bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seismicity Rate Change as a Tool to Investigate Delayed and Remote Triggering of the 2010–2011 Canterbury Earthquake Sequence, New Zealand
Authors: Yin Yifan , Wiemer Stefan , Kissling Edi , Lanza Federica , Rinaldi Antonio P. , Gerstenberger Matthew , Fry Bill 
Published: May 2021

ABSTRACTCrustal earthquakes in low-strain-rate regions are rare in the human life span but can generate disastrous consequences when they occur. Such was the case in the Canterbury earthquake sequence that began in 2010 and eventually led to almost 200 fatalities. Our study explores this earthquake sequence’s origins by producing an enhanced earthquake catalog in the Canterbury Plains and Otago, South Island, New Zealand. We investigate seismicity rate changes from 2005 to before the 2010 Mw 7.2 Darfield earthquake. During this time, major subduction-zone earthquakes, such as the 2009 Mw 7.8 Dusky Sound earthquake, created measurable coseismic and postseismic strain in the region. We use template matching to expand the catalog of earthquakes in the region, and use a support vector machine classifier to remove false positives and poor detections. We then compare the newly obtained seismicity rates with the coseismic and postseismic crustal strain fields, and find that seismicity rate and crustal strain are positively correlated in the low-stress, low-seismicity region of the northern Canterbury Plains. In contrast, near fast-moving plate-boundary faults, the seismicity rate changes rise without much change in the strain rate. Our analysis reveals a substantial seismicity rate decrease in the western rupture area of the Darfield earthquake, which we infer to be an effect of coseismic and postseismic deformation caused by the Dusky Sound earthquake. We show in low-strain-rate regions, stress perturbation of a few kPas creates substantial seismicity rate change. However, the implication that such seismic quiescence is responsible for the nucleation of the Darfield earthquake requires further studies.
Multiscale Temporal and Spatial Estimation of the b-Value
Authors: García-Hernández Rubén , D’Auria Luca , Barrancos José , Padilla Germán D. , Pérez Nemesio M. 
Published: May 2021

Abstract
The estimation of the b-value of the Gutenberg–Richter law is of great importance in different seismological applications. However, its estimate is strongly dependent upon selecting a proper temporal and spatial scale, due to the multiscale nature of the seismicity. For this reason, we propose a novel approach (MUltiscale Spatial and Temporal estimation of the B-value [MUST-B]), which allows consistent estimation of the b-value, avoiding subjective “a priori” choices, by considering simultaneously different temporal or spatial scales. A reliable appraisal of the b-value is obtained by applying a robust median over the estimates computed over all the considered scales.
We validate the method using a synthetic dataset, showing its superior performances, compared to traditional approaches, in detecting sharp changes in the b-value as well as inconsistently mapping it for highly heterogeneous catalogs.
We apply MUST-B to study the temporal and spatial variations of the b-value during the complex 2016–2017 seismic sequence in central Italy, revealing various interesting patterns. In particular, we observe a marked drop of the b-value after the Accumoli (24 August 2016 M 6.0) mainshock. The drop is also observed when realizing a tridimensional mapping of the b-values, showing the drop occurs mainly in the proximity of major earthquake hypocenters. In accordance with previous studies, we interpret these variations as the effect of the release of crustal fluids following the major earthquakes.
We maintain that MUST-B can also be applied to other contexts, such as volcanic and induced seismicity, because of its capacity of dealing consistently with highly heterogeneous seismicity patterns.
An approximate solution of the steady forced vibration of a system of one degree of freedom under the influence of various types of damping1
Authors: Jacobsen Lydik S. 
Published: May 2021

AbstractIn this paper the author presents a general method of obtaining approximate solutions of the steady forced vibration of a damped system of one degree of freedom for the case of sinusoidally varying disturbing forces.The approximation consists in expressing all the damping terms of the original differential equation by a single equivalent damping term, proportional to the first power of the velocity of motion.In the case of a system influenced by a centrifugal disturbing force and damped by constant friction and by friction proportional to the first power of the velocity, experimental evidence is in good agreement with the approximate solution.While the paper deals solely with a system of one degree of freedom, there is no reason aside from complexity why the approximate solution cannot be applied to systems of several degrees of freedom.
Discussion of fundamental factors involved in the underwriting of earthquake insurance*
Authors: Chick Alton C. 
Published: May 2021

Summary
This discussion of the fundamental factors involved in the underwriting of earthquake insurance is presented as a focus for constructive criticism and further discussion.
The underwriting of earthquake insurance at the present time calls for the best judgment that can be exercised in order to be fair to the insurance company as well as to the property-owner. Long strides are now being made in gathering data upon the magnitude and type of earthquake motions, and more comprehensive analyses are being made upon the effect of earthquakes upon various types of structures, so that in the future we may anticipate having much more information upon which to promulgate proper rates to be charged for earthquake insurance.
A simplification in the conditions for the zero-length-spring seismograph*
Authors: LaCoste Lucien J. B. 
Published: May 2021

Abstract.
It has been found that for the zero-length-spring seismograph recently described the length of the arm need not equal the distance from the pivot to the point of attachment of the spring. The proof of the infinite period is given for the more general case, and the effect on the period of slight deviations from the conditions for infinite period is shown.
The Richmond Quarry blast of August 16, 1934
Authors: Byerly Perry , Wilson James T. 
Published: May 2021

SummaryThe records of the Richmond Quarry blast of August 16, 1934, indicate that the speed of longitudinal waves in the Franciscan formation of the San Francisco Bay region is 4.3 km/sec. The speed of transverse waves in the same medium is very probably 2.4 km/sec. The speed in the underlying medium is 5.4 km/sec. for the longitudinal waves and possibly 3.1 km/sec. for the transverse waves. The medium may therefore be identified as granite, which was to be expected from geological considerations.The thickness of the Franciscan formation in the region as computed from data given by this blast is about one kilometer.
Local earthquakes in New England*
Authors: Collins Mary P. 
Published: May 2021

Summary
During 1934 and 1935, records of approximately 150 definitely local disturbances were obtained on the Benioff seismographs at the Harvard Seismograph Station. Because of a curious concentration in the daytime hours and the few earthquakes reported felt during this interval, an attempt was made to establish criteria by which records of blasts and of local earthquakes might be distinguished from each other. Three, the ratio of the maximum P to the maximum S, the character of the surface waves, and the angle of emergence are discussed. The records of 32 of these disturbances, well recorded on all three Benioff components, are described. It is concluded that, although some of New England's seismic activity is artificial, there is, nevertheless, a greater amount of natural activity than is ordinarily attributed to this region.
The New Hampshire earthquakes of November 9, 1936, and further data on New England travel times*
Authors: Collins Mary P. 
Published: May 2021

Summary
Two earthquakes were reported felt in northern and central New Hampshire on the evening of November 9, 1936. These were the third and fourth reported from the state in fourteen months. The epicenters of these two shocks have been determined as 43° 33′ N, 71° 26′ W, and 44° 39′ N, 71° 40′ W. The previous seismic history of the state and the relation of these earthquakes to the geology of the region are discussed.
The Alaskan earthquake of July 22, 1937*
Authors: Adkins John N. 
Published: May 2021

SummaryThe study of the Alaskan earthquake of July 22, 1937, is based on the examination of original seismograms and photographic copies from seismological observatories throughout the world.The arrival times of P at 71 stations were used in locating the epicenter. By Geiger's method and the use of Jeffreys' travel times, the position of the epicenter was found to be: geographical latitude, 64.67±.04° N, longitude, 146.58±.12° W, and the time of occurrence to be 17h 9m 30.0±.25s, U.T. The epicenter lies in the Yukon-Tanana upland in central Alaska, which is not a region of frequent major earthquakes.The disagreement caused by the apparently early arrivals at College and Sitka was reduced by replacing the standard travel-time curve of P by a linear travel-time curve in the interval of epicentral distance 0° to 16° and by interpreting the first arrival at College as P.It was possible to determine the direction of the first motion of P for 51 stations. The observed distribution of first motion and the geological trends in the region of the epicenter are consistent with the earthquake's having been caused by movement along a fault with strike between N 30° E and N 37° E, and dip between 64° and 71° to the southeast, in which the southeast side of the fault was displaced relatively northeastward with the line of movement pitching between 12° and 16° northeast.A wave designated F (for “false S”) was found to precede S on the records by 20 to 55 seconds, depending on the epicentral distance. The wave is longitudinal in type and the arrival times define a linear travel-time curve. It is suggested that this wave may be a longitudinal surface wave, of the type proposed by Nakano, produced at the surface of the earth by the arrival of a transverse wave which has been reflected at a surface of discontinuity within the earth.The records show two impulses near the time when S is expected. The average time interval between the two impulses is 11.3 sec. The first, called S1, has a plane of vibration intermediate in direction between the plane of propagation and the normal thereto. The second impulse, called S2, is nearly pure SH movement.The writer wishes to express his indebtedness to Professor Perry Byerly for invaluable suggestions and criticism during the course of the investigation.
On the very large Pacific earthquake of November 10, 1938*
Authors: Mukherjee S. M. , Rangaswami M. R. 
Published: May 2021

Summary
Using the observed times of P, the epicenter of the very large shock of November 10, 1938, is located at 55°.3N and 158°.5W, about 80 miles to the south of the Alaskan Peninsula, in the Pacific. The time of occurrence is obtained as 20h 18m 40s, G.M.T.
Analysis of P and S residuals reveals that there were three successive shocks, the second and the third occurring 7 and 12 sec. after the first. Examination of the Indian seismograms points to a fourth shock, about 20 sec. after the first. The multiple character of the shock is brought out more conspicuously when the observed times are compared with Jeffreys' surface-focus tables and corrected for ellipticity, than when compared with normal tables. The epicenters of the first three shocks are found to be the same.
The possibility of identifying the second movement of P with sP or pP, and that of S with sS, was considered, but was found to be untenable in view of the depth of focus and available noninstrumental observations. The hypothesis of “surface focus” appears to fit in best with the present series of observations. The magnitude of the shock is calculated as 8.2.
In conclusion, we tender our respectful thanks to Dr. S. R. Savur, M.A., Ph.D. (Lond.), for his continued interest and some helpful criticisms.
A mechanical analyzer for the prediction of earthquake stresses*
Authors: Biot M. A. 
Published: May 2021

Abstract
The earthquake stresses in a structure are generally greater than those which would be produced by a constant acceleration equal to the maximum value reached during the earthquake; there is an amplification due to resonance. This effect depends on the period of the structure and is measured by a function of the period, designated here as the spectrum of the earthquake. A mechanical analyzer is described by which the spectrum curves for several strong-motion earthquakes have been plotted. It is shown how the spectrum can be used for the evaluation of earthquake stresses in complicated structures, and the particular example is treated of a multistory building with an elastic first story.
Earthquake magnitude, intensity, energy, and acceleration*
Authors: Gutenberg B. , Richter C. F. 
Published: May 2021

Summary
The paper investigates the principal physical elements of earthquakes: the magnitude M, energy E, intensity I, acceleration a, and their relation to the depth h and radius of perceptibility r. (r2 + h2 = R2. Subscript zero (0) refers to the epicenter.) Equations
log ⁡ a = I 3 − 1 2
and
A D 2 T 2 = constant
(A = ground amplitude, T = period, D = hypocentral distance for a given shock) are established empirically for California shocks. Equation (9) holds very generally, and offers a basis for a more accurate definition of I, like that suggested by Cancani. Equation (4) is here used very generally at short distances; but it is approximate only, may differ regionally, and bridges over the probably discontinuous transition of the maximum acceleration from S̄ to some other transverse wave, with increasing distance. However, consequences derived from (4) nowhere conflict seriously with observation.
The instrumental earthquake-magnitude scale has been extended to cover short distances. The results enter into an empirical relation
M = 2.2 + 1.8 log ⁡ a 0
from which and (9) follows
M = 1.3 + 0.6 I 0
These two equations are established and verified for the California region; they should also hold in other regions of similar structure for earthquakes originating at about the same depth (which is roughly 18 km.).
The simplest possible assumptions (constant velocity, negligible absorption, sinusoidal waves) lead to the general equation
log ⁡ E = 14.9 + 2 log ⁡ h + log ⁡ t 0 + 2 log ⁡ T 0 + 2 log ⁡ a 0
(t0 = duration, T0 = period, of sinusoidal wave train at the epicenter).
Equations (27), (9), and (4) give the generally applicable results
a 0 h 2 = a D 2 = a r R 2
I 1 − I 2 = 6 log ⁡ D 2 D 1
I 0 − 1.5 = 6 log ⁡ R h
ar, the minimum perceptible acceleration, is approximately 1 gal.
For shocks at the usual depth in California
log ⁡ E = 11.3 + 1.8 M
For other depths, and probably for other regions,
log ⁡ E = 9.5 + 3.2 log ⁡ h + 1.1 I 0
log ⁡ E = 11.1 + 6.4 log ⁡ R − 3.2 log ⁡ h
A summary of the physical elements for shocks in California is given in table 10.
Equation (13) is used to calculate apparent depths for earthquakes in the United States and Europe. The results tend to confirm the relatively shallow origin of shocks on the Pacific Coast compared with those occurring elsewhere, particularly under the Canadian Shield, the central Mississippi Valley, and the southern Appalachians.
The amplitude ratio, PP/P, as recorded by Galitzin seismographs*
Authors: Mei Alexis I. 
Published: May 2021

Abstract
The ratio of the amplitude of the longitudinal wave reflected at the surface of the earth to that of the direct wave as recorded by Galitzin seismographs was examined to find whether it might be used as a means of distinguishing between Pacific and continental reflections.
Theoretically, assuming that equal energy is radiated in all directions from the source, the amplitude ratio, PP/P, for Pacific reflections should be smaller than for continental reflections at all epicentral distances, if the speed of P waves near the surface is higher under the Pacific than under the continents.
The records of 194 earthquakes with epicenters at distances from 19° to 103°, and having reflections under the continents or the Pacific Ocean, were examined for the purpose. No such pattern as expected by theory was observed; on the contrary there resulted a general scattering when these ratios were plotted, for both types of reflection, against epicentral distances.
The observed values of the apparent angle of incidence agreed better with those calculated for V = 8.00 km/sec. than with those for V = 6.00 km/sec., where V is the velocity of P waves near the surface of the earth. Since 8.00 km/sec. is the velocity of longitudinal waves below the surface layers of the continents, while 6.00 km/sec. is an intermediate velocity within the layers, it was concluded that the waves recorded by the Galitzin seismographs were not refracted into the surface layers of the earth and consequently that the amplitudes of waves of the periods recorded on Galitzin seismographs (4 sec. to 12 sec.) do not afford a means of differentiating between reflections at a layered surface such as the continent and at an unlayered surface such as Gutenberg considers the Pacific to be.
However, comparison of some twenty records of the vertical Benioff seismograph of approximately 0.7 sec. free period (recorded waves of periods 1 sec. to 2 sec.) with those of the same earthquakes recorded by the Galitzins of 12 sec. free period showed no essentially different behavior.
It was observed that the Berkeley, California, and Florissant, Missouri, stations, both using Galitzin instruments of nearly the same constants, were situated at the same distances from eight Mexican epicenters, and both received impulses from these earthquakes over the same kind of continental paths. An examination of their respective values of PP/P showed this to be larger at one station or another according as the first recorded motion at Berkeley was a condensation or a rarefaction. This variation in the values of PP/P shows that energy is not sent out equally in all directions from the source, as was assumed, and therefore that the mechanism at the focus plays an important part in the value of this ratio.
Further developments in the wavelet theory of seismogram structure*
Authors: Ricker Norman 
Published: May 2021

Abstract
In this paper the wavelet theory of seismogram structure previously proposed by the author has been extended to obtain the form of the seismic disturbance (due to a sharp seismic pulse) at various distances from the source. The solution of Stokes's differential equation is given in the form of a series of wavelet functions, and calculated seismograms are presented to show the manner in which the shape, breadth, and amplitude of the disturbance vary with the distance from the source. Tables are given of the wavelet functions and wavelet-form functions used in the calculations.
De bassin cotonnier à bassin anacardier: facteurs explicatifs de l’expansion de la culture de l’anacarde à Fronan en Côte d’Ivoire
Authors: Nanfouhoro Paul-Kévin Ouattara 
Published: May 2021

Traditionnellement culture industrielle des paysans de la Sous-Préfecture de Fronan dans la Région du Hambol en Côte d’ivoire, le coton a désormais fait la place à la culture de l’anacardier. Les paysans tagbanan de cette localité ont abandonné l’agriculture cotonnière au profit de celle de l’anacarde. La présente étude examine les facteurs qui ont milité en faveur du basculement des paysans. Il s’agit de connaitre les causes de l’expansion de la culture de l’anacarde sachant qu’elle n’a pas bénéficié d’une stratégie de vulgarisation et surtout ne bénéficie pas d’un encadrement de proximité à l’image du coton. Les données ont été collectées au moyen de guides d’entretien avec les anciens acteurs de la filière coton notamment les anciens responsables de GVC et des anciens cultivateurs de coton, les planteurs d’anacarde. Ces informations ont été complétées par une observation du terrain et l’exploitation de la documentation relative à la question. Il en ressort que les facteurs qui ont favorisé le dynamisme de la culture de la noix de cajou à Fronan sont nombreuses. L’étude relève d’une part des raisons économiques et structurelles. Elles sont relatives aux difficultés de la filière cotonnière dans les années 1980. Elle note également que des prédispositions sociales et psychologiques favorisées par les investissements de planteurs de café et de cacao de retour au village ont influencé leur choix. Ainsi, en procédant par comparaison avec la culture de coton, les agriculteurs d’anacarde ont trouvé cette dernière plus avantageuse et plus rentable.
Mots clés : Agriculture, économie de plantation, coton ; anacarde, Fronan, Hambol
Patriot – new variety of vegetable pieas
Authors: Besedin A. G. , Tikhonova A. V. , Putina O. V. 
Published: May 2021

Relevance. The purpose of the research was to produce a new medium-ripe, high-yielding variety of vegetable peas with the usual type of leaf to expand the variety in the now used conveyor variety selection of the Krymsk EBS VIR Branch.Materials and methods. The experience was laid on the fields of the Krymsk EBS VIR Branch (Russia, Krasnodar Region, Krymsk) in 2019-2020. Varieties and strain were evaluated in a competitive variety testing. Sowing was carried out with a selection seeder SKS-6-10. The plot area was 10 m2 , the experiment was repeated four times. In the phase of technical ripeness, the sheaves were selected for description and the yield was taken into account. The conservation of green peas was done at the Tech Evaluation Lab.Results. Competitive variety testing in the mid-ripeness group was held by two strains 2014/7 and 344/16. The strain 2014/17 for green pea yields surpassed the standard "Parus" and G-344/16 in both years of study. Fresh and processed green peas were rated by the Tasting Commission at 5.0 and 4.8 points, respectively. High yield is achieved due to the paired beans on the peduncle and a large number of grains in the bean, up to 10 pieces. The grain in technical ripeness has a dark green color and the linear dimensions are 9.0x8.1 mm. In biological maturity, the seeds are intensely green, angular-compressed with a mass of 1000 pieces. 188-225 g.Conclusion. The results of field and laboratory analyses carried out on the complex of economicvaluable characteristics made it possible to distinguish the strain 2014/7, which in 2020 was transferred to the State Variety Testing under the name "Patriot". It is recommended as a supplement to the existing set of vegetable pea varieties of the Krymsk EBS VIR Branch in the mid-ripe group.