Friday, March 27, 2009

Salton Sea quake swarm

Lee Allison has an interesting picture of the quakes in the Salton Sea . A big one there could effect the
near-by towns in Arizona.

Arizona Geology: Bombay Beach earthquake swarm continuing

Wait and see

Harry Allen

Monday, March 23, 2009

Mount Redoubt in Alaska Erupting

Late last night, March 22, Mount Redoubt in Alaska started erupting. It has been showing signs of activity for some time, and the eruption followed two days of increasing seismic activity. Redoubt is near Cook Inlet not far from Anchorage, so volcanic ash is a concern for airplanes. Follow the activity at the Alaska Volcano Observatory:

Saturday, March 21, 2009

Havasupai Opens May 1st

The Havasupai will reopen the trails May 1 st after all the trail damage from the big flood is finished. It could be a chance to really see the effects of the flood.

Havasupai Tribe

Harry Allen

Thursday, March 19, 2009

Magnitude 7.9 - TONGA Earthquake

Here is the details on the Tanga Quake
Thanks to the USGS

Magnitude 7.9 - TONGA REGION

Harry Allen

Thursday, March 12, 2009

Archaeology Meets Astronomy & Geology

Dr. Ted Bunch will be speaking at the Smoki Pueblo Museum on Saturday March 28 at 2:00 pm. He will talk about his "Black Mat Theory," hypothesizing that an extraterrestrial body exploding in the upper atmosphere 13,000 years ago was the culprit that lead to a "mini nuclear winter" that devastated the earth, wiping out most of the megafauna and their habitat.
This is part of Archaeology Awareness Month, and the Smoki Museum will be open to the public at no charge that day.

Tuesday, March 3, 2009

March 7 field trip

This is Paul Lindburg explaining the origin of the sinkholes in the Sedona area. They are from collapse of the overlying sandstone into a cave system in the Redwall limestone 500 or more feed below. The Redwall is the aquifer carrying water from the Rim to the Verde River under the town of Sedona.

This is Paul explaining the outcrop evidence for the timing of the faulting that formed the Verde Valley.

Paul again put on a tremendous field trip. It was attended by 35 people of all levels of geologic expertise and they all learned new things. His ability the communicate the "Geologic Story" to everyone makes for a great trip.

Harry Allen

gigapan: verde outcrop

I took my first Gigapan of one of the outcrops we visited on our Club field trip to the Sedona area last weekend .
Paul Lindburg lead us on another great trip-- his third. This outcrop is important in explaining the origin of the Verde Valley.
Check the whole outcrop here:

gigapan: verde outcrop

This is a labeled detail view of the faulting.
Pz is the red Permian Supai Sandstone which was deposited first.
Across the normal fault on the downdropped side are the Tertiary Volcanics from the House Mountain Volcano (Miocene) which overlay the Supai.
On top of the Permian is Gravel 1 which was transported to the north carrying clasts from the highlands in central Arizona. These deposits include include Paleozoic and Mazatzal gravels derived from the south, indicating they were deposited when the Bradshaw Mountains were much higher and rivers flowed to the north and northeast in the opposite direction from today.
On top of the entire outcrop and younger than the faulting is Gravel 2 which was transported to the west towards the center of the Verde Grabben. It contains clasts from both the underlying Tertiary House Mountain basalt and the Supai in a red matrix of mud and sand.
The conclusion from this outcrop is that the formation of the Verde Valley Grabben occurred during the Basin and Range Extentional Orogeny (6 m.a. more or less) and after the the Eruption of the Volcanics from House Mountain (aprox 13m.a.).
Harry Allen