very well because of personal circumstance. However, I know that just about everybody who went through the eruption, even at greater distances, felt its impact. I'd say overall we went from viewing those frosty mountains from being just big lumps of snow covered rock to active volcanoes. I remember hearing about people that didn't believe the mountain would erupt and wouldn't evacuate. Half of the people I knew thought the geologists were nuts. We were far enough away where we didn't have to evac. Sorry if I gave that impression, was not intended. The ash hit a huge amount of area in Washington and Oregon both and the mudflows impacted a pretty good chunk of Washington, at least from kid memory. After they cleared I-5, I remember driving on it and seeing all the mess on the sides. It was bad. We used to go fishing out at Spirit Lake and I remember crying when I heard that it had been destroyed.

The initial response that my family had was actually my mother zooming home and driving us to the highest point in the area to get a full fledged view of the eruption and it was terrible and awesome at the same time. It seemed pretty far away though so there wasn't any fear but when the ash cloud turned and started dumping down on us, masks were bought. Couldn't go outside without them because inhaling it was bad for the lungs. Whole neighborhood got together to clear the heaps of ash that covered everything once it ceased. There were 10 foot piles of ash at the end of all the streets in my neighborhood. Like I said, before that, there was no sense of danger at all to the area. We had moved from a tornado prone area to the Pacific NW because of the lack of tornadoes. Like I said, sleeping frost covered lumps of rock was the perception.

As for us today, we all make sure that we have some level of preparedness. My children and I do have plans in case of a natural disaster. They know where all the closest "safe" spots are in the house for each section and what to do in the event that it occurs while at their schools. As far as my parents and sibling go, we're dysfunctional as hell in all things but we're bound together on that one subject. We don't keep masks, lol, still but we do all have a level of "just in case" food. My mother went a little wonky with it and has a large pantry full of canned food items and tons of water. She's always saying that, if anything happens and we run out, make our way to her house.h I think it was a pretty good learning lesson for a lot of people out here. Most of my friends all keep disaster/earthquake kits. I have an absurd number of friends that went SCA. I know that I took the time after that to learn about local medicinal herbs that grow in the area and their uses. So varying degrees of survival nut, lol, and some coming equipped with garb.

I took it half seriously when I was growing up but Mt. St. Helens was one of the reasons why I took so much geology. We don't fear another mountain erupting or the big earthquake though. That'll happen whether we fear it or not. No point in living in fear about something that could happen any day or not in one's lifetime. All you can do is be prepared and that's my family's motto.

PS. My sister and I have been harassing our mother for years about how "safe" the Pac NW is, lol. After I took all the geology and found out about the megathrust quake history, we tacked that in, too. Windstorms, volcanoes, massive earthquakes--real safe, Mom! lol It's a family joke.

reply to post by WhiteAlice


Oh wow...I missed your first post. We must have lived close to each other, and be similar in age. (Yakima? I graduated in 90)

My memories are SO similar to yours and the experience is also what fuels my interest in seismology and volcanology. (okay, experiencing the 6.7 Nisqually quake, too. I am now on the West side of the mountains!)

I don't know if you ever read my short story 'The Day My World Shook', that I wrote for a contest here on ATS. It's a first person account of that day way back when. I have it in my tag line so you can click on it if you want. Might bring back some memories!!

reply to post by westcoast


Close enough, lol. The range of its impact was so big. We lived a bit west of you. Graduated a year early in '87 so a bit younger. Definitely was something else to experience. I remember the Nisqually Quake well. I had to play dodge a modern bookcase with my eldest in my arms as it was swaying at the top of the stairs. Now I use those wall mounts to fix things to the walls just in case, lol. First one was the Spring Break Quake aka Scott Mills in '93. I was sleeping towards the top of a 16 story building during that one. Scarred me for life. Been afraid of heights ever since but I was going to college at the time so first thing I did after it was all done was to run to the geology department to look at the seismograph, lol. Not going to lie, I've been looking at the USGS site for earthquake activity not long after the site came up. I like to know what's trembling and where even if there's nothing I can do about it.

Good work on the story. I remember feeling that same dread. It was fine when the plume was a long way off but when it was clear that it was coming, it was downright terrifying. I think my mom raced back home faster than she did driving up the mountain road to our lookout point, worried that we'd miss it. Everything looked like a wasteland to me after all the ash fell. It seemed like all color was gone outside because everything seemed coated with gray. We still have jelly jars filled with ash. I remember going down to the big pile and scooping ash into the jars on my mom's orders.

Was just looking through old eruption photos and found this one of the plume's spread. You see that coming towards you, you can't help but fearing death: keenanevans.files.wordpress.com...

Living in the Pacific NW sure can be exciting, eh? Just thankfully the excitement has long spells of a whole lot of nothing going on. Keeps us on our toes.

reply to post by WhiteAlice


Love your post. Takes me back...I too remember everything seeming to be drained of color. It's so hard to explain to someone who didn't experience it.

That picture is perfect. It really was something to see, and yes, terrifying.

I live in Humboldt County and drove yesterday to Petrolia, the place closest to the epicenter of the quake. There was no damage there and nothing has been reported in town, not even things falling off shelves. I have been talking to people and we all agree this one was somewhat different and felt more like a wave. Of course, those are merely subjective observations. But what I find strange is how a 6.9 quake could cause NO damage. One explanation offered was that the direction of the release of energy was toward the west, further out into the ocean. But I had always seen the effects of earthquakes pictured in circles surrounding the epicenter, and not a straight line in any direction.

reply to post by gwynned


How much damage occurs from an earthquake depends on depth and wave type.

Here's a link that kind of explains the different types of waves: allshookup.org...

My guess is that what was experienced in this quake was a Rayleigh wave type. It'd feel like everything was on a boat for the duration of the quake. They aren't as destructive as the ironically named Love wave, which is the type most often associated with lots of damage. Rayleigh waves lose amplitude the further they are from the center or source of the quake. Think of dropping a pebble into a still pond. The bigger waves are towards the center and the further out the rings go, the smaller the wave.

I think the Scotts Mill quake in 1993 was probably a similar type of quake. I was sleeping at the start and was dreaming that somebody had stuck me in a dryer, lol. When I awoke, the movement was like a ripple although exaggerated by being in a taller building. As I was running down to the internal staircase, I looked out the window at the rest of the city and saw all the tall buildings swaying from the quake. In lower buildings, people reported it like it was more like an ocean wave coming through. There wasn't a whole lot of damage in that one either although the epicenter was much closer and inland.

reply to post by westcoast


Yep, was the same for me. I have issues with amnesia but I never forgot the eruption. It's always been the most cohesive childhood memory that I've had. Being able to recollect other details of the whole experience was really great for me as it made the total memory even more filled out so thank you.

Aftershocks are still rolling in, which is to be expected.
The most recent was a Mag 4.4 near the mainshock epicenter.

I do think a stronger aftershock is still probable--in the Mag 5.6-6.0 range.
The magnitudes 5.1 & 5.2 were near the spreading ridge & Blanco fracture zone transform fault; not even close to the mainshock region--so they don't count, in my view.
That means the largest aftershock proper, was only Mag 4.5.

Here is a look at the past 30 days in the area, mag 2.5+, from USGS