Year: 2017

Earthquake database for Utah Geological Survey Map 277: Utah earthquakes (1850–2016) and Quaternary faults: Utah Geological Survey Open-File Report 667

Posted on by Paul Roberson

The Utah Geological Survey (UGS), University of Utah Seismograph Stations (UUSS), and Utah Division of Emergency Management (UDEM) recently published the Utah Earthquakes (1850–2016) and Quaternary Fault Map (UGS Map 277). The new map shows earthquakes within and surrounding Utah from 1850 to 2016, and faults considered to be sources of large earthquakes.

Utah Earthquakes (1850-2016) and Quaternary Faults

 

The faults shown on the map are considered geologically active, have been sources of large earthquakes (about magnitude 6.5 and greater) during the Quaternary Period (past 2.6 million years), and are the most likely sources of large earthquakes in the future. Most of the small to moderate-sized earthquakes on the map are “background” earthquakes not readily associated with known faults and too small to have triggered surface faulting (under about magnitude 6.5).

 

There is a 57% probability (over 1 in 2 chance) that a magnitude 6.0 or greater earthquake will occur in the Wasatch Front region in the next 50 years. To address this threat, the Utah Earthquake Program, consisting of the UGS, UUSS, and the UDEM, developed the map so the public could more fully understand the hazard from earthquakes and faults, as well as the resulting risk to property, infrastructure, and life safety in Utah. Users of the map will be able to determine past earthquake locations and relative magnitudes (size), along with the locations of active faults and the timing of their most recent movement.

 

Printed copies of the map are available for $15 at the Utah Department of Natural Resources Map & Bookstore. The map is also available as a PDF download at https://ugspub.nr.utah.gov/publications/maps/m-277.pdf (44 by 62 inches in size) and can be printed on a wide-format printer.

The database for the seismicity plotted on the map, together with explanatory information, is provided in a companion report:
Arabasz, W. J., Burlacu, R., and Pechmann, J. C., 2017, Earthquake database for Utah Geological Survey Map 277: Utah earthquakes (1850–2016) and Quaternary faults: Utah Geological Survey Open-File Report 667, 12 p. plus 4 electronic supplements, available as a PDF download.
The electronic supplements include the data for the seismic events plotted on the map, which are listed in two separate catalogs, each in the form of a Microsoft Excel workbook and an ArcGIS feature class within a file geodatabase. The catalog files are available for download.

Sulphur Peak Earthquake Information

Posted on by Paul Roberson

On September 02, 2017, in eastern ​Idaho ​near ​the ​town of ​Soda Springs a magnitude 5.3 earthquake occurred that was widely felt throughout southeastern Idaho and northern Utah.  This earthquake has been followed by a very active aftershock sequence. These earthquakes are slightly outside of the University of Utah Seismograph Stations area of responsibility, but the area is of interest to UUSS and the USGS Earthquake Hazards Program.

UUSS in partnership with USGS have deployed two UUSS 3-channel strong-motion systems and six USGS 6-channel seismic systems (broadband and strong-motion) within 50 km of the seismicity.

The following page includes information about the earthquake sequence and webicorders for the temporary stations.  We will update the page with more information over time.

Magnitude 3.4 earthquake near Monroe, UT

Posted on by Paul Roberson

PRESS RELEASE

University of Utah Seismograph Stations

Released: September 24, 2017 1:00 PM MDT

The University of Utah Seismograph Stations reports that a minor earthquake of magnitude 3.4 occurred at 10:38 PM on Saturday,
September 23, 2017 (MDT), in southern Utah. The shock was located beneath the Sevier Plateau, 6 km ( 4 mi) east-southeast of the town
of Monroe, UT, and 18 km (11 mi) south of the town of Richfield, UT. The earthquake was reported felt in the towns of Monroe, Richfield,
and Joseph, Utah. It was followed by two small aftershocks, one of M 1.7 at 10:46 pm on Saturday night and the other of M 1.6 at 09:43
on Sunday morning.

Yesterday evening’s earthquake occurred within a seismically active area of Utah A total of 23 earthquakes of magnitude 3.0 or greater
have occurred within 25 km (16 mi) of the epicenter of this event since 1962. The largest of these events was a magnitude 5.2 on
October 04, 1967, 10.1km ( 6.3 mi) ESE of Sevier, 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): September 24, 2017 Time (UTC): 04:38

Date (local): September 23, 2017 Time (local): 10:38 PM MDT

Latitude: 38 36.39′ N

Longitude: 112 3.43′ W

Preferred magnitude: 3.4 Ml

Magnitude 3.3 near Park City, UT

Posted on by Paul Roberson

PRESS RELEASE

University of Utah Seismograph Stations

Released: September 18, 2017 12:00 PM MDT

The University of Utah Seismograph Stations reports that a minor earthquake of magnitude 3.3 occurred at 11:21 AM on September 18, 2017 (MDT). The shock was located 14 km (8 miles) beneath the Wasatch Mountains, 5 km (3 miles) south of the town of Summit Park, Utah, and 11 km ( 7 mi) WNW of Park City, UT. This earthquake was reported felt in Park City and Salt Lake City, Utah, other locations in the Salt Lake Valley, and in northern Utah County. Four other earthquakes of magnitude 3.0 or greater have occurred within 25 km (16 miles) of the epicenter of this event since 1962. The largest of these events was a magnitude 3.6 on June 30, 1999, 6.9km ( 4.3 mi) W of Park City, 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): September 18, 2017 Time (UTC): 17:21

Date (local): September 18, 2017 Time (local): 11:21 AM MDT

Latitude: 40 42.05′ N

Longitude: 111 36.55′ W

Depth: 11.0 km below sea level
13.6 km below the surface

Preferred magnitude: 3.30 Ml

Magnitude 5.3 near Soda Springs, ID

Posted on by Paul Roberson

Press Release

University of Utah Seismograph Stations

Released: September 02, 2017 8:00 PM MDT

The University of Utah Seismograph Stations reports that a moderate
earthquake of magnitude 5.3 occurred at 05:57 PM on September 02, 2017
(MDT), as computed by the USGS. The epicenter of the shock was located
11 mi E of Soda Springs, ID. This event was preceded by a magnitude 4.3
foreshock and followed by numerous aftershocks, including seven with
magnitudes between 3.2 and 4.1 (all USGS magnitudes).
The 5.3 mainshock was reported felt in Idaho, Wyoming, and also across
northern Utah in the cities of Logan, Bringham City, Ogden, Salt Lake City,
Draper, and Provo.

Since 1962, a total of 87 earthquakes of magnitude 3.0 or greater have
occurred within 16 mi of the epicenter of today’s magnitude 5.3 event.
The largest of these events was a magnitude 4.7 on October 13, 1982,
9 mi NNW of Georgetown, ID.

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 (USGS parameters):

Date (UTC): September 02, 2017 Time (UTC): 23:57

Date (local): September 02, 2017 Time (local): 05:57 PM MDT

Latitude: 42 37.44′ N

Longitude: 111 23.46′ W

Preferred magnitude: 5.3 Mw

UUSS 2016 Annual Report

Posted on by Paul Roberson

cover page of 2016 annual report2016 Annual Report

In April of 2016 the University of Utah Seismograph Stations (UUSS) celebrated the 50th anniversary of its creation as an organizational unit within the University of Utah. We celebrated this milestone with a party honoring the founding director, Dr. Ken Cook, and the unveiling of a new historical display just outside the Rio Tinto Earthquake Information Center. The ceremony was well attended by current and former UUSS employees, colleagues in the College of Mines and Earth Sciences, representatives of sister agencies in the Utah Earthquake Program, members of Dr. Cook’s family, and many other friends of UUSS. Here’s to another 50 years of reducing the risk from earthquakes in Utah through research, education, and public service.

2016 was also a year of transition for UUSS. Our administrative manager, Martha Knowlton, retired after 14 years of service. We will miss Martha’s attention to detail, professionalism, and strong work ethic. UUSS communications specialist Sheryl Peterson, who has worked in various capacities for UUSS since 1989, also left in the fall of 2016. Sheryl’s competence, cheerfulness, and organizational skills will serve her well as she pursues a new career as director of advancement operations at Southern Virginia University. We will also miss Katherine Whidden, a research scientist, student mentor, and the UUSS public information officer, who left in 2016 (ending a five-year stint with UUSS) to travel the country in an RV with her husband, John. In other news, Cindi Meier, who worked at UUSS during 1994-1999, agreed to return as our new full-time administrative officer. In 2016, we also welcomed Dr. Hao Zhang to UUSS as a post-doctoral research scientist focusing on the detection and location of sequences of very small earthquakes.

We look forward to an exciting new year in 2017. I encourage you to visit our revamped web page at quake.utah.edu to stay up- to-date on our new initiatives and products as well as to nd out about the latest seismic activity in Utah. You can also follow UUSS on Twitter with the handle @UUSS_Quake_Info.

Ongoing Yellowstone Earthquake Swarm North of West Yellowstone, MT.

Posted on by Jamie Farrell

August 03, 2017 UPDATE: The University of Utah Seismograph Stations (UUSS) is monitoring an earthquake swarm which is currently active on the western edge of Yellowstone National Park.  The swarm began on June 12th, 2017 and, as of 13:00 MDT on August 2nd, 2017, is composed of 1,562 events with the largest magnitude of ML 4.4 (MW 4.4) (Figure 1).  The swarm consists of one earthquake in the magnitude 4 range, 8 earthquakes in the magnitude 3 range, 134 earthquakes in the magnitude 2 range, 505 earthquakes in the magnitude 1 range, 879 earthquakes in the magnitude 0 range, and 35 earthquakes with magnitudes of less than zero.  These events have depths from ~0.0 km to ~14.0 km, relative to sea level.  At the time of this report, there were 125 felt reports for the M4.4 event that occurred on June 16, 2017 at 00:48:46.94 UTC (June 15, 2017 at 18:48:46.94 MDT).  The M4.4 event has an oblique strike-slip moment tensor solution (Figures 1 & 2).  In addition, four other earthquakes in the swarm have been reported felt.

 

 

Figure 1. Location of the earthquakes that are part of the swarm as of August 3, 2017 at 01:00 PM MDT (red symbols).

 

Figure 2. Moment Tensor solution for the M4.4 event showing the fit between data (black) and synthetics (red dashed).

Moment Tensor for M 4.5

Figure 3. Animation of the June 2017 Yellowstone earthquake swarm.  Earthquakes appear as red circles as they happen, then transition to blue.  After they have occurred, they appear as black circles.  The size of the circles are proportional to the earthquakes magnitude.

Earthquake swarms are common in Yellowstone and, on average, comprise about 50% of the total seismicity in the Yellowstone region.

UUSS will continue to monitor this swarm and will provide updates as necessary.

 

If you think you felt an earthquake, please fill out a felt report at: http://earthquake.usgs.gov/earthquakes/dyfi/.

Yellowstone swarm continues with M 3.6 felt near West Yellowstone, MT

Posted on by Paul Roberson

Released: July 18, 2017 03:15 PM MDT

The University of Utah Seismograph Stations reports that a minor
earthquake of magnitude 3.6 occurred at 02:31 PM on July 18, 2017
(MDT). The epicenter of the shock was located 9.3 mi N of W.
Yellowstone, MT. This earthquake is part of an ongoing sequence
of earthquakes that began on June 12, 2017 and included a
a magnitude 4.4 event on June 15, 2017, 9.0 mi NNE of W.
Yellowstone, MT. Today’s M 3.6 earthquake was reported felt in
Yellowstone National Park and in West Yellowstone, MT. It was
followed by numerous smaller earthquakes, the largest of which
had magnitudes of 2.8 and 2.9. The total number of located
earthquakes in the current sequence has now exceeded 1200.

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): July 18, 2017 Time (UTC): 20:31

Date (local): July 18, 2017 Time (local): 02:31 PM MDT

Latitude: 44 47.25′ N

Longitude: 111 2.27′ W

Preferred magnitude: 3.60 Ml

1928 – Helena, MT – M 5½ ±

Posted on by webdev

Intermountain Seismic Belt Historical Earthquake Project

February 29, 1928 – Helena, MT – M 5½ ±

The 1928 Helena, Montana earthquake had no reported injuries or damage. The shaking startled people throughout the city of Helena and was more noticeable on upper floors of buildings with two or more stories above ground. The shaking was severe enough to disrupt a trial in one city courthouse. Without taking time to formally adjourn the proceedings, the judge and others fled the courtroom as the shaking began.

The earthquake was reported felt in areas southeast of Helena including: Trident, Three Forks, Manhattan, Logan, Lombard, and Sixteen-Mile Canyon. White Sulphur Springs, to the east of Helena, also reported earthquake shaking.

There were reports of shaken buildings, windows rattling, furniture moving, and goods being shaken from shelves.

 

For additional information about this earthquake:

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

For more information about this project:

ISB Hist EQ Proj