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Thread: Juan de Fuca Plate Activity

  1. #61
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    No additiona quakes list week, other then the noted 2.

    A 3.1 EQ this moring just off the coast west of Newport. Same region as last weeks events.

  2. #62
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    A 4.1 EQ 2am this morning on the southern area of the Rift Zone, it Doesn't appear to be volcanic.

  3. #63
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    This moring starting just after 1:30am PDT, a micro-swarm of Earthquakes occured on Jaun De Fuca plate along the Subduction region just off the coast of Newport Oregon. Quake's registered in at 3.2, 3.7, then 3.1, at about 30km depth, then the swarm immediately stoped.

    I can't really say what this is, as I haven't seen such a small number of quakes in a swarm before, with magnitudes over 1.8. This swarm is around the estimated depth of the Jaun-der-Fuca/Pacific junction area however, so I suspect these were not Strike/Slip quakes, but Lateral/Slip quakes. No movement solutions were posted for them yet, so thats only a guess.

  4. #64
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    As long as they don't send a major tsunami up the actual Strait of Juan de Fuca, I'm good with that. I spend way too much time looking out at it and wouldn't want any unpleasantries.
    Last edited by Trebuchet; 2012-Mar-21 at 12:52 AM. Reason: typo
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  5. #65
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    Another 1.9 over the weekend, and just a few (11:04am PDT) minutes ago, an unspecified Mag quake that showed on almost all Oregon siemographs, with Reedssport being the closest one to the quake. This isn't even posted to the auto events yet. Soon as i find out mroe i'll post a followup.

  6. #66
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    Quote Originally Posted by dgavin View Post
    And just a few (11:04am PDT) minutes ago, an unspecified Mag quake that showed on almost all Oregon siemographs, with Reedssport being the closest one to the quake. This isn't even posted to the auto events yet. Soon as i find out mroe i'll post a followup.
    It was a preliminary 6.0 quake 500 miles offshore of Acapulco, Mexico, on the Pacific Rift, 9.9 km deep. Scratch this one of the Jaun-de-Fuca list

  7. #67
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    Not to be left out, the was a 4.4 mag quake last night on the Juan De Fuca ridge, due west of Coos Bay Oregon.

  8. #68
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    Juan. And Coos Bay.
    _____________________________________________
    Gillian

    "Now everyone was giving her that kind of look UFOlogists get when they suddenly say, 'Hey, if you shade your eyes you can see it is just a flock of geese after all.'"

    "You can't erase icing."

    "I can't believe it doesn't work! I found it on the internet, man!"

  9. #69
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    2 aftershocks so far from the 4.4 event, both registering 2.1 magnitude.

  10. #70
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    There was a 5.9 Quake along the Juan-de-Fuca Ridge (Slip) area, off the Oregon coast, west of Brandon, OR, about 2 hours ago.

    This puts the amount of strong quakes at 1 over the normal yearly average. I have no additional comments yet on that little fact.

  11. #71
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    I think that would be Bandon, not Brandon. Home of one of my favorite little lighthouses. Which I see they've at least partially painted since we were there.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  12. #72
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    So far 3 aftershocks to the 5.9 Quake, off the coast of Bandon Oregon, last weeks aftershocks were 2.6 and 2.8. This mornings was a 3.4.

  13. #73
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    2 More quakes since yesterdays report. Both along the subduction region this time, a 4.1 Mag near Eureka, CA and a 2.8 Mag near Newport, OR.

  14. #74
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    4.1 Mag Yesterday near northern edge offshore of Canada

  15. #75
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    Busy week for Juan de Fuca plate.

    The 4.1 in prior post the offshore Canada quake was updated to a 4.4, and there were 3 subsequent evens in same region, 3.9, 4.0 and 4.4 magnitudes.

    At the otherside of the plate off shore of California, there was a 2.5, 3.0 and a 3.8 mag.

  16. #76
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    So far since last report

    2 more quakes off shore of Canada, in same region as others, a 4.5 mag and a 4.0 Mag.

    Off shore of california another 3.8 mag quake.

  17. #77
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    After quite some time of quietness, there have been four events this week. A 5.1 and a 5.2 earthquake along the southern plate edge, off of california's coast, and a 4.1 and a 4.2 in the mid plate slip flault zone, off the oregon coast.

  18. #78
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    Starting on the 29th, there has been what now qualifies as a small earthquake swarm, on the subduction region about 20-30km off shore of Gold Beach, Oregon

    2.9 34km SW of Gold Beach, Oregon 2012-08-02 00:00:44 42.204N 124.746W 21.9
    2.6 29km SW of Gold Beach, Oregon 2012-08-01 10:59:38 42.235N 124.693W 0.0
    2.8 31km SW of Gold Beach, Oregon 2012-08-01 07:15:17 42.228N 124.718W 4.8
    2.2 29km SW of Gold Beach, Oregon 2012-08-01 04:30:45 42.210N 124.665W 0.0
    2.1 26km SW of Gold Beach, Oregon 2012-08-01 03:03:05 42.223N 124.627W 0.1
    1.9 28km SW of Gold Beach, Oregon 2012-08-01 02:15:17 42.196N 124.627W 18.3
    2.2 26km SW of Gold Beach, Oregon 2012-08-01 01:00:50 42.241N 124.649W 0.0
    2.5 27km SW of Gold Beach, Oregon 2012-08-01 00:34:29 42.238N 124.670W 0.0
    3.0 30km SW of Gold Beach, Oregon 2012-07-31 23:53:11 42.220N 124.687W 21.9
    2.1 27km SW of Gold Beach, Oregon 2012-07-31 09:13:10 42.234N 124.653W 0.0
    1.6 25km SW of Gold Beach, Oregon 2012-07-30 11:47:42 42.236N 124.629W 0.0
    1.6 24km SW of Gold Beach, Oregon 2012-07-29 14:35:59 42.249N 124.620W 0.1
    1.6 23km SW of Gold Beach, Oregon 2012-07-29 11:34:08 42.257N 124.618W 0.0
    2.1 26km SW of Gold Beach, Oregon 2012-07-29 09:30:48 42.239N 124.654W 0.0

  19. #79
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    This week three quakes so far, a 4.3 mag in the same location as the swarm two weeks ago. Plus a 4.5 and a 4.9 along the midplate-slip zone of the Jaun-de-Fuca rift area.

  20. #80
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    Moderate Quake, plus two aftershocks on the 19th. A 5.5 Mag just off northern most washingtons coast. Followed by a 3.1 and then a 4.2 aftershook.

  21. #81
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    Another aftershock this morning, 4.1 magnitude. All four events so far this week have been at 10km depth.

  22. #82
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    Moving to a monthly report on this thread. 36 Jaun de Fuca/Cacadia Subduction Earthquakes this last month, three of them coming in at the 4.1 -4.5 magnitude range.

  23. #83
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    A question: I'm curious to know if any geologists have used strata along the shores or bathymetry to determine the angle of the NA plate in relation to the subducting plate to get an idea of how stressed it might be and how close it may be to snapping back.
    Et tu BAUT? Quantum mutatus ab illo.

  24. #84
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    Quote Originally Posted by Ara Pacis View Post
    A question: I'm curious to know if any geologists have used strata along the shores or bathymetry to determine the angle of the NA plate in relation to the subducting plate to get an idea of how stressed it might be and how close it may be to snapping back.
    The earthquakes themselves can pretty much map that out, way deeper than bathymetry or strata, and more accurately--however not good enough to make any sort of stress calculations or timing predictions, which are mostly based on historical data, IIANACI.

  25. #85
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    Quote Originally Posted by grapes View Post
    The earthquakes themselves can pretty much map that out, way deeper than bathymetry or strata, and more accurately--however not good enough to make any sort of stress calculations or timing predictions, which are mostly based on historical data, IIANACI.
    I'm not sure I follow, nor do I know what IIANACI means. I'm referring to bending stress. When the Japanese earthquake happened last year, parts of Sendai alongthe coast subsided and were inundated (before the tsunami hit), while the portion of plate near the subduction fault snapped upwards. So, it's like a portion of the crust did a seesaw motion along some pivot line. I was wondering if we have historical data that we can look at angle that the crust is deforming and how close that angle is to historical maxima which is relaxed via an earthquake.
    Et tu BAUT? Quantum mutatus ab illo.

  26. #86
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    Ara,

    Yes there has been investigation in the strata along the NW coast lines, indicating about a once per 700 year time frame for cosatal inudation due to subsidence after a likely megathrust EQ event.

    This is what led to the seperate thread I made, about a major Oregon EQ actualy being predicted over the next few decades.

    The native american legends about a mythical "Thunderbird", are now thought to be related to stories about these huge plate altering earthquake events. The times of these legends that are datable, seem to roughly coincide with the strata evidence of the megathrust events.

    From the Strata evidence, there are some low lying area's along the coast that would likely be underwater after such an event. This may possibly include most of Pacific City and Beverly Beach state park, along with parts of Astoria, Lincoln City, Newport, Coos Bay, and Depot Bay.

  27. #87
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    Quote Originally Posted by dgavin View Post
    Ara,

    Yes there has been investigation in the strata along the NW coast lines, indicating about a once per 700 year time frame for cosatal inudation due to subsidence after a likely megathrust EQ event.

    This is what led to the seperate thread I made, about a major Oregon EQ actualy being predicted over the next few decades.

    The native american legends about a mythical "Thunderbird", are now thought to be related to stories about these huge plate altering earthquake events. The times of these legends that are datable, seem to roughly coincide with the strata evidence of the megathrust events.

    From the Strata evidence, there are some low lying area's along the coast that would likely be underwater after such an event. This may possibly include most of Pacific City and Beverly Beach state park, along with parts of Astoria, Lincoln City, Newport, Coos Bay, and Depot Bay.
    Right, but is that only related to periodicity or to an angular deviation from zero level?
    Et tu BAUT? Quantum mutatus ab illo.

  28. #88
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    The strata evidence all seems to point to the periodicity of megathrust or larger quakes. Andd there seems to be some variences in how often.

    The follow URL repost from another thread, I think will answer some of your questions about strata evidence and quakes.

    http://www.pnsn.org/outreach/earthqu...biditeevidence

  29. #89
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    Quote Originally Posted by dgavin View Post
    The strata evidence all seems to point to the periodicity of megathrust or larger quakes. Andd there seems to be some variences in how often.

    The follow URL repost from another thread, I think will answer some of your questions about strata evidence and quakes.

    http://www.pnsn.org/outreach/earthqu...biditeevidence
    Nope. It doesn't even touch on tilt.
    Et tu BAUT? Quantum mutatus ab illo.

  30. #90
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    Catching up here.

    On October 28th a Large 7.8 Mag just north of the Juan De Fuca edge. Listing all events upto today.

    M Location UTC Lat Lon D-km
    4.1 165km SSW of Masset, Canada 2012-11-07 15:04:23 52.649N 133.085W 10.0
    4.0 158km SSW of Masset, Canada 2012-11-06 15:47:13 52.717N 133.062W 10.0
    4.6 194km SSE of Masset, Canada 2012-11-06 10:27:03 52.335N 131.305W 10.2
    4.6 167km S of Masset, Canada 2012-11-04 18:27:19 52.522N 132.346W 20.3
    4.9 186km S of Masset, Canada 2012-11-04 12:27:36 52.339N 132.031W 10.4
    4.1 142km S of Masset, Canada 2012-11-04 07:42:15 52.741N 131.859W 10.0
    4.0 156km S of Masset, Canada 2012-11-04 05:07:53 52.617N 131.957W 10.0
    4.2 165km S of Masset, Canada 2012-11-03 17:49:14 52.535N 132.007W 22.4
    4.0 187km SSW of Masset, Canada 2012-11-03 12:18:42 52.380N 132.751W 9.8
    4.0 157km S of Masset, Canada 2012-11-03 09:48:24 52.611N 132.378W 10.1
    4.4 166km S of Masset, Canada 2012-11-03 04:25:19 52.522N 131.870W 12.8
    4.0 203km S of Masset, Canada 2012-11-02 08:37:10 52.186N 132.160W 10.4
    4.5 182km S of Masset, Canada 2012-11-02 08:19:59 52.379N 132.025W 10.2
    4.2 170km S of Masset, Canada 2012-11-02 07:15:45 52.497N 131.759W 11.0
    4.9 161km S of Masset, Canada 2012-11-01 03:16:00 52.564N 131.943W 10.3
    5.1 181km SSE of Masset, Canada 2012-11-01 03:15:23 52.500N 131.100W 1.0
    4.0 165km S of Masset, Canada 2012-10-30 17:33:29 52.535N 132.323W 1.8
    4.6 192km S of Masset, Canada 2012-10-30 14:10:59 52.285N 131.948W 10.0
    4.7 208km S of Masset, Canada 2012-10-30 04:40:15 52.170N 131.604W 10.2
    5.0 199km S of Masset, Canada 2012-10-30 02:55:08 52.222N 132.116W 19.2
    6.2 210km S of Masset, Canada 2012-10-30 02:48:58 52.129N 132.320W 18.6
    4.1 179km S of Masset, Canada 2012-10-30 00:35:09 52.423N 131.655W 10.0
    4.0 166km S of Masset, Canada 2012-10-30 00:32:18 52.526N 131.936W 10.0
    4.3 158km S of Masset, Canada 2012-10-29 22:00:33 52.593N 132.273W 10.0
    4.6 188km SSE of Masset, Canada 2012-10-29 20:49:49 52.366N 131.459W 26.5
    4.1 198km S of Masset, Canada 2012-10-29 16:33:08 52.231N 131.971W 10.0
    4.0 216km S of Masset, Canada 2012-10-29 15:38:29 52.074N 132.137W 10.0
    4.0 225km S of Masset, Canada 2012-10-29 15:15:02 51.989N 132.225W 10.0
    4.0 224km S of Masset, Canada 2012-10-29 15:01:06 52.013N 131.757W 10.0
    4.4 163km S of Masset, Canada 2012-10-29 12:05:14 52.574N 132.552W 10.2
    4.1 119km S of Masset, Canada 2012-10-29 06:03:52 52.959N 132.377W 3.3
    4.1 173km S of Masset, Canada 2012-10-29 03:47:55 52.461N 132.190W 10.0
    4.0 182km S of Masset, Canada 2012-10-29 02:40:53 52.396N 132.502W 10.0
    4.6 165km S of Masset, Canada 2012-10-29 01:49:02 52.530N 131.965W 10.0
    4.3 184km S of Masset, Canada 2012-10-29 00:26:49 52.358N 132.096W 10.0
    4.0 174km SSE of Masset, Canada 2012-10-29 00:18:50 52.612N 130.948W 10.0
    4.1 126km SSE of Masset, Canada 2012-10-28 23:55:02 52.978N 131.333W 10.0
    4.7 161km S of Masset, Canada 2012-10-28 23:34:23 52.570N 132.291W 10.0
    4.9 144km S of Masset, Canada 2012-10-28 23:26:50 52.733N 132.436W 10.0
    4.2 158km S of Masset, Canada 2012-10-28 23:11:17 52.608N 132.454W 12.5
    4.7 189km S of Masset, Canada 2012-10-28 22:41:28 52.316N 131.904W 10.0
    4.6 158km S of Masset, Canada 2012-10-28 21:38:19 52.602N 131.893W 24.7
    5.1 166km S of Masset, Canada 2012-10-28 19:16:55 52.544N 132.580W 47.2
    5.5 190km S of Masset, Canada 2012-10-28 19:09:56 52.315N 131.860W 14.8
    5.4 151km SSW of Masset, Canada 2012-10-28 19:03:24 52.742N 132.902W 32.8
    6.3 177km SSW of Masset, Canada 2012-10-28 18:54:16 52.480N 132.793W 20.0
    4.3 169km SSE of Masset, Canada 2012-10-28 16:17:03 52.537N 131.508W 10.0
    4.6 140km SSW of Masset, Canada 2012-10-28 15:59:11 52.786N 132.595W 10.0
    4.4 161km SSW of Masset, Canada 2012-10-28 15:57:15 52.638N 132.866W 10.7
    4.4 177km S of Masset, Canada 2012-10-28 15:48:45 52.427N 132.261W 10.0
    4.4 191km S of Masset, Canada 2012-10-28 15:44:59 52.309N 132.408W 10.0
    4.0 185km SSE of Masset, Canada 2012-10-28 15:42:21 52.404N 131.422W 10.0
    4.3 135km S of Masset, Canada 2012-10-28 15:24:22 52.803N 132.113W 10.0
    4.0 166km S of Masset, Canada 2012-10-28 15:10:34 52.516N 132.066W 10.0
    4.4 178km S of Masset, Canada 2012-10-28 15:06:55 52.417N 132.169W 10.0
    4.0 164km SSE of Masset, Canada 2012-10-28 14:14:28 52.588N 131.440W 7.7
    4.2 154km S of Masset, Canada 2012-10-28 14:04:27 52.635N 132.403W 10.0
    4.1 190km SW of Bella Bella Islands, Canada 2012-10-28 13:45:48 51.127N 130.305W 10.0
    4.8 175km S of Masset, Canada 2012-10-28 13:09:14 52.445N 131.842W 10.0
    4.1 127km S of Masset, Canada 2012-10-28 12:38:46 52.870N 132.204W 10.1
    4.0 142km S of Masset, Canada 2012-10-28 12:18:00 52.750N 131.769W 10.0
    4.1 161km S of Masset, Canada 2012-10-28 12:09:43 52.568N 132.065W 10.0
    4.7 175km S of Masset, Canada 2012-10-28 11:53:21 52.438N 132.201W 10.5
    4.8 180km S of Masset, Canada 2012-10-28 11:27:46 52.395N 132.161W 11.1
    4.3 183km SSE of Masset, Canada 2012-10-28 11:17:22 52.400N 131.566W 10.6
    4.0 172km S of Masset, Canada 2012-10-28 10:59:14 52.477N 131.769W 9.7
    4.3 170km S of Masset, Canada 2012-10-28 10:50:32 52.484N 131.945W 10.3
    4.7 157km S of Masset, Canada 2012-10-28 10:45:50 52.621N 132.500W 10.2
    4.5 145km SSW of Masset, Canada 2012-10-28 10:23:09 52.753N 132.678W 10.2
    4.3 171km S of Masset, Canada 2012-10-28 10:10:27 52.482N 132.247W 10.3
    4.3 119km S of Masset, Canada 2012-10-28 10:04:37 52.948N 132.285W 10.0
    4.1 127km S of Masset, Canada 2012-10-28 09:52:58 52.892N 131.733W 10.0
    4.4 127km S of Masset, Canada 2012-10-28 09:45:39 52.886N 132.392W 10.2
    4.4 221km S of Masset, Canada 2012-10-28 09:41:16 52.029N 132.187W 10.0
    4.6 196km S of Masset, Canada 2012-10-28 09:36:36 52.258N 132.343W 10.3
    4.4 173km SSE of Masset, Canada 2012-10-28 09:22:50 52.551N 131.193W 10.0
    5.1 197km S of Masset, Canada 2012-10-28 09:17:27 52.243N 131.996W 10.0
    4.2 215km S of Masset, Canada 2012-10-28 09:15:48 52.102N 131.653W 10.0
    4.2 277km SSW of Masset, Canada 2012-10-28 08:47:38 51.634N 133.314W 10.0
    4.3 216km S of Masset, Canada 2012-10-28 08:22:04 52.067N 132.073W 10.0
    5.0 198km SSE of Masset, Canada 2012-10-28 07:25:22 52.270N 131.493W 10.6
    4.9 140km S of Masset, Canada 2012-10-28 07:16:37 52.775N 132.456W 11.4
    4.6 212km S of Masset, Canada 2012-10-28 07:12:14 52.109N 132.221W 10.0
    4.4 231km S of Masset, Canada 2012-10-28 07:02:19 51.941N 131.836W 10.8
    5.0 203km SSE of Masset, Canada 2012-10-28 06:16:53 52.268N 131.212W 11.5
    4.5 139km SSW of Masset, Canada 2012-10-28 05:51:17 52.815N 132.714W 10.3
    4.3 181km SSE of Masset, Canada 2012-10-28 05:47:08 52.430N 131.451W 10.1
    4.1 248km S of Masset, Canada 2012-10-28 05:38:38 51.786N 132.312W 10.1
    4.3 211km S of Masset, Canada 2012-10-28 05:21:36 52.140N 131.571W 10.0
    4.3 169km S of Masset, Canada 2012-10-28 05:15:12 52.499N 132.222W 10.1
    4.5 178km S of Masset, Canada 2012-10-28 05:02:49 52.409N 132.165W 10.3
    4.3 180km S of Masset, Canada 2012-10-28 04:54:46 52.403N 132.439W 10.1
    4.7 155km SSW of Masset, Canada 2012-10-28 04:41:05 52.648N 132.597W 20.0
    4.6 140km SSW of Masset, Canada 2012-10-28 04:33:51 52.906N 133.120W 10.0
    5.1 254km SSW of Masset, Canada 2012-10-28 04:25:17 51.930N 133.642W 20.0
    4.8 183km S of Masset, Canada 2012-10-28 03:52:25 52.372N 131.823W 20.0
    5.8 154km S of Masset, Canada 2012-10-28 03:14:10 52.629N 132.243W 10.0
    7.8 141km S of Masset, Canada 2012-10-28 03:04:09 52.742N 132.131W 20.1

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