UUSS 2016 Annual Report

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.

A uniform moment magnitude earthquake catalog and background seismicity rates for the Wasatch Front and surrounding Utah region: Appendix E in Working Group on Utah Earthquake Probabilities (WGUEP)

Arabasz, W.J., Pechmann, J.C., and Burlacu, R., 2016, A uniform moment magnitude earthquake catalog and background seismicity rates for the Wasatch Front and surrounding Utah region: Appendix E in Working Group on Utah Earthquake Probabilities (WGUEP), 2016, Earthquake probabilities for the Wasatch Front region in Utah, Idaho, and Wyoming: Utah Geological Survey Miscellaneous Publication 16-3, variously paginated.

This appendix to the report by the Working Group on Utah Earthquake Probabilities (2016) describes full details of the construction and analysis of a refined earthquake catalog and the calculation of seismicity rates for the Wasatch Front and surrounding Utah region. The earthquake catalog covers the period from 1850 through September 2012. The catalog region extends from lat. 36.75° to 42.50° N and from 108.75° to 114.25° W. A uniform moment magnitude, M (and quantified magnitude uncertainty), is determined for each earthquake in the catalog.

Electronic Supplements (.xlsx)

E-1.  Best-Estimate Moment Magnitude (BEM) Earthquake Catalog

E-2.  Moment Magnitude Data

E-3.  Merged Subcatalog A, Jan. 1850-June 1962

E-4.  Merged Subcatalog B, July 1962-Dec. 1986

E-5.  Merged Subcatalog C, Jan. 1987-Sept. 2012

E-6.  Worksheets for Mobs, M~, Mpred (I0)

E-7.  Worksheets for Xnon, Xmix (Subcatalogs A, B)

E-8.  Worksheets for Xvar, Xi (Subcatalog B)

E-9.  Worksheets for Xvar, Xi (Subcatalog C)

E-10.  N* Counts for the WGUEP and Utah Regions

Earthquake Probabilities for the Wasatch Front region in Utah, Idaho, and Wyoming

Wong, I., W. Lund, C. DuRoss, P. Thomas, W. Arabasz, A. Crone, M. Hylland, N. Luco, S. Olig, J. Pechmann, S. Personius, M. Petersen, D. Schwartz, R. Smith, and S. Bowman (2016). Earthquake Probabilities for the Wasatch Front region in Utah, Idaho, and Wyoming, Utah Geological Survey Miscellaneous Publication 16-3,  418 pp.

UUSS 2015 Annual Report

UUSS Annual Report 2015

2015 Annual Report

2015 has been another vibrant and productive year for the University of Utah Seismograph Stations (UUSS). Our longstanding partnership with the United States Geological Survey (USGS) was extended with a new, 5-yr cooperative agreement from the USGS Earthquake Hazards Program. This award ensures that earthquake monitoring in Utah will continue to operate with state-of-the-art equipment and software at least through 2020. Congratulations to the UUSS staff for all their hard work on the USGS proposal, it was truly a team effort.

The legacy of UUSS in earthquake monitoring and research was recognized in 2015 as two former UUSS Directors received prestigious awards for career accomplishments. Research Professor Emeritus Dr. Walter J. Arabasz received the 2015 Alfred E. Alquist Special Recognition Medal from the Earthquake Engineering Research Institute, while Professor Emeritus Dr. Robert B. Smith received the 2015 Paul G. Silver Award from the American Geophysical Union. Congratulations to Walter and Bob for the leadership and service they have provided to the seismological community over the last several decades.

UUSS developed a new monitoring capability in 2015 with the acquisition of nearly 50 new wireless seismographs. The instruments were purchased in collaboration with Dr. Fan-Chi Lin and other University of Utah geoscientists, and will allow for the imaging of shallow Earth structure at a very small scale as well as the detection of small aftershocks that follow regional earthquakes. Please look inside to read about one of the first experiments carried out with the new instruments.

We expect great new things in 2016 as well. Keep an eye out for an updated UUSS web page and expanded social media presence. We also look forward to a celebration of the 50th anniversary of UUSS, in April 2016.

Tracking North America: Long‐term Observation to Build on the Legacy of USArray

West, M., S. Bilek, P. Boden, G. Kent, K. Koper, W.‐Y. Kim, N. Ruppert, V. Tsai, and J. Vidale (2015). Tracking North America: Long‐term Observation to Build on the Legacy of USArray, whitepaper for workshop on Future Seismic and Geodetic Facility Needs in the Geosciences, Leesburg, Virginia, May 4‐6, pp. 1‐2.

Paleoseismology of the northern segments of the Great Salt Lake fault, Utah

Dinter, D. A., and J. C. Pechmann (2015). Paleoseismology of the northern segments of the Great Salt Lake fault, Utah, in Proc. of the Basin and Range Province Seismic Hazards Summit III, Salt Lake City, Utah, January 12‐17, W. R. Lund (Editor), Utah Geological Survey Misc. Publ. 15‐5, CD (electronic poster).

Scenario for a Magnitude 7.0 Earthquake on the Wasatch Fault–Salt Lake City Segment: Hazards and Loss Estimates

Pankow, K., W. J. Arabasz, R. Carey, G. Christenson, J. Groeneveld, B. Maxfield, P. W. McDonough, B. Welliver,
Segment: Hazards and Loss Estimates, Earthquake Engineering Research Institute, Utah Chapter, 53 p.

Paleoseismology of the Promontory Segment, East Great Salt Lake Fault

Dinter, D. A., and J. C. Pechmann (2014). Paleoseismology of the Promontory Segment, East Great Salt Lake Fault, U.S. Geol. Surv. Final Technical Rept., Award No. 02HQGR0105, 23 pp, http://earthquake.usgs.gov/research/external/reports/02HQGR0105.pdf
With funding from this project, we collected 367 km of high resolution seismic reflection data in the Great Salt Lake in 2003 and 2006: 205 km in the north arm and 162 km in the south arm, where the north and south arms are defined as the parts of the lake north and south of the railroad causeway, respectively.  Because the quality of the north arm data that we obtained was insufficient to meet the goals of the project, we collected an additional 380 km of data with new, state-of-the-art instrumentation in 2009 and 2010: 160 km in the north arm and 220 km in the south arm. The 2009 fieldwork was part of a collaborative industry-funded study. The 2010 field work was carried out using boat and equipment time that became available after the successful completion of a seismic reflection study in Utah Lake for another USGS/NEHRP-funded study.
We used the seismic reflection data to map the Great Salt Lake fault (GSLF) and associated subsidiary faults in the north arm of the Great Salt Lake and to revise an analogous map for the south arm of the lake that we constructed for a previous USGS/NEHRP-funded project. We also mapped the trace of the Carrington fault, another major normal fault in the Great Salt Lake, using our seismic reflection data and high-resolution bathymetry data for the lake.  Based on the geometry of our mapped surface trace for the GSLF, variations in the amount of lakebed offset along this fault, and other evidence for recency of faulting, we hypothesize that the GSLF consists of the following four segments from north to south (with end-to-end length measurements): the Rozel segment (≥ 18 km), the Promontory segment (≥27 km), the Fremont Island segment (24 km), and the Antelope Island segment (35 km).
Seismic reflection profiles across the GSLF in the north arm show clear evidence for individual paleoearthquakes in the form of stratigraphically limited subsidiary faults and monoclines and coseismic bedding rotations adjacent to the fault. Based on these types of features, we have identified seismic event horizons for two or three paleoearthquakes on the Rozel segment and two or three paleoearthquakes on the Promontory segment , all within ~8 m of the lake bottom.  A possible fourth Promontory segment earthquake is suggested by the higher fault scarps along this segment. The earthquake event horizons that we have identified in this study can be cored and dated to establish a paleoearthquake history for the Rozel and Promontory segments of the GSLF. In the meantime, based on comparisons with the depths of dated event horizons on the Antelope Island and Fremont Island segments, it seems reasonable to assume that the average recurrence interval of 4200 ±1400 years that we have determined for these two segments is also applicable to the Rozel and Promontory segments