Pretty Serious Swarm at Long Valley right now, Intensifying- 3.9, 3.8, 3.2

its certainly shaking and rattling, GPS stations at the center of caldera (displayed as stars) have been showing lifts of 6-8 meters since 2011. Looks like the magna chamber is rising from this graph

This is somewhat disturbing. I mean its one of the largest calderas in the world, and a supervolcano. These quakes seem to be located on south-southeast rim of resurgent dome. That caldera is huge! Approx. 32 km wide (20 miles). This is as dangerous as Yellowstone. On the other note, the caldera itself is extinct, as the magma is crystallized and not molten. But this will be interesting to monitor.

Wow, look this uplift:

earthquake.usgs.gov...

earthquake.usgs.gov...

So does this mean an extinct volcano is now active again? Or that lava is flowing again and needs a place to flow /release out ofAnd this caldron is it? .....could this be related to the Hawaii volcano that's actively flowing?

When I went to bed last night there was a little over 100 quakes, when I got up there were over 400
In the half hour it took me to get ready for work there are now over 500

wow

And what exactly does 500 mini quakes mean? ( other than a ton of quakes and a lot of movement)...is this gonna blow and split Cali off I to the ocean?. Has there ever been activity like this before in the history of volcanos/earthquakes,and if so, what happened?....

a reply to: Meldionne1


Albeit Wiki sourced if you scroll down to eruptions it details previous activity - hope it helps.en.wikipedia.org...

Here is a great 3D representation of the current swarm activity that was just posted and how it's connected to other recent earthquakes, specifically the Anchorage and Oklahoma activity.

Geez, I just fired up the compy to see 575 quakes over the past 24 hours, yikes! In Long Valley caldera...double yikes!
This is something significant. If this was under Mammoth, I would think this was just a dike intrusion, but this location is more worrisome. It began 2 days ago under the SE edge of the resurgent dome, and has spread quickly under most of the whole darn dome.


image source



usgs

originally posted by: Meldionne1
And what exactly does 500 mini quakes mean? ( other than a ton of quakes and a lot of movement)...is this gonna blow and split Cali off I to the ocean?. Has there ever been activity like this before in the history of volcanos/earthquakes,and if so, what happened?....

The Long Valley caldera is still a mystery. There is no hotspot like in Yellowstone or Hawaii. There was "Glass Mountain", made from obsidian before its eruption 760 000 years ago, which destroyed the mountain. The eruption released 600 cubic kilometers of material, on the comparison Mt. Saint Helens released just 1,2 cubic kilometers. So its really big volcano. Lets hope it stays extinct. We are talking about apocalyptic eruption here.

I've been looking at the USGS site and have noticed that this morning we are seeing quakes very near the surface. This appears to be escalation, but I am not knowledgeable on this. Can someone please elaborate? Are we looking at the beginning of a break in the upper crust prior to an eruption at Long Valley?



I modified the chart to show only today's quakes for the Long Valley Caldera.



This makes it easier to see all of the activity at or near the surface, so far, for 09/26/2014.

Bishop

originally posted by: Meldionne1
So does this mean an extinct volcano is now active again?

The Long Valley volcanic system is far from extinct.

Early eruptions was fed from magma chambers with more basaltic magma (which is thought to be extinct), while later eruptions (in geological terms) including the caldera forming eruptions was fed from magma chamber with more rhyolitic magma (explosive).

Several people have asked what we could expect if Long Valley erupted. Below, I've pieced together what the pros at the California Volcano Obseravtory (CAlVO) have published on their website.

Volcanic unrest through the 1980's to 1990's in the southern part of the Long Valley caldera reminds us that the volcanic system is young. Volcanic activity and related hazards are likely in the future.

Geologists have pieced together the dramatic sequence of eruptions and ground cracking that occurred along the Inyo volcanic chain about 600 years ago. This eruptive sequence provides probably the best "scenario" for future volcanic activity in the Long Valley area.

The activity 600 years ago included 17 explosive eruptions and 3 effusive eruptions. Read about those events here:

The Inyo eruptive episode about 600 years ago, Long Valley caldera, California
This included pyroclastic flows that travelled over 3 miles, and tephra deposits over 1/2 meter thick 7.5 miles away.

So not another caldera forming sized event, not even Mount St. Helen's sized; but sufficently large enough and explosive enough to harm life and livelihood for residents of the area. It really depends on location and the direction of the prevailing winds.

Well, these are the scientists' public thoughts on the likely future activity....but nobody knows for certain.

(the italics are mine--to emphasize that Long Valley is certainly not extinct.)

Ok so, a little more communication has taken place with a couple of my favorite scientists.

1) I was reminded that there have been other swarms at LV that have included M>4 events, like in the 90's. They described this swarm as "healthy"- but not necessarily "massive". YET.

2) Regarding the uplift, it has been in uplift mode for about 4 years, at a steady rate. What they are looking for is a change in the RATE of uplift- like if it increases suddenly. It was also suggested to me that eventually due to this uplift, micro fractures in the rock start to break from the stress, hence the earthquakes. And to quote- "Swarms are the norm at calderas, and they correlate with deformation." That means both inflation and deflation- and we certainly have witnessed the results at LV and at YS.

To Olivine:
I like that when I talk to you guys, I don't have to be so guarded and reserved. Talking with scientists I am always on edge. I don't want to screw up. Anyways- you bring about an important point that this is happening in the dome.
An obvious speculation, of course, is that there is a new magma intrusion into the dome. But it would seem GPS would reflect that. So I'd say we'd better watch the GPS stations like a hawk over the next weeks- for a sudden increase in RATE.

I will also mention that I have been troubled in recent weeks by some signatures at station MLH, looking like long, deep tremors, with frequencies centered on about 3.5 Hz. And on a couple of those, there have actually been harmonic overtones. Not sure if these signatures are noise or what. But it adds to the mystery for me. So let's just say to see a swarm like this, after seeing THOSE signatures- yeah, I am a bit nervous about this swarm.

And an update: It has died back down a bit in intensity, but it still continues.

Also here is a map of 7-day activity:

a reply to: Olivine
and from your link Olivine...

Increased volcanic unrest (including earthquake swarms, ground deformation, and CO2 gas emissions) in the Long Valley area since 1980 increases the chance of an eruption occurring in the near future, but scientists still lack adequate data to reliably calculate by how much. Volcanic unrest in some other large volcanic systems has persisted for decades or even centuries without leading to an eruption. But since volcanic unrest can escalate to an eruption quickly--in a few weeks, days, or less--USGS scientists are monitoring the activity closely.

originally posted by: TrueAmerican

An obvious speculation, of course, is that there is a new magma intrusion into the dome. But it would seem GPS would reflect that. So I'd say we'd better watch the GPS stations like a hawk over the next weeks- for a sudden increase in RATE.

I will also mention that I have been troubled in recent weeks by some signatures at station MLH, looking like long, deep tremors, with frequencies centered on about 3.5 Hz. And on a couple of those, there have actually been harmonic overtones. Not sure if these signatures are noise or what. But it adds to the mystery for me. So let's just say to see a swarm like this, after seeing THOSE signatures- yeah, I am a bit nervous about this swarm.

Really interesting about the possible long period events--keep watching for us. I've been watching the Casa Benchmark bi-hourly spectro, but it is a hot mess to look at.

I can't see any obvious inflation or deflation over the past few days.
Unfortunately, the GPS rate change/displacement data at Long Valley haven't been updated since May.
The tilt and strainmeter webpage is still "temporarily unavailable".
If you click on the nearby GPS stations from the CalVO monitoring page, they are current, and don't show any extreme movement over the past few days/weeks. For example, Hot Creek GPS:


I'd be curious to know if any changes have taken place at nearby Hot Creek. It's been closed (swimming holes) since 2006 due to increased activity, including geysering. wiki

Looking at the seismos, it doesn't look like this swarm is finished yet.

a reply to: Olivine

Well to illustrate what I mean, here is one case of such an event at MLH:


Again, not sure if that is noise or what. Could be noise. Yeah, noise that is CLIPPING the seismometer?

originally posted by: TrueAmerican
a reply to: Olivine

Well to illustrate what I mean, here is one case of such an event at MLH:

Again, not sure if that is noise or what. Could be noise. Yeah, noise that is CLIPPING the seismometer?

Well it sure isn't a glacier, mwhahaha!

That is low frequency over a long duration (your screen grab is showing minutes long event, right?)

a reply to: Olivine



lol I thought of the exact same thing! They can't claim it is a glacier.

Umm, yeah, they don't call them Long Period Events for nothing! Love you long time.

Out of curiousity, what does the spectro look like of this low amplitude "stuff" beginning at 15:11 UTC until about 15:14?
(I'm looking at MLAC in GEE--nearest live seismo I've got access to)

Just background noise?

a reply to: TrueAmerican
Here is a Seizmo capture for MRH Rocky Hill

What are the 2 missing sections about, yet the lines (red and blue) extend quite far below ?