Roundup of recent Earth/Solar events

Roundup of recent Earth/Solar events..

I know all eyes are on Ophelia but there are some other events that interesting to note for Earth science lovers. First and foremost, the sun has been going nuts. 3 X-class, 5 M-class and 10 C-class flares all in the last two days. Reminiscent of Fall 2003.

http://www.solarmonitor.org/index.php
http://www.n3kl.org/sun/noaa.html
http://www.spaceweather.com/
http://sec.noaa.gov/rt_plots/bou_12h.html

Then we turn to SoCal. The Brawley Seismic Zone, which has been mostly dormant since the 80's, has shown signs of life. The most recent swarm warranted this statement from USGS..

“Renewed seismic activity in the Brawley Seismic Zone began late on 28 August 2005 but reached a sustained higher level of activity, announced by back-to-back M4.6 and M4.5 events at 3:47 and 3:50 p.m. (local time; PDT ) on 31 August 2005. The swarm then intensified, with a M 5.1 event on 1 Sept. at 6:27 p.m. PDT. As of this writing, seismic swarm activity persists at a slightly diminished level, yet activity can reasonably be expected to continue (see STEP map). We now have recorded a total of 8 events of M 4.0+, 29 additional events of magnitude between 3.0 and 4.0, and 175 events between magnitude 2.0 and 3.0. In all, 554 events of M 1.0+ have occurred in the swarm so far.
The activity is reminiscent of similar swarms that occurred in the Brawley Seismic Zone throughout the 1970’s and 1980’s, during which time the zone was among the most active areas in all of California. The Brawley Seismic Zone is a north-striking zone of northwest and northeast-striking faults that extends from the southern end of the San Andreas fault to the northern end of the Imperial fault. Across this zone, tectonic spreading that is oriented NW-SE occurs within the transition from the Gulf of California mid-ocean ridge to the San Andreas transform fault.

Historically, activity includes both northeast-oriented cross-faults that typically involve left-lateral faulting, such as is currently occurring, and activity on northerly to northwesterly-oriented strands of the zone. The set of nearly orthogonal strike-slip faults accommodates the overall tectonic NW-SE opening, partly through the rotation of crustal blocks.
The largest earthquakes to have occurred on the cross-faults were the magnitude 6.2 Elmore Ranch event in 1987, which is considered to have triggered the magnitude 6.6 Superstition Hills event less than 12 hours later, and the magnitude 5.7 Westmorland event in 1981. Although Brawley Seismic Zone activity is clearly proximal to the southern San Andreas fault, the San Jacinto fault zone, and the Imperial fault, the current activity is remaining more than 10 km distant from any of these major faults. Obsidian Butte is part of the Salton Buttes Lava Domes, which are primarily formed by their namesake volcanic rock type, with nearby geothermal activity and energy production.

The pattern of Brawley swarms of the 1970’s was a large number of very small earthquakes (sometimes exceeding 10,000 events) with up to a dozen moderate events of magnitude 4 or so, but no clear mainshock larger than the other events. The 1970’s swarms would be highly active for a few days and then taper off over the next week or two.

In 1999 and 2001, two other smaller swarms occurred on northeast-striking faults in the Salton Sea. Compared to those two sequences, this week’s swarm has significantly more events, but also is located significantly farther away from the San Andreas fault."

http://earthquake.usgs.gov/eqinthenews/2005/ObsidianSwarm/


In addition to this swarm, the USGS released some preliminary findings of their annual report on the Sisters Range in Oregon. The bulge now encompasses 100 square miles.(!)

"They say it probably began growing in 1997 and has been rising ever since at a rate of about 1.4 inches a year. It was first observed from space using a relatively new imaging technology known as radar interferometry that can measure changes in the Earth's surface.

The likely cause of the bulge is a pool of magma that, according to Deschutes National Forest geologist Larry Chitwood, is equal in size to a lake 1 mile across and 65 feet deep.

The magma lake is rising 10 feet each year, under tremendous pressure, and it deforms the Earth's surface as it expands, causing the bulge.

Other causes could be anything from the birth of a new volcano — a fourth Sister in the making — to a routine and anticlimactic pooling of liquid rock, researchers say.

"The honest and shortest answer is, we don't know," said Dan Dzurisin, a USGS geologist."

http://www.casperstartribune.net/articles/2005/09/09/news/regional/abddfb1da55dae268725707400673e44.txt

Cool satellite map of Sisters uplift here:

http://tinyurl.com/cb429

http://news.nationalgeographic.com/news/2004/09/0909_040909_earthmagfield.html

We don't know how long this process takes... It could take 1000 years... or 10.

Humans had an interesting run, but we don't adapt so well anymore.