scholarly journals Development of Large-Scale City-Gas Network Alert System Based on Monitored Earthquake Ground Motion.

1995 ◽  
pp. 331-340 ◽  
Author(s):  
Fumio Yamazaki ◽  
Tsuneo Katayama ◽  
Shigeru Noda ◽  
Yoichi Yoshikawa ◽  
Yasuaki Otani
Keyword(s):  
Ground Motion ◽  
Large Scale ◽  
Earthquake Ground Motion ◽  
Alert System ◽  
Gas Network ◽  
City Gas

High-frequency ground-motion variability for rough-fault ruptures  

2021 ◽  
Author(s):  
Jagdish Chandra Vyas ◽  
Martin Galis ◽  
Paul Martin Mai
Keyword(s):  
Ground Motion ◽  
Large Scale ◽  
Earthquake Ground Motion ◽  
Small Scale ◽  
Dynamic Rupture ◽  
Roughness Effects ◽  
Ground Shaking ◽  
Fault Surface ◽  
Fault Roughness ◽  
Ground Motion Variability

<p>Geological observations show variations in fault-surface topography not only at large scale (segmentation) but also at small scale (roughness). These geometrical complexities strongly affect the stress distribution and frictional strength of the fault, and therefore control the earthquake rupture process and resulting ground-shaking. Previous studies examined fault-segmentation effects on ground-shaking, but our understanding of fault-roughness effects on seismic wavefield radiation and earthquake ground-motion is still limited.  </p><p>In this study we examine the effects of fault roughness on ground-shaking variability as a function of distance based on 3D dynamic rupture simulations. We consider linear slip-weakening friction, variations of fault-roughness parametrizations, and alternative nucleation positions (unilateral and bilateral ruptures). We use generalized finite difference method to compute synthetic waveforms (max. resolved frequency 5.75 Hz) at numerous surface sites  to carry out statistical analysis.  </p><p>Our simulations reveal that ground-motion variability from unilateral ruptures is almost independent of  distance from the fault, with comparable or higher values than estimates from ground-motion prediction equations (e.g., Boore and Atkinson, 2008; Campbell and Bozornia, 2008). However, ground-motion variability from bilateral ruptures decreases with increasing distance, in contrast to previous studies (e.g., Imtiaz et. al., 2015) who observe an increasing trend with distance. Ground-shaking variability from unilateral ruptures is higher than for bilateral ruptures, a feature due to intricate seismic radiation patterns related to fault roughness and hypocenter location. Moreover, ground-shaking variability for rougher faults is lower than for smoother faults. As fault roughness increases the difference in ground-shaking variabilities between unilateral and bilateral ruptures increases. In summary, our simulations help develop a fundamental understanding of ground-motion variability at high frequencies (~ 6 Hz) due small-scale geometrical fault-surface variations.</p>

scholarly journals Large-scale experimental investigation of a low-cost PVC ‘sand-wich’ (PVC-s) seismic isolation for developing countries

2020 ◽  
Vol 36 (4) ◽  
pp. 1886-1911 ◽  
Author(s):  
Anastasios Tsiavos ◽  
Anastasios Sextos ◽  
Andreas Stavridis ◽  
Matt Dietz ◽  
Luiza Dihoru ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Developing Countries ◽  
Ground Motion ◽  
Seismic Isolation ◽  
Large Scale ◽  
Low Cost ◽  
Seismic Energy ◽  
Earthquake Ground Motion ◽  
Isolation System ◽  
Seismically Isolated

This study presents a large-scale experimental investigation on the seismic performance of an innovative, low-cost seismic isolation system for developing countries. It is based on the beneficial effect of the encapsulation of sand grains between two PVC surfaces on the initiation of sliding and the dissipation of seismic energy between the surfaces. A three-times scaled-down, idealized, seismically isolated model of a prototype single-story structure located in Nepal is subjected to an ensemble of recorded earthquake ground motion excitations. The experimentally derived response of the seismically isolated structure is compared with the response of the corresponding fixed-base structure. This system is part of a wider hybrid design approach where the structure is designed to resist the seismic forces at the design acceleration level. The seismic isolation system sets an upper bound to the response of the structure for ground motion excitations exceeding the design level.

scholarly journals 3D NUMERICAL MODELLING OF THE SEISMIC RESPONSE OF THE THESSALONIKI URBAN AREA: THE CASE OF THE 1978 VOLVI EARTHQUAKE

2017 ◽  
Vol 50 (3) ◽  
pp. 1433
Author(s):  
C. Smerzini ◽  
K. Pitilakis ◽  
K. Hashemi
Keyword(s):  
Numerical Modelling ◽  
Urban Area ◽  
Ground Motion ◽  
Large Scale ◽  
Spectral Element ◽  
Seismic Wave Propagation ◽  
Earthquake Ground Motion ◽  
Ground Shaking ◽  
3D Numerical Modelling ◽  
Wide Scale

This study aims at showing the numerical modelling of earthquake ground motion in the Thessaloniki urban area, using a 3D spectral element approach. The availability of detailed geotechnical/geophysical data together with the seismological information regarding the relevant fault sources allowed us to construct a large-scale 3D numerical model suitable for generating physics based ground shaking scenarios within the city of Thessaloniki up to maximum frequencies of about 2 Hz. Results of the numerical simulation of the destructive MW6.5 1978 Volvi earthquake are addressed, showing that realistic estimates can be obtained. Shaking maps in terms of ground motion parameters such as PGV are used to discuss the main seismic wave propagation effects at a wide scale.

scholarly journals Seismic rocking effects on a mine tower under induced and natural earthquakes

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Piotr Adam Bońkowski ◽  
Juliusz Kuś ◽  
Zbigniew Zembaty
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Ground Surface ◽  
Tall Buildings ◽  
Earthquake Ground Motion ◽  
Seismic Action ◽  
Seismic Effects ◽  
Copper Ore ◽  
Rotational Components ◽  
Natural Earthquakes

AbstractRecent research in engineering seismology demonstrated that in addition to three translational seismic excitations along x, y and z axes, one should also consider rotational components about these axes when calculating design seismic loads for structures. The objective of this paper is to present the results of a seismic response numerical analysis of a mine tower (also called in the literature a headframe or a pit frame). These structures are used in deep mining on the ground surface to hoist output (e.g. copper ore or coal). The mine towers belong to the tall, slender structures, for which rocking excitations may be important. In the numerical example, a typical steel headframe 64 m high is analysed under two records of simultaneous rocking and horizontal seismic action of an induced mine shock and a natural earthquake. As a result, a complicated interaction of rocking seismic effects with horizontal excitations is observed. The contribution of the rocking component may sometimes reduce the overall seismic response, but in most cases, it substantially increases the seismic response of the analysed headframe. It is concluded that in the analysed case of the 64 m mining tower, the seismic response, including the rocking ground motion effects, may increase up to 31% (for natural earthquake ground motion) or even up to 135% (for mining-induced, rockburst seismic effects). This means that not only in the case of the design of very tall buildings or industrial chimneys but also for specific yet very common structures like mine towers, including the rotational seismic effects may play an important role.

scholarly journals Automated Quality Assessment of Interferometric Ring Laser Data

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3425
Author(s):  
Andreas Brotzer ◽  
Felix Bernauer ◽  
Karl Ulrich Schreiber ◽  
Joachim Wassermann ◽  
Heiner Igel
Keyword(s):  
Quality Assessment ◽  
Ground Motion ◽  
Ring Laser ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Scientific Field ◽  
Optical Frequency ◽  
Laser Array ◽  
Laser Data ◽  
Rotational Motions

In seismology, an increased effort to observe all 12 degrees of freedom of seismic ground motion by complementing translational ground motion observations with measurements of strain and rotational motions could be witnessed in recent decades, aiming at an enhanced probing and understanding of Earth and other planetary bodies. The evolution of optical instrumentation, in particular large-scale ring laser installations, such as G-ring and ROMY (ROtational Motion in seismologY), and their geoscientific application have contributed significantly to the emergence of this scientific field. The currently most advanced, large-scale ring laser array is ROMY, which is unprecedented in scale and design. As a heterolithic structure, ROMY’s ring laser components are subject to optical frequency drifts. Such Sagnac interferometers require new considerations and approaches concerning data acquisition, processing and quality assessment, compared to conventional, mechanical instrumentation. We present an automated approach to assess the data quality and the performance of a ring laser, based on characteristics of the interferometric Sagnac signal. The developed scheme is applied to ROMY data to detect compromised operation states and assign quality flags. When ROMY’s database becomes publicly accessible, this assessment will be employed to provide a quality control feature for data requests.

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