Showing papers on "Fault model published in 1974"

Seismo-tectonics of the 1923 kanto earthquake

Abstract: Kanto earthquake of 1923 was associated with various sorts of seismic and tectonic effects such as surface displacements, seismic damages, tsunamis and volcanism. The writer previously proposed a fault-origin model of the earthquake from a geodetic viewpoint. The present paper is to develop the geodetic model on the idea that the various sorts of the associated effects in 1923 can be interpreted with a simple fault-origin model, equally well. The geodetic model is slightly revised to fit the effects. Thus it is found out that the fault model can be much simplified except for the area immediately adjacent to the fault. The fault is tectonically interpreted as one of the transform faults along the northeastern boundary of the Philippine-Sea plate with the Asian plate.

Fault tree synthesis for chemical processes

Abstract: This paper outlines the concepts for a systematic approach to the safety analysis of chemical processing systems. A procedure for automatically generating fault trees is presented. The fault trees describe nearly all the failure modes for the system under analysis. The fault tree generation procedure uses information on (1) the description of the system (detailed flowsheet), (2) physical and chemical properties of materials in and around the system, and (3) unit models which describe the behavior of the units within the system and which are assembled to describe the behavior of the complete system. The unit models are connected to form an information flow structure for the complete processing system. Unit failure models are also defined for common chemical units. By systematically defining hazard states and searching the information flow structure for the system, it is possible to generate fault trees for the complete process. An analysis of the fault trees can reveal the important failure modes for the process.

Generation of tsunami by a fault model

Abstract: Characteristics of tsunami waves caused by a fault model are investigated theoretically in detail. Effect of focal parameters on tsunami amplitudes, relation with the static deformation at the source area, sense of initial motion and directivity are discussed.Main results are summarized as follows: The dip-angle, fault length and focal depth play important roles in the generation of tsunami. As an estimate of the directivity, we define an index α, which is the ratio of the maximum amplitude in the wave train at φ=90°, where φ is measured from a direction along the strike of the fault plane, to that at φ=0°. The index α is strongly affected by the change of the dip-angle and the ratio (fault width)/(fault length). The moving directions of initial motions of tsunami waves at φ=90° and 270° reflect the sense (upheaval or subsidence) of the static deformation but not at φ=0°.

Seismic displacement and ground motion near a fault: The Saitama Earthquake of September 21, 1931

Abstract: The dislocation parameters of the Saitama earthquake (M = 7.0, 36.15°N, 139.24°E) of September 21, 1931, are determined on the basis of first-motion data, aftershock area, and close-in seismograms obtained by a low-magnification long-period seismograph. The earthquake represents a left-lateral strike slip faulting on a plane dipping 80° toward N 196°E with dimensions of 20 km (length) × 10 km (width). The strike of the fault plane is found to be almost parallel to that of the eastern extension of the median tectonic line. A synthetic study suggests that the rupture grows bilaterally at a velocity of 2.3 km/s. The rise time, the final dislocation of the linear ramp dislocation time function, and the particle velocity of the fault dislocation are estimated to be 2 s, 100 cm, and 50 cm/s, respectively. The near-source ground displacements and ground motions derived from the above seismic fault model are consistent with high-precision leveling data and with the field survey that determined the directions of collapse of structures.

The Effects of Races, Delays, and Delay Faults on Test Generation

Abstract: Test sequences constructed by most test generation procedures often create time dependent results when applied to a circuit. These dependencies often invalidate the test. The main cause for this situation is that the test generation procedures and circuit models employed do not take into account many aspects of delay associated with a circuit. In this paper we present modeling techniques to be used by conventional test generation procedures to alleviate some of these problems. These models include the cases of equal, unequal and ambiguous delay values. Both inertial and transport delays are considered. Both static and dynamic output behavior is studied, though we restrict inputs to fundamental mode operation. Finally, a new type of fault, caUed a delay fault, is introduced, and a model developed so that a test to detect this class of fault can be generated via conventional test generation techniques. In summary, this paper attempts to outline procedures and identify problem areas so that test generation is more of a science rather than a hit and miss process, and so that the correctness of results need not always be verified via simulation or physical fault injection.

Application of Linear Inversion Theory Toward the Estimation of Seismic Source Parameters

Abstract: A discussion is given concerning the development of methods for obtaining an accurate representation of the forward elastostatic problem of describing the processes which accompany faulting. A method is suggested by which a more complicated and arbitrary static dislocation function could be approximated with the formulations derived for simple dislocation sources. A stochastic inverse is used to provide optimum estimates of the source description when observed elastostatic phenomena are systematically related to the media response of the various source parameters. This method is applied to the observed static displacement data from the 1964 Alaska earthquake and the 1971 San Fernando, California, earthquake. For the Alaskan event, the surface static displacements are calculated with the finite-element numerical modeling technique in which the effects of known geologic heterogeneities of the region are taken into account. The fault model used is that of a shallow angle fault underthrusting the Alaskan continental block. The calculated optimum static offset, stress drop, and strain energy density along the fault were found to be variable with a maximum offset of about 30 m. The region of maximum stress drop (218 bars) and maximum strain energy density change is found to correspond to the region of maximum compressional wave radiation. The resolution and resolvability of the calculated static fault model is discussed. For the San Fernando earthquake, the static dislocation along the assumed fault plane was also found to vary considerably. The observed surface displacements are fit to a high degree of accuracy by the given model. Included in the inversion data set are changes in the local gravity field caused by the earthquake. These changes can be predicted from known changes in elevation when a Bouguer correction is applied to the gravity data. The spatial and frequency distribution of path-corrected Rayleigh waves from the San Fernando earthquake are systematically related to the faulting process. The surface wave source is taken to be a depth-distributed set of double couples. A least-squares inversion is used to find the set of source parameters which optimally fit the variance-weighted data. The inversion results indicate a depth-distributed moment of 1.7 x 1026 dyne-cm. The slip angles of the sources varied in such a way along the fault that the displacements became more predominantly dip slip as the dislocation propagated upward from the point of initial rupture at about 3.0 km/sec. A sophisticated error analysis is performed to estimate the uncertainties of the calculated model variables. An appendix is included in which the analytical expressions are derived for the complete strain field due to a dislocation on an arbitrarily inclined fault in a homogeneous half-space. Although the expressions are lengthy, the strain values can be calculated quickly on a computer since no numerical integration is necessary.

Timing analysis for digital fault simulation using assignable delays

Abstract: The techniques to be described in this paper are generally applicable to any time domain, parallel fault, digital logic simulation system. The particular implementation was done on the CC-TEGAS3 system and quoted results are from this system.The first technique to be considered provides accuracy of fault simulation when using assignable nominal delays for different element types. The second technique provides for handling fault induced activity in a network, in such a way as to considerably reduce the amount of simulation time required.

A Fail-Safe Asynchronous Sequential Machine

Abstract: This paper examines the dynamic fault behavior of asynchronous sequential machines, specifically identifying the faults which cause critical races and hazards, and presents a state assignment technique leading to a machine that enters one of a small set of error states whenever a fault occurs. Entry into an error state can be checked by very simple check circuits; a self-testing check circuit and one requiring only two tests for fault detection are discussed. An extension of the state assignment technique to produce a machine that is fail-safe is also presented. The fail-safe design has the property that once a fault has caused the machine to malfunction and enter an error state, the machine never leaves the error state and therefore does not produce erroneous outputs. This machine detects all but a small class of multiple faults.

Source Process of Earthquakes as Deduced from Long.Period Seismic Body Waves

Abstract: impulse response with the source function. This relationship is employed to determine the time duration of the source function from the 五rst half-period of observed P waves. The time duration of the source function determined for event 1 is shown to be azimuthally patterned. This suggests that a shear faulting is more preferable rather than a phase transition for the source mechanism of the intermediate-dep th earthquake. It is found that the rupture propagates along one of nodal planes which is an actual fault plane ， by a minimum deviation t巴chnique. Event 2 is shown to be a multiple shock from the analysis of two successive P phases. The temporal and spacial relation of the first and the second shocks are determined based on the differences between the arrival times of the first and the s巴cond P phases. The position of the focus of the second shock is situated on one of nodal planes of the 五rst shoc k. The synthetic seismograms of S waves are calculated based on the fault model obtained from the P wave data ， and they are compared with the observed S waves. The agreement between them is fairly good for event 1， but poor for event 2. These results further support the shear faulting for the source mode l. The fault planes of these events selected from two nodal planes are parallel to the strike of the seismic plane in this region and steeply dipping. The sense of the motion along the fault plane is that the deeper sid 巴 block slips down.