A New Plate Boundary in the Making? The Walker Lane

Blue Dot 159, by Dave Schlom and Matt Fidler, Sept. 20, 2019

Listen to this 53-minute audio interview with Jim Faulds.

“Dave investigates the idea that the boundary between the North American and Pacific tectonic plates may be in the process of “stepping” eastward from the San Andreas Fault to the so called “Walker Lane.” He visits with Nevada Bureau of Mines and Geology tectonics expert Jim Faulds, who is one of the leading proponents of the new theory.

We take a virtual geologic field trip from the Gulf of California, up through the Eastern California Shear Zone (where the July 4-5 Ridgecrest earthquakes rocked the high desert) and up one of the most scenic highways in the world — Highway 395 east of the Sierra Nevada.

It’s been the setting of countless westerns and commercials and for good reason — the spectacular scenery due to the volcanic and tectonic forces unleashed over time in this part of eastern California and western Nevada. Will Reno be beachfront property? Probably, but you’ll have to wait a few million years to find out!”

Blue Dot: Each week Blue Dot takes you to curiosities across our universe. Featuring interviews with leading scientists, authors, filmmakers and journalists from around the world, Blue Dot examines our home from a planetary perspective. Whether it’s a discussion about our life-giving oceans, the imperiled climate systems, the depths of space, or how a rock guitar works, Blue Dot is an adventure of discovery.

Hosted by Dave Schlom, and co-produced by North State Public Radio, Blue Dot digs deep into conversations about earth and space. For the past 12 years, Schlom has adorned the airwaves with his warm, relaxed style. His extensive scientific and journalistic background and his gift for engaging natural and thought-inducing conversations make Blue Dot a program you don’t want to miss.

https://www.mynspr.org/programs/blue-dot

NBMG Research Featured in Wired Magazine

An article in WIRED magazine recently released describes cutting-edge research by Jim Faulds, Bill Hammond, and Rich Koehler (Nevada Bureau of Mines and Geology) on fault systems in the Walker Lane and how this region could one day become the primary boundary between the Pacific and North American plates.

Read the story here—or listen to the audio version (following the third paragraph in the full article):

Move Over, San Andreas: There’s an Ominous New Fault in Town

by Geoff Manaugh (WIRED, Science, 4-18-19, 6:00 AM)

https://www.wired.com/story/walker-lane-move-over-san-andreas-fault/?mbid=email_onsiteshare

“U.S. Route 395 is a geologic master class disguised as a road. It runs north from the arid outskirts of Los Angeles, carrying travelers up to Reno along the eastern flank of the Sierra Nevada. On the way, they pass the black cinder cones of Coso Volcanic Field and the eroded scars of a mighty 19th-century earthquake near Lone Pine. In winter, drivers might see steam rising from Hot Creek, where water boils up from an active supervolcano deep underground. About an hour from the Nevada border, Mono Lake appears, with its bulbous and surreal mineral formations known as tufa towers. Even for someone with no particular interest in rocks, these are captivating, otherworldly sights. But for James Faulds, Nevada’s state geologist, they are something more—clues to a great tectonic mystery unfolding in the American West. If he’s right, all of this, from the wastes of the Mojave Desert to the night-lit casinos of Reno, will someday be beachfront property.” (Click on link above for complete story.)

Fairview Peak and Dixie Valley Earthquakes M7.1 and M6.9 — December 16, 1954

1954_6_dixie_valley_karl_steinbrugge
Ground offset of about eight feet from the 1954 Dixie Valley earthquake forming the small cliff to the left of the cabin. Karl Steinbrugge photo from NBMG Special Publications 27 and 37.

 

You can visit the site of these earthquakes and view the scarps using this road guide:
The Great Highway 50 Rock Tour, by D.D LaPointe, David Davis, Jon Price and Beth Price
http://pubs.nbmg.unr.edu/The-great-Highway-50-rock-tour-p/e044.htm

You can also take a virtual tour of the area and view the scarps—check out the Travel Nevada links on theNBMG Facebook page:
https://www.facebook.com/pages/Nevada-Bureau-of-Mines-and-Geology/106397989390636[facebook.com]

This excerpt was taken from NBMG Special Publication 37:
Damaging Earthquakes in Nevada: 1840s to 2008, by Craig dePolo:
http://pubs.nbmg.unr.edu/Damaging-earthquakes-in-NV-p/sp037.htm

On December 16, 1954 there were two large, back-to-back earthquakes east of the Fallon area that were felt throughout Nevada and created several large ground ruptures. The first event, the Fairview Peak earthquake, a right-normal-oblique-slip event, occurred at 3:07 a.m. PST and had a magnitude of 7.1 (Pancha and others, 2006). This was followed four minutes and 20 seconds later (3:11 a.m.) by a magnitude 6.9 event, the Dixie Valley earthquake, a normal-slip event (Slemmons and others, 1965). Both earthquakes created spectacular surface ruptures over a total area of 100 km (62 mi) long and 14.5 km (9 mi) wide, with ground offsets of as much as 3.8 m (12.5 ft) vertical and 2.9 m (9.5 ft) right lateral (Slemmons, 1957; Caskey and others, 1996).

The earthquake was in a sparsely populated region, and there were no reported injuries and only minor building damage and content losses. In Dixie Valley, an “adobe cellar, gasoline tank and water tank, and stone wall collapsed,” a stove moved several feet, and a woman was thrown from her bed due to the shaking (Murphy and Cloud, 1956). In one living room, a piano “kangarooed” its way to the opposite side of the room during the shaking (FS 12/22/54). In the surrounding region, dishes broke, walls and chimneys were cracked in the towns of Austin, Luning, Mina, Rawhide, Fallon, Lovelock, Eureka, and Carson City (Murphy and Cloud, 1956). Damage in Carson City included cracked walls and fallen plaster in the Capitol building, the State Printing Building, and the State Prison (Murphy and Cloud, 1956). Water lines were broken at Lovelock, Mina and near Gabbs (Murphy and Cloud, 1956).

PERSPECTIVE (by Craig dePolo)
After 1959, earthquake activity subsided in the Fallon region and has been at a relatively low level since then. However, Nevada has a rich earthquake history, over 1500 Quaternary faults, and has active deformation detected by geodetic measurements. Major earthquakes are in Nevada’s future and much attention will be focused on these events when they occur and on earthquake preparedness and resilience. Nevada has had a window of opportunity to prepare for the next events, and great things such as freeway bridge seismic retrofits have occurred during this window. But preparedness for earthquakes must continue, especially at a personal level, if we are to have fewer injuries and property losses from future events. “Give the gift of preparedness.”

AEG Meeting—Earthquake Hazards in Carson City—by Craig dePolo

AEG_Logo_Revised-9-28-05_0

ASSOCIATION OF ENVIRONMENTAL AND ENGINEERING GEOLOGISTS, GREAT BASIN SECTION (AEG)

MEETING ANNOUNCEMENT

Thursday, January 21, 2016
SPEAKER: Dr. Craig dePolo, Nevada Bureau of Mines and Geology

“The Capital of Earthquake Country: Earthquake Hazards in Carson City”

LOCATION:
RAPSCALLION SEAFOOD HOUSE & BAR
1555 S. WELLS AVENUE, RENO, NEVADA 89502

SOCIAL HOUR: 5:30 PM, DINNER: 6:30 PM

PRESENTATION: 7:00 PM

RSVP NO LATER THAN 5 PM, TUESDAY JANUARY 19
@ 775¬221¬1369 or justin.mcdougal@amecfw.com

Cost: Members: $25.00; non¬members: $29.00

The first 4 students that RSVP and check in at the registration table will be sponsored this month compliments of Wood Rodgers.

ABSTRACT
Carson City has the highest earthquake hazard in Nevada and, perhaps, in the entire Basin and Range Province. Several historical earthquakes have shaken the city, including one of the most damaging earthquakes in Nevada, the 1887 Carson City earthquake. Background earthquakes, magnitude 3 and smaller, are frequent. Areas of persistent background seismicity include the northern part of Carson City, south of Prison Hill, and the northern Pine Nut Mountains. Several young earthquake faults exist in and around Carson City. Larger faults bound the mountains and smaller faults are within the mountains and/or basins. There is evidence in the geologic record of local paleoearthquakes with magnitudes in the upper 6 to 7 range, some of which were ~200 years apart along a single fault. Probability calculations indicate it is likely (78–79%) Carson City will experience Modified Mercalli Intensity (MMI) VI shaking levels over a 50-year time period. The probability of damaging MMI VII shaking over a 50-year time period the probability is 55–57%. Carson City also faces potential surface ruptures, earthquake-induced liquefaction, and earthquake-induced landslides and rock falls.

BIOGRAPHY
Ph.D. Geology, University of Nevada, Reno, 1998
M.S. Geology, University of Nevada, Reno, 1989
B.S. Geology, California State University, Sacramento, 1982

Dr. dePolo is a Research Geologist for the Nevada Bureau of Mines and Geology at the University of Nevada, Reno, Mackay School of Earth Sciences and Engineering. His areas of expertise include paleoseismology, earthquake hazard characterization, neotectonics, and Quaternary geology. He has professional experience as an assistant technician in the Nevada Seismological Laboratory at the University of Nevada, Reno, as a consulting geologist for D.B. Slemmons, and as a teaching assistant in the Department of Geological Sciences and Engineering at the University of Nevada, Reno.

American Canyon M6.1 Earthquake in CA – data from Nevada Geodetic Laboratory

A message from Bill Hammond at the NBMG Nevada Geodetic Laboratory:

American Canyon M6.1 earthquake in the northern San Francisco Bay area: NBMG researchers have derived rapid earthquake displacement maps from GPS data that illustrate how the earth around the rupture underwent permanent coseismic deformation.  See:  http://geodesy.unr.edu

Further observations, data, photos, and rapid analysis products are available as they come in to http://scec.usc.edu/eqresponse/node/353

Earthquake Faults in Las Vegas—video on News 3

Late Quaternary faults in Las Vegas are in need of a modern state-of-the-art analysis of their earthquake potential. This news clip, prepared by Channel 3 in Las Vegas, reviews some of the Las Vegas Valley faults with a local reporter and how we can wisely develop around faults with ground rupture potential. A resident is featured on the clip that was unaware of the fault and earthquake hazard potential in Las Vegas. Unfortunately, this may be the norm and not the exception. It underscores the need for all Nevadans to be aware of their earthquake risks and do what they can to reduce them (please see http://www.nbmg.unr.edu/dox/sp27.pdf for mitigation information). Practicing the safest response to the next Nevada earthquakes can help prevent injuries from those events. Thus, we encourage everyone to sign up for the annual Nevada earthquake drill, the Great Nevada ShakeOut in October, and to practice Drop, Cover, and Hold during that exercise (see http://shakeout.org/nevada/).

…message from Craig dePolo

Link to the video:

http://www.mynews3.com/content/news/story/Believe-it-There-are-many-earthquake-faults-in/C68FGas5YUyayNmbk1bPCg.cspx#.U8WG1NvZHV0.email

New OFR on Eglington Fault—Clark County

Open-File Report 13-12
Evidence for High Contemporary Slip Rates along the Eglington Fault, Clark County, Nevada
by Craig M. dePolo, Wanda J. Taylor, and James E. Faulds
2013

of1312

8 pages, color, $2.40:
http://www.nbmg.unr.edu/sales/pbsdtls.php?sku=OF13-12

or free online:
http://www.nbmg.unr.edu/dox/of1312.pdf

The Eglington fault in northern Las Vegas Valley is an unusual fault in that it is expressed as a faulted warp at the surface and accommodated a large vertical surface offset (10-14 m) in latest Pleistocene sediments relative to its short length of 11 km. Coupled with a competing hydro-compaction hypothesis for faults within Las Vegas Valley, the earthquake hazard of the Eglington fault has been poorly understood and likely underrepresented. Radiocarbon dates from faulted sediments in the area indicate that the vertical displacement across the fault has occurred in the last ~22 kyr. A preferred vertical fault slip rate of 0.6 m/kyr, and range of 0.25 to 0.9 m/kyr, are estimated using available data. How single event displacements are manifested along the Eglington fault and what the size of those displacements might be is not known, generating uncertainty in estimating the potential earthquake recurrence interval for the fault.