Quakes – Odd Cascadia Cluster

There is an odd cluster of very small quakes (under 3.0) at the point where the San Andreas heads off shore and the Cascadia region begins.

On the one hand, a bunch of ‘little stuff’ is generally meaningless. It’s everywhere all the time. On the other hand, large events are often preceded by a bunch of small pre-shocks. Unfortunately, the definition of ‘pre’ in pre-shocks depends on the arrival of a bigger quake later, so can never be known in advance of that larger quake. So by definition it’s not predictive.

Yet this is an odd cluster, right at the point where the faults diverge and right at the point where stresses and strains have to ‘turn a corner’ or two on their propagation along the fault system. So, to me, it looks like some forces being redistributed; which implies some forces are showing up there to be redistributed.

But only time will tell if this is a set of pre-shocks or just a bit of stress easing by to dissipated and forgotten.

The Map (static capture):

Cascadia Cluster 10April2012 125-41

Cascadia Cluster 10April2012 125-41

Original Live image with clickable areas and info links

Here’s a North America view for a broader context:

Quakes 10April2012 N_America

Quakes 10April2012 N_America

So, does it mean anything? Donno… but it’s interesting to see all the activity around Mexico that’s old and quieting down, while the rest of the world is also slowing. Yet the mid Atlantic ridge just had a 5.x as I was watching.

OK, here’s the rest of the live maps:

North America

North America and Mid Atlantic Ridge Quake Map

North America and Mid Atlantic Ridge Quake Map

Original with clickable details

And remember, I have a dedicated CSZ page with closeups

Northern Hemisphere

North Polar Earthquake Map

North Polar Earthquake Map

Original Image with Clickable Details

Southern Hemisphere

A view of Earthquakes from the South Pole

A view of Earthquakes from the South Pole

Original Image with Clickable Details

Asia and Russia

Asia Quake Map

Asia Quake Map

Original Image with clickable areas

Australia / New Zealand

This is a live map of the Australia / Indonesia / New Zealand area:

Australia / Indonesia / New Zealand Quake Map

Australia / Indonesia / New Zealand Quake Map

Original with clickable regions to zoom in

California Map

Action Closer to Me

As I live in California, it makes it easier for me if I keep them in the list where I can see what’s shaking near me.

Here is an alternative view of things with the fault lines highlighted:

California Quakes with fault lines

California Quakes with fault lines

Original Image

Map of Plates

You can see it is where plates collide here:

Plates Of The World

Plates Of The World

Original Image, and with other language options.

Some Volcano Stuff

This page:

http://pangea.stanford.edu/~dsinnett/Pages/Links.html has a nice collection of links to volcano monitor pages. Just click the pictures for the different volcano observatories.

The Smithsonian page:


USGS Page listing recent major quakes:


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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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23 Responses to Quakes – Odd Cascadia Cluster

  1. George says:

    Eh, I don’t think this is all that odd for the Mendocino Triple Junction.

  2. E.M.Smith says:

    Well, it’s odd enough that I noticed it

    It’s not odd to have one or two somewhere or other on the Cascadia system, but 1/2 dozen in an
    area about 25 x 50 miles is ‘different’ from what I remember most of the time

    More quibbling on that bit later, we just had an 8.9 quake near Australia:

    2012 April 11 08:38:30 UTC

    This event has been reviewed by a seismologist.

    Magnitude 8.9 (Preliminary magnitude — update expected within 15 minutes)

    Wednesday, April 11, 2012 at 08:38:30 UTC
    Wednesday, April 11, 2012 at 02:38:30 PM at epicenter

    Location 2.043°N, 92.518°E
    Depth 33 km (20.5 miles) set by location program

    495 km (308 miles) SW (219°) from Banda Aceh, Sumatra, Indonesia
    1027 km (638 miles) W (263°) from KUALA LUMPUR, Malaysia

    Location Uncertainty Error estimate not available
    Parameters NST= 14, Nph=0, Dmin=0 km, Rmss=0 sec, Gp=198°,
    M-type=”moment” magnitude from initial P wave (tsuboi method) (Mi/Mwp), Version=B

    NOAA Pacific Tsunami Warning Center

    Event ID pt12102000

    Likely to be a Tsunami from it

  3. omanuel says:

    Thanks for the information, E.M.

    When observations are odd, unexpected, unusual, rare, amazing, etc, the science is probably flawed. For decades, astronomers and astrophysicists took great pride in finding unexpected, unusual, rare, and amazing events in the sky, . . . oblivious to this message.

    If Climategate fully collapses, as seems increasingly likely, many other fields of science will also benefit – astronomy, astrophysics, cosmology, nuclear, particle, planetary, seismology, and solar physics. Einstein’s finding (E = mc^2) is basic to all of these.


    Then we will need to identify a leader who is capable of restoring integrity to science, rights of citizens and citizen control of government, without reviving racism, retaliation, and/or the threat of nuclear warfare.

  4. adolfogiurfa says:

    Please look at the forgotten earthquakes swarm, many months long, at the Caribbean Islands of Puerto Rico and Dominican… There it goes the next big earthquake

  5. E.M.Smith says:


    I’ve mentioned them before… FWIW, I’m hoping for a volcano in the Caribbean… not enough subduction for a really Great Quake, IMHO.

  6. E.M.Smith says:

    Well, a 5.9 off the coast of Oregon… So now the question is: Foreshock?

    Magnitude 5.9 – OFF THE COAST OF OREGON
    2012 April 11 22:41:47 UTC

    Earthquake Details

    This event has been reviewed by a seismologist.

    Magnitude 5.9

    Wednesday, April 11, 2012 at 22:41:47 UTC
    Wednesday, April 11, 2012 at 01:41:47 PM at epicenter
    Time of Earthquake in other Time Zones

    Location 43.593°N, 127.557°W
    Depth 10.2 km (6.3 miles)
    Distances 271 km (168 miles) W of Coos Bay, Oregon
    303 km (188 miles) WSW of Newport, Oregon
    317 km (196 miles) WNW of Brookings, Oregon
    391 km (242 miles) WSW of SALEM, Oregon
    Location Uncertainty horizontal +/- 15.8 km (9.8 miles); depth +/- 2.8 km (1.7 miles)
    Parameters NST=455, Nph=456, Dmin=273.8 km, Rmss=0.97 sec, Gp= 94°,
    M-type=regional moment magnitude (Mw), Version=A

    Magnitude: NOAA West Coast and Alaska Tsunami Warning Center, Palmer, Alaska, USA
    Location: USGS NEIC (WDCS-D)

    Event ID usc00090yf

  7. p.g.sharrow says:

    Things have warmed up on the west coast of north americia. Now it looks like the rest of the ring of the pacific. Maybe it ‘s our time in the barrel. Only the Canadian section is still blank. pg

  8. adolfogiurfa says:

    @P.G. It´s for you the fun now!

  9. p.g.sharrow says:

    A 4 to 6 is fun. An 8 can ruin your week! pg

  10. R. de Haan says:

    12-APR-2012 07:15:48 28.79 -113.14 6.9 10.3 BAJA CALIFORNIA, MEXICO
    12-APR-2012 07:06:01 28.84 -113.07 6.2 10.1 BAJA CALIFORNIA, MEXICO
    12-APR-2012 06:48:38 28.80 -113.05 4.9 9.8 BAJA CALIFORNIA, MEXICO

    And a smaller one in Utah and another one off the US East Coast, Atlantic
    All from Iris Seismic Monitor

  11. E.M.Smith says:

    I don;t know if I ought to say “hang on tight” or “pack your shit” (kudos to George Carlin)….but some kind of shit is hitting some kind of fan. Details TBD…

  12. adolfogiurfa says:

    @E.M.: Both!… or just relax and give us the pleasure of reading a new post from you.

  13. adolfogiurfa says:

    BTW: An interesting phenomenon: Many people here (Lima, SA) among family and friends are suffering from feeling sick (Meniere´s syndrome)…could it be due to variations of the gravity vector?

  14. John says:

    One potential influence is the positions of the sun and moon. We’ll be having a total solar eclipse this year in November. What this means is that the tidal incluences of both the sun and the moon are acting in close to the same plane. It will be precisely the same plane at the eclipse. This pull may offer a little “relief” in bound fault systems, losening them, allowing percolation of water, lubricating the fault and permitting motion that otherwise would have to wait until adequate energy was stored to trigger an earthquake regardless of the tides.

  15. John says:

    You might also notice the swarm around Cobb just south of Clear Lake too. That area lies within the Geysers geothermal zone and there a number volcanic features nearby, such as Mt Konocti and Borax Lake at Clear Lake.

  16. E.M.Smith says:


    I tend to get a kind of transient ‘disoriented’ feeling when a quake happens, and sometimes just a while before it happens… Just saying… So, how big do they get down there? ;-)


    I think I’ve noticed an increase in quakes around several volcanic areas. I’ve been staring at quake maps for a few years now, and the fact is, we have a cluster on top of Hawaii, Puerto Rico / Caribe, Calistoga / Geysers, all over the Indonesia / Australia / New Zealand arc – remember that Christchurch is on an old volcanic site… and several other places. To me, it looks like more of the quakes are away from slip faults and on top of volcanic areas. But I’ve not had time or energy to look at any formal pattern proof. ( Heck, I’ve not even properly kept up on WSW postings).

    But yes, I’m secretly hoping to see a minor volcano wake up somewhere in California ;-)

    In 1914 Mount Lassen had a minor burp, and when I climbed to the top in about 1970 it was still warm and doing a bit of steam / sulphur… so a ‘minor’ burp there would be nice…

    The SIM thesis (Solar Inertial Motion) has a tie of our present state with more volcanoes…

    And, just to note the particulars on the 6.9 in the Gulf of California, noted by R. de Haan above:

    Magnitude 6.9 – GULF OF CALIFORNIA
    Earthquake Details

    This event has been reviewed by a seismologist.

    Magnitude 6.9

    Thursday, April 12, 2012 at 07:15:48 UTC
    Thursday, April 12, 2012 at 12:15:48 AM at epicenter
    Time of Earthquake in other Time Zones

    Location 28.790°N, 113.142°W
    Depth 10.3 km (6.4 miles)
    Distances 133 km (82 miles) NE of Guerrero Negro, Baja Calif. Sur, Mexico
    179 km (111 miles) NNW of Santa Rosalia, Baja Calif. Sur, Mexico
    215 km (133 miles) W of Hermosillo, Sonora, Mexico
    526 km (326 miles) SSW of PHOENIX, Arizona
    Location Uncertainty horizontal +/- 18.1 km (11.2 miles); depth +/- 4.1 km (2.5 miles)
    Parameters NST=331, Nph=331, Dmin=216 km, Rmss=1.32 sec, Gp=162°,
    M-type=regional moment magnitude (Mw), Version=D

    Magnitude: USGS NEIC (WDCS-D)
    Location: USGS NEIC (WDCS-D)

    Event ID usc00091a1

    I also note that the USGS is saying they are phasing out some various maps and pages:

    This webpage has been replaced by a new version and will be phased out in the future. Please use our new Real-time Earthquake Map to access the latest earthquake information and event details. The links to the World, US, and CA/NV maps that were in the navigation on the left side of the page have been replaced by the links at the top of the new Map. The Real-time Earthquake Map User Guide describes how to use the map and all its features.

    So at some point this standard form of quake posting with the live maps in it may suddenly die. I’ll have to see if I can still get similar images from the new system…

    Oh, and earlier today there was a 3.5 just a was south of me on the San Andreas… Looks like that energy that was kicking booty in S. America, then worked up to Mexico, is arriving up north… I’m also having a bit of that ‘dizzy’ feeling I get sometimes around quake time. (So am I reacting to the one that already happened, or…)

  17. MichaelM says:

    6.2 in the Drake Passage of all places

  18. E.M.Smith says:

    @Michael M:

    That’s a bizarre one! Good catch!

    Magnitude 6.2 – DRAKE PASSAGE
    2012 April 14 10:56:18 UTC

    Earthquake Details

    This event has been reviewed by a seismologist.

    Magnitude 6.2

    Saturday, April 14, 2012 at 10:56:18 UTC
    Saturday, April 14, 2012 at 06:56:18 AM at epicenter
    Time of Earthquake in other Time Zones

    Location 57.588°S, 65.414°W
    Depth 9.9 km (6.2 miles)
    Distances 358 km (222 miles) SSE of Ushuaia, Tierra del Fuego, Argentina
    447 km (277 miles) SSE of Rio Grande, Tierra del Fuego, Argentina
    604 km (375 miles) SSE of Punta Arenas, Magallanes, Chile
    816 km (507 miles) SSW of STANLEY, Falkland Islands
    Location Uncertainty horizontal +/- 17.8 km (11.1 miles); depth +/- 5.7 km (3.5 miles)
    Parameters NST=163, Nph=163, Dmin=812.6 km, Rmss=1.42 sec, Gp= 61°,
    M-type=regional moment magnitude (Mw), Version=7

    Magnitude: USGS NEIC (WDCS-D)
    Location: USGS NEIC (WDCS-D)

    Event ID usc00093ie

    The quake historic map is fairly empty down there. Some, not a lot.


    You can see a few, but not a lot, at sea. The comparison maps for Cascadia show a lot on the sea floor…


    So not unheard of, but still not frequent.

  19. R. de Haan says:

    Four quakes in Oklahoma over the past two weeks…
    Just observing…

  20. E.M.Smith says:

    Another one in Cascadia. Larger than the little ones cluster, smaller than the big one further up.


    2012 April 17 20:31:35 UTC

    Earthquake Details
    This event has been reviewed by a seismologist.Magnitude 4.1
    Date-Time Tuesday, April 17, 2012 at 20:31:35 UTC
    Tuesday, April 17, 2012 at 01:31:35 PM at epicenter
    Time of Earthquake in other Time Zones
    Location 40.974°N, 124.422°W
    Depth 19.8 km (12.3 miles)
    Distances 26 km (16 miles) WSW (247°) from Trinidad, CA
    27 km (17 miles) W (276°) from McKinleyville, CA
    27 km (17 miles) WSW (254°) from Westhaven-Moonstone, CA
    30 km (19 miles) NW (313°) from Eureka, CA
    369 km (229 miles) NW (318°) from Sacramento, CA
    Location Uncertainty horizontal +/- 0.4 km (0.2 miles); depth +/- 0.6 km (0.4 miles)
    Parameters Nph= 68, Dmin=37 km, Rmss=0.14 sec, Gp=187°,
    M-type=regional moment magnitude (Mw), Version=7
    Source California Integrated Seismic Net:
    Event ID nc71766345

  21. p.g.sharrow says:

    Nice cluster of quakes at the north end. 5 – 3.5 to 4 off of Cambell River, BC in the last 3 days. pg

  22. E.M.Smith says:


    Nice catch!


    shows them all in one spot on the subduction area.

    Looks like California dropped from over 400 down to about 370 and is now waking up again. Tiny red spot near Mammoth and a lot of little ones along the Hayward / Calaveras area and on up into The Geysers. LA had a 4ish even a couple of days ago. (Must have been a low news day as they had it on the TV news. Usually a 4 isn’t worth notice.)

    Japan and Indonesia both getting some more mid sized ones too.

    Looks to me like a lot of movement in places that have already had quakes and the residual building up in Cascadia / N. California. (East Bay and San Andreas north of SF). Mexican quakes and “Popo” volcano look like energy / movement being sent north. The Salton Sea to East L.A. area lit up with consistent quakes as the energy moves through. Then it splits. Some going into translation along the San Andreas. Some headed out into the Basin and Range.

    Rejoining back in The Cascadia.

    I’ve lived with this for 1/2 Century, gradually building awareness. ( About 40 years ago had a local 5 ish scale quake that ‘got me looking’ and I’ve been watching closely since.) This particular set of activity has me more worried than in most other years. Something just feels wrong about it…

    For anyone who missed it:


    MEXICO CITY — Glowing red rocks were thrown from the top of the active Popocatepetl volcano at dawn Friday, producing more spectacular (and slightly frightening) images from the peak southeast of populous Mexico City. But authorities did not raise the alert level for a potential major eruption.

    “Popo” or “Don Goyo,” as the volcano is affectionately known, has been shooting plumes of ash, gas and rocks for a week. Residents of the semirural communities near the volcano have reported hearing hours of “low-pitched roaring” emanating from the 17,887-foot Popocatepetl.

    President Felipe Calderon said Friday during a meeting with governors of the peak’s neighboring states that the government is prepared, in case evacuations become necessary. Authorities said contingency plans are ready if the volcanic activity threatens residents in the states of Mexico, Puebla and Morelos.

    “The volcano is in command,” said Roberto Quaas, director of Mexico’s National Disaster Prevention Center.

    The government has not raised its alert level on the volcano since Monday. Yet a week of sustained exhalations has produced worry among some Mexicans who live near “Popo,” which is visible from some points of Mexico City on days with relatively low pollution.

  23. adolfogiurfa says:

    Michele Casti says at:
    It ‘began releasing energy.
    Classical dynamics “post” phase heating along the Ring of Fire.
    Now we project the configuration n ° 2
    Entry into the full moon / lunar perigee and alignments Mercury-Earth-Saturn & Mercury-Venus-Mars (05)
    To monitor the descent of the solar wind.

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