bluuebunny/crossref_metadata_2025 huggingface dataset:
Seismicity in Utah, 1850 through June 1965
Authors: Cook Kenneth L. , Smith Robert B.
Published: July 2021

abstract

During 1850 through June 1965, at least 609 earthquakes occurred in Utah, of which at least 38 were damaging. Pertinent data of these earthquakes are listed, and an earthquake epicenter map of Utah is presented. The epicenter determinations of about 344 earthquakes (all felt) in Utah during 1850 through 1949 (Williams and Tapper, 1953) were non-instrumental. The epicenters and magnitudes and depths of focus (when determined) of the earthquakes during 1950 through June 1962 (77) were generally instrumental determinations taken from the Coast and Geodetic Survey, U. S. Department of Commerce (CGS). The epicenters of the earthquakes during July 1962 through June 1965 (188) were all instrumental and were obtained as follows: 23 were obtained from already-published CGS data; 165 were obtained by the University of Utah, of which 68 epicentral determinations were also made by the CGS. The comparisons of epicenter locations were generally good. Our epicenters were determined using a slightly modified Geiger's method programmed on an IBM 7044 digital computer at the University of Utah. The computer program used unpublished travel-time curves (B. H. Atwell, 1967) computed from the earth crustal model of Berg and others (1960) for the Utah region and included depths-of-focus data at 10-km-depth intervals from 0 to 60 km. The data show recent earthquake activity in the Ephraim (1961), Cache Valley (1962), and Levan (1963) areas, and swarm activity in the lehman Caves (1963) area. During 1962-1964 Utah averaged about 60 earthquakes per year for which instrumental epicenter determinations were made.
Foundation—Structure interaction in the analysis of wave motions
Authors: Scavuzzo R. J.
Published: July 2021

abstract

During shock motion, inertia forces of large structures will influence the foundation motion locally. In the present study, the structure-foundation problem is analyzed by coupling an N-mass structure with a one dimensional wave; the resulting solution is formulated as a Volterra integral equation. By using an input wave similar to those encountered in earthquake motions, the significance of this interaction was investigated. Results show that the reduction in spectrum acceleration is significant and depends both on structure frequency and weight for a given foundation input.
An analysis of the travel times of S waves to North American stations in the distance range 28° to 82°
Authors: Doyle H. A. , Hales A. L.
Published: July 2021

abstract

The travel times of S waves from 20 earthquakes to stations in North America in the distance range 28° to 82° have been studied. The deviations from J-B times were analyzed into station, source and distance components using the least-squares time-term approach of Cleary and Hales. Station anomalies had a range of about eight seconds, as compared to three seconds for the P anomalies, and are believed to be caused largely by variations in the upper mantle velocity distribution. S residuals, like the P residuals, were generally positive in the western United States, and negative in the central and eastern United States. P and S residuals at the same station correlated with a coefficient of 0.75, the slope of the regression of S anomaly on P anomaly being 3.72. Corrections to J-B times for S were of the order of the standard errors of the determinations. Within the distance range of 28° to 82° large changes of the S travel times, such as were required by the lower mantle velocities proposed by MacDonald and Ness (1961), are not permitted by the present data. The analysis was checked by carrying out a univariate analysis of variance of the same data.
Dissipation in the earth's mantle and rigidity and viscosity in the earth's core determined from waves multiply reflected from the mantle-core boundary
Authors: Sato R. , Espinosa A. F.
Published: July 2021

abstract

Spectral amplitude ratios of 33 shear waves multiply reflected from the core (from a deep-focus earthquake recorded in the epicentral distance range from 7° to 80°) are used to determine statistically the following quantities: (a) the quality factor, Q, of shear waves in the mantle, (b) the rigidity of the earth's core, and (c) the viscosity of the earth's core.

The determined mean value of Q for the whole mantle, using eight stations in the epicentral range of 7° to 80°, is much lower than any mean Q value obtained previously. This Q value is called the mean apparent quality factor of shear waves in the earth's mantle. The mean lower bound value of Q determined from 13 observations when two close stations are used is 581 ± 33. In this case, when Q is assumed to depend upon period, its value decreases with increasing period, from 720 at 34 sec to 232 at 90 sec. When the recording stations are grouped according to epicentral distances, the mean apparent values of Q obtained from the combined series for each group show a tendency to decrease as the epicentral distance increases.

An upper bound of the mean core rigidity is determined to be 5.45 × 1010 dynes/cm2, shear velocity in the core = 0.73 km/sec, when the mantle is assumed to be a perfect elastic body (Q = ∞). When the core is assumed to be a viscous-liquid medium and the mantle is assumed to have an infinite Q, an upper bound for the viscosity of the upper part of the outer core is found to be 8.61 × 1011 dynes-sec/cm2. The computed values of the rigidity and viscosity of the earth's core are affected by the assumed Q distribution in the earth's mantle. Since there is insufficient data available on Q as a function of depth, various μc and vc for 13 assumed Q distributions as a function of depth have been computed and tabulated.
Spatial distribution and source mechanism of microearthquakes in Central Nevada
Authors: Stauder William , Ryall Alan
Published: July 2021

During the summer of 1966 a small tripartite array was established at the southern extremity of the surface faulting of the Fairview Peak earthquake of 1954. Over a period of six weeks an average 31 earthquakes per day were detected. Of these approximately 400 were selected for detailed study. Site corrections were made to reduce arrival times for all elements of the array to a common base, and the properties of the array and S-P time intervals were used to determine direction of approach, apparent surface velocity across the array, and hypocentral coordinates.

Foci were found to concentrate at a depth of 10 to 15 kilometers and to cluster toward the end of the surface faulting of the 1954 earthquake. The foci were also found to lie along two planar zones. The first is parallel to the fault plane solution (strike N 11° W, dip 62° E) of the Fairview Peak earthquake and terminates at the southern extremity of the surface fracture. The second begins at this point and extends to the southwest, with foci distributed about a plane striking N 50° E and dipping 50° to the southeast. The latter zone apparently marks the southern terminus of the 1954 faulting. The polarity of the first motion of P at the array indicates predominantly dip-slip motion along the faults of both zones. The character of the seismic signatures from foci occurring closely together in space and time indicates that the complexity of the signature arises chiefly from propagation effects rather than from complexity of the time history at the source.
Propagation of waves in a multilayered elastic medium and their dependence on source mechanisms
Authors: Chakrabarty S. K.
Published: July 2021

The stress equations of motion for a multilayered elastic medium subjected to body forces of general type have been solved in terms of three new variables which are functions of the displacement components and their space derivatives. The contributions of the different layers appear as separate 2 × 2 and 4 × 4 matrices whose elements are functions of the material constants and thickness of the particular layer. Some simple applications of the analysis have been discussed.
A two-dimensional ultrasonic model study of compressional and shear-wave diffraction patterns produced by a circular cavity
Authors: Teng T. L. , Wu F. T.
Published: July 2021

abstract

Diffraction patterns of compressional (P) and shear (SV) waves produced by a circular hole were experimentally obtained on a two-dimensional ultrasonic model. The shapes of the Fresnel patterns were found to depend on, 1) α/λ, the ratio of the radius of the cylinder to the wavelength; and, 2) the wave type. The transitional zone between the illuminated and the shadow regions broadens, and the half-amplitude point shifts away from the geometrical shadow as α/λ decreases. For comparable α/λ, the shadow boundary of the SV wave appears to start much earlier than that of the P wave.
The focus of the 1906 California earthquake
Authors: Bolt Bruce A.
Published: July 2021

abstract

The location of the 1906 California earthquake is reexamined using both the P and S recordings at teleseismic distances and the local observations. Analysis of the observed travel times using modern empirical tables rules out a focus of the principal shock south of the Santa Cruz Mountains or north of Point Arena. By inter-comparison with the measurements from the 1957 San Francisco earthquake, it is demonstrated that the lines of evidence are slightly more favorable to a principal focus near that of the 1957 California shock (37°40′N, 122°29′W) with t0 = 13h12m21s than to Reid's focus near Olema, although the latter is not precluded.

There is no evidence from the travel times against the hypothesis that the first rupture was associated with the San Andreas fault and occurred within the crust. The analysis confirms that the rupture was of the (perhaps unusual) bilateral type. Calculations which confirm the contentious magnitude of 814 are set down.
Correlation function of teleseismic noise
Authors: Johnson K. R.
Published: July 2021

A theoretical calculation is made of the correlation function for the vertical component of Earth motion caused by teleseismic microseismic noise. The calculation pertains to an idealized case in which the Earth is assumed to be spherically symmetric and to transmit seismic waves as a non-dispersive linear system, and in which all noise is assumed to originate at the Earth's surface. Diffraction effects are neglected. Only phases that originate and terminate as longitudinal waves are considered, although the method of analysis is readily applicable to other phases. The correlation function for teleseismic noise is calculated and plotted for the case of isotropic noise having a specific noise spectrum. The theoretical noise reduction is calculated and plotted versus average seismometer spacing for a set of seven-seismometer seismic arrays for the cases of teleseismic noise alone, surface noise alone, and a combination of teleseismic and surface noise.
Three-dimensional fields due to a Volterra dislocation imbedded in a layered half-space: Analytical representation of a seismic mechanism
Authors: Braslau David , Lieber Paul
Published: July 2021

Strike-slip faulting in the crust and its mechanical interaction with the underlying mantle is presented as the basis for an earthquake and aftershock mechanism. The usual problem of a fault in a homogeneous half space is a special case of the present model, where both layering and time-dependence play an important role. The system is characterized by a three-dimensional problem in static linear elasticity and viscoelasticity, where the fault is represented by a vertical Volterra disclocation in the layer with slip parallel to the surface. Both materials are assumed to be incompressible. The problem is solved by means of a modified form of the Galerkin vector and use of double Fourier transforms, and solutions are obtained in quadrature for the surface displacements and some of the stresses at the interface. Time-dependent properties are introduced formally into the quadrature by use of the correspondence principle of linear viscoelasticity.
Geologic and related effects of the Taltal earthquake, Chile, of December 28, 1966
Authors: Lemke Richard W. , Dobrovolny Ernest , Alvarez S. Leonardo , Ortiz O. Francisco
Published: July 2021

abstract

Surface effects of the Taltal earthquake were comparatively small, probably because of the deep focus, although the magnitude was 7 ¾. Small fractures broke the ground surface along fault zones in the vicinity of Taltal. Minor slumping occurred on a few steep natural slopes and in some cuts and fills along highways. There was minor damage at a few open pit mines. At Taltal, the town most affected by the earthquake, 250 buildings out of a total of 1,100 were heavily damaged.
The agreement of proposed earth models with observed body-wave travel times
Authors: Walker Daniel A. , Sutton George H.
Published: July 2021

abstract

A computer program was used to evolve a model of compressional and shearwave velocity for the earth's mantle which would be consistent with the travel times given in the Jeffreys-Bullen (J-B) tables. The sensitivity shown by our computed travel times to changes in layer velocities suggests that models containing low-velocity channels would produce travel times different from those given in the tables. Travel times associated with velocity models proposed by others were also computed. The significance of travel-time residuals depends primarily on the reliability of observed travel times for those epicentral distances at which the model fails.
Smoothing travel-time tables
Authors: Arnold E. P.
Published: July 2021

Various techniques for smoothing travel-time tables are discussed and a derivation of the most useful of these, the Method of Summary Values, is given. The results of applying this technique to the new travel times is given and discussed.
Velocity and displacement of explosion-induced earth tremors derived from acceleration
Authors: Poppitz J. V.
Published: July 2021

Velocity and displacement time histories which are derived by integrating acceleration time histories of nuclear-explosion-induced earth tremors usually end in values that are obviously too large. It can be demonstrated that small errors, which are within the range of error one would expect from field-recorded data, could cause such unacceptable velocities and displacements. Assuming that such errors do exist but realizing that they cannot be determined exactly, two “correction” procedures are presented which adjust the acceleration data so that it is more rational. The two procedures are the least-mean-square-velocity technique (by G. V. Berg and G. W. Housner and used extensively with seismic data), which is based on the criterion of minimizing the mean of the velocity squared, and the end-time-zero technique, which depends on boundary conditions at the beginning and end of the tremor. The end-time-zero technique is recommended for use with nuclear-explosion-induced data.
Maximum response ranges of nonlinear multi-story structures subjected to earthquakes
Authors: Giberson Melbourne F.
Published: July 2021

The earthquake responses of a twenty-story nonlinear structural frame representative of a modern high-rise building were calculated. The structure was modeled by a two-dimensional frame with girders and columns having bilinear bending moment-end rotation hysteretic characteristics. In addition to hysteretic damping, viscous damping mechanisms were assumed. The earthquakes used were the El Centro (N-S) earthquake of May 18, 1940 and several pseudo-earthquakes having statistics similar to those of previously recorded earthquakes. Time history plots for displacements, bending moments, joint rotations, etc., at several stations in the structure are presented. A displacement envelope and a plot of the ductility factors, which measure the amount of yielding incurred, are also given. It was possible to identify certain behavior characteristics of the structural responses which appeared to be determined more by the properties of the structure than by the earthquake. For the series of pseudo-earthquakes used, a large range was found in the maximum values of the responses of the yielding structure. For example, the spread between extremum values of the maximum absolute displacements was 50 per cent of the arithmetic mean value. Statistics of the magnitudes of the displacements and ductility factors were compared with three common measurements of the strength of earthquake accelerograms. It was found that none of these three measurements correlated well with the trend of the maximum responses.
Amplitude spectra of PcP and P phases
Authors: Buchbinder Goetz G.R.
Published: July 2021

Amplitude spectra were obtained from short-period PcP and P phases from seven explosions and six earthquakes. Long-period PcP and P amplitude spectra were obtained from two earthquakes.

PcP and P amplitude spectra for both explosions and earthquakes are similar for any one event; therefore, station and core-mantle boundary effects are small and the general shape of the spectra is related to the source. All of the explosions studied have characteristic spectra with a pronounced minimum in the spectrum near one second. The period of this minimum increases with magnitude of the event. Short-period amplitude spectra from some intermediate- and deep-focus earthquakes resemble those from explosions. Spectra from the other earthquakes studied differ markedly from those of explosion; they have either no minimum in the spectrum near one second or very little energy for periods less than one second. The characteristics of the spectra may be of help in the classification of sources. On a plot of magnitude mb versus period of the minimum Td in the spectrum of explosions, the data form a straight line. Earthquakes with an amplitude spectrum similar to that of an explosion are randomly distributed on the plot of mb versus Td.

Systematic effects of focal depth were not observed. Layering at the coremantle boundary was not detected.
A crust-mantle profile from Mould Bay, Canada, to Tucson, Arizona
Authors: Wickens A. J. , Pec K.
Published: July 2021

Love-wave phase velocities were determined for five adjacent segments of a 5000 kilometer great circle path from Mould Bay, Canada, to Tucson, Arizona. Mean-phase velocity curves were obtained from curves based on reciprocal data, thus minimizing the detrimental effects of non-parallel layering. By careful selection and precise treatment of the data over relatively short distances (800 km), detail hitherto suppressed has been retained. Finally, by using reciprocal seismograms, the effect of sloping interfaces was observed.

The crustal and upper mantle models obtained indicate significant differences in structure between different provinces of the Precambrian Shield.
On the synthesis of shear-coupled PL waves
Authors: Chander Ramesh , Alsop L. E. , Oliver Jack
Published: July 2021

Using the shear-coupled PL wave hypothesis of Oliver as a basis, a method is developed for computing synthetic long-period seismograms between the onset of the initial S-type body phase and the beginning of surface waves. Comparison of observed and synthetic siesmograms shows that this hypothesis can explain, in considerable detail, most of the waves with periods greater than about 20 sec recorded during this interval. The synthetic seismograms are computed easily on a small digital computer; they resemble the observed seismograms much more closely than the synthetic seismograms obtained through the superposition of normal modes of the Earth that have been reported in the literature. The synthesis of shear-coupled PL waves depends on a precise knowledge of the phase-velocity curve of the PL wave and travel-time curves of shear waves. Hence, in principle, if one of these quantities is well-known the other can be determined by this method. Phase-velocity curves of the PL wave are determined for the Baltic shield, the Russian platform, the Canadian shield, the United States, and the western North-Atlantic ocean, on the assumption that J-B travel-time curves of shear waves apply to these areas. These dispersion curves show the type of variations to be expected on the basis of the current knowledge of the crustal structures in these areas. Examples are presented to show that J-B travel-times of shear waves along paths between Kenai Peninsula, Alaska and Palisades, equatorial mid-Atlantic ridge and Palisades, and Kurile Islands and Uppsala need to be revised. Shear-wave travel-time curves that are not unique for reasons explained in the study but that give synthetic seismograms in agreement with the observed seismograms were obtained. The new S curves are compared with the J-B travel-time curves for S; and they all predict S waves to arrive later than the time given by J-B tables for epicentral distances smaller than about 30°. The new S curve for the Alaska to Palisades path appears to agree with one of the branches of a multi-branched S curve proposed recently by Ibrahim and Nuttli for the ‘average United States’ insofar as travel-times are concerned, but there are some differences in the slopes of the two curves.
The Fairbanks earthquakes of June 21, 1967; aftershock distribution, focal mechanisms, and crustal parameters
Authors: Gedney Larry , Berg Eduard
Published: July 2021

A series of moderately severe earthquakes occurred in the vicinity of Fairbanks, Alaska, on the morning of June 21, 1967. During the following months, many thousands of aftershocks were recorded in order to outline the aftershock zone and to resolve the focal mechanism and its relation to the regional tectonic system. No fault is visible at the surface in this area.

Foci were found to occupy a relatively small volume in the shape of an ablate cylinder tilted about 30° from the vertical. The center of the zone lay about 12 kilometers southeast of Fairbanks. Focal depths ranged from near-surface to 25 kilometers, although most were in the range 9-16 km. In the course of the investigation, it was found that the Jeffreys and Bullen velocity of 5.56 km/sec for the P wave in the upper crustal layer is very near the true value for this arec, and that the use of 1.69 for the Vp/Vs ratio gives good results in most cases.

The proposed faulting mechanism involves nearly equal components of right-lateral strike slip, and normal faulting with northeast side downthrown on a system of sub-parallel faults striking N40°W. The fault surface appears to be curved—dipping from near vertical close to the surface to less steep northeast dips at greater depths. The relationship of this fault system with the grosser aspects of regional tectonism is not clear.
Travel times and amplitudes of S waves from nuclear explosions in Nevada
Authors: Nuttli Otto W.
Published: July 2021

The underground Nevada explosions HALF-BEAK and GREELEY were unique in creating relatively large amplitude and long-period body S waves which could be detected at teleseismic distances. Observations of the travel times of these S waves provide a surface focus travel-time curve which in its major features is similar to a curve calculated from the upper mantle velocity model of Ibrahim and Nuttli (1967). This model includes a low-velocity channel at a depth of 150 to 200 km and regions of rapidly increasing velocity beginning at depths of 400 and 750 km. Observations of the S wave amplitudes suggest that a discontinuous increase in velocity occurs at 400 km, whereas at 750 km the velocity is continuous but the velocity gradient discontinuous.

Body wave magnitudes calculated from S amplitudes are 5.3 ± 0.2 for GREELEY and 4.9 ± 0.2 for HALF-BEAK. These are about one unit less than body wave magnitudes from P amplitudes as reported by others.

The shape and orientation of the radiation pattern of SH for both explosions are consistent with the Rayleigh and P-wave amplitude distribution of BILBY as given by Toksoz and Clermont (1967). This suggests that the regional stress field is the same at all three sites, and that the direction of cracking as well as the strain energy release in the elastic zone outside the cavity is determined by the regional stress field.
The composition of P codas using magnetic tape seismograms
Authors: Basham P. W. , Ellis R. M.
Published: July 2021

abstract

The short-period P codas of 41 seismic events recorded on the plains of western Alberta are examined for compressional and shear phases. A non-linear “P-Detection” polarization filter is applied to 25 seconds of the records following the P onset. Numerous compressional wave signal pulses are detected amid the codas; these include PcP and PKP phases for events at appropriate distances and the common depth phases pP and sP. The phase pP is detected on the records of 25 events, 16 of which have reported depths shallower than 40 km. For events with pP visible at two stations, pP-P times are accurate to about ±1 second, allowing focal depth assignment to an accuracy of about ±15 km. Locally-generated shear phases are studied using particle-motion plots in the vertical (vertical-radial) and horizontal planes. There are large variations in SV/P amplitude ratios for individual events at stations separated by 60 to 160 km. Anomalous SV and SH-type motions are attributed to a complex Precambrian basement.
Dynamic elasto-plastic response of a reinforced concrete spandrel frame
Authors: Walpole W. R. , Shepherd R.
Published: July 2021

abstract

Following the construction of the sixteen story Jerningham Apartments building in Wellington, New Zealand, small amplitude shaking tests were conducted on the building and the development of an inelastic analysis procedure enabled the possible elastoplastic response of a portion of the reinforced concrete framework to be investigated using a digital computer. In this paper the correlation between the predicted and measured periods of elastic vibration is briefly referred to and the results of elastic and elasto-plastic analyses of the selected portion of the spandrel beam frame are presented.
Excitation of mantle Love waves and definition of mantle wave magnitude
Authors: Brune James N. , Engen Gladys R.
Published: July 2021

abstract

A study is made of the excitation of mantle Love waves of 100 seconds period as a function of magnitude. 153 measurements of Love wave spectral density for earthquakes since 1930 ranging in magnitude from 6.0 to 8.9 are used to determine an excitation curve. The observations were first corrected to a standard distance of 90°. The excitation curve supports earlier results for mantle Rayleigh waves and, for strike-slip motion, an earlier curve for seismic moment versus mantle-wave magnitude. For dip-slip motion, the moments should be multiplied by a factor of about 212. A definition of mantle wave magnitude MM, is set up, and the largest earthquake since 1930 found on this scale is the Alaskan earthquake of March 28, 1964 where MM = 8.9. Other comparably large earthquakes, MM = 8.8, were the Kamchatka earthquake of November 4, 1952 and the Chilean earthquake of May 22, 1960. It is suggested that mantle-wave magnitudes be used as a diagnostic aid in estimating the Tsunami potential of earthquakes.
The design of electromagnetic damping circuits
Authors: Rihn W. J.
Published: July 2021

This paper describes a method for determining the size of the magnet required for coil-magnet transducers directly from the seismic mass, period, and damping. It is shown that the coil wire size and resistance do not influence the size of the magnet. To achieve the desired generator constant, it is immaterial whether the transducer is designed with a large flux density and short wire length, or with a small flux density and long wire length. It is also shown that the transducer is more efficient when the entire coil is immersed in the magnetic field rather than having the coil extend beyond the pole pieces.
Effect of an elastically-restrained boundary on dilatational wave radiation patterns
Authors: Huang Y. T.
Published: July 2021

abstract

In this paper, the effect of a boundary restraint, peculiar to the local geology, on dilatational wave radiation patterns is studied for an arbitrary combination of the Lamé constants of the Earth. Depending upon the degree of boundary restraint, significant change in radiation patterns can take place. This phenomenon is probably related to amplitude anomalies often observed in field records. General solutions are given for a homogeneous, isotropic half space.
The S velocity at the core-mantle boundary, from observations of diffracted S
Authors: Cleary John
Published: July 2021

abstract

A regression line has been fitted to times of diffracted S observed at Canberra from 11 earthquakes. When corrections are made to the observed times to compensate for probable mislocations of the earthquakes, a value of 8.9 sec/deg is obtained for the travel time gradient, with a 95 per cent confidence interval estimate of 0.2 sec/deg. Assuming a core radius of 3473 km, this corresponds to an S velocity at the core-mantle boundary of 6.8 km/sec. This is 0.5 km/sec lower than the value given by Jeffreys (1939). The analysis also provides an estimate of the S time at 100° distance which is about 12 sec greater than that given in the Jeffreys-Bullen tables.

The results suggest that current models of the lowest part of the mantle are significantly in error. Revision of the model in this region should enable a more satisfactory reconciliation with free oscillation data.
Dislocation models and seismomagnetic calculations for California 1906 and Alaska 1964 earthquakes
Authors: Shamsi Sabiha , Stacey Frank D.
Published: July 2021

For eathquakes occurring on fault planes whose horizontal dimensions are very much greater than the vertical dimensions, the assumption of infinite fault length allows the dislocation stress fields to be expressed by simple analytical equations. This facilitates an important generalization of the dislocation theory of earthquakes, in which the fault displacement is graded to zero at the edges of the fault planes, thus avoiding singularities in the stress fields, which are still represented by straightforward analytical expressions. This development is necessary for realistic calculations of seismomagnetic anomalies, due to the piezomagnetic effect in rocks above the Curie point isotherm. The best fit to geodetic observations on the San Francisco earthquake of 1906 is given by a model in which a horizontal slip of 5m at the surface grades either linearly or sinusoidally to zero at (5 ± 1.5) km depth. Vertical displacements of the Alaskan earthquake of 1964 are represented by a compound dislocation having a vertical slip with a maximum value of 40m at 65m depth, graded to zero at 5km and 125km. Maximum total magnetic field anomalies for these models are respectively 2 gammas and 1 gamma per 10−3 e.m.u. of rock magnetization.
Autocorrelation and power spectral density functions of the Parkfield earthquake of June 27, 1966
Authors: Liu Shih-Chi
Published: July 2021

The autocorrelation and power spectral density functions of a total of 14 strong-motion accelerograms of the Parkfield earthquake are obtained. When the ground motions are treated as random phenomena, these functions are found appropriate to be used as statistical characterization functions for the ground motions. Spectral simulation procedure is employed to determine the modal contributions of the motion and the ground characteristic damping and frequency at each station. The results can be used to construct reasonable single- or two-degree-of-freedom linear filters for the generation of a stationary stochastic model for the ground motion. The implications and engineering significance of the basic results are also discussed in some detail.
Earthquake magnitude and source parameters
Authors: Chinnery Michael A.
Published: July 2021

abstract

Previous attempts to find empirical linear relationships between the magnitude, M, of an earthquake and the logarithm of one or more of the source parameters (length L, width W, displacement D) are reviewed. The fault parameters associated with a set of 27 earthquakes with strike-slip movement in the magnitude range 3.4 to 8.3 are used to test these empirical relationships. It is found that there is no linear relationship between M and log L or log W that is valid over the whole magnitude range. However, a rather good linear relationship is found between M and log D. Using all of the present data, this relationship is

M = 1.32 log ⁡ D + 4.27

If only large magnitude events are used, this becomes

M = 1.04 log ⁡ D + 4.96

Some improvement in determinations of the displacement D for low magnitude events is necessary in order to distinguish between these two formulas. It is surmised that the second may be closer to the truth. The consequences of such a relationship are discussed.
High frequency teleseismic energy from Aleutian sources
Authors: Bufe C. G. , Willis D. E.
Published: July 2021

abstract

The Long Shot event, detonated at Amchitka in the Aleutian Islands, was recorded at three sites in Michigan at distances of 57 to 63 degrees. Analysis of the data recorded on magnetic tape shows significant high frequency (4-5 Hz) energy in the first compressional wave arrivals at all three stations, although the most prominent spectral peaks are in the range 1.0 to 1.6 Hz. Initial P phases of aftershocks of the Good Friday earthquake of 1964 recorded at the Ann Arbor station do not contain appreciable energy above about 2 Hz. However, the P-wave spectrum of an earthquake of comparable magnitude whose epicenter is near Long Shot is very similar to that of Long Shot, and indicates a favorable signal-to-noise ratio to 5 Hz.

The Long Shot spectra and apparent angle of incidence at the Michigan stations appear to be influenced by the presence of pP and by crustal layering. The effective response of an intermediate-depth well system is shown to be strongly affected by surface reflections.
PERAN RUANG RELAKSASI PADA PERANCANGAN BERKONSEP KREATIF UNTUK PENINGKATAN KREATIVITAS KARYAWAN KANTOR 24SLIDES INDONESIA
Authors: Nagara Aurellia Cintana Satya , Widiyanti Hana Kireina , Vionita Mellani , Tsania Rizquita , Agustina Ira Audia
Published: July 2021

In the creative industries offices, all of the employees are required to work professionally with creative and innovative ideas. According to the professional work that already mentioned before, the positive feedback and customer’s satisfaction will be easily achieved. The perfect results behind are cannot be detached from the office's atmosphere and team collaboration within the office itself. A study research conveys if a company treats their workers as valuable assets, it will brings reciprocity from their workers. That is a perfect and convenient output. It is relatable with one of the 24Slides office's vision which prioritizes the happiness and joy of their employees in order to produce optimal results. Cooperative companies will make way to improve the performance and motivation of workers by facilitating and designing offices that are exhilarating and professional. If a creative industry office requires new creativity and innovation ideas, then a relaxation facility with some communicative games is recommended to stimulate the brain. Providing these facilities will restore workers' enthusiasm before taking a break or starting an activity. Lounge facilities or lounge rooms are also not provided that simple way. With an attractive interior design, it could be the other proponent as well as supporting housing from the office. Thus, the authors make a study research related to the design of a relaxation room that suitable for the 24Slides office. The purpose of this research is to figuring out the creativity and productivity enhancement of workers with the existence of a relaxation room, knowing the responses of workers, and designing concepts. Design Thinking is used as a method of this research, consisting of emphatisize, define, ideate, prototype and test. Data collection was carried out by conducting interviews with 5 respondents and a field survey at the 24Slides office. The data analysis carried out in the form of assessing existing analyzes, field surveys and interviews that had been obtained. The results of this study will be used as a reference to carry out the design of the relaxation room (funspace) at the 24Slides Indonesia office.
REPRESENTASI VISUAL PRASI UNTUK MEMPERTAHANKAN KEARIFAN LOKAL MASYARAKAT BALI PADA ERA DISRUPTIF 4.0
Authors: Firmansyah Novian Wahyu , Sutrisno Andika Agung , Pujiyanto Pujiyanto , Herwanto Andhika Putra
Published: July 2021

Eksistensi merupakan  kebutuhan yang mendasar untuk mempertahankan kearifan  lokal di era disrupsi 4.0. Masyarakat bali masih mempertahankan berkarya prasi, yakni menorehkan wujud visual   pada  daun   lontar  dengan   menggunakan   penguprak (sebuah pisau kecil).   Pendekatan  fenomenologi  di gunakan untuk mengalokasikan analasis data  yang diperoleh.  Dalam  perkembangan teknologi di  era  digitalisasi  saat  ini,  eksistesni  karya  tradisi  sangat  dipertaruhkan.  Bukan  menghindar akan tetapi  harus beradaptasi, kompromi dengan  perkembangan teknologi  menjadi strategi. Representasi  visual  menjadi titik awal  dalam  melihat  keberadaan  desain  yang  muncul  pada karya prasi pada era digitalisasi saat ini, wujud desain secara visual membangun  persepsi postif dalam   mempertahakan   seni   tradisi   menjadi   hal   esensial   dari   karya   prasi.   Digitalisasi menggunakan  teknologi manjadi penting mempertahankan eksistensi karya prasi, dikarenakan karya ini dapat diinformasikan secara luas dengan dokumen  yang berbentuk digital. Selain itu, diharapkan penelitian ini dapat memberikan inspirasi bagi karya-karya tradisional lainnya dapat bertahan di era disrupsi 4.0 ini dengan memanfaatkan digitalisasi, tidak hanya di Bali, namun juga di daerah-daerah lainnya di Indonesia.
Antilogías de la presunción de inocencia en el sistema penal acusatorio colombiano : una propuesta desde la razón
Authors:   Universidad Libre, Caro Nestor
Published: July 2021

La aspiración de justicia como sistema de valores se hace posible a través del enfoque constitucional del derecho procesal, el cual consagra la forma de proceder frente al implicado, la repartición del peso probatorio, el estándar de conocimiento necesario para valorar la conducta, y las consecuencias para los intervinientes en el evento de no acatar el sistema. En este sentido, la presente obra devela las diferentes concepciones del derecho, tendientes a la búsqueda de soluciones consideradas fundantes y correctas para la organización social, y analiza desde el ámbito legal, jurisprudencial y doctrinal las contradicciones semánticas derivadas de las premisas que desarrollan la presunción de inocencia, por cuenta de la interpretación judicial. En su desarrollo, se advirtió que el abuso de las medidas cautelares (especialmente la detención preventiva), cuestionan el trato brindado al reo al interior del proceso penal; en segundo lugar, que la teoría de la contribución diligente de la prueba es un instituto ajeno al derecho procesal penal, y su aplicación controvierte la máxima según la cual, en ningún caso se puede trasladar a la defensa; y finalmente, que la ausencia de criterios objetivos para saber cuándo el juez ha alcanzado el estándar probatorio denominado más allá de la duda razonable diluyen la precisión conceptual de la garantía procesal, y comprometen el derecho a la defensa. Con lo anterior no se quiere impedir que el Estado cumpla su función constitucional de investigar, perseguir y acusar a los presuntos infractores de la ley penal, ni se propone que la defensa asuma una actitud pasiva en la contienda procesal, por el contrario, dadas las consecuencias negativas que conlleva la afectación de las garantías mínimas del justiciable, se resalta el deber de armonizar las contradicciones evidenciadas. De ahí que se sostenga, que mientras se define la responsabilidad penal, el término presunción de inocencia resulta impreciso, por ende, es mejor hablar del estado de inocencia que rodea a las personas; que dadas las consecuencias que conlleva la importación de la teoría de la carga dinámica de la prueba al proceso penal, el vocablo dialéctica procesal resulta más adecuado; y ante el umbral subjetivo de convencimiento para proferir sentencia de condena, en cumplimiento de los mandatos de prevención y garantía reconocidos por la Convención Interamericana de Derechos Humanos, la trilogía (hechos, prueba y argumentación) le brindan a la defensa criterios objetivos para enfrentar a su contradictor dialéctico, preservar el estado de inocencia, y trabajar la duda a su favor.
Evaluation of zygomatic bone region for placement of quad zygomatic implants using CBCT in postmenopausal women
Authors: Vaibhav Neelam Manoj , Amirisetty Ramesh , Nichenametla Rajesh , Chandana Gonabhavi Siri , Prathyusha M Santhi , Kumar C Naresh , Reddy B Tanuja
Published: July 2021

Insufficient height and width of the alveolar ridge at the implant site remains with inadequate bone volume following extraction in older age people especially in postmenopausal women. Postmenopausal women are susceptible to primary osteoporosis where more bone resorption than formation is seen resulting in decreased bone mass. Hence the present study aims to evaluate the zygomatic bone region for placement of quad zygomatic implants using CBCT.

: A total of 120 CBCT images of female patients who were between the age group of 45 yrs to 65 yrs were taken. The zygomatic bone was evaluated for pneumatisation zones and thickness of zygomatic bone at three different regions i.e., superior, middle and inferior at nine points on zygoma bone along with bone to implant contact (BIC) region using virtual software.

The largest thickness in the superior, middle and inferior regions were at Point A2(8.01+/-2.10 mm), Point B2 (7.01+/-1.62 mm), and Point C1 (6.65+/-1.64 mm), respectively. The virtually placed implants at Point A3 (15.92+/-4.16 mm) and Point B2 (12.02+/-3.62 mm) had the highest BICs.

: To obtain the largest BICs, results suggested that the posterosuperior region (Point A3) and the centre of zygoma (Point B1) were the optimal places for the placement of quad zygomatic implants.
Variations in root canal morphology of the permanent mandibular first molar in Indian population- A CBCT study
Authors: Santosh Vasavi , John Rhea Reji , Waghmare Mandavi , Manoj Reema
Published: July 2021

The purpose of this study was to determine the variations in the number of canals and its morphology in permanent mandibular first molars using cone-beam computed tomography (CBCT) in a subset of Indian population.

A total of 350 CBCT scans were collected and evaluated in all three orthogonal planes to determine the number of root canals and study their anatomic variations using Vertucci’s classification.

: The total number of roots and root canals, the root canal configuration, the incidence, and the correlations between left- and right-side occurrences and between males and females were analysed. Statistically significant differences were evaluated using the chi-square test with SPSS 16.0 for Windows (SPSS, Chicago, IL), with significance set at p < 0.05.

: The results of this study showed that predominantly, two thirds of the subjects had type VI mesial canal configuration and two-thirds had type I distal canal configuration. Also there was significant variance in the canal anatomy across gender and age of the subjects.

: CBCT is a clinically useful tool in understanding the variations in root canal morphology, which guides in the assessment of the canal morphology aiding in successful root canal treatment.
Rare case of unilateral hypertrophy of left lamina and spinous process of C6 with associated C2-C3 block vertebra: A case report
Authors: Sharma Monika , Sharma Deepak
Published: July 2021

We report a rare case of congenital cervical anomaly in a 32 yr old female, who was referred in our department for the complaints of chronic cervical and shoulder pain with a hard cervical mass. Antero-posterior and lateral radiographs of the cervical spine were performed, which show a rib like bony projection, in the left side of neck and on the lateral radiograph, it was corresponding to a hypertrophied C6 spinous process. CT study was done for better delineation of this congenital anomaly, which showed hypertrophied left lamina of C6 and spinous process, crossing midline and towards the left side, extending inferiorly up to the level of thoracic inlet. There was associated fusion of C3 and C4 vertebrae, resulting in block vertebra (Klippel- Feil syndrome Type 1) and unfused spinous process of C6 vertebra.

This case report is the first case, where hypertrophied lamina and spinous process of C6 with unfused spinous processes and block vertebra, congenital cervical anomalies were seen in the same patient.
Trans-nasal endoscopic repair without stenting in bilateral congenital bony choanal atresia: Our technique
Authors: Shivnani Deepa , Raman E V , Amle Dnyansh
Published: July 2021

: Choanal atresia is a commonly observed congenital nasal abnormality. Incidence of choanal atresia is 1 in 7,000 live births. There are various techniques which has been described for the choanal atresia repair. Here we are sharing step by step trans-nasal technique to get good results post-operatively.

: The aim of this study to explain and share the technique to treat a bony choanal atresia without any stenting in the nasal cavity of a neonate. The purpose of this study to analyse the surgical outcome of single stage bony choanal atresia repair in terms of restenosis and revision surgery.

: We have described the step by step approach for the repair of bony choanal atresia without using any stent in the nasal cavity. Pre surgery evaluation and surgical steps have been explained with photograph to understand this technique better.

: Bony choanal atresia can be treated without any stent placement which was the most common method for the repair of congenital choanal atresia in neonates. Clinical significance: This technique will reduce the chances of complication which arises because of stenting in the nasal cavity. This technique is simple and easily reproducible in the practise.
Eye contact in a month in a toddler with autism spectrum disorder
Authors: Mehta Ishani , Shah Priyal , Kondekar Santosh , Mahale Bharatkumar
Published: July 2021

Autism is characterized by deficits in verbal and nonverbal communication and repetitive behaviors. There is a lack of data available regarding pharmacological treatment in autism spectrum disorders.
Perspectivas desde el ecofeminismo frente al cambio climático y la Amazonía
Authors: Miranda Camila
Published: July 2021

Sin duda alguna, el cambio climático se ha convertido en uno de los mayores desafíos de nuestra era. A raíz de la inclusión de personajes contrapuestos como Greta Thunberg y Jair Bolsonaro en la escena ambiental, el debate sobre la actual crisis socio-ecológica ha adoptado nuevos matices. A su vez, espacios como la Amazonía han puesto en relieve las voces que, una disciplina visiblemente estado-céntrica y con un fuerte bagaje imperial como, las Relaciones Internacionales, ha enmudecido. A diferencia de aquellos discursos hegemónicos basados en suposiciones antropocéntricas y positivistas, según el ecofeminismo, la crisis ambiental tiene origen en ciertos procesos de dominación que han oprimido a las mujeres, grupos sociales poco privilegiados y la naturaleza. Es así que, integrar procesos de dominación como el colonialismo y el patriarcado en las discusiones sobre el medio ambiente se vuelve imperante para hacer frente a este tipo de planteamientos dominantes. De este modo, esta reflexión tiene como fin vislumbrar, desde una perspectiva de género, aquellos discursos, estructuras y prácticas hegemónicas que han hecho de la naturaleza y las mujeres un otro subalternizado.