Seismic hazards astride the boundary between the eastern Snake River Plain and northern Basin and Range Province Idaho

Conference · Thu Apr 01 00:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5097573

Wong, I G; Hemphill-Haley, M A; Sawyer, T L ^[1]; Coppersmith, K J; Youngs, R R ^[2]; Smith, R P; Jackson, S M; Hackett, W R ^[3]; Silva, W J; Stark, C M ^[4]; Knuepfer, P L.K. ^[5]; Bruhn, R L; Wu, D ^[6]

---

1. Woodward-Clyde Federal Services, Oakland, CA (United States)
2. Geomatrix Consultants, San Francisco, CA (United States)
3. Idaho National Engineering Lab., Idaho Falls, ID (United States)
4. Pacific Engineering and Analysis, El Cerrito, CA (United States)
5. State Univ. of New York, Binghamton, NY (United States). Dept. of Geological Sciences
6. Univ. of Utah, Salt Lake City, UT (United States). Dept. of Geology and Geophysics

The occurrence of the damaging 1983 M[sub w] 6.8 Borah Peak, Idaho earthquake, which ruptured a central segment of the Lost River fault, has increased the awareness of seismic hazards in this portion of the Northern Basin and Range Province (NBR). As a result, comprehensive deterministic and probabilistic seismic hazard analyses were performed for the Idaho National Engineering Laboratory (INEL) which is located within the eastern Snake River Plain (ESRP) but adjacent to the NBR. In this region, the most significant seismic sources are three late-Quaternary NBR normal faults, the Lost River, Lemhi and Beaverhead faults, and ESRP volcanic zones. For each source, the maximum earthquake, source geometry, recurrence and their uncertainties were estimated and incorporated into the probabilistic analysis through the use of logic trees. Recent paleoseismic trenching of the Lost River and Lemhi faults and volcanic mapping in the ESRP provided much of the data necessary to characterize the most significant seismic sources. Issues such as fault segmentation, temporal clustering, the nature of fault termination, and the maximum magnitude and recurrence of volcanic zone earthquakes were evaluated in the hazard analyses. Deterministic and probabilistic ground motions were computed using both empirical and stochastic approaches. In the deterministic analysis, the southern segments of the Lemhi fault controlled the hazard at the INEL due to their proximity and potential to generate M[sub w] [approximately]7 earthquakes. In the estimation of deterministic ground motions, potential rupture scenarios were evaluated for a Lemhi earthquake. In the probabilistic analysis, the hazard is dominated by the ESRP random earthquake, and the Lemhi and Lost River faults. The difference in the results of the two analyses points out the uncertainties in assessing seismic hazards due to random earthquakes and in regions of large but infrequent earthquakes.

• OSTI ID: 5097573
• Report Number(s): CONF-9305259-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 25:5; Conference: 89. annual meeting of the Cordilleran Section and the 46th annual meeting of the Rocky Mountain Section of the Geological Society of America (GSA), Reno, NV (United States), 19-21 May 1993; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
EARTHQUAKES
RISK ASSESSMENT
GEOLOGIC FAULTS
SEISMICITY
IDAHO
EARTHQUAKE MAGNITUDE
GROUND MOTION
HAZARDS
IDAHO NATIONAL ENGINEERING LABORATORY
QUATERNARY PERIOD
SEISMOLOGY
SNAKE RIVER PLAIN
CENOZOIC ERA
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
MOTION
NATIONAL ORGANIZATIONS
NORTH AMERICA
SEISMIC EVENTS
US DOE
US ERDA
US ORGANIZATIONS
USA
580000* - Geosciences