Energy contents of the spectra of the destructive frequencies of seismic waves as the epicentral distance varies in solid granite

1975 ◽  
Vol 11 (2) ◽  
pp. 108-111
Author(s):  
M. F. Drukovanyi ◽  
Yu. F. Kucheryavyi ◽  
N. A. Shevchenko
Keyword(s):  
Seismic Waves ◽  
Epicentral Distance

STUDIES ON SEISMIC WAVES: III. PROPAGATION OF ELASTIC WAVES IN THE NEIGHBORHOOD OF A FREE BOUNDARY

Geophysics ◽  
1947 ◽  
Vol 12 (1) ◽  
pp. 57-71 ◽  
Author(s):  
C. Y. Fu
Keyword(s):  
Surface Waves ◽  
Elastic Waves ◽  
Seismic Waves ◽  
Classical Method ◽  
Epicentral Distance ◽  
Harmonic Waves ◽  
Inhomogeneous Waves ◽  
Different Types ◽  
Propagation Of Elastic Waves ◽  
The Waves

Continuous and spherical harmonic waves are generated at an internal point of the medium. By use of the classical method of Sommerfeld, the different modes of propagation near a free surface after the arrival of the waves are examined. From the approximate evaluations of the integrals, it is found that in addition to the ordinary types of body and surface waves, there are also inhomogeneous waves and surface waves which are not of the Rayleigh type. The amplitude factors of these latter waves vary inversely as the square instead of as the square root of the epicentral distance. Altogether, there are not less than five different types of waves and they are obtained from integrations in the neighborhood of the singularities of the integrals.

scholarly journals Various Far-Field Hydrological Responses During 2015 Gorkha Earthquake at Two Distant Wells

2020 ◽  
Author(s):  
Xudong Huang ◽  
Yu Zhang
Keyword(s):  
Water Level ◽  
Seismic Waves ◽  
Amplitude Ratio ◽  
Epicentral Distance ◽  
Water Levels ◽  
Earth Tides ◽  
Tibet Plateau ◽  
Far Field ◽  
Gorkha Earthquake ◽  
2015 Gorkha Earthquake

Abstract Aquifer hydraulic parameter can change during earthquakes. Continuous monitoring of the response of water level to seismic waves or solid Earth tides provides an opportunity to document how earthquakes influence hydrological properties. Here we use data of two groundwater wells, Dian-22 (D22) and Lijiang (LJ) well, in southeast Tibet Plateau in response to the 2015 Mw 7.8 Gorkha earthquake to illustrate hydrological implications. The coherences of water level and seismic wave before and after the far-field earthquake show systematic variations, which may confirm the coseismic dynamic shaking influence at high frequencies (f > 8 cpd). The tidal response of water levels in these wells shows abrupt coseismic increases of both phase shift and amplitude ratio after the earthquake, which may be interpreted as an increase in the horizontal permeability of a confined aquifer in D22 well, and an occurrence in the vertical permeability of a switched semiconfined aquifer with larger epicentral distance and but high seismic ground motion. Using the continuous transmissivity monitoring, we show that the possible preseismic initial for ~ 1 day, coseismic response for ~ 3 days and postseismic healing for ~ 10 days during the earthquake. Thus, the dynamic shaking during the Gorkha earthquake may have caused confined aquifers to semiconfined aquifers by reopening of preexisting vertical fractures and later healing at epicentral distances about 1500 km.

Is an Earthquake Felt Inside a Car?

2021 ◽  
Author(s):  
Paola Sbarra ◽  
Patrizia Tosi ◽  
Valerio De Rubeis ◽  
Diego Sorrentino
Keyword(s):  
Seismic Waves ◽  
Epicentral Distance ◽  
Macroseismic Intensity ◽  
Hypocentral Distance ◽  
Resonance Phenomena ◽  
Macroseismic Scale ◽  
Definition Of ◽  
Observer System

Abstract The analysis of how an earthquake is felt was addressed with the data provided by citizens through a website dedicated to the perception of earthquakes in Italy (Data and Resources). The analysis focused on the perception of earthquakes by observers inside both parked and moving cars. These situations were compared with outdoor ones. The felt percentage of each situation was quantified for epicentral distance ranges and European Macroseismic Scale (EMS) degree. One of the main findings was the greatest sensitivity to shaking for people inside parked cars due to resonance phenomena of the automobile–observer system. The distribution of the intensity of perception in the car was analyzed as a function of the hypocentral distance and the magnitude of the earthquake. It was possible to define the attenuation trends of these intensities. The comparison of these trends with those of the equations for estimation of response spectral ordinates allowed us to have an evaluation of the frequency values of the seismic waves that caused the vibrations felt, which were found to agree with the typical frequencies of the car–observer system, as highlighted by independent studies. The results of this analysis show the possibility to include the perception of the earthquake inside a parked and moving car among the diagnostics used in the definition of macroseismic intensity degree of the EMS.

scholarly journals Manifestation features of near-surface sedimentary rock electric and acoustic responses on seismic waves from earthquakes

2019 ◽  
Vol 127 ◽  
pp. 02015 ◽  
Author(s):  
Pavel Muratov ◽  
Oleg Rulenko ◽  
Yuriy Marapulets
Keyword(s):  
Sedimentary Rock ◽  
Seismic Waves ◽  
Epicentral Distance ◽  
Earthquake Magnitude ◽  
Source Depth ◽  
Near Surface ◽  
Acoustic Responses

The results of analysis of near-surface sedimentary rock electric and acoustic responses on seismic waves from five Kamchatka earthquakes with the magnitudes of 4.9 – 7.3 at the distances of 79 – 498 km from epicenters are presented. Manifestation features of these responses, depending upon earthquake magnitude, epicentral distance, source depth and direction to an epicenter, are considered.

Seismic stability of the underground main pipeline

2011 ◽  
Vol 8 (1) ◽  
pp. 275-286
Author(s):  
R.G. Yakupov ◽  
D.M. Zaripov
Keyword(s):  
Laplace Transformation ◽  
Seismic Waves ◽  
Generalized Functions ◽  
Seismic Stability ◽  
Main Pipeline ◽  
Motion Equations ◽  
Numerical Example ◽  
Earthquake Force ◽  
Deformed State

The stress-deformed state of the underground main pipeline under the action of seismic waves of an earthquake is considered. The generalized functions of seismic impulses are constructed. The pipeline motion equations are solved with used Laplace transformation by the time. Tensions and deformations of the pipeline have been determined. A numerical example is reviewed. Diagrams of change of the tension depending on earthquake force are provided in earthquake-points.

Isolation Performance of Intelligent Seismic Isolation System Using Air Bearing

2009 ◽  
Author(s):  
Satoshi Fujita ◽  
Keisuke Minagawa ◽  
Mitsuru Miyazaki ◽  
Go Tanaka ◽  
Toshio Omi ◽  
...  
Keyword(s):  
Seismic Isolation ◽  
Seismic Waves ◽  
Three Dimensional ◽  
Vertical Motion ◽  
Air Bearings ◽  
Natural Period ◽  
Isolation System ◽  
Vertical Excitation ◽  
Long Period ◽  
Isolation Performance

This paper describes three-dimensional isolation performance of seismic isolation system using air bearings. Long period seismic waves having predominant period of from a few seconds to a few ten seconds have recently been observed in various earthquakes. Also resonances of high-rise buildings and sloshing of petroleum tanks in consequence of long period seismic waves have been reported. Therefore the isolation systems having very long natural period or no natural period are required. In a previous paper [1], we proposed an isolation system having no natural period by using air bearings. Additionally we have already reported an introduction of the system, and have investigated horizontal motion during earthquake in the previous paper. It was confirmed by horizontal vibration experiment and simulation in the previous paper that the proposed system had good performance of isolation. However vertical motion should be investigated, because vertical motion varies horizontal frictional force. Therefore this paper describes investigation regarding vertical motion of the proposed system by experiment. At first, a vertical excitation test of the system is carried out so as to investigate vertical dynamic property. Then a three-dimensional vibration test using seismic waves is carried out so as to investigate performance of isolation against three-dimensional seismic waves.

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