bluuebunny/crossref_metadata_2025 huggingface dataset:
Modern possibilities of antiepileptic therapy at the start of treatment of focal epilepsy
Authors: Vlasov P. N.
Published: July 2021

The report presents data on the evaluation of efficacy and tolerability, as well as the dynamics of epileptiform activity index in adolescents and adults with newly diagnosed focal epilepsy during lacosamide therapy.
PATERNALİST LİDERLİĞİN ÖRGÜTSEL SİNİZME ETKİSİ
Authors: Çetinkaya Fatih Ferhat
Published: July 2021

İşletmelerin başarılı olmalarında liderlerin rolü bilinmektedir. Liderlik son yıllarda farklı açılardan ele alındığından birçok liderlik yaklaşımından bahsedilmektedir. Paternalist (babacan) liderlikte bunlardan bir tanesidir. Örgütsel sinizm ise, çalışanların çeşitli nedenler ile işletmelerine karşı olumsuz davranışlarını ifade etmektedir. Paternalist liderlik davranışının örgütsel sinizmi azaltacağı düşünüldüğünden bu çalışma önemli görülmüştür. Araştırmanın amacı ise, paternalist liderliğin örgütsel sinizm ve alt boyutları üzerinde etkisinin olup olmadığını tespit etmektir. Bu amaçla, Kırşehir ilinde kamu kurumlarında çalışan 454 kişiden anket tekniği ile veri toplanmıştır. Yapılan analizler sonucunda, Paternalist liderlik ile hem sinizm, hem bilişsel ve duyuşsal sinizm, em de davranışsal sinizm arasında negatif yönlü ve anlamlı ilişki tespit edilmiştir. Yine paternalist liderliğin alt boyutlarından yardımsever ve ahlaki liderlik ile sinizm, bilişsel ve duyuşsal sinizm, davranışsal sinizm arasında negatif yönlü anlamlı ilişkiler tespit edilmiştir. Paternalist liderlik arttıkça örgütsel sinizm düzeyleri azalmaktadır. . Yardımsever/ahlaki liderlik davranışının bilişsel/duyuşsal sinizmi negatif yönde etkilediği tespit edilmiştir Yardımsever/ahlaki liderlik davranışının davranışsal sinizmi negatif yönde etkilediği, ama otoriter liderlik davranışının ise davranışsal sinizmi pozitif yönde etkilediği tespit edilmiştir.
Seismically-induced fluctuations of the water level in the Nunn-Bush well in Milwaukee
Authors: Rexin Elmer E. , Oliver Jack , Prentiss David
Published: July 2021

Expanded time-scale recordings of the water level in a well in Milwaukee, Wisconsin, show many of the familiar seismic phases, including Love waves which in theory have no associated dilatation. Comparison of seismograms from distant earthquakes recorded by the well seismograph at Milwaukee and by conventional inertial instruments at Palisades demonstrates the superior response of the well, relatively, to waves of long periods.
On the nature of three Alaskan aftershock sequences of 1957 and 1958
Authors: Utsu Tokuji
Published: July 2021

This paper deals with three aftershock sequences which occurred during IGY 1957/58. The frequency distributions of aftershocks with respect to magnitude and time are studied. These distributions fit eqs. (1) and (4) respectively with constants b, p, and c given in table 1 as shown in figs. 4, 5, 8, 9, 12, and 13. These figures also show the independence of magnitude-frequency relation on time and time-frequency relation on magnitude. The fluctuation of frequency in time-frequency distribution is nearly that which is to be expected in random sampling from a population whose frequency distribution is exactly expressed by equation (4). The geographical variation in the mode of aftershock occurrence in the aftershock area seems to be different from sequence to sequence. For the Aleutian sequence, the central part of the aftershock area is characterized by comparatively small energy release and small value of c in eq. (4), while for the southeastern Alaska sequence the greatest activity is concentrated near the epicenter of the main shock with no indication of geographical variation in magnitude- and time-frequency distributions.
Computation of surface wave dispersion for multilayered anisotropic media
Authors: Harkrider David G. , Anderson Don L.
Published: July 2021

With the program described in this paper it is now possible to compute surface wave dispersion in a solid heterogeneous halfspace containing up to 200 anisotropic layers.

Certain discrepancies in surface wave observations, such as disagreement between Love and Rayleigh wave data and other independent evidence, suggest that anisotropy may be important in some seismological problems. In order to study the effect of anisotropy on surface wave dispersion a program was written for an IBM 7090 computer which will compute dispersion curves and displacements for Rayleigh waves in a layered halfspace in which each layer is transversely isotropic. A simple redefinition of parameters makes it possible to use existing programs to compute Love wave dispersion.
Rayleigh wave dispersion in the Pacific Ocean for the period range 20 to 140 seconds
Authors: Kuo John , Brune James , Major Maurice
Published: July 2021

Rayleigh wave data obtained from Columbia long-period seismographs installed during the International Geophysical Year (I.G.Y.) at Honolulu, Hawaii; Suva, Fiji; and Mt. Tsukuba, Japan, are analyzed to determine group and phase velocities in the Pacific for the period range 20 to 140 seconds. Group velocities are determined by usual techniques (Ewing and Press, 1952, p. 377). Phase velocities are determined by assuming the initial phase to be independent of period and choosing the initial phase so that the phase velocity curve agrees in the long period range with the phase velocity curve of the mantle Rayleigh wave given by Brune (1961). Correlations of wave trains between the stations Honolulu and Mt. Tsukuba are used to obtain phase velocity values independent of initial phase.

The group velocity rises from 3.5 km/sec at a period of about 20 see to a maximum of 4.0 km/sec at a period of about 40 sec and then decreases to 3.65 km/sec at a period of about 140 sec. Phase velocity is nearly constant in the period range 30–75 sec with a value slightly greater than 4.0 km/sec. Most of the phase velocity curves indicate a maximum and a minimum at periods of approximately 30 and 50 sec respectively. At longer periods the phase velocities increase to 4.18 km/sec at a period of 120 sec.

Except across the Melanesian-New Zealand region, dispersion curves for paths of Rayleigh waves throughout the Pacific basin proper are rather uniform and agree fairly well with theoretical dispersion curves for models with a normal oceanic crust and a low velocity channel. Both phase and group velocities are comparatively lower for the paths of Rayleigh waves across the Melanesian-New Zealand region, suggesting a thicker crustal layer and/or lower crustal velocities in this region.
Seismic refraction measurements of the bottom structure off the North shore of Prince Edward Island
Authors: Macpherson J. D.
Published: July 2021

During September and November of 1960, two sets of unreversed seismic refraction profiles were made at two locations off the North shore of Prince Edward Island. The depths and velocities of the four sedimentary layers detected at both these locations were identical within the limits of experimental error.
Torsional oscillation of a homogeneous elastic spheroid
Authors: Usami Tatsuo , Satô Yasuo
Published: July 2021

abstract

There are several causes for the observations of splitting of the spectral peaks determined from the free oscillation of the earth. In this paper, the splitting due to the ellipticity is studied assuming a homogeneous earth described by oblate spheroidal coordinates. Ellipticity causes the iTn mode to split into (n + 1) modes, while the earth's rotation causes it to split into (2n + 1) modes. 1/297.0 is adopted as the ellipticity of the earth. Numerical calculations are carried out for the fundamental mode (n = 2, 3, 4) and for the first higher harmonics (n = 1). The difference between the extreme frequencies for each value of n is 0.7% (n = 2), 0.5% (n = 3), and 0.4% (n = 4).
The use of ScS-wave data in focal mechanism determinations
Authors: Furumoto Augustine S.
Published: July 2021

abstract

In this paper the S wave method of focal mechanism determination is extended to include the ScS wave. By the establishment of the quantitative relationship between the directions of vibration of the S and the ScS, ScS wave data can be reduced to a form of S wave data usable for focal mechanism determinations.

The new extension has been checked by reobtaining focal mechanism solutions for four heartquakes using ScS wave data. Results were consistent with previous solutions by the S wave method or P wave method.
Signal-to-noise ratio and spectra of explosion-generated Rayleigh waves
Authors: Sherwood J. W. C. , Spencer T. W.
Published: July 2021

abstract

This preliminary theoretical study is basically concerned with the estimation of the depth of an explosive source from a knowledge of the radiated Rayleigh wave. Details are given of the dependence of the amplitude spectrum on the explosive yield, depth of burial, horizontal range, and the elastic parameters of the medium. It is assumed that the medium is a homogeneous and isotropic half space which, as far as the Rayleigh wave is concerned, possesses a mechanical quality factor, or Q, which is independent of frequency. Furthermore, it is assumed that the explosive shot has been effectively decoupled from the medium by locating it within a cavity of appropriate size. It is shown that changes in either shot depth or Q can produce an identical change in the Rayleigh wave spectrum. Hence a lack of knowledge of Q limits the accuracy with which source depth may be estimated. An additional inaccuracy may result from the ambient ground motion preventing the recovery of the Rayleigh wave spectrum. For this reason estimates are given of the theoretically anticipated Rayleigh signal-to-noise ratio per kiloton of explosive in a seismically quiet location. It is emphasized that the study is preliminary in nature. To be of significant practical use it is believed that the theory must be extended to take into account the effect of surface layering of the medium.
The effect of boundaries on wave propagation in a liquid-filled porous solid: III. Reflection of plane waves at a free plane boundary (general case)
Authors: Deresiewicz H. , Rice J. T.
Published: July 2021

abstract

A general solution is derived of Biot's field equations governing small motions of a porous solid saturated with a viscous liquid. The solution is then employed to study some of the phenomena attendant upon the reflection from a plane, traction-free boundary of each of the three body waves predicted by the equations. The problem, though more complex, bears some similarity to that of electromagnetic waves in a conducting medium, in that some of the reflected waves are inhomogeneous, planes of constant amplitude not coinciding with planes of constant phase.

Analytical expressions are displayed for the phase velocities, attenuation coefficients, angles of reflection and the amplitude ratios, and explicit formulas are given for the limiting cases of low and high frequencies, representing first-order corrections for porosity of the solid and viscosity of the liquid, respectively. The paper concludes with a presentation of results of numerical calculations pertinent to a kerosene-saturated sandstone.
Note on use of a Sofar geophone to determine seismicity of regional oceanic areas
Authors: Shurbet D. H.
Published: July 2021

abstract

Daily Bermuda short period seismograms are compared with Sofar geophone records for a period of three years. Many short-period seismic signals were recorded on the geophone record that are not on the seismograms. Therefore, it is suggested that a geophone array could be most useful in determining regional seismicity in oceanic areas. The large number of geophone signals recorded gives some indication that the advantages of the expected quiet of the ocean bottom may be somewhat offset.
The San Agustin fault system of southern Peru
Authors: Rodriguez B. A. , Steinhart J. S. , Asada T.
Published: July 2021

abstract

A study of the hypocentral location of 133 small earthquakes in southern Peru reveals the existence of a vertical fault zone parallel to, and west of, the axis of the Andes chain. This zone is named the San Agustin fault zone in honor of the University where the work was done.
Period equation for Rayleigh waves in a layer overlying a half space with a sinusoidal interface
Authors: Kuo John T. , Nafe John E.
Published: July 2021

abstract

The problem of the Rayleigh wave propagation in a solid layer overlying a solid half space separated by a sinusoidal interface is investigated. The amplitude of the interface is assumed to be small in comparison to the average thickness of the layer or the wave length of the interface. Either by applying Rayleigh's approximate method or by perturbating the boundary conditions at the sinusoidal interface, plane wave solutions for the equations which satisfy the given boundary conditions are found to form a system of linear equations. These equations may be expressed in a determinant form. The period (or characteristic) equations for the first and second approximation of the wave number k are obtained.

The phase and group velocities of Rayleigh waves in the present case depend upon both frequency and distance. At a given point on the surface, there is a local phase and local group velocity of Rayleigh waves that is independent of the direction of wave propagation.
Generally applicable solutions of Zoeppritz' amplitude equations
Authors: McCamy Keith , Meyer Robert P. , Smith Thomas J.
Published: July 2021

abstract

A crustal model, in addition to satisfying travel-time data, should agree with the observed distribution of amplitude in time and range. The study of observed amplitudes in seismic crustal work depends directly on the partition of the amplitude of an incident wave front at an interface. The Zoeppritz equations describe this partition for a plane wave and while they are simple simultaneous linear equations, their solution by hand methods is tedious and receptive to errors. Solutions of these equations have been obtained by numerical methods for both the incident P and SV cases and are presented in the form of curves showing the ratio of the amplitude of the resultant ray to that of the incident ray plotted against the angle of incidence. By solving the equations for velocity ratios ranging from 0.25 to 4.0, families of curves covering most realistic situations were obtained.

That generally applicable solutions of these equations can be presented in curve families ranging over velocity contrast alone, is demonstrable from the studies of the velocity vs. density relation made by Nafe and Drake and independently by Woollard.

The curves presented permit rapid, quantitative solution of the amplitude partition at an interface, thereby, greatly facilitating the study of wave train modifications.
A note on the effect of ripple firing on the spectra of quarry shots
Authors: Willis D. E.
Published: July 2021

A series of controlled quarry shots were recorded at a distance of approximately 900 feet to ascertain the effect of ripple firing on amplitude and spectra of the seismic waves. A measurable reduction in the amplitude of compressional and shear wave was observed at some frequencies. This effect was not so pronounced for the surface waves.
The Chilean earthquakes of May, 1960: A structural engineering viewpoint
Authors: Steinbrugge Karl V. , Flores A. Rodrigo
Published: July 2021

abstract

The series of major earthquakes which occurred in south-central Chile during May of 1960 were of large Richter magnitude and were accompanied by major geologic changes. Epicenters were distributed throughout populated regions; the earthquakes violently shook many substantial buildings which had been specifically designed to resist earthquake forces.

In general, damage to earthquake resistive structures of reinforced concrete, structural steel, and wood frame was slight and the overall performance was quite satisfactory. When major damage did occur to structures with earthquake bracing, construction practices were almost always recognizably poor. The minor damage to earthquake resistive structures was instructive and a number of case histories are discussed. Of particular interest are the instances of shear wall rotation on compressible soils, construction and design errors, relative rigidity problems, and the performance of inverted pendulum structures.
The measurement of ground motion of destructive earthquakes
Authors: Hudson D. E.
Published: July 2021

abstract

The need for a greatly expanded network of strong-motion accelerographs throughout the seismic regions of the world is stressed. A summary of the characteristics of currently available strong-motion accelerographs is presented, and the design details are given for an instrument suitable for acquiring the basic data needed by structural engineers for earthquake resistant design. It is shown that for such an instrument, the natural period must be less than 0.1 seconds, and that the recording speed must be at least 1 cm/sec. The critical nature of the inertia starting device is discussed, and some information is given on the transient response of the standard pendulum starter used in the United States Coast and Geodetic Survey Strong-Motion Accelerograph. The use of simpler, non-time-recording instruments such as the U.S.C.G.S. Seismoscope to supplement the accelerograph network is described.
Rayleigh waves in a two-layer heterogeneous medium
Authors: Dutta Subhas
Published: July 2021

The possibility of propagation of Rayleigh waves in an incompressible crust of constant density and rigidity varying exponentially with depth lying on (i) a semi-infinite incompressible homogeneous medium and (ii) a semi-infinite compressible homogeneous medium is studied in this paper. The variation of rigidity is assumed as μρ=beβZ, where b and β are constants. To fix ideas we suppose that the crust has the thickness 37.5 km. in which the rigidity increases exponentially from 2.747 × 1011 to 4.53 × 1011 dynes/cm2 over the ultrabasic material of infinite depth in which the rigidity is constant and equal to 6.47 × 1011 dynes/cm2. Frequency equations and their numerical solutions are obtained in both the cases. The results thus obtained are compared with the results derived from those given by Newlands.
Radiation pattern of Rayleigh waves from a fault of arbitrary dip and direction of motion in a homogeneous medium
Authors: Haskell N. A.
Published: July 2021

Expressions for the displacements in the body waves radiated in an unbounded, homogeneous elastic medium by dipolar point sources of arbitrary orientation may be readily derived in Cartesian coordinates from formulae given by Love. The free-surface boundary conditions are, however, most conveniently expressed in terms of Sezawa's cylindrical wave functions. The necessary transformation between the two representations is provided by the Sommerfeld integral and others that may be derived from it by differentiations with respect to the radial and axial (vertical) coordinates. By this means the total radiation field (direct plus surface reflected) is expressed in terms of integrals of cylindrical wave functions. The Rayleigh wave component may then be separated out by calculating the residue at the Rayleigh pole of the integrand. The azimuthal dependence of the Rayleigh wave displacements appears as the sum of three terms, one independent of the azimuth angle, φ, another depending upon sin φ and cos φ, and a third depending upon sin 2φ and cos 2φ. The coefficients of these terms are functions of the direction cosines of the normal to the fault plane and the direction of the relative displacement vector in the fault plane. Equations are presented for sources of both single and double couple types. The effect of fault propagation with finite velocity over a finite distance may be included by multiplying these expressions by the finite source factor previously derived by Ben-Menahem.

Polar plots of the amplitude and initial phase are presented for single and double-couple representations of a number of different types of faults. It is noted that for one certain orientation a shallow double-couple source generates no Rayleigh waves.
Additional evidence relating to “A worldwide storm of microseisms with periods of about 27 seconds”
Authors: Oliver Jack
Published: July 2021

The hypothesis that the worldwide storm of ultralong period microseisms in early June 1961 was caused by ocean swell of the same periods striking the coast of the Gulf of Guinea is supported by mariners' observations of unusual swell and its effects at the places and times predicted by the hypothesis.
Three forgotten earthquakes
Authors: MacCarthy Gerald R.
Published: July 2021

For a given maximum intensity, most earthquakes of the Eastern United States are felt over much wider area than their western counterparts. Several of these eastern shocks, have, because of their relatively low maximum intensities, received little or no attention in seismological literature. Three such earthquakes will be described in terms of contemporary accounts: those of March 9, 1828, April 29, 1852, and of August 31, 1861. In no case did the maximum intensity exceed about VI on the Mercalli Scale, yet each was felt over many thousands of square miles. The 1828 shock affected at least 190,000 square miles, and was reported from Pennsylvania to South Carolina. That of 1852 affected about 187,000 square miles, and was reported from New York to North Carolina. That of 1861 affected at least 280,000 square miles, and was reported from Maryland to the Georgia-Alabama border. All three were felt from the Atlantic Coastal Plain westward into Ohio.
Discussion of “earthquake analysis by response spectrum superposition” by R. W. Clough
Authors: Arias S. Arturo , Husid L. Raul
Published: July 2021

A formula for approximating the maximum earthquake response of shear-buildings is given. This formula gives maximum shears as a linear combination of the r.m.s. superposition and the absolute value superposition of modal maxima. A comparison is made with a previously proposed method and some comments are made on the accuracy.
Seismic measurements of large underwater shots
Authors: Willis D. E.
Published: July 2021

A series of 10,000-pound high-explosive shots was fired at various water depths off San Clemente Island, California during August 1961. These shots were recorded on magnetic tape at one fixed station (123 km) and at portable stations located at 180, 196, 500, and 518 km. The effect of water depth on the amplitude and spectra of the seismic waves generated by these shots is discussed, and a comparison is made with the maximum displacement of underground shots. A spectral comparison is also made with a local earthquake recorded at two of the shot recording sites.
Comparison of seismic waves generated by different types of source
Authors: Willis David E.
Published: July 2021

A comparison of the seismic waves generated by a nuclear explosion and an earthquake is discussed. The epicenter of the earthquake was located within the Nevada Test Site. Both events were recorded at the same station with the same type of equipment. The earthquake waves contained slightly lower frequency than the waves generated by the nuclear shot. The early P phases of the shot had larger amplitudes while the phases after Pg for the earthquake were larger. Seismic waves from collapses were generally found to be composed of lower frequencies than the waves from the original shot. Aftershocks of the Hebgen Lake earthquake were found to generate seismic waves whose frequency content was related to the magnitude of the aftershock. Spectral differences in quarry shot recordings that correlate with source duration times are also discussed.
Spectral energy density for quarry explosions
Authors: Frantti G. E.
Published: July 2021

Several explosions of varying time duration have been recorded at 156 km along a constant propagation path from a central Michigan limestone quarry. Energy density for body waves and surface waves is examined as a function of frequency and observed to peak between 1 and 10 cps. A correlation between spectral amplitudes and source duration time is revealed and is emphasized at shot durations which approximate the dominant period of seismic waves. A study of the data suggests that seismic energy levels may be controlled, in part, by regulating the time duration of delayed quarry blasts. This parameter (total duration time) has been generally neglected in published studies involving commercial blasts.
Energy spectra for underground explosions and earthquakes
Authors: Frantti G. E.
Published: July 2021

Energy density for the entire seismogram is examined as a function of frequency for underground explosions and earthquakes. Anomalous differences in the spectra appear to correlate with the time duration of the source. Ratios of aftershock to earthquake energy show a relatively flat frequency dependence. In contrast, corresponding ratios for nuclear shot-collapse events change rapidly with increasing frequency.

Analysis of these data suggests that measurements of total seismogram energy might be usefully applied in the seismic source discrimination problem.
Amplitude, energy, and phase angles of plane SV waves and their application to earth crustal studies
Authors: Costain John K. , Cook Kenneth L. , Algermissen S. T.
Published: July 2021

Energy ratios from Knott's energy equation and amplitude ratios and phase angles from the Zoeppritz equations were calculated for a plane SV wave incident on a plane elastic discontinuity. All computations were programmed in Fortran for an IBM 1620 digital computer. Incident angles were varied from 0° to 90° in increments of two degrees except near the critical angles, where the ratios were calculated in increments of 0.25 degree generally. Both real and imaginary coefficients were considered in the calculations. The varying parameters were the velocity ratio and density ratio across each interface, and the angle of incidence. Poisson's ratio was kept constant at 0.25. Compressional velocity ratios (transmitted/incident) of 0.7, 0.8, and 0.9, and density ratios (transmitted/incident) of 0.7, 0.8, 0.9, and 1.0 were used. The data are presented in an integrated album which consists of a total of 144 curves (48 curves for each of the 3 characteristics studied). The theoretical amplitudes of PS converted waves, which are seismic body waves resulting from the conversion of an incident parent P wave at a boundary within the earth's crust to a refracted vertically polarized SV wave, were computed (using a fortran program on an IBM 1620 digital computer) for several multi-layered hypothetical and actual crustal models. Preliminary results indicate that the amplitudes of successive PS converted waves arriving from successively deeper layers will continually increase provided that the velocity ratios (upper medium/lower medium) continually decrease with depth. The effects of the wave period have not yet been considered. Particle-motion diagrams obtained from seismograms of two underground nuclear explosions show some shear motion in the first ten seconds which is provisionally interpreted to be from PS converted waves.
Some theories of microseisms in the light of more recent findings
Authors: Hjortenberg Erik
Published: July 2021

A review of a few recent discussions concerning different theories of generation and propagation of the 2–10 sec. microseisms is given and it is shown that Dr. Jensen's (1961) large number of determinations of direction of approach confirms some of the older findings, e.g. the microseismic barrier in the eastern North Sea. Furthermore it is shown that the dependence of microseisms on air temperature in the source area can be explained satisfactorily in terms of Longuet-Higgins theory.

After a short discussion about correlation between microseisms and meteorological data, including wave height observations, a discussion is given of an attempt to correlate microseisms in Greenland with observed waves at a certain weathership. The result was negative as far as the variation from day to day is concerned, but the characteristics of the seasonal variation of the two variables give some support to the Longuet-Higgins theory of the origin of microseisms.
The seismic sea wave of 22 May 1960 along the Chilean coast
Authors: Sievers C. Hellmuth A. , Villegas C. Guillermo , Barros Guillermo
Published: July 2021

This paper details the efforts of the Chilean Navy in warning of the tidal waves that followed the earthquakes of May 1960 and the efforts made to collect information concerning the tsunami. Details of time of arrival, damages, wave height and run up are presented for almost all ports in the affected area beginning at Puerto Aysen and working northward. Changes in water depth, caused by erosion, deposition, and changes in land elevation are reported.

The fates of several ships caught in the great waves are described in detail. Marigrams of the tsunami are given for all available Chilean ports.

The times of high and low tides in the Gulf of Chiloé changed following the earthquakes.
The tsunami of 23 May 1960 in the Hawaiian Islands
Authors: Cox Doak C. , Mink John F.
Published: July 2021

The tsunami of 23 May 1960 was detected in Hilo Bay at 0007 hours HST and recorded on the Honolulu tide gauge at 0033 HST. Runup heights ranged from 2 to 17 feet except in Hilo where the wave formed a bore and reached 35 feet. Sixty-one people were killed and 282 injured in spite of elaborate warning 5 hours in advance of the arrival of the tsunami.

Damage and effects are discussed for all the Hawaiian Islands and recommendations are made to prevent future catastrophes. A brief history of Hawaiian tsunamis is given.
Relation between geology and the effects of the earthquakes of May 1960 in the city of Castro and vicinity, Chiloé
Authors: Galli O. Carlos , Sanchez R. Joaquin
Published: July 2021

The rocks and sediments of the region have been divided into eight units: metamorphic rocks of pre-Mesozoic age, composed of mica schists; volcanic rocks, columnar andesites, tentatively assigned to the Tertiary, that outcrop in a small area to the west of Castro; fluvioglacial deposits, uncemented sands and gravels that in almost all cases overlie three terraces of Pleistocene age that are indicated on the map as morphologic units; slope deposits, friable hybrid material neither classified nor consolidated, that cover one of the most dangerous areas in which to construct; beach deposits—unconsolidated coastal sediments; unconsolidated alluvial sediments distributed in the beds of rivers and in the river deltas presently in formation; and deposits of artificial fill, gravels, sands, bricks, trash, etc.

Damage to structures is clearly related to the geology. In areas of artificial fill and of slope deposits, catastrophic destruction was caused almost exclusively by geologic and morphologic factors. Some areas with a favorable morphology, such as the intermediate and high terraces, are formed of sound material, such as metamorphic rocks, and had little or no damage.
Relation between the geology and the effects of the earthquakes of May 1960 in the city of Ancud and vicinity, Chiloé
Authors: Galli O. Carlos , Sanchez R. Joaquin
Published: July 2021

The rocks and sediments of Ancud and suburbs have been grouped into five units. The volcanic rocks are included in a unit, or geologic formation, called the Volcanic Complex of Ancud. The complex is tentatively considered to be Tertiary or Quaternary in age and is formed of andesites, welded tuffs, breccias and agglomerates that outcrop in almost all the hilly region, the coast, and the surroundings of Ancud. In some sections terraces have been formed over the rocks of this complex. The outcrops of the complex are weathered to a reddish-yellow material easily disaggregated with a hammer. Terrace deposits are observed in some of these terraces to be poorly cemented gravel, clay, and limonite. The alluvial deposits are distributed in the stream courses of Rio Pudeto and in Matadero and La Toma Creeks; they are composed of unconsolidated gravels, sands, silts, and clays. Beach deposits are observed along the length of the coast, and are principally a poorly consolidated aggregate of gravels and sands. Artificial fill is deposited in the coastal zone; its materials are gravels, sands, silts, bricks, wood, debris, etc.

There is a relation between the geology and the damage produced by the earthquakes in works of man. The areas underlain by the Volcanic Complex of Ancud are those that best resisted the effects of the earthquakes, and these are suggested as the most suitable for the expansion of the city. The most serious damage from the earthquakes are observed over the alluvial deposits and at the edges of one of the terraces. The last observation suggests that these areas are unfavorable, and that any future plans for construction over these should be preceded by a study of soil mechanics. It is indicated that the geographic position of Ancud with respect to tidal waves is unfavorable. It is suggested that the construction be prohibited near the sea, and that absolutely indispensible coastal buildings should be carefully studied with regard to a possible repetition of the phenomena.
Studies made between Arauco and Valdivia with respect to the earthquakes of 21 and 22 May 1960
Authors: Alvarez S. Leonardo
Published: July 2021

The earthquake of 21 May was felt as a brusque horizontal movement; the large shock of 22 May was felt as a suave movement of large amplitude similar to a ship at sea. Lebu was extensively damaged. The shoreline at Lebu was elevated 1.5 meters, rendering docks and waterside facilities useless; a large expanse of new beach was exposed. Rio Lebu is no longer navigable because of the uplift. Details of tsunami are reported for several towns on the Arauco Peninsula and south to Tolten.
Relation between the geology of Valdivia, Chile, and the damage produced by the earthquake of 22 May 1960
Authors: Doyel William W. , Moraga B. Aldo , Falcon M. Eduardo
Published: July 2021

A study was made to determine the relation between the damage caused by the earthquake of the 22nd of May, 1960, in Valdivia, Chile, and the geology of the city. A geologic map and an investigation of the damage was made. There was no evidence in the area of fault movements produced by the earthquake. The inundation of extensive areas of Valdivia and its environs are attributed more to compaction of Recent sediments than to a general sinking of the coast. Validivia is situated in the basin of the Rio Valdivia. The geologic formations that crop out there are composed of Pleistocene and Recent sediments. Six mapable units have been selected for the preparation of this report. The great part of the damage in the city of Validivia was caused by defective construction; nevertheless, the greatest damage is observed in areas where Unit QV 6, Recent alluvium or artificial fill, crops out. More detailed geologic studies should be made upon which to base construction and future planning. The studies should be complemented by drilling, gravimetric investigations, and soil studies.
Geologic report on the effects of the earthquake of 22 May 1960 in the city of Puerto Varas
Authors: Thomas Herbert , Bowes William , Bravo S. Nelson
Published: July 2021

Damage in Puerto Varas was largely confined to the low, central part of the town, to the steeper slopes, and to the edges of terraces. The topography and geology are discussed and recommendations made as to steps to be taken to prevent future damage.
Field observations made between Puerto Montt and Maullin
Authors: Thomas Herbert , Bowes William , Bravo S. Nelson
Published: July 2021

The effects of the earthquakes between Puerto Montt and Maullin were lurches in soft material and a possible fault movement just east of Los Muermos.

Pine forests were killed by submergence of the land and the city of Maullin has descended at least 1.5 meters and several of the streets are now inundated.
Model experiments on refraction arrivals from a linear transition layer
Authors: Nakamura Yosio
Published: July 2021

abstract

Ultrasonic model experiments were performed to examine the effect of a transition layer on the frequency spectra of refraction arrivals. Two-dimensional, layered structures with transition layers constructed from polystyrene and Plexiglas sheets served as the models. The materials were so chosen that the model simulated the relation between the crust and the mantle. A pulsed sinusoidal wave with variable frequency and a square-wave pulse were used. The amplitude of the refraction arrivals showed a rapid decrease with increasing frequency starting at a frequency f0 which was found to have the value 1.7 k, where k is the velocity gradient in the transition layer. It is expected that a similar effect will be observed for the refraction arrivals from the Mohorovičić discontinuity if a transition layer exists at the boundary.
Higher mode surface waves and their bearing on the structure of the earth's mantle
Authors: Kovach Robert L. , Anderson Don L.
Published: July 2021

abstract

A detailed numerical investigation of surface wave dispersion and particle motion associated with the higher Love and Rayleigh modes over realistic earth models has been carried out as a preliminary to the routine use of these waves in studies of the crust-mantle system. The suggestion that the so-called channel waves, such as the Lg, Li, and Sa phases, can be interpreted by higher mode group velocity dispersion curves is verified in detail. Furthermore, Sa should have a higher velocity across shield areas than across normal continental areas and a higher velocity across continents than across oceans.

Higher mode Rayleigh wave data are presented for long oceanic paths to Pasadena. The observed data favor the CIT 11 model of Anderson and Toksöz (1963) over the 8099 model of Dorman et al. (1960) and indicate that under the Pacific Ocean the low-velocity zone extends to a depth perhaps as deep as 400 km followed by an abrupt increase in shear velocity.
Improvement of array seismic recordings by digital processing
Authors: Ryall Alan
Published: July 2021

abstract

This paper contains a brief review of the operations that are involved in digital processing of array seismic recordings by the methods of velocity filtering, summation, cross-multiplication and integration, and by combinations of these methods (the UK method and multiple correlation).

Analyses by the several techniques were made on array recordings that were obtained by the U. S. Geological Survey of seismic waves from chemical and nuclear explosions in the western United States.

Seismograms were synthesized, using recordings of seismic noise and a Pn signal, such that the signal-to-noise ratio, onset time and apparent velocity of the signal were predetermined for the synthetic records. These records were then analyzed by summation, cross-multiplication and the UK method, and the results were compared.

From the examples presented, it appears that for recordings with initial peak-signal-to-rms-noise ratio less than about 0.8, the best improvement can be obtained by the process of velocity filtering and summation of all the traces. For a six-element array improvement can be obtained by this method on records which have an original signal-to-noise ratio of 0.4 or greater. When the initial signal-to-noise ratio is greater than 0.8, multiplicative compounding yields about the same improvement as a process involving additive compounding and subsequent raising of the summation trace to large powers.
The velocity of shear fracture
Authors: Mansinha L.
Published: July 2021

abstract

The maximum velocity of fracture in an homogeneous isotropic elastic medium under pure shear stress and with an added compressive stress is computed by an extension of Yoffe's method. The maximum velocity of shear fracture is smaller than the velocity of transverse waves in the medium. It increases as Poisson's ratio increases and decreases as the compressive stress increases. The maximum velocity of pure shear fracture is higher than the velocity of pure tensile fracture in the same medium. For a medium with Poisson's ratio of 0.25 the former is 0.775 and the latter is 0.631 of the transverse wave velocity.
The effect of boundaries on wave propagation in a liquid-filled porous solid: V. Transmission across a plane interface
Authors: Deresiewicz H. , Rice J. T.
Published: July 2021

abstract

The passage of plane body waves across a plane interface from one to another, contiguous, porous aggregate is examined, with particular attention paid to motions involving wave lengths large in comparison with cross-sectional pore dimensions. The results are obtained for a rather general set of boundary conditions which take account of possible resistance to flow due to partial nonalignment of pores at the interface. It is found that when certain conditions of equality of material constants for the two media are met one or more of the reflected and transmitted waves are extinguished.
The effect of boundaries on wave propagation in a liquid-filled porous solid: VII. Surface waves in a half-space in the presence of a liquid layer
Authors: Deresiewicz H.
Published: July 2021

abstract

The velocity dispersion relation and the expression for the attenuation coefficient are derived appropriate to surface waves in a porous half-space supporting a layer of liquid, generalizing a solution due to Stoneley.
Tsunamis and seismic seiches reported from the eastern Atlantic south of the Bay of Biscay
Authors: Berninghausen William H.
Published: July 2021

abstract

Tsunamis have been reported from widely distributed locales with the area under consideration. They seem to be more common in the Azores and the Iberian peninsula than elsewhere. This may result partly from the lack of, or inavailability of data rather than the absence of the phenomena.
Earthquake mechanism determination by S-wave data
Authors: Stevens Anne E.
Published: July 2021

The nature of force systems at the foci of earthquakes can be studied by analyzing initial longitudinal (P) and transverse (S) displacements produced by them on the surface of the earth. The force system described in this paper results from a superposition of three mutually orthogonal double forces which act at a point focus. A family of equations is derived which depends only on S polarization angles and not on initial P displacements to determine the orientation of this generalized force system. An IBM 1620 computer has been programmed to solve the family of equations for two particular focal mechanisms—the single couple (Honda's Type I) and the double dipole (Honda's Type II). Two possible force systems are thus calculated for each earthquake using only S angles. The appropriate mechanism for each earthquake is selected by comparing the distribution of initial P displacements actually recorded, with that predicted from the solutions of the mechanism equations making use of S data.

Computer solutions are presented for 32 earthquakes for which data are available in the literature. The orientation of the force system for each earthquake calculated from S data alone is in general agreement with that determined from P data.
Spheroidal free periods of the earth observed at eight stations around the world
Authors: Alsop L. E.
Published: July 2021

Spectral peaks corresponding to the spheroidal free periods of oscillation of the earth exist in the spectra of eight seismograms written at stations in different parts of the world shortly after the great Chilean earthquake of 22 May 1960. These data have been combined with those previously reported by various authors to obtain a very precise phase velocity vs period curve for Rayleigh waves in the period range of 200 to 3200 seconds. The observed spectral amplitudes lend some support to the assumption of a moving source, but they also indicate that the present theory is not adequate. The vertical motion is found to be symmetric with respect to reflections through the pole.
Seismicity of northern California and western Nevada
Authors: Niazi Mansour
Published: July 2021

abstract

Nearly 1500 recent northern California and western Nevada earthquakes of magnitude 2 and above have been used to study aspects of the seismicity of the region. In an area covering 512 degrees of latitude by 8 degrees of longitude, each square degree was subdivided into 16 approximately equal quadrilateral blocks. The seismic energy and associated strain release in each block were computed for time intervals up to five years. The computed representations of strain release for each year are contoured to define the distribution of seismic zones in the area and to give a dynamic measure of thier variation.

The observed surface creep along the San Andreas fault at the Vineyard seismographic station is compared with the intensity of the seismic activity in the immediate neighborhood of the fault zone. The frequency distribution of earthquakes of different magnitude is discussed.
Sedimentary velocities of the western North Atlantic margin
Authors: Houtz R. E. , Ewing J. I.
Published: July 2021

During the 1954 cruise of the USS San Pablo and USS Rehoboth, 27 seismic refraction profiles were shot primarily to obtain detailed sedimentary data in the western North Atlantic. This work combined with later work, which also emphasized sedimentary data, provides 60 profiles in which gain and filter settings were adjusted to give coherent sedimentary arrivals. Good agreement was found among solutions obtained by several different methods for sediment thickness and velocity. Results indicate that velocity gradients are variable and are greatest near the liquid-sediment interface; wide-angle sedimentary arrivals in the deepsea profiles are reflections; refracted arrivals from the sediments are restricted to a zone shoreward of about halfway up to the continental rise.
Dispersion of Rayleigh waves in the Gulf of Mexico and Caribbean Sea
Authors: Papazachos Basil C.
Published: July 2021

Group and phase velocities of Rayleigh waves along 57 paths between Central America and the central United States were determined. The waves examined were of period between 15 and 60 seconds and crossed the Gulf of Mexico and Caribbean Sea in many directions. The following conclusions about the structure of the region are drawn:

Along the paths crossing the western and central Gulf and the regions near the coast of Texas and the eastern coast of Mexico the velocities were found to be very low. This is attributed to the great thickness of the sediments in these regions.

The velocities along paths crossing the eastern Gulf and westernmost Caribbean were found to be higher than the typical continental velocities. This is considered as an indication of a difference in structure between the eastern and western Gulf of Mexico. Along one path in the western Caribbean Sea between Colombia and Cuba the velocities were almost continental. High velocities found for part of the eastern Caribbean indicate an almost oceanic character for this region.

For each earthquake examined the initial phases were determined with an error less than ± π/4. For a given earthquake in all cases except two the initial phases were found to be the same at all stations.
A comparison of multiple solutions of focal mechanisms
Authors: Stauder William
Published: July 2021

The occurrence of focal mechanism solutions of the same earthquake by different authors is examined. Of 42 instances of such multiple solutions for earthquakes which occurred around the borders of the Pacific Ocean, it is found that of 84 possible pairs of multiple solutions agreement is excellent in 8 cases, good in 13, fair in 19, poor in 19, and no agreement in 25. The implication for focal mechanism studies is illustrated by examining the focal mechanism solutions of deep-focus earthquakes under the Sea of Japan.