bluuebunny/crossref_metadata_2025 huggingface dataset:
Amplification and differential motion due to an antiplane 2D resonance in the sediment valleys embedded in a layer over the half-space
Authors: Moczo Peter , Labák Peter , Kristek Jozef , Hron Franta
Published: September 2021

We investigate an antiplane 2D resonance in a certain class of the sedimentary structures using the finite-difference modeling. Our models are derived from the realistic local geologic conditions beneath the colosseum in Rome and are significantly different from those investigated in the previous theoretical articles on a 2D resonance. They include a trough at the bottom of the horizontal surface layer as well as relatively deep sediment valleys embedded in a single layer over the halfspace.

We present the finite-difference algorithm for SH waves on a combined (h × h and 2h × 2h) rectangular grid. Although being simple, the algorithm allowed us to save up to 75% of the grid points compared with the regular grid h × h that would cover the same computational region.

A 2D resonance may develop in the valleys that do not satisfy Bard and Bouchon's existence condition.

A simple trough at the bottom of the horizontal surface layer can give rise to the fundamental mode of a 2D resonance whose frequency, spectral amplification, and the maximum time-domain differential motion are very close to those in the closed sediment valley.

Our results confirm that the resonance phenomenon is quite robust and that it is to be expected in many configurations of sediment valleys or basins.
Physical significance of earthquake quanta
Authors: Wu Z. L. , Chen Y. T. , Kim S. G.
Published: September 2021

The physical significance of “earthquake quanta” is discussed in the perspective of a proposed concept “seismon.” It is pointed out that the physical significance of earthquake quanta may be understood in the way similar to that of phonon in solid-state physics. Using the statistical properties of the seismons, the property such that for large earthquakes the mean stress drop is approximately constant, while for small events the mean stress drop increases with the seismic moment, may be obtained, without detailed considerations of the failure criteria and the interaction between different earthquake quanta.
What is a reference site?
Authors: Steidl Jamison  H. , Tumarkin Alexei  G. , Archuleta Ralph  J.
Published: September 2021

Many methods for estimating site response compare ground motions at sites of interest to a nearby rock site that is considered a “reference” motion. The critical assumption in these methods is that the surface-rock-site record (reference) is equivalent to the input motion at the base of the soil layers. Data collected in this study show that surface-rock sites can have a site response of their own, which could lead to an underestimation of the seismic hazard when these sites are used as reference sites. Data were collected from local and regional earthquakes on digital recorders, both at the surface and in boreholes, at two rock sites and one basin site in the San Jacinto mountains, southern California. The two rock sites, Keenwild and Piñon Flat, are located on granitic bedrock of the southern California peninsular ranges batholith. The basin site, Garner Valley, is an ancestral lake bed with watersaturated sediments, on top of a section of decomposed granite, which overlies the competent bedrock. Ground motion is recorded simultaneously at the surface and in the bedrock at all three sites. When the surface-rock sites are used as the reference site, i.e., the surface-rock motion is used as the input to the basin, the computed amplification underestimates the actual amplification at the basin site for frequencies above 2 to 5 Hz. This underestimation, by a factor of 2 to 4 depending on frequency and site, results from the rock sites having a site response of their own above the 2-to 5-Hz frequencies. The near-surface weathering and cracking of the bedrock affects the recorded ground motions at frequencies of engineering interest, even at sites that appear to be located on competent crystalline rock. The bedrock borehole ground motion can be used as the reference motion, but the effect of the downgoing wave field and the resulting destructive interference must be considered. This destructive interference may produce pseudo-resonances in the spectral amplification estimates. If one is careful, the bedrock borehole ground motion can be considered a good reference site for seismic hazard analysis even at distances as large as 20 km from the soil site.
The influence of errors in source parameters on phase velocity measurements of surface waves
Authors: Muyzert Everhard , Snieder Roel
Published: September 2021

The phase of both Love and Rayleigh waves can be very sensitive to errors in the source parameters. This unstable behavior of the phase depends on the source parameters and is frequency dependent. Fractional errors larger than 10° in the phase measurements can arise when realistic errors in the source parameters are considered. When these phase measurements are interpreted as phase velocity, uncertainties up to 3% can occur when errors in the source parameters are considered. The frequency bands where the unstable behavior occurs can be found by calculating the partial derivative of the initial phase with respect to the various source parameters. We have tested this method on a Rayleigh wave data set and find a good correlation between outliers in the data set and large partial derivatives of the source parameters.
Interpretation of significant ground-response and structure strong motions recorded during the 1994 Northridge earthquake
Authors: Shakal A. F. , Huang M. J. , Darragh R. B.
Published: September 2021

Some of the largest accelerations and velocities ever recorded at ground-response and structural sites occurred during the Northridge earthquake. These motions are greater than most existing attenuation models would have predicted. Although the motions are large, the correspondence between measured acceleration and damage requires further study, since some sites with high acceleration experienced only moderate damage. Also, some peak vertical accelerations were larger than the horizontal, but in general, they are smaller and fit the pattern observed in previous earthquakes. Strong-motion records processed to date show significant differences in acceleration and velocity waveforms and amplitudes across the San Fernando Valley.

Analysis of processed data from several buildings in the San Fernando Valley indicates that short-period buildings such as shear-wall buildings experienced large forces and relatively low inter-story drift during the Northridge earthquake. However, long-period (1 to 5 sec) steel or concrete moment-frame buildings experienced large inter-story drift. For this earthquake, accelerations did not always amplify from base to roof for flexible structures like the moment-frame buildings, but the displacements were always larger at the roof. The drifts at many of the moment-frame buildings were larger than the drift limit for working stress design in the building code. The records from a base-isolated building indicate that high-frequency motion was reduced significantly by the isolators. The isolators deformed about 3.5 cm, which is much less than the design displacement. The records from a parking structure show important features of the seismic response of this class of structure.
Seismological studies at Parkfield IV: Variations in controlled-source waveform parameters and their correlation with seismicity, 1987 to 1995
Authors: Karageorgi E. , McEvilly T. V. , Clymer R.
Published: September 2021

Since June 1987 at Parkfield, California, the 10-station borehole network of three-component sensors has been illuminated 52 times using a shear-wave vibrator in three orientations at up to eight source points, in a search for temporal changes in elastic wave P and S velocities, anisotropy, or attenuation. The monitoring interval includes the beginning and end of a severe 3-yr drought and four earthquake sequences, two of which produced the only A-level alerts to date in the Parkfield Prediction Experiment. A comprehensive study of the entire data set reveals a progressive travel-time advance in the coda of S waves propagating in a localized region southeast of Middle Mountain. The anomalous wave field exhibits high apparent velocities, suggesting deep penetration of the fault zone, although similar changes are not seen in waveforms from repeating similar microearthquakes. Accompanying the changes in travel time were systematic variations in spectral content and polarization of the same segments of the wave field. These variations correlate well in time and space with significant features of seismicity, fault creep, and water levels at Parkfield. A preferred mechanism for the phenomenon is changing hydrologic conditions along the affected stretch of the fault zone, possibly deformation-induced, that perturb the shallow-propagating S coda in the upper few hundred meters of section.
Site amplifications for generic rock sites
Authors: Boore David M. , Joyner William B.
Published: September 2021

Seismic shear-wave velocity as a function of depth for generic rock sites has been estimated from borehole data and studies of crustal velocities, and these velocities have been used to compute frequency-dependent amplifications for zero attenuation for use in simulations of strong ground motion. We define a generic rock site as one whose velocity at shallow depths equals the average of those from the rock sites sampled by the borehole data. Most of the boreholes are in populated areas; for that reason, the rock sites sampled are of particular engineering significance. We consider two generic rock sites: rock, corresponding to the bulk of the borehole data, and very hard rock, such as is found in glaciated regions in large areas of eastern North America or in portions of western North America. The amplifications on rock sites can be in excess of 3.5 at high frequencies, in contrast to the amplifications of less than 1.2 on very hard rock sites. The consideration of unattenuated amplification alone is computationally convenient, but what matters for ground-motion estimation is the combined effect of amplification and attenuation. For reasonable values of the attenuation parameter κ0, the combined effect of attenuation and amplification for rock sites peaks between about 2 and 5 Hz with a maximum level of less than 1.8. The combined effect is about a factor of 1.5 at 1 Hz and is less than unity for frequencies in the range of 10 to 20 Hz (depending on κ0).

Using these amplifications, we find provisional values of about Δσ = 70 bars and κ0 = 0.035 sec for rock sites in western North America by fitting our empirically determined response spectra for an M 6.5 event to simulated values.

The borehole data yield shear velocities (V30) of 618 and 306 m/sec for “rock” and “soil” sites, respectively, when averaged over the upper 30 m. From this, we recommend that V30 equals 620 and 310 m/sec for applications requiring the average velocity for rock and soil sites in western North America.

By combining the amplifications for rock sites and the site factors obtained from our analysis of strong-motion data, we derive amplifications for sites with V30 = 520 m/sec (NEHRP class C, corresponding to a mix of rock and soil sites) and V30 = 310 and 255 m/sec (average soil and NEHRP class D sites, respectively). For the average soil site, the combined effect of amplification and attenuation exceeds a factor of 2.0 for frequencies between 0.4 and about 4 Hz, with a peak site effect of 2.4; the peak of the NEHRP class D site effect is 2.7.
An absolute method of vertical seismometer calibration by reference to a falling mass with application to the measurement of the gain
Authors: Canuteson Eric , Zumberge Mark , Hanson Jeffrey
Published: September 2021

We measure the gain of a vertical seismometer by simultaneously recording the output of the seismometer and repeatedly measuring the displacement between the seismometer and a free-falling mass in a vacuum. The falling object provides an inertial reference frame. By comparing the ground motion measured by the seismometer with the independent record of displacement between the seismometer and inertial space, we obtain the gain. It is an absolute measurement of the gain relative to the local Lorentz reference frame. Bootstrap error estimates show that a high precision in the estimate of the gain can be obtained with a small number of individual drops. The method derived can be extended to multi-parameter searches of the vertical response function. The technique is also shown to reduce noise in absolute gravity measurements due to ground noise. Finally, we discuss the potential for replacing vibration isolation schemes in absolute gravity systems with digital noise reduction.
Static stress changes and earthquake triggering during the 1954 Fairview Peak and Dixie Valley earthquakes, central Nevada
Authors: Caskey S. J. , Wesnousky S. G.
Published: September 2021

The 16 December 1954 Dixie Valley (MS 6.8) earthquake followed the Fairview Peak (MS 7.2) earthquake by only 4 min and 20 sec. A three-dimensional model of the two dip-slip fault systems based on recent detailed field studies shows the ruptures were separated by a 6-km step in surface trace. A boundary-element approach shows that the static stress changes imposed by rupture of the Fairview Peak earthquake are in the correct sense to explain the northward propagation of faulting along four distinct faults that comprise the Fairview Peak earthquake and the subsequent triggering of the Dixie Valley earthquake. The location of rupture end points at sites where static stresses change sign is also used to suggest that static stress changes may play a role in controlling the extent of fault ruptures. We also observe that the largest coseismic surface displacements tend to correlate with those sections of the faults showing the largest positive stress change from preceding ruptures.
An evaluation of generalized likelihood ratio outlier detection to identification of seismic events in western China
Authors: Taylor Steven R. , Hartse Hans E.
Published: September 2021

The generalized likelihood ratio outlier detection technique for seismic event identification is evaluated using synthetic test data and frequency-dependent Pg/Lg measurements from western China. For most seismic stations that are to be part of the proposed International Monitoring System (IMS) for the Comprehensive Test Ban Treaty (CTBT), there will be few or no nuclear explosions in the magnitude range of interest (e.g., mb < 4) on which to base an event-identification system using traditional classification techniques. Outlier detection is a reasonable alternative approach to the seismic discrimination problem when no calibration explosions are available. Distance-corrected Pg/Lg data in seven different frequency bands ranging from 0.5 to 8 Hz from the Chinese Digital Seismic Station WMQ are used to evaluate the technique. The data are collected from 157 known earthquakes, 215 unknown events (presumed earthquakes and possibly some industrial explosions), and 18 known nuclear explosions (1 from the Chinese Lop Nor test site and 17 from the East Kazakh test site). A feature selection technique is used to find the best combination of discriminants to use for outlier detection. Good discrimination performance is found by combining a low-frequency (0.5 to 1 Hz) Pg/Lg ratio with high-frequency ratios (e.g., 2 to 4 and 4 to 8 Hz). Although the low-frequency ratio does not discriminate between earthquakes and nuclear explosions well by itself, it can be effectively combined with the high-frequency discriminants. Based on the tests with real and synthetic data, the outlier detection technique appears to be an effective approach to seismic monitoring in uncalibrated regions.
Slip history of the 1994 Sanriku-Haruka-Oki, Japan, earthquake deduced from strong-motion data
Authors: Nakayama Wataru , Takeo Minoru
Published: September 2021

We analyzed the seismic waves of the 1994 Sanriku-Haruka-Oki earthquake (Mw = 7.7), which occurred in the aftershock area of the 1968 Tokachi-Oki earthquake (Mw = 8.2). Applying a multiple-time window inversion scheme to near-source strong-motion data, we obtained a detailed spatiotemporal rupture process and compared it with that of the Tokachi-Oki earthquake. The fault geometry is constructed based on the aftershock distribution. The obtained rupture model is consistent with the CMT solution even for a non-double-couple component. The total seismic moment is 4.0 × 1020 N-m. Large slips are concentrated in three asperities: the first asperity centers about 40 km south and 50 km west from the hypocenter with a maximum slip of 4.4 m, the second one centers about 60 km west from the hypocenter with a maximum slip of 2.2 m, and the third one lies about 110 km west from the hypocenter with a maximum slip of 2.6 m. The obtained moment rate and the duration on the first and second asperities are lower and much longer than those on the third asperity, respectively. The first asperity does not overlap with an area of large slip during the Tokachi-Oki earthquake, but the second or third seem to overlap with or be adjacent to the asperity of the Tokachi-Oki earthquake. Our inversion result also shows an abrupt change of the rupture velocity (from 1.8 to 3.0 km/sec) at the central part of the fault plane. A difference of the seismic coupling between the oceanic and the continental lithospheres at the trenchward side and at the landward side of the 143° E meridian seems to affect the rupture process of this earthquake.
Frequency response of a strainmeter
Authors: Lomnitz Cinna
Published: September 2021

The amplification of a strainmeter is frequency dependent. As the wavelength λ approaches the length L of the strainmeter, the amplitude vanishes, because the two extremes of the strainmeter are in phase. The sign of the response is inverted at zero crossings such that λ = L/n, n = 1, 2,…. Between L < λ < 2L, the amplitude of an incoming signal may be reduced by 60% or more. Filtering of the output may worsen the problem. Thus, strainmeters may be poorly suited for certain research purposes, including surface-wave studies and first-motion studies. The output of long-base strainmeters sited on low-velocity materials (such as the 732-m-long strainmeters at Piñon Flat Observatory) may require correction for amplitude distortion.
Evidence for stability in coda Q associated with the Egion (central Greece) earthquake of 15 June 1995
Authors: Tselentis G-Akis
Published: September 2021

One hundred seventy-two seismograms, recorded at one seismological station located close to the source region of the Egion (Ms = 6.2) 15 June 1995 earthquake, were used to measure values of Q from the decay of the earthquake coda. The collected data were compared between events that occurred before and after the main event. The analysis showed no significant temporal variation in the value of coda Q for the region.
Ground-motion characteristics estimated from spectral ratio between horizontal and vertical components of microtremor
Authors: Konno Katsuaki , Ohmachi Tatsuo
Published: September 2021

The spectral ratio between horizontal and vertical components (H/V ratio) of microtremors measured at the ground surface has been used to estimate fundamental periods and amplification factors of a site, although this technique lacks theoretical background. The aim of this article is to formulate the H/V technique in terms of the characteristics of Rayleigh and Love waves, and to contribute to improve the technique. The improvement includes use of not only peaks but also troughs in the H/V ratio for reliable estimation of the period and use of a newly proposed smoothing function for better estimation of the amplification factor. The formulation leads to a simple formula for the amplification factor expressed with the H/V ratio. With microtremor data measured at 546 junior high schools in 23 wards of Tokyo, the improved technique is applied to mapping site periods and amplification factors in the area.
Dynamic stress changes during earthquake rupture
Authors: Day Steven M. , Yu Guang , Wald David J.
Published: September 2021

We assess two competing dynamic interpretations that have been proposed for the short slip durations characteristic of kinematic earthquake models derived by inversion of earthquake waveform and geodetic data. The first interpretation would require a fault constitutive relationship in which rapid dynamic restrengthening of the fault surface occurs after passage of the rupture front, a hypothesized mechanical behavior that has been referred to as “self-healing.” The second interpretation would require sufficient spatial heterogeneity of stress drop to permit rapid equilibration of elastic stresses with the residual dynamic friction level, a condition we refer to as “geometrical constraint.” These interpretations imply contrasting predictions for the time dependence of the fault-plane shear stresses. We compare these predictions with dynamic shear stress changes for the 1992 Landers (M 7.3), 1994 Northridge (M 6.7), and 1995 Kobe (M 6.9) earthquakes. Stress changes are computed from kinematic slip models of these earthquakes, using a finite-difference method. For each event, static stress drop is highly variable spatially, with high stress-drop patches embedded in a background of low, and largely negative, stress drop. The time histories of stress change show predominantly monotonic stress change after passage of the rupture front, settling to a residual level, without significant evidence for dynamic restrengthening. The stress change at the rupture front is usually gradual rather than abrupt, probably reflecting the limited resolution inherent in the underlying kinematic inversions. On the basis of this analysis, as well as recent similar results obtained independently for the Kobe and Morgan Hill earthquakes, we conclude that, at the present time, the self-healing hypothesis is unnecessary to explain earthquake kinematics.
Correcting regional seismic discriminants for path effects in western China
Authors: Hartse H. E. , Flores R. A. , Johnson P. A.
Published: September 2021

The effect of path on regional seismic wave propagation can be significant. In an effort to improve discriminant performance, we explore the effect of path upon Pg/Lg ratios. Our primary objective is to find path corrections that reduce scatter within earthquake and explosion ratio populations, while at the same time increasing the separation between the two populations. We emphasize the 1.5- to 3-Hz and 2- to 4-Hz bands, as Pg and Lg in these bands can often be observed at smaller magnitudes and greater distances than higher-frequency bands, which have previously been shown to be reliable discriminants. For data, we use 271 earthquakes from northwest China, 25 nuclear explosions from the Kazakh test site (KTS), and one nuclear explosion from the Lop Nor test site recorded at station WMQ. We also use 185 earthquakes from the same region and seven nuclear explosion from the Lop Nor test site recorded at station AAK. Event-station distances range from 200 to 1400 km, earthquake magnitudes range between mb 2.5 and 6.2, and explosion magnitudes range between mb 4.5 and 6.5. In addition to ratio-distance trends, we examine Pg/Lg ratio-parameter trends related to topography, basin thickness, and crustal thickness. The parameters we consider are mean, roughness, gradient mean, and gradient roughness of the topography, basin thickness, and crustal thickness along each event-station path. We also consider the same parameters after weighting by path length. Through linear regressions, we found path corrections that reduce scatter within event populations, and we also found path corrections that increase the separation between earthquakes and KTS explosions recorded at WMQ. We obtained the best improvement in discrimination performance at WMQ by removing the trends of topography roughness, mean topography, and the gradient of basin thickness after weighting the parameters by path length. For AAK, we found that removing the trends of mean topography and the basement roughness improved discrimination performance over the uncorrected case. However, unlike WMQ, weighting these parameters by path length degraded discriminant performance. Because we see no predictable or repeatable trends for “adjacent” central Asian stations and overlapping regions of interest, we recommend an even more empirical approach to correcting for the effect of path. Where earthquakes are abundant, such as the Tian Shan, contouring a grid of ratio residuals (for each band of interest) may be a simpler method of finding appropriate path corrections.
A global test of a time-frequency small-event discriminant
Authors: Hedlin Michael A. H.
Published: September 2021

The Comprehensive nuclear-Test-Ban Treaty (CTBT), which was recently adopted by the UN General Assembly and signed by President Clinton, has lowered the testing yield limit to zero and raised the profile of small earthquakes and mining blasts. Because relatively small events are very common, there is a strong need for automated algorithms that can be used to screen out the events that are obviously chemical or natural and identify those few curious enough to warrant closer scrutiny. The primary objective of this article is to assess the utility of high-frequency spectral modulations for the discrimination of mining blasts from earthquakes and single explosions at near-regional distances. Mining blasts commonly yield spectral modulations that are independent of time and the recording component. This article describes an automated discriminant that looks for these delay-fire diagnostics in data recorded on one or three components by single stations, arrays, or regional networks. Distinct deployments in central Asia, Europe, and North America are used to assess the transportability of the approach. The discriminant tests give misclassification probabilities, estimated with multivariate statistics, ranging from 0.5 to 3.5%. Discrimination using time-frequency expansions does not rely on expert interpretation but is quite routine.

The article explores likely causes of the occasional discrimination outliers. Factors that can eliminate spectral modulations from a delay-fired event include attenuation, detonation anomalies (where deviations from the designed, regular, shot sequence occur), and waveform variability. Some natural events and single explosions will exhibit spectral modulations that most likely result from propagation resonance. Data from Kyrgyzstan and Nevada is used to illustrate these effects; however, inadequate ground truth information and lack of calibration explosions in most of these datasets keeps definitive conclusions, regarding why the method will sometimes fail, out of reach. These observations underscore the need to train this algorithm to most effectively deal with these processes and pair it with other, complementary, discriminants to allow accurate characterization of all small events.
Self-consistent retrieval of source parameters using mantle waves
Authors: Gouget Karine , Ihmlé Pierre F. , Campos Jaime , Montagner Jean-Paul
Published: September 2021

The large number of high-quality stations from global networks (e.g., IRIS, GEOSCOPE) allows for rapid and robust recovery of source parameters of large earthquakes. We present a self-consistent analysis of surface waves in terms of directivity parameters. The boxcar is often used to recover source parameters but is rarely a faithful representation of an event's time function. We demonstrate that more reliable estimates of directivity parameters can be obtained when we take into account the source time function (STF) of the event. A low-frequency STF is obtained from first (R1) and second (R2) orbit Rayleigh waves in the range 2 to 15 mHz, with a spectral synthesis and inversion method. We measure the differential amplitudes between data and 3D synthetics. We use the R1/R2 ratio of differential amplitudes to invert, in a single narrow-frequency band, for the event's apparent rupture azimuth and velocity. For the Mw 8.1 Chile 1995 event, data are consistent with unilateral southward propagation, with a velocity of about 2.4 km/sec. For the Mw 7.9 Mexico 1995 earthquake, the rupture propagated toward the NW at about 2.0 km/sec. Our low-frequency estimates agree with broadband studies of both events and can be retrieved rapidly on a routine basis after a large earthquake.
Attenuation relationship for estimation of peak ground horizontal acceleration using data from strong-motion arrays in India
Authors: Sharma M. L.
Published: September 2021

An attenuation relationship for peak horizontal ground accelerations for Himalayan region in India has been developed. The data base consists of 66 peak ground horizontal accelerations from five earthquakes recorded by strong-motion arrays in India. The present analysis uses a two-step stratified regression model. The attenuation relationship proposed is

log ( A ) = − 1.072 + 0.3903 M − 1.21 log ( X + e 0.5873 M ) ,

where A is the peak ground acceleration (g), M is the magnitude, and X is the hypocentral distance from the source. The residual sum of squares is 0.14. Comparison with other such attenuation relationships have been made. The proposed relationship giving lesser values at shorter distances compared to other relationships needs further investigation with a larger data set. The attenuation relationship needs upgradation when more data become available in future.
A physical model of the effect of a shallow weak layer on strong ground motion for strike-slip ruptures
Authors: Brune James N. , Anooshehpoor Abdolrasool
Published: September 2021

We report results of foam rubber modeling of the effect of a shallow weak layer on ground motion from strike-slip ruptures. Computer modeling of strong ground motion from strike-slip earthquakes has in some cases involved somewhat arbitrary assumptions about the nature of slip along the shallow part of the fault (e.g., fixing the slip to be zero along the upper 2 km of the fault plane). Fault-slip inversion studies indicate that the high-frequency radiation from the shallow part of strike-slip faults is typically less than that for the deeper parts of the fault. In many cases, faults (1) may be weak along the upper few kilometers of the fault zone and may not be able to maintain high levels of shear strain required for high dynamic energy release during earthquakes and (2) may have different constitutive relations for fault slip, for example, slip strengthening. The object of this article is to present results of physical modeling using a shallow weak layer, in order to support the physical basis for assuming a long rise time and a reduced high-frequency pulse for the slip on the shallow part of faults. A weak zone was modeled by inserting weak plastic layers of a few inches in width into the foam rubber model. The long-term strength of the weak layer is about an order of magnitude less than the rest of the model. The transient strength is velocity strengthening with the strength estimated to be about three times higher at slip velocities typical of dynamic slip events. It appears a 2-km-deep, weak zone along strike-slip faults could indeed reduce the high-frequency energy radiated from shallow slip and that this effect can best be represented by superimposing a small-amplitude, short rise-time pulse at the onset of a much longer rise-time slip. For the 15-cm weak zone, the average pulse amplitude is reduced by a factor of about 0.4. The reduction factor for the 20-cm case is about 0.2. For the 30-cm case, it is about 0.1. From these results, we can see that the thicker the weak layer, the more difficult it is for a short rise-time acceleration pulse to push its way through the weak layer to the surface. The velocity strengthening property of the weak layer further damps the slip motion and increases the rise time. These results support reducing the high-frequency radiation from shallower parts of strike-slip faults in modeling studies if it is known that the shallow part of the fault is weak or has not stored up a large shear stress.
Using safety inspection data to estimate shaking intensity for the 1994 Northridge earthquake
Authors: Thywissen Katharina , Boatwright John
Published: September 2021

We map the shaking intensity suffered in Los Angeles County during the 17 January 1994, Northridge earthquake using municipal safety inspection data. The intensity is estimated from the number of buildings given red, yellow, or green tags, aggregated by census tract. Census tracts contain from 200 to 4000 residential buildings and have an average area of 6 km2 but are as small as 2 and 1 km2 in the most densely populated areas of the San Fernando Valley and downtown Los Angeles, respectively. In comparison, the zip code areas on which standard MMI intensity estimates are based are six times larger, on average, than the census tracts. We group the buildings by age (before and after 1940 and 1976), by number of housing units (one, two to four, and five or more), and by construction type, and we normalize the tags by the total number of similar buildings in each census tract. We analyze the seven most abundant building categories. The fragilities (the fraction of buildings in each category tagged within each intensity level) for these seven building categories are adjusted so that the intensity estimates agree. We calibrate the shaking intensity to correspond with the modified Mercalli intensities (MMI) estimated and compiled by Dewey et al. (1995); the shapes of the resulting isoseismals are similar, although we underestimate the extent of the MMI = 6 and 7 areas. The fragility varies significantly between different building categories (by factors of 10 to 20) and building ages (by factors of 2 to 6). The post-1940 wood-frame multi-family (≧5 units) dwellings make up the most fragile building category, and the post-1940 woodframe single-family dwellings make up the most resistant building category.
Quick and reliable determination of magnitude for seismic early warning
Authors: Wu Yih-Min , Shin Tzay-Chyn , Tsai Yi-Ben
Published: September 2021

This article reports efforts toward using real-time earthquake monitoring by the Taiwan Central Weather Bureau to meet the needs of seismic early warning. Twenty-three sets of strong-motion data from moderate earthquakes (ML > 5.0) in the Taiwan area are used to demonstrate the feasibility of this goal. For earthquakes larger than ML 5, epicenters can be reliably determined in about 15 sec after the arrival of the P wave at the nearest station. The earthquake magnitude ML cannot be determined in the same time frame due to incomplete recording of shear waves at some stations. However, the magnitude based on the first 10 sec of signal (ML10) can be related to ML as follows:

M L = 1.28 * M L 10 − 0.85 ± 0.13 .

Our results show that the real-time strong-motion system routinely used by the Central Weather Bureau can be used to determine epicenters and magnitudes in about 30 sec after occurrence of earthquakes in Taiwan. Such information hopefully can be used to reduce damage to society.
Propuesta financiera para la creación de la ruta agro turística cafetera del municipio de Gramalote, Norte de Santander
Authors: Mogrovejo Andrade Johanna Milena , Panizo Cardona Cesar Augusto , López Echeverry Marilyn
Published: September 2021

En el presente artículo se analizó la viabilidad de la creación de una ruta agroturística del café para el Municipio de Gramalote, Norte de Santander, Colombia. La propuesta se realiza debido a las dificultades por ingresos monetarios que presentan las personas del campo, situación que ha creado una enorme brecha económica entre lo rural y lo urbano. En este sentido, el municipio de Gramalote y sus veredas aledañas han sido tradicionalmente productoras del grano de café y cuenta con un rico acervo cultural y gastronómico, así como con una geografía privilegiada que la convierte en un atractivo potencial para las personas que buscan una forma de turismo diferente, basado en la tranquilidad y el aire limpio, así como la búsqueda de experiencias nuevas. Igualmente, la declaración del paisaje cultural cafetero, por la Unesco, como patrimonio de la humanidad, ha contribuido a que muchos turistas, especialmente los extranjeros, se interesen por este tipo de actividad. La investigación tuvo como objetivo general identificar las apuestas competitivas para la ruta agro turística del sector cafetero del municipio de Gramalote Norte de Santander, concluyéndose que esta es viable desde el punto de vista económico, y que los residentes de las zonas están interesados en la posibilidad de su creación debido que puede convertirse en una excelente fuente de ingresos, permitiéndoles mejorar su calidad de vida.
International online seminar "Artificial Societies and Information Technologies"
Authors: Konkova Tatiana
Published: September 2021

In 2020, the team of the Central Economics and Mathematics Institute of the Russian Academy of Sciences launched a regular international online seminar "Artificial Societies and Information Technologies". The seminar was attended by leading researchers in the field of agent modeling from Brazil, South Korea, India, China, France, Germany and other countries.
How Intelligence is Understood Today
Authors: Khasanov Rustam
Published: September 2021

The article is devoted to understanding the ways of explaining intellectual abilities in the light of new developments in the field of artificial intelligence and discoveries related to the study of complex adaptive animal behavior based on the reward system. The paper reviews the latest advances in the development of biologically plausible learning algorithms, the purpose of which is to explain the large amount of accumulated data from the field of neuroscience. Within the framework of this approach, reinforcement learning algorithms are proposed as the basis for any kind of cognitive activity. Understanding intelligence as a set of flexible adaptive abilities to achieve a goal provides a new conceptual framework for explaining how the brain works at a functional level. The formation of forecasts for the future, the construction of time steps and the existence of an internal assessment system in such systems is psychologically and biologically plausible and can potentially become a new milestone in the study of intelligence.
Влияние пространственного и временного факторов инициатора на возбуждение волн горения и детонации в горючих смесях
Authors: Васильев А.А.
Published: September 2021

Представлены результаты исследований по инициированию газовых горючих смесей с помощью внешних инициаторов, энерговыделение которых при передаче энергии инициатора к смеси характеризуется конечными (ненулевыми) временными и пространственными масштабами. Обсуждены основные результаты. Показано, что воздействуя на временные и пространственные характеристики вводимой от инициатора энергии можно заметно изменять величину критической энергии E+, необходимой для возбуждения в смеси самоподдерживающихся волн горения и детонации и считающейся основным параметром, по которому оценивается пожаро- и взрывоопасность горючих смесей: чем меньше E+, тем более опасна смесь.
Влияние механохимической активации на состав, свойства и структуру шунгитовых пород
Authors: Байгулбаева М.М. , Онгарбаев Е.К. , Тилеуберди E. , Жамболова А.Б. , Жумахан K.
Published: September 2021

В работе изучено влияние механохимической активации на состав, свойства и структуру шунгитовых пород месторождения Коксу. Использование наноструктурированного порошка шунгита в сорбентах может привести к улучшению их сорбционных свойств. В результате механохимической активации в образцах шунгитовых пород карбонатного и сланцевого происхождения уменьшается массовая доля углерода, массовая доля кремния увеличивается. В составе пород также увеличивается содержание кислорода, алюминия и железа, что способствует улучшению сорбционных свойств шунгита. Механохимическая активация привела к увеличению удельной поверхности, удельного объема и размера пор образцов. В результате механохимической активации образцов шунгита происходит изменение поверхностной структуры материала, при этом получаются углеродные материалы с более развитой поверхностной структурой и повышенной пористостью.
Супергидрофобные материалы и покрытия: обзор
Authors: Нажипкызы М.
Published: September 2021

Способность супергидрофобных поверхностей оставаться сухими, самоочищаться и избегать биообрастания является привлекательной для применения в стройтельстве, сельскохозяйстве и т.п. Приобретенная поверхность имеет уменьшенную площадь контакта между подложкой и жидкостью, из-за чего капли жидкости будут легко скатываться с поверхности. Благодаря этой возможности к скатыванию такая высоко отталкивающая поверхность обладает свойством самоочищения. В данной статье представлен обзор работ автора по получению наноматериалов в пламени, созданию супергидрофобного песка на основе порошка, полученного при сжигании силиконовых отходов, созданию антиобледенительных покрытий, исследованию влияния гидрофобного песка на рост растений, созданию лакокрасочных покрытий на основе гидрофобной сажи.
Technical Efficiency and the Factors that Affect it in Rice Production in Indonesia
Authors: Muhardi  , Effendy
Published: September 2021

Most of the population of Asia depends on consuming rice to support their lives. This implies that rice production needs attention. The existence of inefficiencies in lowland rice production could reduce rice yields for consumption, so the measurement of technical efficiency in lowland rice production needed to be studied. This research aimed to analyze the level of technical efficiency in lowland rice cultivation and identify the factors affecting it. The research was done in the Palolo and Torue subdistrict of Indonesia. The number of samples used was 249 lowland rice farmlands, consisting of 106 and 143 farmers of organic and inorganic lowland rice cultivation, respectively. The results show that land, fertilizer, seeds, and labor had a positive and significant effect on lowland rice production. The average technical efficiency of lowland rice cultivation was around 78.2%. The results also show that manager education, extension contacts, superior seeds, and organic lowland rice cultivation have a significant effect on the level of technical efficiency in lowland rice production. We concluded that there is an opportunity for farmers to increase lowland rice yields if they can manage production factors in an efficient manner. The government could provide support for farmers, such as formal and informal education, extension, superior seeds, and ready-to-use organic materials.
Análise das Condições de Acesso ao Financiamento pelas Micro, Pequenas e Médias Empresas em Moçambique-Caso do Banco Nacional de Investimento
Authors: Mavundla Lucio Daniel
Published: September 2021

Em Moçambique muitas empresas comerciais, indústrias, agrícolas e de prestação de serviços são classificadas como Micro, Pequenas e Médias Empresas (MPME). Elas constituem uma peça central na economia nacional, ou seja, uma alavanca à economia, tanto em tempos de prosperidade como em tempo de crise. A pesquisa procura avaliar a aplicabilidade das condições de acesso a linha de crédito COVID-19 do Banco Nacional de Investimento (BNI) MPME tendo em consideração a realidade do sector empresarial Nacional. A pesquisa é de cunho qualitativo quanto a abordagem e descritiva quanto aos objectivos tendo usando a entrevista para a colecta dos dados. A pesquisa documental foi usada para acesso a material institucional do BNI para além da observação durante o processo de colecta de dados. Foi conclusão deste estudo que as condições de acesso a linha de financiamento BNI são aplicáveis para as empresas no geral, mas não para as nacionais tendo em consideração as dificuldades que estas vêm enfrentando agravadas pela COVID-19 que assolou de maneiras a tesouraria das empresas. Como recomendações, o BNI deve adequar as condições de acesso ao financiamento as dificuldades das MPME e O Estado deve garantir a promoção da literacia financeira e monitoria permanente da actividades financeira no País. As MPME devem procurar fontes alternativas de financiamento como é o caso da Bolsa de Valores para alem de apostar na formação do capital humano.
Perspektywa indywidualna
Authors: Januszkiewicz Katarzyna
Published: September 2021

Autor niniejszego opracowania rozpoczyna je od diagnozy najważniejszych determinant zmian w funkcjonowaniu jednostki, następnie wskazuje, jak czynniki te modyfikują współczesny obraz kariery zawodowej oraz jakie są tego konsekwencje psychologiczne.
Transformacja ról i umiejętności menedżera
Authors: Bednarska-Wnuk Izabela
Published: September 2021

Dla autorki niniejszej publikacji w dążeniu do integracji ról menadżera czy kierownika zasadnym wydaje się ich przedstawienie z perspektywy organizacji: tradycyjnej, współczesnej i przyszłej. Zaprezentowana w ten sposób poniższa charakterystyka roli i umiejętności menedżera ma przede wszystkim uwypuklić ich reprezentatywność oraz wyeksponować podstawowe orientacje typowe dla danego okresu, w którym funkcjonowała określona organizacja. Autorka zwraca uwagę również i na to, że przedstawione role kierownika organizacji tradycyjnej, współczesnej i jutra nie są ograniczone horyzontem czasowym. Znaczy to, że cechy roli kierownika tradycyjnego mogą być również przypisywane współcześnie osobom zarządzającym np. organizacjami publicznymi, które charakteryzują się przede wszystkim strukturą hierarchiczną i zasadami odnoszącymi do organizacji tradycyjnych.
Nowy wymiar komunikacji organizacyjnej
Authors: Zalewska-Turzyńska Magdalena
Published: September 2021

Autor w niniejszym rozdziale koncentruje się w obszarze komunikacji organizacyjnej na jej funkcjach, związkach ze strukturą organizacyjną, kompetencjami pracowników i rozwojem technologii. Celem rozdziału jest wskazanie ewolucji zagadnień komunikacji w organizacjach tradycyjnych, nowoczesnych i organizacjach przyszłości. Autor przedstawi sytuację komunikacyjną w określonym czasie, siłę, jaka miała wpływ i spowodowała zmianę, a także konsekwencje komunikacyjne owej zmiany. W niniejszym rozdziale pokazano również kierunki i sposoby komunikowania się w tradycyjnych organizacjach.
Kluczowe obszary zmian organizacji jutra
Authors: Januszkiewicz Katarzyna , Bednarska-Wnuk Izabela , Czajkowska Maria , Kołodziejczak Małgorzata , Michalak Joanna Małgorzata , Świątek-Barylska Ilona , Zalewska-Turzyńska Magdalena
Published: September 2021

Autorki dzięki przeprowadzonych wcześniej analizach pozwoliły sobie na wskazanie kierunków zmian i wyodrębnienie następujących tendencji zachowań ludzi w organizacjach przyszłości.
La faute inassurable en droit français
Authors: Leduc Fabrice
Published: September 2021

Jusqu’à présent, la Cour de cassation s’était employée à promouvoir une conception résolument restrictive de la faute inassurable. Primo, la Cour de cassation considérait qu’en visant la «faute intentionnelle ou dolosive »de l’assuré, le législateur n’identifie pas deux sortes de fautes distinctes susceptibles d’exclure l’assurance, mais bien une seule, la faute intentionnelle. En d’autres termes, la Cour de cassation adoptait une conception moniste de la faute inassurable :celle-ci se réduit à la faute intentionnelle, la référence légale à la faute dolosive étant purement et simplement occultée. Secundo, la faute intentionnelle a toujours fait l’objet d’une définition très étroite : elle se caractérise, en effet, par la volonté, chez son auteur, de causer le dommage tel qu’il est survenu. Elle implique donc non seulement la volonté de l’action dommageable mais aussi la volonté de toutes les conséquences dommageables de l’action. En adoptant une définition aussi restrictive de la faute inassurable, la Cour de cassation cherchait de toute évidence à doter l’assurance d’une efficacité optimale. Mais, coup de théâtre, la Cour de cassation manifeste, en 2013, sa volonté d’élargir le périmètre de la faute exclusive de la garantie d’assurance. Cet élargissement de la faute inassurable doit être constaté d’abord, mesuré ensuite, apprécié enfin.