bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient Propagation of Epistemic Uncertainty for Probabilistic Seismic Hazard Analyses (PSHAs) Including Partial Correlation of Magnitude–Distance Scaling
Authors: Lacour Maxime , Abrahamson Norman
Published: July 2021

Probabilistic seismic hazard analysis (PSHA) is moving from ergodic ground-motion models (GMMs) to nonergodic GMMs that account for site-source-specific source, path, and site effects and which require a much larger number of GMM branches on the logic tree to capture the full epistemic uncertainty. An efficient method for computing PSHA with a large number of GMM branches was developed by Lacour and Abrahamson (2019) using polynomial chaos (PC) expansion with the key assumption that the epistemic uncertainty in the median ground motion is fully correlated. In the current study, we remove the assumption of full correlation using a multivariate PC expansion. The correlation structure of the available median GMMs across scenarios is computed empirically. The median ground motion is modeled as a Gaussian random process with the correlation structure of the GMMs across the range of relevant earthquake scenarios. This Gaussian random process is discretized using the Karhunen–Loeve expansion, which leads to multivariate PC expansions of uncertain hazard curves. The hazard fractiles can be reconstructed during an efficient postprocessing phase that includes the effects of partial correlation between the GMMs. Multivariate PC expansions require significantly more terms than for the fully correlated case, which increases the calculation time by about a factor of 5, but it is still much more efficient than direct sampling of the branches of the GMM logic for a large number of branches. An example hazard calculation shows that the effect of using partial correlation in place of full correlation of the GMMs is small for the Next Generation Attenuation-West2 (NGA-West2) set of GMMs, indicating that the fully correlated assumption may be adequate for many applications. The multivariate PC method can be used to evaluate the effects of the partial correlation of the GMMs for sets of GMMs that are different from the NGA-West2 GMMs.
Effects of Earthquake Magnitude, Distance, and Site Conditions on Spectral and Pseudospectral Velocity Relationship
Authors: Zhang Haizhong , Zhao Yan-Gang
Published: July 2021

The spectral velocity (SV) is necessary information in the seismic design of structures with supplemental velocity-dependent dampers, and it is conventionally approximated by the pseudospectral velocity (PSV), which is available in seismic codes. Because of the significant approximation error, it is important to clarify the relationship between the two spectra to establish a suitable formulation to relate SV to PSV. Recent studies have point out that this relationship is influenced not only by the oscillator period and damping ratio but also by earthquake characteristics (Papagiannopoulos et al., 2013; Samdaria and Gupta, 2018). To clarify the seismological effects, in this study, an approach to relate SV to PSV based on the random vibration theory is proposed, and it is verified by comparing its results with those of traditional time-series analysis. The effects of earthquake magnitude and distance as well as site conditions on the relationship between the two spectra are explored based on the proposed approach as well as statistical analysis of recorded seismic motions. It is found that the SV approaches the PSV with increasing magnitudes at long oscillator periods but performs oppositely at short oscillator periods. The demarcation range beyond which the opposite trend is observed varies from (0.07–0.24) to (0.12–0.87) s using the proposed approach and considering the regions of central and eastern North America. The range varies from (0.1–0.15) to (0.3–0.7) s based on the results obtained by the statistical analysis of seismic records in Japan. The observed phenomena were theoretically explained, and the seismological effects were found to be governed by the ground-motion frequency content.
The 1953 Suva earthquake and tsunami
Authors: Houtz R. E.
Published: July 2021

The epicenter of the Suva earthquake of Sept. 14, 1953, (U.S.C. & G.S. data: H = 00h26m36s UT 1812°S,17812°E;M=634; h about 60 kilometers) has been redetermined on the basis of landslide intensity, isoseismic analysis, damage criteria, the bathymetry of the epicentral zone, and by other means. The new epicenter is at 18.2° S, 178.3° E with an estimated probable error of five miles. Employing the new epicenter, P residuals of 15 stations (U.S.C. & G.S. data) were computed, assuming a normal and a 60 kilometer depth of focus. A normal depth of focus was decidedly the most likely.

Arrival times of the ensuing tsunami at various points were reconciled to show that the tsunami had an extended source from Suva harbor to Beqa island. The tsunami was clearly caused by the slumping of marine sediments immediately after the earthquake. The direct action of the earthquake produced small waves that served as warnings on Beqa and Kadavu islands. These waves are presumed to have been created by the vibration of the reef against the water. The destructive waves, arriving later, were produced by slumping effects originating on the edge of the marginal shelf. Their observed arrivals are consistent with this mechanism.

The bathymetry of the affected area was resurveyed and bottom changes up to 300 feet vertically were found. At a distance of more than 30 miles from the slumps, submarine cables were disrupted and displaced by as much as 13,000 feet. It is inferred that these effects were caused by turbidity currents travelling down a gradient of about 5 per cent for the first 10 miles and nearly flat thereafter.
Experimental investigation of PL modes in a single layer
Authors: Gilbert Freeman , Laster Stanley J.
Published: July 2021

A two dimensional seismic model has been set up to simulate the problem of elastic wave propagation in a single layer overlying a uniform half space. Both the source and the receiver are mounted on the free surface of the layer. Seismograms are presented as a funciton of range. In addition to the Rayleigh and shear modes, PL modes are observed. Experimentally determined phase and group velocities compare fairly well with theoretical curves. The decay factor for PL is maximum at the arrival time of P waves in the half-space. There is also a secondary maximum at the arrival time of P waves in the layer. Although the decay of PL is small, phase equalization of PL does not yield the initial pulse shape because the mode embraces an insufficient frequency band to permit good resolution.
Effects of decoupling on spectra of seismic waves
Authors: Willis D. E. , Wilson James T.
Published: July 2021

A series of controlled high explosive shots were conducted by the Atomic Energy Commission in a salt mine near Winnfield, Louisiana, to investigate seismic decoupling theories. Two recording stations were used by the University of Michigan at various distances between 1.1 and 14.7 kilometers for a majority of these shots. Frequency analyses of the magnetic tape recordings were made and the results are presented showing the relationship of the frequency spectra as a function of charge size, distance from the source, and coupled vs decoupled shots. The smaller decoupled shots detonated in the large spherical cavities were observed to have somewhat higher predominate frequencies than the equivalent size coupled shots. A change in cavity size produced no significant difference in the shape of the spectra of the large decoupled shots.
Observed asymmetry of amplitudes from a high explosive source
Authors: DeNoyer John , Willis D. E. , Wilson James T.
Published: July 2021

Frequency analysis of seismic magnetic tape records from a 500-ton high-explosive source shows a pronounced variation of amplitude with frequency for two different azimuths from the source. This amplitude variation is attributed, at least in part, to diffraction effects produced by the geologic structure in the vicinity of the source. The possibility of generating both SV and SH waves from P waves within this structure seems very probable.
A worldwide storm of microseisms with periods of about 27 seconds
Authors: Oliver Jack
Published: July 2021

abstract

On 6 June 1961, a storm of microseisms with periods of about 27 seconds and a duration of about 8 hours was detected by long period seismographs throughout the world. At Palisades, ultra-sensitive seismographs detected the storm for an interval of about 2 days during which the periods of the waves decreased from about 28 to about 20 seconds. The seismic waves appear to be largely of the Rayleigh type and seem to originate in the southern or equatorial Atlantic Ocean.

The favored hypothesis on the nature of the source mechanism suggests that the seismic waves were generated by dispersed ocean waves striking the coast of the Gulf of Guinea. A second hypothesis suggests that the microseisms are a form of harmonic tremor associated with magmatic activity beneath the South Atlantic Ocean.
The travel times of the longitudinal waves of the Logan and Blanca atomic explosions and their velocities in the upper mantle
Authors: Lehmann I.
Published: July 2021

abstract

The P travel times of the Logan and Blanca atomic explosions are found to be consistent with an upper mantile structure having a discontinuity surface at about 215 km depth at which the velocity and the velocity gradient increase abruptly while the velocity varies only slightly or is constant above this depth.
A direct digitizing seismograph
Authors: De Bremaecker J. Cl. , Donoho Paul , Michel J. G.
Published: July 2021

abstract

A seismograph is described in which capacitance transducers on either side of the inertial reactor determine the frequencies of two Clapp oscillators. The oscillators are heterodyned and the resulting frequency, varying between 10 kc and 100 kc, is detected by a frequency or period counter and an analog output. The latter drives a self-balancing potentiometer through a cathode follower and an adjustable twin-T filter. It also drives a circuit with a very long time constant which keeps the boom centered through a coil and magnet transducer. The electronic noise corresponds to a boom displacement of less than 1.25 mμ. The sensitivity is about 400 cps per micron. The dynamic range is about 100 db at constant resolution. The digital output is temporarily in the form of printed or punched tape. A special magnetic tape recorder is being built.
Application of a seismograph network and electronic computer in near earthquake studies
Authors: Cleary J. , Doyle H.
Published: July 2021

A description is given of the application of a close network of seismograph stations and of an IBM 650 computer program to the study of a sequence of near earthquakes in southeastern Australia. The epicenters, depths, and origin times of a moderate sized earthquake and its aftershocks were determined with unusual accuracy, revealing an interesting pattern of foci. The position and origin time of the main shock were then used to study arrivals at more distant stations; Pn arrivals were found to fit a linear travel-time equation closely to a distance of 15 degrees, with a surface velocity of 8.16 ± 0.03 km/sec. The Sn phase was not clear and gave an approximate velocity of 4.7 ± 0.2 km/sec. The possibility of a small velocity decrease in the upper mantle below eastern Australia is discussed.
Generation of earthquakes by a volume source with moment
Authors: Scholte J. G. J. , Ritsema A. R.
Published: July 2021

abstract

The theory developed in paper I* has been used to determine the influence of the focal radius on the P and S wave radiation from a spherical source on which the stress τz=Tyr0eivt acts. The result has been applied to two earthquakes of which the P and S wave distribution around the focus was studied in paper II. † In an appendix, the present model of the focus is compared with similar models that are described in literature.

* This bulletin p. 711 † This bulletin p. 723
Note on the effect of record balancing upon strong motion earthquake response spectra
Authors: Wiggins John H.
Published: July 2021

abstract

From an investigation of over 100 doubly integrated strong motion accelerograms, observations are made concerning the effect of apparent errors within the records upon computed response spectra. The two most influential sources of error are false impulses and unreal long period oscillations.
Particle motion near a nuclear detonation in halite
Authors: Weart Wendell D.
Published: July 2021

abstract

Strong motion parameters from the Project gnome operation were measured in the region extending 60 to 480 meters from the center of detonation or working point along both vertical and horizontal radii.

Travel time data from the horizontal radius reveals three distinct arrivals. First arrivals are propagated through a polyhalite layer with a velocity of 4.839 km/sec. This is followed by the direct elastic wave arrival in the salt horizon (4.318 km/sec) and the plastic wave which decreases in velocity as the stress level diminishes.

Vertically, the velocity varies from 5.1 km/sec at about 60 meters above the shot to 0.785 km/sec a few meters below the surface.

Peak accelerations in the salt are best fitted by the relations A = 890 R−5.3 from 60 to 122 meters and A = 560 R−2.7 from 122 to 480 meters. (R in hundreds of meters and A in units of gravity.) Peak particle velocity in the salt is given by U = 13 R−3.56 from 60 to 100 meters and U = 13 R−1.36 from 100 to 480 meters.

Motion of the ground above the shot reveals that spalling occurred at several horizons. The deepest spall separation was below 92 meters. These effects were most pronounced at the surface where the initial acceleration, velocity and displacement peak values were A = 25 g, U = 5.6 m/s, and D = 168 centimeters. Residual upward displacement at surface zero at +5 minutes was 79 centimeters.
Regional variations in Pn velocity and their effect on the location of epicenters
Authors: Herrin Eugene , Taggart James
Published: July 2021

abstract

Evidence from recent earthquakes and explosions is presented showing substantial regional variations in the velocity of Pn in the United States. These variations have a significant effect on the location of epicenters by the least-squares method. We have included a contour map of Pn velocity in the United States. A new method for computer location of epicenters is described, and is shown to decrease the error of location for events in the western United States by as much as an order of magnitude.
Ground effects from the gnome and logan explosions
Authors: Carder D. S.
Published: July 2021

abstract

Seismic waves resulting from a low yield nuclear detonation 1200 feet deep in a salt bed near Carlsbad, New Mexico were measured by strong-motion seismographs operated by the Coast and Geodetic Survey on the surface in the distance range from 0.5 to 8.8 miles and underground in a potash mine 8.7 to 11.2 miles distant. In addition, many temporary and permanent seismographs were operated by the Coast and Geodetic Survey and other organizations on a continentwide and a world-wide basis. Ground particle accelerations exceeded those from the Logan shot, a like detonation in tuff, by a factor of about 4, and accelerations underground in the salt bed were about half those on the nearby surface. There was no evidence of damaging accelerations in nearby commercial operations or dwellings. Nearby transient ground particle displacements were about the same as those from the logan shot, except that the frequencies were higher. Attenuation with distance across the plains to the east was relatively low as compared with similar effects in the mountain and plateau area toward the west. Upper mantle velocities likewise were higher toward the east, 8.3 to 8.4 km/sec, as compared with 7.8 to 8.1 km/sec toward the north, west, and northwest. The estimated magnitude of the gnome shot was from 4.5 to 5.0, depending on the choice of data.
Travel times and amplitudes of principal body phases recorded from gnome
Authors: Romney Carl , Brooks Billy G. , Mansfield Robert H. , Carder Dean S. , Jordan James N. , Gordon David W.
Published: July 2021

abstract

gnome, an undergound nuclear explosion in salt near Carlsbad, New Mexico, produced seismic waves which were recorded widely throughout the United States and at a few foreign stations. The travel times of P were strongly dependent on the path of propagation, and were as much as 12 seconds earlier in the eastern United States than at equivalent distances in the western part of the United States. At the few stations more distant than 25°, P was about 2 seconds earlier than predicted by the Jeffreys-Bullen table for surface focus. Amplitudes of Pn were similarly dependent upon the path of propagation; although the measurements showed great scatter, amplitudes to the east were generally larger than those to the west. Pn travel time and amplitude anomalies suggest a systematic relationship to crustal thickness. There is evidence from the difference in the speeds and attenuation rates that Lg and P are not transmitted along analogous paths through the crust. Short period body waves were two or three times larger than expected from an explosion of the same energy in tuff at the Nevada Test Site. Surface waves, however, were relatively weak compared with explosions of similar yield in tuff.
Computer program for a fault-plane solution
Authors: Kasahara Keichi
Published: July 2021

In its earthquake mechanism studies the Dominion Observatory has been producing solutions graphically, but a program based on a probability function defined by Knopoff has been written for the IBM 1620 which permits the best solution to be obtained by a series of successive approximations from a given first approximation. The program prints out the strike and dip of the two nodal planes, their standard errors, the azimuth and plunge of their line of intersection, and a list of the stations producing inconsistent data. Weights can be assigned to each station; in practice these weights would depend on the past reliablity of the station.

The machine time required depends on the number of stations used, the accuracy of the first approximation and other factors; in general 20 to 30 minutes is required for a solution involving 30-40 stations.
Comparative spectra of microseisms and swell
Authors: Haubrich R. A. , Munk W. H. , Snodgrass F. E.
Published: July 2021

Spectra of seismic and ocean wave recordings near San Diego, California, show closely related features. The wave spectra consist of a sharp peak whose frequency, f(t), increases linearly with time and consistent with the expected dispersive behaviour from a source at 6150 nautical miles (presumably a storm in the Ross Sea). The seismic spectra show peaks at f(t) and at 2 f(t); the double frequency peak contains 100 times the energy of the peak at the primary frequency. A comparison between the peak frequencies and band widths of the seismic and ocean wave spectra, and an estimate of the direction and beam width of the seismic radiation, leads to the following conclusions: that the microseismic generation area is predominantly local, being confined to a distance of 100 miles up or down the coast. For the primary frequencies the generative strip is presumably confined to shallow water; for the double frequencies it extends 200 miles seaward.
Propagation of an SH-torque pulse in a layered solid
Authors: Pekeris C. L. , Alterman Z. , Abramovici F.
Published: July 2021

In this investigation we determine the motion of the surface of a layered elastic half-space produced by a torque-pulse from a point-source situated inside the layer. The axis of the torque is vertical (SH) and its time variation is represented by a step-function with rounded shoulders. The displacement due to the source approaches a saw-tooth shape at large distances. The displacement of the surface was evaluated exactly by the ray-theory method for ranges r = 100 H and r = 400 H, H denoting the thickness of the layer. The spectrum of the forerunner ground wave and of the Love wave can be interpreted in terms of the normal mode theory. The form of the displacement-curve is found to be sensitive to the width Δ of the pulse at the source. For small Δ the Love wave starts with a strong high frequency amplitude comparable to that of the Airy phase arriving later. This is due to a peak in the excitation function of the first mode. As Δ grows, this peak disappears and the Love wave builds up in the normal fashion to a maximum amplitude at the time of arrival of the Airy phase. For the pulse shape assumed, the normal mode theory predicts a factor of [sin2 (ωΔ/2)]/Δ in the amplitude, where ω denotes the frequency. This is verified in the displacement curves obtained.
Period measurements of structures in Chile
Authors: Cloud William K.
Published: July 2021

abstract

Following the Chilean earthquakes of May, 1960 measurements were made of the natural periods of vibration of steel stacks, elevated water tanks, commercial buildings and other structures. A vibrational analysis of an elevated water tank shows how the measured period provides information about the physical properties of a structure. It is recommended that more extensive measurement of periods be undertaken in Chile.
The effect of diagonal bracing on the earthquake performance of a steel frame building
Authors: Clough Ray W. , Jenschke Victor A.
Published: July 2021

abstract

Diagonal bracing, intended to increase the lateral strength of two steel frame buildings at the University of Concepcion, was broken by the Chile earthquake of May 21, 1960. The unbraced structures then resisted the earthquake of May 22 with no further structural damage, thus raising the question whether the bracing was either necessary or beneficial. To examine this question, a digital computer study was made of the strengthening effect of the diagonal bracing when the buildings were subjected to ground motions recorded at three different earthquakes. The results indicate that for some earthquakes, the bracing may be beneficial. However, for other cases, the bracing induces increased forces in the frame which exceed the strengthening effect of the bracing. Thus, the braced structure actually may be less earthquake resistant than if it were unbraced.
Axially symmetric elastic waves in an unbounded inhomogeneous medium with exponentially varying properties
Authors: Lock M. H.
Published: July 2021

The propagation of elastic waves in a traversely inhomogeneous medium of infinite extent is studied. A method to separate the governing equations of motion is described and solutions are obtained for the elastic waves generated by an impulsive P type point source. These solutions are compared with the corresponding solution for the homogeneous case and the various effects introduced by the inhomogeneity of the medium are discussed.
A new short-period seismometer for field and observatory use
Authors: Willmore P. L. , Connell D. V.
Published: July 2021

The new seismometer is developed from the original Willmore instrument, using the same principle of a suspended magnet and five spoke suspension to yield a compact portable instrument capable of either horizontal or vertical operation. In the new version the flux linkage has been more than doubled to give an e.m.f. exceeding 200 volts/m/sec. from a 500 ohm coil. A device has been introduced which enables the period to be adjusted between 0.6 and 3.0 seconds, and the use of new elastic material for the springs enables the instrument to operate without readjustment over a temperature range of ±50°C. Multi-tap coils are provided to give any desired degree of damping for a low impedance load up to critical at 0.6 second periods and up to five times critical at 3 seconds. The case has been modified to improve the water-proofing, whilst allowing access to the period and mass-position adjustments from outside.
Source-mechanism from spectra of long-period seismic surface waves.
Authors: Ben-Menahem Ari , Toksöz M. Nafi
Published: July 2021

Source-mechanism is derived from amplitude and phase spectra of mantle Love and Rayleigh waves of the Alaska earthquake of July 10, 1958. The signals R2, R3, G2, G4, G5 recorded on the Gilman 80–90 and the Press-Ewing 30–90 seismograph systems at Pasadena, California, are separated, digitized, filtered and Fourier-analyzed. An agreement between theory and observations is obtained for a unilateral fault of 300–350 km, which ruptured with a speed of 3-3.5 km/sec in the direction N40°W. Fault length is in good agreement with the extent of aftershock distribution in the month of July, 1958, and the time of rupture checks with the duration of an impressive T-phase recorded at Hawaii. The phases of the signals are corrected for propagation, instrumental shift and the source finiteness. Initial phases thus obtained agree on a mechanism of a right double-couple with a unit step-function in time.
The stress changes that accompany strike-slip faulting
Authors: Chinnery M. A.
Published: July 2021

In a previous paper (Chinnery, 1961) an investigation of the deformation of the ground around a strike-slip fault was described. This work is now extended to a calculation of the change in stress distribution that is brought about by such a fault. Contour maps of the components of the stress change are included, both for the general rectangular fault, and for the limiting case of a long shallow fault. These maps have a number of interesting features, and show clearly the complexity of the stress change in the neighborhood of the edges of the fault plane. The assumptions involved in the calculation are discussed at some length.
Uncoupled equations of motion in nonhomogeneous elastic media
Authors: Alverson R. C. , Gair F. C. , Hook Joseph F.
Published: July 2021

The method of Helmholtz has been recently employed by Hook to obtain uncoupled equations of motion from the vector wave equations governing the propagation of elastic waves in certain types of nonhomogeneous media. The work reported on in this paper casts the method of Helmholtz in terms of matrices and extends the work of Hook to media with variable Poisson's ratio. It is found that the constitutive parameters must satisfy a pair of nonlinear ordinary differential equations. These differential equations are integrated in a special case and a useful and interesting example of a nonhomogeneous medium is given.
The tsunami of 22 May 1960 in French Polynesia
Authors: Vitousek Martin J.
Published: July 2021

Except for the Marquesas Islands, the islands of French Oceania are relatively safe from tsunamis because of well-developed reefs, inner lagoons, and steep offshore slopes, hence the Chilean tsunami of 22-23 May 1960 was not well developed. Detailed data are given for Tahiti. The greatest runup height was 3.4 meters above low water, the average was 1.7 meters. Runup of 1 meter was observed in the Leeward Islands. In the Austral Islands the highest wave reached 1.8 meters. The Tuamotu Archipelago suffered water level changes of about 1 meter. In the Marquesas Islands runups of about 3 meters were observed.

No human casualties were reported from French Polynesia and damage was slight.
Further observations of geologic and geomorphic changes resulting from the catastrophic earthquake of May 1960, in Chile
Authors: Weischet Wolfgang
Published: July 2021

A geomorphic study of the region in which the earthquake occurred, made after the earthquakes is compared with a similar study made before the earthquakes. Evidence is presented to show changes in land level. Discussion of the effects of the tsunami as it affected geomorphic and geologic processes is presented. Landslides are listed and analysed. Distribution of intensity is discussed.
The distribution of the damage caused by the earthquake in Valdivia in relation to the form of the terrane
Authors: Weischet Wolfgang
Published: July 2021

The western part of the city of Valdivia is more severely damaged than the eastern part. This is because the eastern part is underlain by a firm continuous bed, actually a terrace, of cancagua, a fine-grained soil composed of volcanic ash. The western part consists of a discontinuous surface marked by isolated mesa-like remnants of this terrace, surrounded by soft, incompetent fill. Vibration of the mesa-like columns was severe because of the lack of contiguous support at the contact with the incompetent fill material. Construction on artificial fill was very seriously damaged.
Relation between geology and the damage in Puerto Montt, Chile, caused by the earthquake of 22 May 1960
Authors: Dobrovolny Ernest , Lemke Richard , Bowes William , Thomas Herbert , Bravo S. Nelson
Published: July 2021

The damage in Puerto Montt resulted from landsliding, debris flows, mud flows, and settling of unconsolidated alluvium and artificial fill. Structures on high terraces, away from the edges, were undamaged.
Geologic report on the effects of the earthquake of 22 May 1960 on the city Llanquihue
Authors: Thomas Herbert , Bowes William , Bravo S. Nelson
Published: July 2021

Damage occurred from landsliding and mass movement on the steep slopes of terraces and from subsidence and inundation in the swampy central zone of Llanquihue. Large structures located on well-drained terraces were undamaged. The glacial history of Lake Llanquihue is discussed.
Crustal structure southwest of the San Andreas fault from quarry blasts
Authors: Hamilton Robert M. , Ryall Alan , Berg Eduard
Published: July 2021

abstract

To determine a crustal model for the southwest side of the San Andreas fault, six large quarry blasts near Salinas, California, were recorded at 27 seismographic stations in the region around Salinas, and along a line northwest of the quarry toward San Francisco. Data from these explosions are compared with results of explosion-seismic studies carried out by the U.S. Geological Survey on a profile along the coast of California from San Francisco to Camp Roberts. The velocity of Pg, the P wave refracted through the crystalline crust, in the Salinas region is 6.2 km/sec and the velocity of Pn is about 8.0 km/sec. Velocities of the direct P wave in near-sur-face rocks vary from one place to another, and appear to correlate well with gross geologic features. The thickness of the crust in the region southwest of the San Andreas fault from Salinas to San Francisco is about 22 kilometers.
The response of simple nonlinear systems to a random disturbance of the earthquake type
Authors: Goldberg J. E. , Bogdanoff J. L. , Sharpe D. R.
Published: July 2021

abstract

Stationary properties of the response of simple nonlinear systems to earthquake type (nonstationary) random disturbances are determined. The method used consists in generating member functions of the input processes, integrating the equations of motion using these as inputs to obtain output member functions, and then, from this ensemble of outputs, determining the statistical properties of interest. The method is flexible in that it is easy to apply to simple as well as complex linear and nonlinear systems; it yields a variety of statistical properties of engineering significance; it provides a method for approaching the design of aseismic structures; and more generally, shock resistant structures on a practical basis.

In addition to determining and displaying input and corresponding output member functions, we determine individual as well as average velocity spectra, first passage time probabilities, and extreme value distributions of relative displacements. Comments are also offered on the utility of these results in design.
On elastic strain of the earth in the period range 5 seconds to 100 hours
Authors: Major Maurice W. , Sutton George H. , Oliver Jack , Metsger Robert
Published: July 2021

abstract

Observations of earth strains, covering a wide spectrum of periods, have been made with a three component installation located 1800 feet below the surface in a deep mine at Ogdensburg, New Jersey. This paper is a description of the strain meters and their environment and is a report of several studies based largely on strain observations.

The instruments, modeled after those of Benioff, employ quartz tubes as their standard of length, use variable capacitor transducers, and record simultaneously tidal data at low gain and seismic data at a sensitivity about 40 times that of the tidal signal. A significant reduction of the noise level in the seismic spectrum has been achieved by sealing the tube rooms against air pressure fluctuations.

The present secular strain rate is less than 1.7 × 10−8 per month, almost an order of magnitude less than that observed by Benioff in California, and almost two orders of magnitude less than that observed by Takada in Japan.

A transient strain with a duration of about 100 hours was associated with the storm tide which damaged the eastern coast of the United States on March 5-8, 1962. The strain corresponds to that produced by an anomalous high water mass whose seaward extent was limited to 100 ± 30 km in the azimuth southeast from Sandy Hook. Direct observation of the seaward extent of such storm tides, for areas off coastlines bordering the open ocean, has not been possible in the past because of the lack of deep water tide recorders.

Love's number h and Shida's number l are determined to be 0.53 and 0.037, respectively, from observations of strains associated with the M2 tidal constituent, on the basis of the assumption that the ocean load generated strain has the same phase on both horizontal instruments. The uncertainty in h and l is large, as it is in other measurements of these numbers, because of the effect of ocean load. This uncertainty is examined in a quantitative manner by mapping h and l as functions of ocean load amplitude and phase in the vicinity of the solution.

Strain seismograms of the Kenai Peninsula earthquake of September 5, 1961, and the Prince Edward Island earthquake of December 29, 1961, are unique. The exceptional long period response of the strain seismometers has made it possible to record, on the first pass, waves associated with the group velocity maximum of the Rayleigh wave dispersion curve over a purely continental path across North American and an almost pure oceanic path across the Atlantic. Such data have never before been reported. The shield area of North America is characterized by higher than average Rayleigh wave velocities. The Atlantic data, when compared with data from the Pacific, do not indicate any appreciable difference between the mantle structure below the Atlantic and that below the Pacific.
Geographical interpretation of measurements of average phase velocities of surface waves over great circular and great semi-circular paths
Authors: Backus George E.
Published: July 2021

If the averages of the reciprocal phase velocity c−1 of a given Rayleigh or Love mode over various great circular or great semicircular paths are known, information can be extracted about how c−1 varies with geographical position. Assuming that geometrical optics is applicable, it is shown that if c−1 is isotropic its great circular averages determine only the sum of the values of c−1 at antipodal points and not their difference. The great semicircular averages determine the difference as well. If c−1 is anisotropic through any cause other than the earth's rotation, even great semicircular averages do not determine c−1 completely. Rotation has negligible effect on Love waves, and if it is the only anisotropy present its effect on Rayleigh waves can be measured and removed by comparing the averages of c−1 for the two directions of travel around any great circle not intersecting the poles of rotation. Only great circular and great semicircular paths are considered because every earthquake produces two averages of c−1 over such paths for each seismic station. No other paths permit such rapid accumulation of data when the azimuthal variations of the earthquakes' radiation patterns are unknown. Expansion of the data in generalized spherical harmonics circumvents the fact that the explicit formulas for c−1 in terms of its great circular or great semicircular integrals require differentiation of the data. Formulas are given for calculating the generalized spherical harmonics numerically.
A note on the computation of Rayleigh wave dispersion curves for layered elastic media
Authors: Rosenbaum J. H.
Published: July 2021

In the computation of Rayleigh wave dispersion curves for layered elastic media, difficulties arise which take the form of a loss of significant figures and which can be ascribed to the fact that the motion in one section of the medium is weakly or only partly coupled to the motion in another section. These difficulties can be effectively removed if account is taken of such decoupling effects.
Correlation of E23K gena KCNJ11 polymorphism as a Risk Factor for Obesity with Type 2 Diabetes Mellitus In Jayapura, Papua
Authors: Maay Jems K. R. , Hastuti Pramudji , Sadewa Ahmad H.
Published: July 2021

Background: Pathophysiology of type 2 diabetes mellitus (T2DM) is influenced by the complex interaction of several genes that regulate energy metabolism in the body. Several polymorphisms that occur in many gene encode components of glucose metabolism regulation are significantly implicated in the onset of T2DM.Methods: This case-control study. Case group with 58 subjects of T2DM patients with obesity and a control group with 58 subjects of non-DM obese patients from ethnic Papuans in Jayapura city, Indonesia.Results: The results of the genotype frequency distribution (AA, GA, GG) and allele (A and G) showed statistically no significant differences. The relationship of anthropometry and blood chemical parameters with genotype (AA-GA-GG) gene potassium inwardly rectifying channel sub family J member 11 (KCNJ11) showed no statistically significant difference (p>0.05). The relationship of anthropometry and blood chemical parameters of genotype (AA-GA) gene KCNJ11 indicated that diastolic blood pressure variables, glucose, triglyceride, high density lipoprotein (HDL), insulin levels, homeostatic model assessment (HOMA) β, and insulin resistance (IR) had statistically significant differences.Conclusions: There is no difference in frequency between genotypes and alleles of the gene KCNJ11 in the T2DM and non-DM group with obesity. There is a link between genotypes of the gene KCNJ11 and T2DM occurrence. As for the combined analysis between blood chemical parameters and genotypes of gene KCNJ11, there is a relationship between genotypes of the gene KCNJ11 and the incidence of T2DM in LDL variables, where the coefficient interval value increases in patients with T2DM.
A study to estimate similarities or dissimilarities of thyroid parameters of cord blood and new-born venous blood amongst new-borns
Authors: Gangalam Vamsi K. , Vodapally Deepika
Published: July 2021

Background: Hypothyroidism may be congenital or may be acquired which might or may not have a delayed onset. Incomplete thyroid development and decreased thyroid hormone biosynthesis is a result of congenital hypothyroidism. Screening is usually missed in areas where testing is not done and being the reason for new cases of hypothyroid cases. The aim was to assess/evaluate whether cord blood can be used as a primary screening method for congenital hypothyroidism.Methods: The study was taken up in the department of pediatrics of a tertiary teaching hospital. A total of 200 babies were taken for the study during the whole study period. The cord blood at the time of delivery and 48 hour serum blood was collected and sent to the lab for thyroid profile estimation.Results: The study consisted of 109 males and 91 female infants. Among the 200 subjects, 156 were term babies and 44 preterm. The mean birth weight was 2.44 kgs. The mean cord TSH was 6.89±4.56, the mean T3 level was 81.03±38.84 and mean T4 level among the subjects was 11.17±3.33. The capillary venous blood was collected after 48 hours for thyroid profiling. The mean TSH was 5.15±3.13, mean T3 level was 111.53±36.49 and mean T4 level was 14.65±6.07. On comparison of cord blood and venous blood association was noted between them.Conclusions: From the present study findings it can be suggested cord blood can be used as a marker for early detection of congenital hypothyroidism.
Study of thyroid profile in pre and post-menopausal women: a case control study
Authors: Shetty Aravind Gutlur Nagarajaiah , Lingaraju Suma , Chandregowda Manohara Melur
Published: July 2021

Background:The prevalence and incidence of thyroid disorders is influenced primarily by sex and age are more common in women and in older adults. Thyroid disorders if left untreated will increase risk of cardiovascular diseases and osteoporosis. Hence, screening for thyroid dysfunction must be done as routine investigation in the women presenting with menopausal symptoms.Methods:This case control study includes 50 pre-menopausal women of age group 34-49 years and 50 post-menopausal women of age group 50-55 years, visiting General medicine department of Victoria hospital and hospital affiliated to Bangalore Medical College and Research Institute. All the subjects were subjected for serum triiodothyronine (T3), tetraiodothyronine or thyroxine (T4), thyroid stimulating hormone (TSH), free T3 and T4 levels.Results:Out of all subjects; 23 were hyperthyroid out of which 14 were post-menopausal women, 37 were hypothyroid out of which 19 were post-menopausal women. Chi-square test showed no significant association. Negative and weak correlation was seen between total T3 and age; total T4 and age; TSH and age; free T3 and age; free T4 and age in pre-menopausal women. Negative and moderate correlation was seen between total T3 and age; total T4 and age; free T3 and age. There was a positive and weak correlation seen between TSH and age; weak positive non-significant correlation seen between free T4 and age. Significant correlation was seen between total T3 and age in post-menopausal women.Conclusions:Post-menopausal women should be monitored for serum T3, T4, TSH levels for reducing risk of thyroid dysfunction.
A rare case of peripheral giant cell granuloma
Authors: Brar Gursimrat Kaur , Sodhi S P S , Malhotra Mehak , Goyal Poshali
Published: July 2021

Peripheral Giant Cell Granuloma or the so called “Giant Cell Epulis” is the most common oral giant cell lesion. It is described as non-neoplastic, hyperplastic lesion occurring exclusively on gingival/alveolar crest that appears as a overgrowth of tissues, following trauma or irritation arising from periosteum or periodontal membrane. It can be sessile or pedunculated with size usually less than 2cm. Although being uncommon, this lesion carries a lot of uncertainity in terms of its etiology, growth potential, biological behavior (recurrence), histogenesis of its cells and its treatment. We hereby report a case of a 49-year old male patient, with peripheral giant cell granuloma in mandibular posterior region, who was successfully treated and is on regular follow up since 6 months.
Resultados maternos y neonatales en mujeres con trastornos hipertensivos en embarazos lejos del término
Authors: Buelvas  Ochoa Yadis Marcela , Bula Romero Javier , Cuadrado Banda César Javier
Published: July 2021

Introducción: el impacto social que generan los trastornos hipertensivos trae repercusiones para la mujer en gestación y los sistemas de salud. Objetivo: describir los resultados maternos y neonatales en mujeres con trastornos hipertensivos de la gestación en embarazos lejos del término en el departamento de Córdoba, Colombia. Métodos: estudio descriptivo exploratorio de tipo retrospectivo. La población estuvo conformada por 90 mujeres con trastornos hipertensivos en embarazos lejos del término (de 26 a 32 semanas de gestación). La información se analizó con el subprograma VALIDATE y el paquete estadístico SPSS versión 23; para el análisis multivariado y univariado se usó el modelo de correspondencias múltiples. Resultados: la preeclampsia fue el trastorno hipertensivo de la gestación de mayor proporción en la muestra de estudio. La mayoría de las mujeres convivían en unión libre, tenían estudios de bachillerato completo y pertenecían al régimen subsidiado. La edad de las gestantes osciló entre 14 y 42 años. La paridad se encontraba entre 1 y 9 hijos; el 75 % de ellas tenían pobres controles prenatales y se encontraban en el tercer trimestre del embarazo. Los resultados maternos muestran que el 64,8 % requirió UCI obstétrica, con una estancia entre 2 y 8 días. Los resultados neonatales evidencian que el 80,2 % de los recién nacidos requirieron UCIN y el 47,3 % fueron pequeños para la edad gestacional, y presentaron prematurez extrema como principal complicación neonatal, seguido del síndrome de dificultad respiratoria. Conclusiones: los desenlaces maternos y neonatales en embarazos lejos del término que cursan con un trastorno hipertensivo se encuentran asociados a altas tasas de morbilidad materna y neonatal.
Mapping Relational Database to OWL Ontology Based on MDE Settings
Authors: Bouougada Benamar , Bouchiha Djelloul , Rebhi Redha , Kidar Ali , Lorenzini Giulio , Bouziane Abdelghani , Ahmad Hijaz , Menni Younes
Published: July 2021

Ontology is an important aspect of the semantic web, which is why semantic web developers are interested in constructing ontology in various applications based on domain experts. By transforming an existing application database into ontology, we many construct ontologies without having to hire an expert in the field. Model-driven engineering is the foundation of the suggested strategy (MDE). In a nutshell, the technique is divided into two phases, the first of which attempts to prepare the data needed for the transformation in the form of a model with a database. A compliance relationship between this model and its meta-model is required. Phase (2) applies a set of rules written in the Atlas Transformational Language to change the model produced in the first phase into another model, which is an OWL ontology (ATL). We tested our solution using a set of databases created specifically for this purpose and built it in an eclipse environment using an EMF and ATL transform language. The acquired findings demonstrate the strength and efficacy of the recommended strategy.
Dense Hierarchical CNN – A Unified Approach for Brain Tumor Segmentation
Authors: Sille Roohi , Choudhury Tanupriya , Chauhan Piyush , Sharma Durgansh
Published: July 2021

Brain tumor segmentation is an essential and challenging task because of the heterogeneous nature of neoplastic tissue in spatial and imaging techniques. Manual segmentation of the tumor in MRI images is prone to error and time-consuming tasks. An efficient segmentation mechanism is vital to the accurate classification and segmentation of tumorous cells. This study presents an efficient hierarchical clustering-based dense CNN approach for accurately classifying and segmenting the brain tumor cells in MRI images. The research focuses on improving the efficiency of the segmentation algorithms by considering the qualitative measures such as the dice score coefficient using quantitative parameters such as mean square error and peak signal to noise ratio. The experimental analysis states the efficacy and prominence of the proposed technique compared to other models are tabulated within the paper.