scholarly journals The San Fernando earthquake and public school safety

1974 ◽  
Vol 64 (6) ◽  
pp. 1653-1670 ◽  
Author(s):  
D. E. Hudson ◽  
D. K. Jephcott
Keyword(s):  
Ground Motion ◽  
School Safety ◽  
Earthquake Hazard ◽  
Building Construction ◽  
Earthquake Ground Motion ◽  
Many Instruments ◽  
San Fernando ◽  
Structural Failures ◽  
Serious Injury ◽  
New Buildings

abstract The San Fernando earthquake was an unusually valuable test of school safety because: (1) there were several hundred schools having structures of all types in the heavily shaken area, including 10 schools within 5 miles of the epicenter; (2) the severity of ground motion is believed to have been near the maximum to be expected for an earthquake of any size—a number of campuses were subjected to major ground cracking and deformation; (3) since there were many instruments in the area, the details of the earthquake ground motion are better known than for any other earthquake. On some campuses, pre-Field Act buildings, renovated pre-Field Act buildings, and new buildings existed side by side, and direct comparisons show the efficacy of the Field Act and the associated plan check and field inspection procedures in reducing the earthquake hazard to an acceptably low level. No structural failures, that would have been likely to cause serious injury or death if the buildings had been normally occupied at the time of the earthquake, occurred in any buildings built to current standards. There were, however, some failures of nonstructural elements that could have resulted in a hazardous situation and demonstrate the need for upgrading requirements in this area of building construction.

Highrise building characteristics and responses determined from nuclear seismology

1972 ◽  
Vol 62 (2) ◽  
pp. 519-540 ◽  
Author(s):  
John A. Blume
Keyword(s):  
Ground Motion ◽  
Dynamic Properties ◽  
Spectral Response ◽  
Earthquake Ground Motion ◽  
Structural Dynamic ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Nuclear Events ◽  
San Fernando ◽  
And Behavior

abstract Reliable measurements and detailed analyses of the responses of many buildings to ground motion resulting from underground nuclear explosions are providing new and valuable information on the structural-dynamic properties and behavior of real buildings. Much, if not all, of this knowledge is applicable to the problem of resisting natural earthquake ground motion, and it is being obtained as a byproduct of the AEC underground explosive nuclear safety program which is concerned with developing techniques for making reliable predictions of response and any damage. Information is provided on oscillator spectral response values, building responses, modal contributions and combinations versus elapsed time and at times of maximum response, variations in natural periods, foundation material interaction, and biaxial motion in the horizontal plane. Data are shown for nuclear events JORUM and HANDLEY and then compared to those of prior major events. In addition, peak responses of certain Las Vegas buildings to the distant February 1971 San Fernando earthquake (U.S. Geological Survey, 1971) are provided and compared to responses to nuclear events.

scholarly journals Neo-deterministic seismic hazard maps of Kosovo

2021 ◽  
Author(s):  
Enrico Brandmayr ◽  
Vaccari Franco ◽  
Romanelli Fabio ◽  
Vlahovic Gordana ◽  
Panza Giuliano Francesco
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Seismic Hazard Assessment ◽  
Active Regions ◽  
Earthquake Hazard ◽  
Earthquake Ground Motion ◽  
Hazard Maps ◽  
Source Information ◽  
Deterministic Seismic Hazard ◽  
Traditional Construction

Kosovo is one of the most seismically active regions in Europe, lying within the Alpine-Mediterranean tectonic belt. Historical records for the region show several catastrophic earthquakes with epicentral intensity IX (MCS). However, due to Kosovo’s high population density, high prevalence of traditional construction, and insufficient enforcement of building codes, Kosovo is vulnerable to earthquake damage. In this study, we present earthquake hazard maps for bedrock conditions in Kosovo based on the well-known Neo-deterministic Seismic Hazard Assessment (NDSHA) method. NDSHA relies upon the fundamental physics of wave generation and propagation in complex geologic structures to generate realistic time series, used as input for the computation of several ground motion parameters, integrating the available knowledge of seismic history, seismogenic zones and morphostructural nodes. In accordance with continuum mechanics, the tensor nature of earthquake ground motion is preserved, producing realistic signals using structural models obtained by tomographic inversion and earthquake source information readily available in literature. Our maps are generally consistent with the observed intensity IX (MCS) and suggest that, in some instances, intensity X could be reached.

Stress estimates for the San Fernando, California, earthquake of February 9, 1971: Main event and thirteen aftershocks

1972 ◽  
Vol 62 (3) ◽  
pp. 721-750 ◽  
Author(s):  
M. D. Trifunac
Keyword(s):  
Ground Motion ◽  
Near Field ◽  
Strong Motion ◽  
Earthquake Ground Motion ◽  
The North ◽  
Field Evidence ◽  
North Eastern ◽  
San Fernando ◽  
And Migration ◽  
Stress Drops

Abstract The strong earthquake ground motion recorded in the center of and above the fault plane is combined with field evidence of faulting and instrumental studies of aftershocks to deduce stresses during and after the San Fernando earthquake of February 9, 1971. Stress computations based on Brune's near-field, shear-wave spectra, peak velocity of ground motion, energy calculated from the strong-motion record, and a model of circular dislocation give mutually consistent stress estimates, which suggest that the effective stress operating during the earthquake was approximately 100 bars, while during the earthquake it dropped several tens of bars. The energy of the main event is estimated to be 1022 dyne cm. Thirteen aftershocks, recorded during the first 6 min, were associated with stress drops ranging from 10 to 500 bars, these events clustering along the north-eastern end of the dislocation surface. The strong-motion accelerograms provide invaluable data for detailed investigations of the pattern of earthquake energy release during and immediately after an earthquake. Used for the first time in this study, strong-motion accelerograms gave an excellent picture of stress history and migration of seismic activity during the first 6 min.

scholarly journals Analysis of earthquake parameters to generate hazard maps by integrating AHP and GIS for Küçükçekmece region

2012 ◽  
Vol 12 (2) ◽  
pp. 475-483 ◽  
Author(s):  
T. Erden ◽  
H. Karaman
Keyword(s):  
Ground Motion ◽  
Region Of Interest ◽  
Soil Classification ◽  
Earthquake Hazard ◽  
Earthquake Ground Motion ◽  
Analytic Hierarchy ◽  
Earthquake Parameters ◽  
Spatial Environment ◽  
Definition Of ◽  
Correlated Factors

Abstract. Definition of an earthquake includes parameters with respect to region of interest. Each of those parameters has different weights on the earthquake ground motion and effect. This study examines the weight of common parameters that have an influence on the effects of earthquakes. The Analytic Hierarchy Process (AHP) is used for factor weighting of each parameter and Geographic Information Systems (GIS) are used for simulating the results of the AHP on a spatial environment. In this study, it is aimed to generate a hierarchical structure of the model for the simulation of an earthquake hazard map (EHM). The parameters of the EHM, which are selected by the criterion of non-correlated factors, are: topography, distance to epicenter, soil classification, liquefaction, and fault/focal mechanism. As a result of the study, weights of the parameters that affect the earthquake ground motion at the study area are determined and compared with a selected attenuation relation map.

scholarly journals Seismic rocking effects on a mine tower under induced and natural earthquakes

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Piotr Adam Bońkowski ◽  
Juliusz Kuś ◽  
Zbigniew Zembaty
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Ground Surface ◽  
Tall Buildings ◽  
Earthquake Ground Motion ◽  
Seismic Action ◽  
Seismic Effects ◽  
Copper Ore ◽  
Rotational Components ◽  
Natural Earthquakes

AbstractRecent research in engineering seismology demonstrated that in addition to three translational seismic excitations along x, y and z axes, one should also consider rotational components about these axes when calculating design seismic loads for structures. The objective of this paper is to present the results of a seismic response numerical analysis of a mine tower (also called in the literature a headframe or a pit frame). These structures are used in deep mining on the ground surface to hoist output (e.g. copper ore or coal). The mine towers belong to the tall, slender structures, for which rocking excitations may be important. In the numerical example, a typical steel headframe 64 m high is analysed under two records of simultaneous rocking and horizontal seismic action of an induced mine shock and a natural earthquake. As a result, a complicated interaction of rocking seismic effects with horizontal excitations is observed. The contribution of the rocking component may sometimes reduce the overall seismic response, but in most cases, it substantially increases the seismic response of the analysed headframe. It is concluded that in the analysed case of the 64 m mining tower, the seismic response, including the rocking ground motion effects, may increase up to 31% (for natural earthquake ground motion) or even up to 135% (for mining-induced, rockburst seismic effects). This means that not only in the case of the design of very tall buildings or industrial chimneys but also for specific yet very common structures like mine towers, including the rotational seismic effects may play an important role.

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