ATTENUATION RELATIONSHIPS OF THE SEISMIC WAVES GENERATED BY THE MODERATE SUBCRUSTAL VRANCEA EARTHQUAKES IN THE DAM SITES FROM THE SOUTHWESTERN PART OF ROMANIA

2019 ◽  
Author(s):  
Anica Placinta
Keyword(s):  
Seismic Waves ◽  
Southwestern Part ◽  
Vrancea Earthquakes ◽  
Attenuation Relationships

Larger peak ground accelerations in extra-Carpathian area than in epicenter

2020 ◽  
Author(s):  
Gheorghe Marmureanu ◽  
Florin Stefan Balan ◽  
Alexandru Marmureanu
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Waves ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard ◽  
Unified Framework ◽  
Modeling Tools ◽  
Vrancea Earthquakes ◽  
Peak Ground Accelerations

<p>Devasting ― and, in some sense, unforeseen  ―  earthquakes in Nepal, Sumatra, Haiti, Japan  and elsewhere have triggered a heated debate about the legitimity and limitations of probabilistic seismic hazard  assessment(PSHA). The authors are coming with many recorded data which will open up a new challenge to seismologists studiing nonlinear site effects in 2-D and 3-D irregular geological structures, leading them to a realistic research subject in earth physics, in nonlinear seismology. Shortly, why are we recording PGA values much higher than epicenter value? There was a need to create, for Europe, a unified framework for seismic hazard assessment and to produce a common integrated European probabilistic seismic hazard assessment (PSHA) model and specific scenario based on modeling tools. The leading question is, if this is happening only in this area of Europe. Vrancea is the site of strong intermediate-depth seismicity, down to 160 – 200 km depth and large magnitudes (M<sub>W</sub> ≤ 7.9 - 8.0) and is one of the most active seismic zones in Europe. The latest strong and deep Vrancea earthquakes occurred on August 30, 1986 (Mw = 7.1; h = <strong>131.4 km</strong>, in epicenter a=162.60 cm.s<sup>2</sup> and at Chisinău:212 cm/s<sup>2</sup>;Focsani:310 cm/s<sup>2</sup>;Iaşi:181 cm/s<sup>2</sup>; Otopeni: 220cm/s<sup>2</sup> etc.); May 30, 1990 (Mw = 6.9; h = <strong>90.9</strong> km; in epicenter: 157 cm/s<sup>2</sup>; Chişinau:189 cm/s<sup>2</sup>; Oneşti:242 cm/s<sup>2</sup>;Periş:242 cm/s<sup>2</sup>; Bolintin din Vale:219 cm/s<sup>2</sup>; Campina;271 cm/s<sup>2</sup> etc. & May 31, 1990 (M<sub>W </sub>= 6.4; h = <strong>86.9</strong> km, in epicenter: a=102 cm/s<sup>2</sup>;Focşani:162 cm/s<sup>2</sup>.There are more than 200 values larger than epicenter ones. More, on October 28,2018 an earthquake (Mw=5.89 and h= <strong>147.8 km</strong> ) generate  acceleration of 8.65 cm/s<sup>2</sup> in epicenter Vrâncioaia and accelerations of   69 cm/s<sup>2</sup> in Ploieşti; 65  cm/s<sup>2</sup> in Leova - Republic of Moldova etc. Why in this part of Europe/World there are many peak ground accelerations recorded and are larger than epicenter values ?. Surface waves Rayleigh and Love waves ( A third type of surface wave, the Stonely wave propagates along an interface between two media and is more correctly an interface wave and are not dispersive, thus they decrease in amplitude with distance from the interface) are seismic waves which are guided along the surface of the earth and the layer near the surface and they do not penetrate into the deep interior.</p><p>On the other time, the Alpine Tethys was linked to the Euro-Asian back-arc basins located further east through the Moesia - Dobrogea Transform [G. G. Stampfli; http://sp.Lyellcollection.org/by guest on November 14, 2019]. It is observed along new times that in Dobrogea area the peak ground accelerations recorded in last time are smaller than epicenter ones and our Nuclear Power Plant is  safe  to strong Vrancea earthquakes. Peak ground accelerations recorded   in Muntenia, Moldova   and   Republic of   Moldova are maily larger than   Vrancioaia epicenter values (Gh.Mărmureanu, Certainties/uncertainties in hazard and seismic risk assessment of strong Vrancea earthquake. Romanian  Academy Press,2016,330 page,ISBN 978-973-27-2629-7).</p>

scholarly journals GROUND MOTION PREDICTION AT THE DAM SITES IN SW ROMANIA FOR MODERATE VRANCEA SUBCRUSTAL EARTHQUAKES

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Anica Otilia Placinta ◽  
Emilia Popescu ◽  
Iren-Adelina Moldovan ◽  
Mircea Radulian ◽  
Andrei Mihai
Keyword(s):  
Seismic Hazard ◽  
Seismic Waves ◽  
Physical Parameters ◽  
Attenuation Relations ◽  
Local Conditions ◽  
National Network ◽  
Soil Movement ◽  
Attenuation Relationships ◽  
South West ◽  
Subcrustal Earthquakes

The seismic hazard studies of the last 30 years have been largely carried out taking into account the needs of the construction engineers, by linking the specific quantities of soil movement with the physical parameters determined instrumentally, namely, with the maximum values of soil acceleration. At present, interest in the results of hazard studies has increased and has extended to other areas such as insurance or design companies, environmental protection, etc. A fundamental element in the estimation of seismic hazard is the variation of the amplitude of the movement of the soil according to the distance, magnitude and local conditions. To understand and prevent the effects of the strong Vrancea earthquakes in the dam sites located in the South West of Romania, we study the seismic waves attenuation relations using the accelerations recorded by the national network of K2 accelerometers, following the moderate Vrancea intermediate earthquakes. The study area includes the largest agglomeration of dams in Romania, with almost 100 dams out of the 250 large dams. One of the most important specific requirements towards dams' safety is the seismic risk and hazard assessment and the computation of attenuation relationships is one of the most important steps of the work. The main objective of the present work is the evaluation of the specific attenuation relationships of the seismic wave propagating from Vrancea subcrustal focus toward south-west, with direct application for the dams situated in the area.

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.

ESTIMATION TO ATTENUATION RELATIONSHIPS OF TURBULENCE CAUSED BY MARINE STRUCTURES

2018 ◽  
Vol 74 (2) ◽  
pp. I_1381-I_1386
Author(s):  
Norihiro NISHIMURA ◽  
Yoshiaki AIDA ◽  
Takayuki NAKABAYASHI ◽  
Masakazu USUI
Keyword(s):  
Marine Structures ◽  
Attenuation Relationships

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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