The Borah Peak, Idaho Earthquake of October 28, 1983—Strong Ground Motion

1985 ◽  
Vol 2 (1) ◽  
pp. 51-69 ◽  
Author(s):  
Suzette M. Jackson ◽  
John Boatwright
Keyword(s):  
Ground Motion ◽  
Main Shock ◽  
Near Field ◽  
Free Field ◽  
Ground Level ◽  
Shock Acceleration ◽  
Epicentral Area ◽  
Floor Level ◽  
Ground Floor ◽  
Vertical Accelerations

The 1983 Borah Peak, Idaho Earthquake was the largest normal faulting event to occur in the last 20 years. There were no near-field recordings of ground motion during the main shock, however, thirteen accelerographs in a permanent array at the Idaho National Engineering Laboratory (INEL) recorded the event at epicentral distances of 90-110 km. Peak horizontal accelerations, or PGA, recorded at accelerographs above ground-floor level range from 0.037 to 0.187 g. Accelerographs at basement and free-field sites recorded as low as 0.022 g and as high as 0.078 g. Peak vertical accelerations range from 0.016 g at ground level to 0.059 g above ground-floor level. A temporary array of digital seismographs deployed by the U. S. Geological Survey (USGS) in the epicentral area recorded ground motion from six large aftershocks at epicentral distances of 4-45 km; the largest of these aftershocks also triggered four accelerographs in the INEL array. This paper presents our estimates of near-field ground motion derived from two separate analyses. The first analysis uses the attenuation of the aftershock PGA measurements to extrapolate the INEL main shock PGA measurements into the near-field. This estimates an upper limit of 0.8 g for near-field ground motion. In the second analysis, a set of main shock accelerograms were synthesized. Wave propagation effects were determined from aftershock recordings at one of the USGS portable stations and an INEL seismograph station. These effects were removed from one of the INEL main shock acceleration traces. The synthetic accelerograms were derived for a hypothetical station southwest of Mackay, Idaho. The PGA measured from the synthetic accelerograms were 0.08, 0.14, 0.15, 0.23 g. These estimates correlate well with ground motion expected for an area of intensity VII.

Strong ground motion in the 1983 Borah Peak, Idaho, earthquake and its aftershocks

1987 ◽  
Vol 77 (3) ◽  
pp. 724-738
Author(s):  
Suzette M. Jackson ◽  
John Boatwright
Keyword(s):  
Main Shock ◽  
Near Field ◽  
Free Field ◽  
Time History ◽  
Strong Motion ◽  
Geological Survey ◽  
Shock Acceleration ◽  
Far Field ◽  
Field Station ◽  
Epicentral Area

Abstract Thirteen strong-motion accelerographs sited in a permanent array at the Idaho National Engineering Laboratory (INEL) were the closest instruments to the MS = 7.3 1983 Borah Peak, Idaho, earthquake. They recorded the event at epicentral distances of 90 to 110 km. The peak horizontal accelerations or peak ground accelerations (PGAs) at the basement and free-field sites of the array ranged from 0.022 to 0.078 g. For 2 weeks after the main shock, the U.S. Geological Survey maintained an array of digital seismographs in the epicentral area; these instruments recorded six large aftershocks at epicentral distances of 4 to 45 km. The largest of these aftershocks also triggered four accelerographs in the INEL array. PGAs for the main shock are estimated by two separate analyses. First, the attenuation of the PGAs from the largest aftershock is used to extrapolate the far-field PGA into the near-field, obtaining estimates of 0.54, 0.58, 0.21, and 0.24 g at epicentral distances of 11, 12, 16, and 18 km, respectively. Second, paired recordings for a set of small aftershocks, obtained from a near-field station (U.S. Geological Survey portable instrument) and a far-field station (INEL telemetered station), were used together with an INEL main shock acceleration time history to generate four synthetic accelerograms for a hypothetical recording site 18 km southeast of the main shock. The PGAs measured from these synthetic accelerograms are 0.08, 0.14, 0.15, and 0.23 g.

Near-Field Ground Motion of the 2002 Denali Fault, Alaska, Earthquake Recorded at Pump Station 10

2004 ◽  
Vol 20 (3) ◽  
pp. 597-615 ◽  
Author(s):  
W. L. Ellsworth ◽  
M. Celebi ◽  
J. R. Evans ◽  
E. G. Jensen ◽  
R. Kayen ◽  
...  
Keyword(s):  
Ground Motion ◽  
Near Field ◽  
Free Field ◽  
Monitoring And Control ◽  
Peak Acceleration ◽  
Permanent Displacement ◽  
Soil Response ◽  
Denali Fault ◽  
Field Recording ◽  
Pump Station

A free-field recording of the Denali fault earthquake was obtained by the Alyeska Pipeline Service Company 3 km from the surface rupture of the Denali fault. The instrument, part of the monitoring and control system for the trans-Alaska pipeline, was located at Pump Station 10, approximately 85 km east of the epicenter. After correction for the measured instrument response, we recover a seismogram that includes a permanent displacement of 3.0 m. The recorded ground motion has relatively low peak acceleration (0.36 g) and very high peak velocity (180 cm/s). Nonlinear soil response may have reduced the peak acceleration to this 0.36 g value. Accelerations in excess of 0.1 g lasted for 10 s, with the most intense motion occurring during a 1.5-s interval when the rupture passed the site. The low acceleration and high velocity observed near the fault in this earthquake agree with observations from other recent large-magnitude earthquakes.

scholarly journals A Novel Method for Constructing Main-Aftershock Sequences and Its Application in the Global Damage Accumulation Effects Analysis of Gravity Dams

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Liaojun Zhang ◽  
Yafei Zhai ◽  
Binghui Cui ◽  
Yujie Tang ◽  
Zhonghui Bi
Keyword(s):  
Ground Motion ◽  
Damage Evolution ◽  
Main Shock ◽  
Gravity Dam ◽  
Shock Acceleration ◽  
Rock Foundation ◽  
Dam Foundation ◽  
Energy Characteristics ◽  
Aftershock Sequences ◽  
Dynamic Damage

The traditional linear elastic and Drucker–Prager (DP) models cannot truly reflect the strong nonlinear characteristics of the concrete and rock foundation of the dam under earthquake. Therefore, for comprehensive evaluation of the cumulative damage of the gravity dam structure caused by aftershock, the dynamic damage of the dam body concrete is analyzed by many scholars through the plastic damage mechanics method, but there is little research on rock material at the dam foundation with the method utilized; thus, the simulation of the whole dynamic damage evolution is worthy of investigation of the dam body and dam foundation. According to the randomness of ground motion, the transcendental probability (P) is introduced to express the statistical characteristics of aftershock intensity, and a new method for constructing main-aftershock sequences of ground motion is proposed in this paper. And then, the law of the damage evolution and energy characteristics of the concrete gravity dam under the combined action of the main shock and aftershock sequences is studied. The results are shown as follows: the smaller aftershocks do not cause further damage to the dam; as the aftershock intensity increases, the energy characteristics of the dam body and foundation have shown different changing rules; when the ratio of peak aftershock acceleration to peak main shock acceleration (∇PGA) approximately equals 0.68, the aftershock will cause larger secondary damage to the dam.

scholarly journals The ShakeMaps of the Amatrice, M6, earthquake

2016 ◽  
Vol 59 ◽  
Author(s):  
Licia Faenza ◽  
Valentino Lauciani ◽  
Alberto Michelini
Keyword(s):  
Ground Motion ◽  
Data Exchange ◽  
Main Shock ◽  
Central Italy ◽  
Strong Motion ◽  
Rupture Directivity ◽  
Time Data ◽  
Epicentral Area ◽  
Ground Shaking ◽  
Motion Data

In this paper we describe the performance of the ShakeMap software package and the fully automatic procedure, based on manually revised location and magnitude, during the main event of the Amatrice sequence with special emphasis to the M6 main shock, that struck central Italy on the 24th August 2016 at 1:36:32 UTC. Our results show that the procedure we developed in the last years, with real-time data exchange among those institutions acquiring strong motion data, allows to provide a faithful description of the ground motion experienced throughout a large region in and around the epicentral  area. The prompt availability of the rupture fault model, within three hours after the earthquake occurrence, provided a better descriptions of the level of strong ground motion throughout the affected area.  Progressive addition of  station data and  manual verification of the data insures improvements in the description of the experienced ground motions.  In particular, comparison between the MCS intensity shakemaps and preliminary field macroseismic reports show favourable similarities.  Finally the overall  spatial pattern of the ground motion of the main shock is consistent with reported rupture directivity toward NW and reduced levels of ground shaking toward SW probably linked to the peculiar source effects of the earthquake.

Source modelling and strong ground motion simulations for the 24 January 2020, Mw 6.8 Elazığ earthquake, Turkey

2020 ◽  
Vol 223 (2) ◽  
pp. 1054-1068 ◽  
Author(s):  
Daniele Cheloni ◽  
Aybige Akinci
Keyword(s):  
Ground Motion ◽  
High Frequency ◽  
Main Shock ◽  
Peak Ground Velocity ◽  
Coulomb Stress ◽  
Epicentral Area ◽  
Fault Segment ◽  
Ground Motion Simulations ◽  
Finite Fault ◽  
Motion Characteristics

SUMMARY On 24 January 2020 an Mw 6.8 earthquake occurred at 20:55 local time (17:55 UTC) in eastern Turkey, close to the town of Sivrice in the Elazığ province, causing widespread considerable seismic damage in buildings. In this study, we analyse the main features of the rupture process and the seismic ground shaking during the Elazığ earthquake. We first use Interferometric Synthetic Aperture Radar (InSAR) interferograms (Sentinel-1 satellites) to constrain the fault geometry and the coseismic slip distribution of the causative fault segment. Then, we utilize this information to analyse the ground motion characteristics of the main shock in terms of peak ground acceleration (PGA), peak ground velocity (PGV) and spectral accelerations. The absence of seismic registrations in near-field for this earthquake imposes major constraints on the computation of seismic ground motion estimations in the study area. To do this, we have used a stochastic finite-fault simulation method to generate high-frequency ground motions synthetics for the Mw 6.8 Elazığ 2020 earthquake. Finally, we evaluate the potential state of stress of the unruptured portions of the causative fault segment as well as of adjacent segments, using the Coulomb stress failure function variations. Modelling of geodetic data shows that the 2020 Elazığ earthquake ruptured two major slip patches (for a total length of about 40 km) located along the Pütürge segment of the well-known left-lateral strike-slip East Anatolian Fault Zone (EAFZ), with up to 2.3 m of slip and an estimated geodetic moment of 1.70 $\,\, \times $ 1019 Nm (equivalent to a Mw 6.8). The position of the hypocentre supports the evidence of marked WSW rupture directivity during the main shock. In terms of ground motion characteristics, we observe that the high-frequency stochastic ground motion simulations have a good capability to reproduce the source complexity and capture the ground motion attenuation decay as a function of distance, up to the 200 km. We also demonstrate that the design spectra corresponding to 475 yr return period, provided by the new Turkish building code is not exceeded by the simulated seismograms in the epicentral area where there are no strong motion stations and no recordings available. Finally, based on the Coulomb stress distribution computation, we find that the Elazığ main shock increased the stress level of the westernmost part of the Pütürge fault and of the adjacent Palu segment and as a result of an off-fault lobe.

Characteristics of Free-Field Vertical Ground Motion during the Northridge Earthquake

1995 ◽  
Vol 11 (4) ◽  
pp. 515-525 ◽  
Author(s):  
Youself Bozorgnia ◽  
Mansour Niazi ◽  
Kenneth W. Campbell
Keyword(s):  
Ground Motion ◽  
Near Field ◽  
Free Field ◽  
Seismic Source ◽  
Spectral Ratio ◽  
Response Spectra ◽  
Northridge Earthquake ◽  
Attenuation Relationships ◽  
Vertical Ground Motion ◽  
Vertical Ground

Characteristics of response spectra of free-field vertical ground motion recorded during the 1994 Northridge earthquake are examined. Dependence of vertical and horizontal response spectra, and their ratio, on the site-to-source distance is investigated through development of attenuation relationships for vertical and horizontal spectral ordinates. The database includes 123 response spectra of the motions recorded at 41 alluvial sites. Vertical-to-horizontal (V/H) response spectral ratio is found to be strongly dependent on period and distance of site to the seismic source. V/H spectral ratio largely exceeds the commonly assumed value of 2/3, at short periods in the near-field region. The main characteristics of V/H spectral ratio for the Northridge earthquake are found to be qualitatively similar to those observed in the 1989 Loma Prieta, California, and in several other earthquakes recorded over the SMART-1 array in Taiwan. These characteristics are very likely to be universal.

Lessons from the 1985 Mexican earthquake

1986 ◽  
Vol 13 (5) ◽  
pp. 535-557 ◽  
Author(s):  
Denis Mitchell ◽  
John Adams ◽  
Ronald H. DeVall ◽  
Robert C. Lo ◽  
Dieter Weichert
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Soft Soil ◽  
Near Field ◽  
Lessons Learned ◽  
Background Information ◽  
Soil Conditions ◽  
National Committee ◽  
Severe Damage ◽  
Epicentral Area

Severe damage during the September 19, 1985 Mexican earthquake prompted a site visit by three engineers and two seismologists representing the Canadian National Committee on Earthquake Engineering. This paper includes background information on earthquake history of the region, details of the 1985 earthquake and its strong ground motion, subsoil conditions, and building code provisions. The team's observations of moderate damage in the epicentral area are consistent with the relatively low near-field accelerations (15% g). In the damaged parts of Mexico City, soft soil conditions amplified the ground motion and resulted in almost pure harmonic motion with a period of about 2 s. These characteristics, together with the long duration and high accelerations (20% g) caused severe damage to many structures, as is illustrated in the paper. Lessons learned from the earthquake together with the Mexican emergency code changes are discussed. Key words: seismic, earthquake, Mexico, soils, structures, codes.

scholarly journals Development of a Line Source Dispersion Model for Gaseous Pollutants by Incorporating Wind Shear near the Ground under Stable Atmospheric Conditions

2020 ◽  
Vol 4 (1) ◽  
pp. 17
Author(s):  
Saisantosh Vamshi Harsha Madiraju ◽  
Ashok Kumar
Keyword(s):  
Air Pollution ◽  
Urban Areas ◽  
Wind Shear ◽  
Dispersion Model ◽  
Near Field ◽  
Ground Level ◽  
Gaseous Pollutants ◽  
Air Pollution Control ◽  
Mobile Sources ◽  
Input Variables

Transportation sources are a major contributor to air pollution in urban areas. The role of air quality modeling is vital in the formulation of air pollution control and management strategies. Many models have appeared in the literature to estimate near-field ground level concentrations from mobile sources moving on a highway. However, current models do not account explicitly for the effect of wind shear (magnitude) near the ground while computing the ground level concentrations near highways from mobile sources. This study presents an analytical model based on the solution of the convective-diffusion equation by incorporating the wind shear near the ground for gaseous pollutants. The model input includes emission rate, wind speed, wind direction, turbulence, and terrain features. The dispersion coefficients are based on the near field parameterization. The sensitivity of the model to compute ground level concentrations for different inputs is presented for three different downwind distances. In general, the model shows Type III sensitivity (i.e., the errors in the input will show a corresponding change in the computed ground level concentrations) for most of the input variables. However, the model equations should be re-examined for three input variables (wind velocity at the reference height and two variables related to the vertical spread of the plume) to make sure that that the model is valid for computing ground level concentrations.

Strain, tilt, and rotation associated with strong ground motion in the vicinity of earthquake faults

1982 ◽  
Vol 72 (5) ◽  
pp. 1717-1738 ◽  
Author(s):  
Michel Bouchon ◽  
Keiiti Aki
Keyword(s):  
Ground Motion ◽  
Rotational Velocity ◽  
Near Field ◽  
Strike Slip ◽  
Phase Velocities ◽  
Crustal Structures ◽  
Time Histories ◽  
San Fernando ◽  
Earthquake Faults ◽  
Strong Ground

abstract In the absence of near-field records of differential ground motion induced by earthquakes, we simulate the time histories of strain, tilt, and rotation in the vicinity of earthquake faults embedded in layered media. We consider the case of both strike-slip and dip-slip fault models and study the effect of different crustal structures. The maximum rotational motion produced by a buried 30-km-long strike-slip fault with slip of 1 m is of the order of 3 × 10−4 rad while the corresponding rotational velocity is about 1.5 × 10−3 rad/sec. A simulation of the San Fernando earthquake yields maximum longitudinal strain and tilt a few kilometers from the fault of the order of 8 × 10−4 and 7 × 10−4 rad. These values being small compared to the amplitude of ground displacement, the results suggest that most of the damage occurring in earthquakes is caused by translation motions. We also show that strain and tilt are closely related to ground velocity and that the phase velocities associated with strong ground motions are controlled by the rupture velocity and the basement rock shearwave velocity.

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