Earthquakes

[Turtle]

I haven't done due diligence in completing the graphs of earthquake numbers from the USGS site maps. Mia culpa. :doh: I do however check the maps almost daily, and today I found the highest totals for the US that I've seen in 3+ years of observing.

 

The US count is at 1134, and the highest I found in my records is 762. The World count is at 301, and the highest I recorded is 324. Kinda hard to tell if it's California or Alaska shaking the lead.

 

Here's the main page with a full explanation of the threshholds: >> USGS Earthquake Hazards Program » Latest Earthquakes in the USA - Past 7 days

[freeztar]

Interesting. That's a whole lotta shakin! :doh:

 

I explored the USGS site some more and was surprised to see that an earthquake occurred back in December just 8 mi W of me. ;)

Info for Eq sehwb1228a

 

So if I may ask, what is up with the harmonic signatures you mentioned a few posts back? How can you tell they are harmonic from the wave forms?

[Turtle]

...So if I may ask, what is up with the harmonic signatures you mentioned a few posts back? How can you tell they are harmonic from the wave forms?

 

Perhaps 'harmonic' was a poor choice of word, as it has a specific meaning in regard to the waveforms of quakes. What I saw in those traces I pointed out is a regular 'beat' that is superimposed on the 'usual' traces I see. Look out how the little squiggles themselves are organized in groups of larger squiggles. :D Sorry for the technical jargon. :doh: In checking some sources, I do not find this particular superposition pattern in any of the illustrations. ;) As I say, it may be an artifact of the electronics, but it's no less interesting if that is the case. I haven't seen it again since posting my initial observation. Now heeeeerrrre's Linky! :hyper: >> ..........:doh: http://vulcan.wr.usgs.gov/Imgs/Gif/Monitoring/Seismic/quakes.gif

[freeztar]

Perhaps 'harmonic' was a poor choice of word, as it has a specific meaning in regard to the waveforms of quakes.

 

Do you mean this?

Harmonic tremor - Wikipedia, the free encyclopedia

 

What I saw in those traces I pointed out is a regular 'beat' that is superimposed on the 'usual' traces I see. Look out how the little squiggles themselves are organized in groups of larger squiggles. :D Sorry for the technical jargon. :doh:

 

:doh:

Roger that.

 

In checking some sources, I do not find this particular superposition pattern in any of the illustrations. ;) As I say, it may be an artifact of the electronics, but it's no less interesting if that is the case. I haven't seen it again since posting my initial observation. Now heeeeerrrre's Linky! :hyper: >> ..........:doh: http://vulcan.wr.usgs.gov/Imgs/Gif/Monitoring/Seismic/quakes.gif

 

Thanks for the link.

 

I wonder if it would be possible to reconstruct the seismic waveforms into audible harmonics for use in music.

 

Does the USGS export to MIDI? :D

[Turtle]

Do you mean this?

Harmonic tremor - Wikipedia, the free encyclopedia

 

Yes; like that. I meant to include this link which qualifies tremors/quakes, and contains the gif I linked to.

CVO Website - Earthquakes and Seismicity

 

On 'harmonic tremors', they say this:

Harmonic Tremor: A continuous release of seismic energy typically associated with the underground movement of magma. It contrasts distinctly with the sudden release and rapid decrease of seismic energy associated with the more common type of earthquake caused by slippage along a fault.

 

If then, the unusual signals I identified are indicative of harmonic tremors, then Mt. Adams may indeed be waking up. ;): :eek: I did not write to USGS to ask about this, as the last time I wrote with a similar question I received no response. Damn shame given I have received responses before and that public taxes support them. :doh:

 

I wonder if it would be possible to reconstruct the seismic waveforms into audible harmonics for use in music.

 

Does the USGS export to MIDI? :doh:

 

By all means write and ask. :D Maybe ask about the seismograms too. :doh: ;) :hyper:

 

PS I see my link to that seismogram I posted in #101 is expired, and I cannot find any archive at the site going back that far. :D

[Turtle]

I ran across this new development in the study of earthquakes, and while not predictive in regard to 'when', it sheds some new light on 'where' and 'what' may happen. No small comfort to me that I'm smack dab in the middle. :)

 

 

Supercomputer Unleashes Virtual 9.0 Megaquake in Pacific Northwest

On January 26, 1700, at about 9 p.m. local time, the Juan de Fuca plate beneath the ocean in the Pacific Northwest suddenly moved, slipping some 60 feet eastward beneath the North American plate in a monster quake of approximately magnitude 9, setting in motion large tsunamis that struck the coast of North America and traveled to the shores of Japan.

 

Since then, the earth beneath the region – which includes the cities of Vancouver, Seattle and Portland -- has been relatively quiet. But scientists believe that earthquakes with magnitudes greater than 8, so-called “megathrust events,” occur along this fault on average every 400 to 500 years.

 

To help prepare for the next megathrust earthquake, a team of researchers led by seismologist Kim Olsen of San Diego State University (SDSU) used a supercomputer-powered “virtual earthquake” program to calculate for the first time realistic three-dimensional simulations that describe the possible impacts of megathrust quakes on the Pacific Northwest region. Also participating in the study were researchers from the San Diego Supercomputer Center at UC San Diego and the U.S. Geological Survey. ...

 

Tsunami with that 9.0 quake? :)

[Turtle]

I ran across this new development in the study of earthquakes, and while not predictive in regard to 'when', it sheds some new light on 'where' and 'what' may happen. No small comfort to me that I'm smack dab in the middle. :eek:

 

Supercomputer Unleashes Virtual 9.0 Megaquake in Pacific Northwest

 

 

Tsunami with that 9.0 quake? :cup:

 

Maybe I jiggled it a bit too much when I ran into it!? :eek: Fortunately whatever the cause, the 5.1 this morning on the Juan de Fuca plate boundry was far too small for a tsunami, as was the 4.9 that followed minutes later nearby.

Magnitude 5.1 - OFF THE COAST OF OREGON

Magnitude 4.9 - OFF THE COAST OF OREGON

 

A big bugaboo with predicting quakes in general and along the Juan de Fuca in particular, is trying to determine if quakes like today's relieve stress and so make the likelihood of a large quake less imminent, or if they indicate increased activity and mean a large quake is impending, or something else yet in evidence or postulated. :eek:

[Turtle]

Maybe I jiggled it a bit too much when I ran into it!? :) Fortunately whatever the cause, the 5.1 this morning on the Juan de Fuca plate boundry was far too small for a tsunami, as was the 4.9 that followed minutes later nearby.

Magnitude 5.1 - OFF THE COAST OF OREGON

Magnitude 4.9 - OFF THE COAST OF OREGON

 

A big bugaboo with predicting quakes in general and along the Juan de Fuca in particular, is trying to determine if quakes like today's relieve stress and so make the likelihood of a large quake less imminent, or if they indicate increased activity and mean a large quake is impending, or something else yet in evidence or postulated. :) ;)

 

Four days after these quakes, one of those 'slow-quakes', or 'silent-quakes', began here in Western Washington, and is still ongoing. I did notice a signature on the seismograms that was steady & small, but I attributed it to the weather which has of late caused some erratic signals. I have felt no shaking, and only saw a report a few minutes ago that the quake was underway. The geologists interviewed here in Vancouver showed traces of the quake that matched the pattern I earlier noticed. [The station of the trace in the report wasn't specified, but the silent-quake pattern shown looked like this current one from Mt. Hood :PNSN Webicorder Display ]

 

Here's a report with some links: >> :DWest Coast Quake Keeps Rolling On

An earthquake is occurring right now along the U.S. West Coast' date=' yet no one feels it, according to a new study just released by the National Science Foundation.

 

Discovered by geologists using the satellite-based GPS (global positioning system) system, the phenomenon now called a "slow earthquake," began about Feb. 7 and has been ongoing ever since.

...

According to Central Washington University geologist Meghan Miller, the slow quakes may help relieve the strain between faults without producing surface damage. "Until we had GPS geodesy, we regarded earthquake deformation in two main ways: long-term, steady state faculty motions, and the elastic strain where faults are stuck and let go during earthquakes. If it turns out that a major mechanism for releasing this elastic strain is through slow earthquakes that don't generate seismic shaking, then they become very important to understand," said Miller. ...[/quote']

[Turtle]

The quake activity off the Oregon coast is increasing. Some of the official spokespeople have assured the media that there is nothing to cause concern, even though they have no idea what is going on. :confused: Why do they even open their mouths like that? Caught in the lights & blurting something out? Good grief. Be prepared. Putting Down Roots in Earthquake Country—Your Handbook for the San Francisco Bay Region

 

...GRANTS PASS, Ore. (Map, News) - Scientists listening to underwater microphones have detected an unusual swarm of earthquakes off the central Oregon Coast.

 

Scientists don't know what the earthquakes mean, but they could be the result of magma rumbling underneath the Juan de Fuca Plate - away from the recognized earthquake faults off Oregon, said geophysicist Robert Dziak of the National Oceanic and Atmospheric Administration and Oregon State University's Hatfield Marine Science Center in Newport, Ore.

 

They hope to send out the OSU research ship, Wecoma, to take water samples, looking for evidence that sediment on the ocean bottom has been stirred up and chemicals in the water that would indicate magma is moving up through the crust, Dziak said.

 

There have been more than 600 quakes over the past 10 days in a basin 150 miles southwest of Newport. The biggest was magnitude 5.4 and two others were more than magnitude 5.0, OSU reported. They have not followed the typical pattern of a major shock followed by a series of diminishing aftershocks, and few have been strong enough to be felt on shore. ...

Swarm of Earthquakes Detected Off Oregon - Examiner.com

 

 

Lates quake info: >> Latest Earthquakes in the USA - Last 7 days

[Turtle]

On the local CBS TV evening news out of Portland, Oregon, they reported tonight that a research vessel is on the way to the area of the quake swarm. While not mentioned on their web report, the broadcaster said scientists told him there are no known faults at the location and that it may herald the birth of a new submarine volcano.

Swarm of earthquakes detected off Oregon Coast - KOIN.com

 

My local seismograms appear quiescent right now. :sleep: Cedar Flats volcanic station is the closest station to me.>> Seismogram Displays

 

It's worth noting the coincidence between the slow quake going on that I mentioned a few posts back, and this swarm, just because there is a coincidence in time. :lol: To refresh our quake vocabulary, a 'swarm' differs from a 'shock-aftershock sequence' in that larger quakes may follow smaller quakes. If I recall, the largest quake in this swarm registed a 5.2 or such a matter.

USGS Earthquake Hazards Program: Preliminary Earthquake Report: OFF COAST OF OREGON

Earthquake Hazards Program: Recent Earthquakes - Last 8-30 Days

 

As luck has it, I plan to be in the Cascades tomorrow, & near the flanks of Mt. Adams. If sumpin' busts loose, I'll have the scoop. :phones::

 

That concludes another irregularly scheduled earthquake report, because we still can't predict them. :D

[Turtle]

The swarm continues. :hihi: ;)

 

...Analysis of seismic “decay” rates, which look at the decreasing intensity of the tremors as they radiate outward, suggest that the earthquakes are not the usual sequence of a primary event followed by a series of aftershocks, Dziak said.

 

“Some process going on down there is sustaining a high stress rate in the crust,” he pointed out.

 

Dziak and his colleagues are monitoring the earthquakes through a system of hydrophones located on the ocean floor. The network – called the Sound Surveillance System, or SOSUS – was used during the decades of the Cold War to monitor submarine activity in the northern Pacific Ocean. As the Cold War ebbed, these and other unique military assets were offered to civilian researchers performing environmental studies, Dziak said. ...

Unusual Earthquake Swarm Off Oregon Coast Puzzles Scientists

[Turtle]

We just had a 6.3 up in Alaska, only 40 miles East of a newly discovered underwater volcano. First the volcano:

Found in 2003, this currently underwater volcano remains un-named still as far as I have found. Part of a rich complex of volcanism and hydrothermal activity along the Aleutian chain, this baby may surface in our lifetimes. :lightning: :eek:

 

Alaska Volcano Pops to Attention , Alaska Science Forum

 

Now the quake: Magnitude 6.3

Date-Time Tuesday, April 15, 2008 at 22:59:54 UTC

Tuesday, April 15, 2008 at 01:59:54 PM at epicenter

Time of Earthquake in other Time Zones

 

Location 52.036°N, 179.373°W

Depth 29.6 km (18.4 miles)

Region ANDREANOF ISLANDS, ALEUTIAN IS., ALASKA

Magnitude 6.3 - ANDREANOF ISLANDS, ALEUTIAN IS., ALASKA

 

We also had that 6.2 just 36 miles East of todays, back Saturday, March 22, 2008 at 12:24:12 PM at epicenter.

 

Now only the unofficial geologists can say that these Aleutian quakes and the swarm off of Oregon have a connection, so stay tuned for that.

 

Ohhhhh!!! Gotta run; aftershocks all over coming in.

Latest Earthquakes in the USA - Last 7 days

[Turtle]

Here's a new report from USGS on the swarm off the Oregon Coast; it clarifies 2 different event series have occured.

 

... According to Dr. Dziak, the current earthquake swarm is not typical of other swarms in the region, both with respect to its location (well away from the plate boundary), and its high rate of earthquake occurrence (averaging about 60 per day). The swarm’s center is about 40 miles from the nearest of the recent M5 earthquakes. The swarm began on 30 March, three days before the first of the M5’s. A question that naturally arises is whether or not there is a physical connection between the BFZ earthquakes and the earthquake swarm. Such a relation might be one of “cause and effect”, or perhaps both phenomena share an underlying cause. Perhaps it’s a matter of coincidence. It is not possible to make a definitive statement regarding this matter. ...

Offshore Oregon Sequence

 

And of course today's quakes in Illinois. This is a shock-aftershock series, with the largest a 5.2. Evening news reported this is the largest quake in the area in 40 years. Minor damage, but no apparent injuries resulted from this wide-felt event. :)

 

If you felt it, please report your experience here: Did You Feel It?

 

Main shock: Magnitude 5.2 - ILLINOIS

 

An aftershock: Magnitude 4.6 - ILLINOIS

 

Clickable Map: Map Centered at 37°N, 90°W

[freeztar]

Thunderbird created a thread on the midwest quake. Perhaps it should be merged into this thread.

[Turtle]

Besides the off-shore quakes, & besides the Illinois quakes, and besides the Alaska quakes, we have the strange activity going on in Western Nevada. Obviously no one predicted this. :eek_big: :D

 

The 'Mogul sequence' is especially shallow and is growing over time, defying patterns and predictions.

By Ashley Powers and Thomas H. Maugh II, Los Angeles Times Staff Writers

May 1, 2008

MOGUL, NEV. -- An unusually intense swarm of earthquakes -- more than 1,000 over the last two months -- has struck beneath a small suburb of Reno, leaving residents shaken and scientists puzzling over the cause.

 

More than 20 quakes of magnitude 2 or higher have hit on some days, and the intensity and frequency of the quakes have been increasing rather than following the normal pattern of tailing off. ...

Reno on edge after odd series of earthquakes - Los Angeles Times

 

Currently the highest number of >= mag 1 quakes in US that I have seen in 3 years of watching. :doh: ;) :eek_big:

Saturday May 3, 2:43:12 UTC 2008

1476 quakes on these maps

Latest Earthquakes in the USA - Last 7 days

[Turtle]

Besides the off-shore quakes, & besides the Illinois quakes, and besides the Alaska quakes, we have the strange activity going on in Western Nevada. Obviously no one predicted this. :applause: :applause:

 

Reno on edge after odd series of earthquakes - Los Angeles Times

 

Currently the highest number of >= mag 1 quakes in US that I have seen in 3 years of watching. :rotfl:

Saturday May 3, 2:43:12 UTC 2008

1476 quakes on these maps

Latest Earthquakes in the USA - Last 7 days

 

 

Here's a special report from USGS on the Nevada swarm:

*This ongoing earthquake swarm is a timely reminder that western Nevada has a significant earthquake hazard. Residents of the area are encouraged to check our guide on Living with Earthquakes in Nevada at our Earthquake Preparedness page . Protect your self, Drop, Cover, and Hold On!

West Reno, Nevada Earthquakes - The Nevada Seismological Laboratory

[Turtle]

Here's a new Podcast from USGS on the topic of earthquake prediction: :shrug: >>

Can We Predict Earthquakes?

Host: Jessica Robertson USGS CoreCast: Can We Predict Earthquakes?