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Using zeolites to remediate acid mine drainage - on latest episode of "Arizona Mining Review"

Zeolites are minerals comprised of silicon, aluminum, and oxygen that form frameworks full of cavities and channels that can work as "molecular sieves." Ted Eyde, President of St. Cloud Mining in Tucson, joins us on this month's episode of Arizona Mining Review to describe how certain zeolites are being used to remediate acid mine drainage. Show More Summary

Wishes for a Happy Thanksgiving, and Safety for Those on the Road

Here's hoping that you all have a fine Thanksgiving holiday and that your travels are safe and fun. I offer up one of the things that I am truly thankful for: politicians that put aside their many differences and agreed to establish Pinnacles National Park in 2013. Show More Summary

Getting a Creepy Feeling in Central California: A "Transforming" Experience

Faults can be active without producing major earthquakes. When the fault plane is not locked by frictional resistance, the sides of the fault can slide past each other without building up the stress that leads up to huge quakes. In Central California, there are several faults that creeping on a more or less consistent basis year after year. Show More Summary

Views from Glass Mountain

After we finally arrived at our chosen overlook part way up Glass Mountain, we milled about a bit (it was a geology field trip, after all), and then we gathered 'round a map that one of our tour leaders, Julie Donnelly-Nolan, had placed...Show More Summary

Claremont chert closeup; or, Oakland hills are falling down

On Grizzly Peak Boulevard, pretty much right above the Caldecott Tunnel, there’s a little old fire road that heads downhill to the west. I poked my nose down it the other day. The whole area has excellent exposures of the Charemont chert, starting with the roadside. It’s real nice right now. The ground is moist […]

You Say it's Winter Already? Fall Has Just Arrived in California!

Some people say they could never live in California. The earthquakes are scary and the state will fall into the sea. The politics are too crazy. It's an urban hell. Californians are too flaky. Pick you reason. But there are things that are undeniably nice about California. Show More Summary

AZGS Chief Geologist, Jon Spencer, retires after 33 years

Dr. Jon Spencer, Chief Geologist at AZGS, and head of the geological mapping program, retired on Friday after 33 years with the Survey. We had an informal luncheon honoring Jon, with a small number of family, friends, and colleagues, to thank Jon for his many contributions. Show More Summary

More small quakes on the Intermountain Seismic Belt

There was yet another small quake in northwest Arizona, along the southern end of the Intermountain Seismic Belt [right, red lines are active faults]. This magnitude 1.8 event [blue dot in image] occurred at 4:04 p.m. on Friday, following two others [yellow dots in image] just before noon in the region. Show More Summary

Why did the Road Cross the San Andreas Fault? 13 Years of Geologic Change (an Update)

2002 I've been leading geology field studies trips to lots of places in the American West for 27 years and started to take digital pictures in 2001. I sometimes struggle to find new things to photograph when I visit a place for the 27th time, but in some cases it is not a problem. Show More Summary

A Small City Recognizes Her Greatest Treasure: Tuolumne River Parkway Trail Nears Completion (update)

I've been providing occasional updates on the progress of the Tuolumne River Parkway trail that is being constructed in Waterford, California, where the river leaves the Sierra Nevada behind and flows into the Great Valley. It's been a source of some community pride that the city has finally come to realize the value of the river. Show More Summary

Two more small quakes in northwest Arizona

Northwest Arizona had its fifth and sixth small earthquakes in the last week and a half, today just before noon. A magnitude 2.9 event at 11:48 a.m., local time was followed ten minutes later by a magnitude 1.5 quake very close by that was likely an aftershock. Show More Summary

The Karst Topography...of California? There are more than 1,000 wild caves in California. Here's one of them

There is something special about exploring a wild cave, the kind without admission fees, guides, trails, and railings. There are a thousand limestone caves in California (and hundreds of lava tubes), and not even a dozen of them are show caves, i.e. Show More Summary

4th small quake in northwestern Arizona this week

We've had a small spate of small quakes in the northwest corner of the state this week with the fourth one occurring at 7:53 a.m, yesterday. The earthquakes are still widely scattered and do not appear to be related. The latest one was 17 miles south-southeast of St. Show More Summary

The Karst Topography...of California? A Look at California Caverns

We took a field studies trip a few weeks ago, and it turned into a mini-series on the karst terrain of California, a landscape that forms over limestone and marble. The development of caverns leads to distinctive features on the surface above, including sinkholes and disappearing streams. Show More Summary

2 million page views

This blog passed the 2 million page views level today, so thanks to all of you readers. It probably passed that point some time ago, but I did not start tracking analytics until a year into blogging. I've made over 4,100 posts since beginning, but this past year my blogging has dropped off precipitously. Show More Summary

New interactive map of Arizona wineries, vineyards, and tasting rooms

Arizona's burgeoning wine industry is now showcased in a new online interactive Wine Trail Map, built here at AZGS as part of a new Arizona Wine Country page on the Arizona Experience website.Three regions in Arizona are growing grapes for wine: Sonoita in Santa Cruz County, Willcox in Cochise County, and the Verde Valley in Yavapai County. Show More Summary

Basalt at the foot of Frowning Ridge

I took this photo last Tuesday, the day after our nice good rain. If you weren’t outdoors last week, you missed a brief moment in the Oakland year that lasts just a few days. It’s the period between the first significant rain and the sprouting of the grasses. (Before I continue, this is the last […]

Three small quakes in northwest Arizona last week

Three small earthquakes were recorded widely scattered across northwest Arizona in recent days [right, yellow dots show epicenters of quakes recorded last week. Credit, USGS].A magnitude 1.6 quake occurred on November 11, about 19 miles...Show More Summary

Intense November Weather in Central California...and Tornadoes?

Credit: Jacquetta WehkingI tell my students on occasion that they live in a place that is relatively free of the most serious geological hazards. We are a fair distance from the earthquake faults that wreak havoc on the coastal cities (the San Andreas and Hayward faults, for instance). Show More Summary

My op-ed on geologic hazards published in Arizona Republic

The Arizona [Phoenix] Republic newspaper published my editorial piece today on geologic hazards in Arizona. This was prompted by the Black Canyon City earthquakes on November 1 which were felt over much of central Arizona. The online...Show More Summary

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