AZGS Web Posts

M2.8 aftershock to Duncan earthquake

Arizona Geology Blog - Wed, 2014-09-03 11:20
There was another measurable Duncan aftershock last night about 7p.m.  The M2.8 followed a M2.6 event that morning.   [Right, orange star marks epicenter. Credit, USGS]

Categories: AZGS Web Posts

Small aftershock in Duncan area

Arizona Geology Blog - Tue, 2014-09-02 15:01
A M2.6 earthquake on the Arizona-New Mexico border is likely an aftershock from the June 28, M5.3 Duncan earthquake.  Because of it's small size and the limited seismic station coverage in the area, we suspect the location is not well constrained.     The quake hit at 9:21 a.m. this morning.  We expect aftershocks will continue for weeks to months.  [Right, orange star marks epicenter. Credit, USGS]
Categories: AZGS Web Posts

Portable seismometers pulled from Duncan, heading to Napa

Arizona Geology Blog - Sat, 2014-08-30 20:38
AZGS geologists Jeri Young and Phil Pearthree pulled out four of the seven portable seismometers deployed in the area around June's M5.2 earthquake near Duncan, Arizona.  The portable instruments were installed in July to monitor the aftershocks from the June 28 event, detect small events, and provide accurate locations for all of the aftershocks.

However, the PASSCAL facility that owns the instruments needs to redeploy them in the Napa California area to monitor the aftershocks from last weeks M6.1 earthquake there.

Since they were installed, the portable instruments have recorded hundreds of aftershocks, with the largest a M4.1 event [right.  waveforms of aftershock as recorded by different stations]

Categories: AZGS Web Posts

New Geologic Map of Black Peak and Bobs Well 7.5" quadrangles released

Arizona Geology Blog - Sat, 2014-08-30 10:07
AZGS has published a new geologic map of the Black Peak and Bobs Well 7.5" quadrangles as a digital map.  It is available at our online repository for free viewing and downloading.

Most of the map area is covered by sand dunes and related features of Cactus Plain. The dune field of Cactus Plain is on a low plateau formed primarily on older eroded sediments, with minor bedrock hills protruding from the plain locally. The oldest late Cenozoic deposits in Cactus Plain are undeformed fan deposits composed primarily of crystalline metamorphic clasts, obviously derived from the east and northeast. These deposits are overlain by, and locally may interfinger with, fine-g rained clay, silt, sand and minor limestone deposits that we consider to be part of the Bouse Formation. Bouse carbonate deposits are also extensively exposed on the flanks of Black Peak and related hills near the northern margin of the map area. On the western, north eastern, and southern margins of Cactus Plain, there are extensive well-rounded, lithologically diverse gravel and sand deposits that we tentatively correlate with the early Pliocene Bullhead alluvium. T h is major river aggradation sequence is found all along the Colorado River below the mouth of the Grand Canyon (House et al., 2008; Howard et al., in prep.).
The map was funded in part by the StateMap component of the National Cooperative Geologic Mapping Program managed by the USGS.

Ref: Pearthree, P.A. and Spencer, J.E., 2014, “Geologic Map of the Black Peak and Bobs Well 7.5 Quadrangles, La Paz County, Arizona,” Arizona Geological Survey Digital Geologic Maps DGM-108 v1, scale 1:24,000.
Categories: AZGS Web Posts

Flagstaff's Wayne Ranney leading world tour of northern locales

Arizona Geology Blog - Fri, 2014-08-29 07:48
Today's mail brought a slick brochure from Smithsonian Journeys offering a private jet tour next June around the world of northern locales hopping from Seattle to, among others, Mongolia to Siberia to Svalbard, Greenland, and Iceland before returning home 22 days later. The Boeing 757 private jet seats up to 78 passengers in "two-by-two, VIP-style leather seats."

And it's being led by Flagstaff-based geologist and fellow geo-blogger, Wayne Ranney [photo credit Smithsonian Journeys]    The Smithsonian bio for Wayne says in part:

Wayne Ranney is a veteran of expedition travel, and has lectured on and journeyed to all seven of the Earth’'s continents. With a lifelong interest in the natural and earth sciences, Wayne specializes in making the fascinating story of our planet come alive for fellow travelers. His travels have taken him to all areas of South America including Patagonia; the Polar regions from Antarctica to Iceland, the desert lands of Africa and the American Southwest, and most of Earth’'s outstanding landscapes. He was elected to the Explorers Club and has visited more than 80 countries. Wayne is a retired professor of geology but still teaches an occasional honors course at Northern Arizona University in his hometown of Flagstaff, Arizona.Now, I have a schedule conflict next June, so I won't be able to join Wayne and the other trip participants. The trip cost of $64,950 per person is also a bit daunting for someone on a state salary.
Categories: AZGS Web Posts

Small quake northeast of Kingman

Arizona Geology Blog - Fri, 2014-08-29 07:28
There was a magnitude 1.7 earthquake just after 3a.m. local time this morning, about 27 miles northeast of Kingman, Arizona. [Right, orange star marks the epicenter. Credit, USGS]

An area 40 miles east of Kingman was hit with a cluster of quakes in the magnitude 3+ range two weeks ago.
Categories: AZGS Web Posts
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