Low level seismic (swarm) activity at Mt Hood, Oregon

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SUMMARY

The recent seismic activity at Mount Hood, Oregon, includes a series of small earthquakes ranging from magnitudes 1.0 to 1.9, primarily located on the south side of the mountain near State Road 35 and the Timberline ski area. The United States Geological Survey (USGS) reported no significant earthquakes above magnitude 2.5, confirming that the activity is tectonic rather than volcanic. Mount Hood is recognized as the most seismically active volcano in Oregon, with an average of 1-2 earthquakes detected monthly within 3 miles of its summit. The last eruption of Mount Hood occurred approximately 200 years ago, and current seismic events are attributed to tectonic faults rather than volcanic processes.

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A journalist reported a 'New Earthquake Swarm is Rocking Oregon's Mt Hood.
http://www.wired.com/2016/05/new-earthquake-swarm-rocking-mt-hood

I wouldn't say rocking.

I checked USGS, and didn't find anything over Mag 2.5, so I refined the search in the range of Mag 1 to 2.5, and found a number of small earthquakes in the range of 1 to 1.9 scattered around the south side of Mt. Hood just north of State Rd 35, and just east and south east of the Timberline ski area. The depths are about 3 to 4 km.

Code:
2016-05-17 00:17:39 UTC  3.5 km  1.0  23km ESE of Mount Hood Village, Oregon
2016-05-16 21:59:51 UTC  3.1 km  1.2  23km ESE of Mount Hood Village, Oregon
2016-05-16 21:50:07 UTC  2.9 km  1.7  Other Event 22km E of Mount Hood Village
2016-05-16 21:47:52 UTC  3.7 km  1.4  22km ESE of Mount Hood Village, Oregon
2016-05-16 21:47:40 UTC  3.5 km  1.4  23km ESE of Mount Hood Village, Oregon
2016-05-16 21:35:33 UTC  3.8 km  1.1  23km ESE of Mount Hood Village, Oregon
2016-05-16 19:30:45 UTC  3.2 km  1.0  23km ESE of Mount Hood Village, Oregon
2016-05-16 16:48:35 UTC  3.6 km  1.3  22km ESE of Mount Hood Village, Oregon
2016-05-16 14:31:03 UTC  3.4 km  1.7  22km E of Mount Hood Village, Oregon
2016-05-16 13:53:50 UTC  3.8 km  1.4  22km ESE of Mount Hood Village, Oregon
2016-05-16 13:45:54 UTC  3.6 km  1.5  21km E of Mount Hood Village, Oregon
2016-05-16 13:39:20 UTC  3.3 km  1.9  22km E of Mount Hood Village, Oregon
2016-05-16 13:30:08 UTC  4.2 km  1.4  22km ESE of Mount Hood Village, Oregon
2016-05-16 13:26:56 UTC  3.8 km  1.1  23km ESE of Mount Hood Village, Oregon
2016-05-16 13:21:30 UTC  4.1 km  1.2  22km ESE of Mount Hood Village, Oregon
2016-05-16 13:17:22 UTC  2.6 km  1.4  21km ESE of Mount Hood Village, Oregon
2016-05-16 13:02:33 UTC  4.2 km  1.3  22km ESE of Mount Hood Village, Oregon
2016-05-16 12:53:31 UTC  3.9 km  1.7  23km ESE of Mount Hood Village, Oregon
2016-05-16 12:30:49 UTC  3.8 km  1.1  22km ESE of Mount Hood Village, Oregon
2016-05-16 12:19:43 UTC  3.6 km  1.8  22km ESE of Mount Hood Village, Oregon
2016-05-16 12:03:38 UTC  4.0 km  1.6  23km E of Mount Hood Village, Oregon
2016-05-16 12:03:33 UTC  3.7 km  1.5  22km ESE of Mount Hood Village, Oregon
2016-05-16 11:54:59 UTC  4.0 km  1.2  22km ESE of Mount Hood Village, Oregon
2016-05-16 11:43:48 UTC  3.1 km  1.6  22km E of Mount Hood Village, Oregon
2016-05-16 10:55:00 UTC  3.5 km  1.3  22km ESE of Mount Hood Village, Oregon
2016-05-16 10:39:08 UTC  3.8 km  1.5  23km ESE of Mount Hood Village, Oregon
2016-05-16 10:10:11 UTC  3.6 km  1.1  22km ESE of Mount Hood Village, Oregon
2016-05-16 09:02:55 UTC  3.2 km  1.5  21km ESE of Mount Hood Village, Oregon
2016-05-16 08:53:15 UTC  3.8 km  1.5  23km ESE of Mount Hood Village, Oregon
2016-05-16 08:28:25 UTC  3.6 km  1.2  22km ESE of Mount Hood Village, Oregon
2016-05-16 06:33:10 UTC  3.6 km  1.5  22km E of Mount Hood Village, Oregon
2016-05-16 06:19:36 UTC  3.2 km  1.6  22km ESE of Mount Hood Village, Oregon
2016-05-16 05:56:23 UTC  2.6 km  1.3  22km ESE of Mount Hood Village, Oregon
2016-05-16 05:25:53 UTC  3.5 km  1.1  23km ESE of Mount Hood Village, Oregon
2016-05-16 05:24:41 UTC  3.8 km  1.1  22km ESE of Mount Hood Village, Oregon
2016-05-16 05:07:56 UTC  3.8 km  1.5  22km ESE of Mount Hood Village, Oregon
2016-05-16 02:07:19 UTC  4.1 km  1.1  22km ESE of Mount Hood Village, Oregon
2016-05-16 01:38:33 UTC  3.3 km  1.5  22km E of Mount Hood Village, Oregon
2016-05-16 01:17:42 UTC  4.3 km  1.1  22km ESE of Mount Hood Village, Oregon

2016-05-13 12:09:43 UTC  4.4 km  1.1  20km E of Mount Hood Village, Oregon

I'm not sure what is the 'other event'.
 
Last edited:
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Astronuc said:
A journalist reported a 'New Earthquake Swarm is Rocking Oregon's Mt Hood.
http://www.wired.com/2016/05/new-earthquake-swarm-rocking-mt-hood

I wouldn't say rocking.

I checked USGS, and didn't find anything over Mag 2.5, so I refined the search in the range of Mag 1 to 2.5, and found a number of small earthquakes in the range of 1 to 1.9 scattered around the south side of Mt. Hood just north of State Rd 35, and just east and south east of the Timberline ski area.
Beside the low magnitude. How far is the Yellowstone bubble? This distance concerns me whenever I hear about an earthquake in the US.
 
fresh_42 said:
Beside the low magnitude. How far is the Yellowstone bubble? This distance concerns me whenever I hear about an earthquake in the US.
About 600 miles from Yellowstone, so it's not related. Mt Hood is one of numerous Cascade volcanoes. Hood's last eruption was about 200 years ago.
 
Astronuc said:
I'm not sure what is the 'other event'.

usually refers to something caused by human activity ... mining blast, mine collapse, fracking, etc etc

but noted tho that this "other Event" is in the same area as the other events
so maybe just not well defined ??
 
davenn said:
but noted tho that this "other Event" is in the same area as the other events
so maybe just not well defined ??
I downloaded the data after I saw this thread, and it appears they've thrown that reading out.

I was also surprised to see in the Wired article that this was tectonic activity, and not volcanic, so I double checked that.

Seismic Monitoring at Mount Hood, Oregon [USGS]
Mount Hood is one of the most seismically active volcanoes in the Washington and Oregon Cascades, and the most seismically active volcano in Oregon. In an average month 1-2 earthquakes are located by the Pacific Northwest Seismic Network (PNSN) within 3 miles of the summit. Most Hood earthquakes don't actually occur directly beneath the volcano's summit, but instead in one of several clusters located 2-5 km west, southwest, and southeast of the summit.
...
Scientists believe that earthquakes in the clusters south of the summit occur on tectonic faults and aren't directly related to volcanic processes occurring beneath Mount Hood.

Here's a neat little info-graphic of how often the Cascade volcanoes have erupted over the last 4000 years:

img1052_623w_500h.eruptions.of.cascade.mountains.last.4000.years.jpg

[ref]
 
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