1947 – Virginia City, MT – M 6¼

Intermountain Seismic Belt Historical Earthquake Project

November 23, 1947 – Virginia City, MT – M 6¼

The Virginia City earthquake was reported felt in several communities in Montana, including: Billings, Missoula, Lewistown, Livingston, Helena, Harlowton, Malta, Havre, Glasgow, Kalispell, and Bozeman; and as far south as Idaho Falls, Idaho.

In most areas, the earthquake rocked buildings with, what was described in Helena as, a “long and easy” motion. There were widespread reports of swaying light fixtures, stopped clocks, dishes rattling, and window blinds and curtains moving back and forth. Cracks in plaster were observed and a plaster ceiling fell in a café in Hamilton.

Near the epicenter, in Virginia City, bricks and plaster were shaken loose from buildings, windowpanes were shattered, walls were cracked, and chimneys damaged. There were also reports of pictures being shaken off walls and dishes falling from cupboards.

In some locations sleeping residents were awakened as the shaking dislodged icicles from rooftops. Strange noises were reportedly heard during the shaking, and some residents fled their homes in fear. However, there were no reports of injuries or significant damage resulting from the earthquake.

 

For additional information about this earthquake:

Earthquake Summary 3D Newspaper Articles 3D Additional Resources 3D Blank Thumbnail

For more information about this project:

ISB Hist EQ Proj

 

Magnitude 4.5 near West Yellowstone, MT

PRESS RELEASE

University of Utah Seismograph Stations Released: June 15, 2017 07:55 PM MDT

The University of Utah Seismograph Stations reports that a light earthquake of magnitude 4.5 occurred at 06:48 PM on June 15, 2017 (MDT). The epicenter of the shock was located in Yellowstone National Park, eight miles north-northeast of the town of West Yellowstone, Montana. The earthquake was reported felt in the towns of West Yellowstone and Gardiner, Montana, in Yellowstone National Park, and elsewhere in the surrounding region. Today’s earthquake is part of an energetic sequence of earthquakes in the same area that began on June 12. This sequence has included approximately thirty earthquakes of magnitude 2 and larger and four earthquakes of magnitude 3 and larger, including today’s magnitude 4.5 event. Today’s earthquake is the largest earthquake to occur in Yellowstone National Park since March 30, 2014, when a magnitude 4.8 event occurred 18 miles to the east, near Norris Geyser Basin.

Anyone who felt the earthquake is encouraged to fill out a survey form either on the Seismograph Stations website: www.quake.utah.edu or the US Geological Survey website: earthquake.usgs.gov.

Earthquake Summary:

Date (UTC): June 16, 2017

Time (UTC): 00:48 Date (local): June 15, 2017

Time (local): 06:48 PM MDT

Latitude: 44 46.48′ N

Longitude: 111 2.74′ W

Preferred magnitude: 4.50 Ml

The April 22, 2017 M 3.8 Earthquake Sequence near Rangely, Colorado

On April 22, 2017, a magnitude 3.8 earthquake occurred approximately 4 km northwest of Rangely, Colorado at 11:48 AM local time (05:48 PM UTC).  There were 15 felt reports from the town of Rangely, CO.  Two aftershocks, approximately 1 km NNE of the mainshock, were located by UUSS.  The first aftershock (ML 2.6) occurred on April 27 at 03:11 AM local time (09:11 AM UTC), and the second aftershock (ML 3.3) occurred on May 3 at 01:42 AM local time (07:42 AM UTC). Based on the moment tensor solution for the mainshock this was a predominantly strike-slip earthquake on steeply dipping planes with the strike either northwest or northeast.  From the distribution of the aftershock locations, we tentatively favor the northeast striking plane.  Eighteen earthquakes within 20 km of the mainshock , with magnitude greater than 2.0, have been catalogued since 1962.  The largest historical earthquake (ML 4.6, March 20, 1995) was located 2.3 km NE of the 2017 mainshock.

The Rangely area was one of the first focus sites for the study of fluid-induced earthquakes.  Some of the first documented induced earthquakes occurred near Rangely in the 1960s and 1970s.  During this time water-flood expansion was being used for secondary oil recovery.  It was a good place to test the correlation between fluid injection and seismic events with a controlled experiment (Rayleigh et al., 1976), and the experiment showed a direct link.  The seismicity during the experiment occurred on a ENE-WSW trending plane.  This is rotated from the current seismicity, but the locations of the seismic events have also migrated through time.  Water based fluid injection ended in 1983; since 1986 injection of CO2 has been used for secondary oil recovery.

Given the proximity of the recent seismicity to the Rangely Oil Field, it is fair to ask if the recent sequence is also induced.  Analysis of this sequence is ongoing, but initial work includes the following results.  An STA/LTA detector (detection threshold 3.5) was run across continuous waveforms from the two nearest stations (O20A and RDMU) for the time period April 22, 2017–May 04, 2017.  Requiring simultaneous detections on both stations, in order to reduce the number of false detections, resulted in one new detected event that occurred on May 3.  Using cross-correlation, we found similar waveforms (CC > 0.5) from the four events (mainshock, two aftershocks, and the new detected event) recorded at station O20A, suggesting possible common source properties.

The lack of close seismic stations makes it difficult to clearly associate these seismic events with oil production efforts.

Magnitude 3.7 near Rangely, CO

University of Utah Seismograph Stations

Released: April 22, 2017 02:00 PM MDT

The University of Utah Seismograph Stations reports that a minor
earthquake of magnitude 3.70 occurred at 11:48 AM on April 22, 2017
(MDT). The epicenter of the shock was located in northwestern Colorado,
2.5 miles northwest of the town of Rangely, CO. The earthquake was
reported felt in the town of Rangely. A total of 11 earthquakes of
magnitude 3.0 or greater have occurred within 16 miles of the epicenter
of this event since 1962. The largest of these events was a magnitude
4.6 on March 20, 1995, which occurred in the same area.

Anyone who felt the earthquake is encouraged to fill out a survey form
either on the Seismograph Stations website: www.quake.utah.edu or the
US Geological Survey website: earthquake.usgs.gov.

Earthquake Summary:

Date (UTC): April 22, 2017 Time (UTC): 17:48

Date (local): April 22, 2017 Time (local): 11:48 AM MDT

Latitude: 40 6.60′ N

Longitude: 108 50.48′ W

Preferred magnitude: 3.7 Ml

Magnitude 3.8 near Bluff, UT

PRESS RELEASE

University of Utah Seismograph Stations

Released: April 21, 2017 11:30 PM MDT

The University of Utah Seismograph Stations reports that a minor
earthquake of magnitude 3.8 occurred at 10:01 PM on April 21, 2017
(MDT). The epicenter of the shock was located 13 mi WSW of
Montezuma Creek, UT. One earthquake of magnitude 3.0 or greater has
occurred within 16 mi of the epicenter of this event since 1962. This
was a magnitude 3.7 on June 06, 2008, 9 mi WNW of
Montezuma Creek, UT.

Today’s earthquake was reported felt in the town of Blanding, UT.

Anyone who felt the earthquake is encouraged to fill out a survey form
either on the Seismograph Stations website: www.quake.utah.edu or the
US Geological Survey website: earthquake.usgs.gov.

Earthquake Summary:

Date (UTC): April 22, 2017 Time (UTC): 04:01

Date (local): April 21, 2017 Time (local): 10:01 PM MDT

Latitude: 37 14.73′ N

Longitude: 109 34.10′ W

Preferred magnitude: 3.8 Ml

1988 – San Rafael Swell, UT – M 5.3

Intermountain Seismic Belt Historical Earthquake Project

August 14, 1988 – San Rafael Swell, UT – M 5.3

This earthquake was located approximately 10 miles ESE of Castle Dale, Utah in Emery County.

There were no reports of injuries or serious damage resulting from the earthquake. Reports indicate that the earthquake was felt as far east as Golden, Colorado, as far south as Albuquerque, New Mexico, as far west as Delta, Utah, and as far north as Brigham City, Utah. The earthquake was reportedly felt particularly in valleys, while less noticed in mountain areas.

Minor damage in Emery County consisted of cracks in foundations, chimneys, and old buildings. Dishes and store goods fell from shelves and pictures were dislodged from wall hooks. Cracks and plaster damage were also observed in ceilings and walls.

Calls about the earthquake were received from several coal mines in the area, but there were no reports of injury or damage. Local dams were examined and found to be sound.

Rock falls were a notable feature of this earthquake. Fallen boulders impeded travel on some roadways. In many locations, falling rocks sent up clouds of dust that were visible for many miles.

Near the epicenter, north of Ferron, Utah a resident reported seeing dust clouds on the western ridge that partially obscured Ferron Mountain and the cliffs around the Wilberg Mine. “You couldn’t see the mountain up around Wilberg for five to 10 minutes because of the dust. Same on the desert [to the east]. Just a big string of dust from as far south to as far north as you could see.”

 

For additional information about this earthquake:

Earthquake Summary 3D Newspaper Articles 3D Photos 3D Blank Thumbnail
Personal Accounts 3D Additional Resources 3D Blank Thumbnail Blank Thumbnail

For more information about this project:

ISB Hist EQ Proj

 

Magnitude 3.3 near Cedar City, UT

PRESS RELEASE

University of Utah Seismograph Stations

Released: March 05, 2017 1:30 PM MST

The University of Utah Seismograph Stations reports that a minor
earthquake of magnitude 3.3 occurred at 12:14 PM on March 05, 2017
(MST).  The epicenter of the shock was located in the Cedar Valley,
6 miles WSW of Enoch, UT and 7.1 miles NNW of Cedar City, Utah.

The earthquake was reported felt in the vicinity of Cedar City.
A total of 34 earthquakes of magnitude 3.0 or greater have
occurred within 16 miles of the epicenter of this event since 1962.

Anyone who felt the earthquake is encouraged to fill out a survey form
either on the Seismograph Stations website: www.quake.utah.edu or the
US Geological Survey website: earthquake.usgs.gov.

Earthquake Summary:

Date (UTC):   March 05, 2017         Time (UTC):   19:14

Date (local): March 05, 2017         Time (local): 12:14 PM MST

Latitude:     37 45.82′ N

Longitude:    113 7.99′ W

Preferred magnitude: 3.30 Ml

The 2013 Bingham Canyon landslide, moment by moment

In spring 2013, observation systems at Utah’s Bingham Canyon copper mine detected ground movement in a hillslope surrounding the mine’s open pit. Out of caution, mine managers evacuated personnel and shut down production, waiting for the inevitable.

 

On April 10, at 9:30 p.m. and again at 11:05 p.m., the slope gave way and thundered down into the pit, filling in part of what had been the largest man-made excavation in the world. Later analysis estimated that the landslide was at the time the largest non-volcanic slide in recorded North American history. Now, University of Utah geoscientists have revisited the slide with a combined analysis of aerial photos, computer modeling, and seismic data to pick apart the details. The total volume of rock that fell during the slide was 52 million cubic meters, they report, enough to cover Central Park with 50 feet of rock and dirt. The slide occurred in two main phases, but researchers used infrasound recordings and seismic data to discover 11 additional landslides that occurred between the two main events. Modeling and further seismic analysis revealed the average speeds at which the hillsides fell: 81 mph for the first main slide and 92 mph for the second, with peak speeds well over 150 mph.

 

The study shows how the team’s methods can be used to remotely characterize a landslide, and the details they elicited from the data may be useful in planning for and modeling future landslide events.

The results are published in Journal of Geophysical Research-Earth Surface.

 

Animations of both phases of the slide can be found here:

http://geohazards.earth.utah.edu/images/S1_phase1Animation.mp4

http://geohazards.earth.utah.edu/images/S2_phase2Animation.mp4

1934 – Hansel Valley, UT – M 6.6

Intermountain Seismic Belt Historical Earthquake Project

March 12, 1934 – Hansel Valley, UT – M 6.6

Believed to be the most severe earthquake in Utah’s recorded history, the 1934 Hansel Valley earthquake was reportedly felt as far west as Elko, Nevada and as far east as Rawlins, Wyoming. Felt reports were also issued from as far north as Boise, Idaho and as far south as Richfield, Utah.

The main shock occurred approximately 30 miles north of the Great Salt Lake at 8:05 a.m. local time. Five significant aftershocks were recorded over a nearly eight-week period from March 12 to May 6, 1934.

Some of the most severe damage was reported in Logan, Utah and surrounding communities. At least two public buildings in the area had to be abandoned. A three-story brick building on the campus of the Utah State Agricultural College was, reportedly, split from top to bottom. In Preston, Idaho, the shaking dislodged a 150-pound capstone from the top of the local high school building, separating the west wall from the rest of the building.

Other reports of damage included falling chimneys, broken windows, cracked walls and falling plaster. Swinging light fixtures were observed during the earthquake. Furniture rocked back and forth or rolled across floors. Dishes and goods fell from shelves and clocks stopped. Near the epicenter, in Snowville, Utah, the water main was broken and out of service for 10 hours. In some locations schools were evacuated and closed, particularly following the first aftershock.

Near the epicenter of the earthquake the appearance of several fissures or cracks in the ground surface were observed. Witnesses reported hearing loud roars as the fissures ruptured. A geologist who later examined the area reported one of the fissures to be about eight miles in length. He found a maximum fissure width of 14 inches, with a maximum drop of the ground on one side measuring 19 inches. Other reports noted a downward displacement of the ground on the east of the larger, predominantly north-south trending fissures.

Phenomena described as sand or mud cones were observed near the epicenter. There were also sightings of new springs and streams changing course. Artesian wells that had been long dry began flowing with water. Other wells, active prior to the earthquake, ceased to flow for several hours.

In many locations, shaking from the earthquake sent people running out of doors. There were also reports of people fainting from fright. In areas of intense shaking, people were unable to stand during the earthquake.

Two deaths were attributed to the earthquake. Ida Atkinson died instantly from a heart attack upon hearing that the shaking she felt was due to an earthquake. Salt Lake City waterworks employee Charles Bithel was injured when a six-foot trench in which he was working at the time of the earthquake caved in. Bithel died from his injuries the following day in a local hospital.

 

For additional information about this earthquake:

Earthquake Summary 3D Newspaper Articles 3D Photos 3D Blank Thumbnail
Personal Accounts 3D Additional Resources 3D Blank Thumbnail Blank Thumbnail

For more information about this project:

ISB Hist EQ Proj