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