scholarly journals Seismic monitoring by piezoelectric accelerometers of a damaged historical monument in downtown L’Aquila

2015 ◽  
Vol 57 (6) ◽  
Author(s):  
Giuseppe Di Giulio ◽  
Maurizio Vassallo ◽  
Giosuè Boscato ◽  
Alessandra Dal Cin ◽  
Salvatore Russo
Keyword(s):  
Monitoring System ◽  
Damping Ratio ◽  
Central Italy ◽  
Great Part ◽  
Seismic Monitoring ◽  
Dynamic Monitoring ◽  
In Situ Data ◽  
Seismic Characterization ◽  
Low Amplitude ◽  
The Church

<p>We show the preliminary seismic monitoring of a historical church in L’Aquila (central Italy), which was strongly damaged by the 2009 seismic sequence. This structure, S. Maria del Suffragio church, suffered the collapse of a great part of the dome during the April 6th 2009 Mw 6.1 earthquake. In this paper, recordings of ambient noise and local earthquakes have been analyzed. The seismic data were recorded by means of a dynamic monitoring system (19 mono-directional and 3 tri-directional piezoelectric accelerometers) and of two velocimeters, with all the instruments installed into the church. The aim of this research is the evaluation of the performance of the accelerometers of the monitoring system in case of low-amplitude vibrations. Simple techniques of analysis commonly employed in the seismic characterization of buildings have been applied. The reliability of the in-situ data was evaluated and the main modal parameters (natural frequencies and damping ratio) of the church were presented.</p>

Recorded Earthquake Responses from the Integrated Seismic Monitoring Network of the Atwood Building, Anchorage, Alaska

2006 ◽  
Vol 22 (4) ◽  
pp. 847-864 ◽  
Author(s):  
Mehmet Çelebi
Keyword(s):  
Reinforced Concrete ◽  
Monitoring System ◽  
Mode Coupling ◽  
Free Field ◽  
Monitoring Network ◽  
Seismic Monitoring ◽  
Field Site ◽  
City Block ◽  
Propagation Of Waves ◽  
Low Amplitude

An integrated seismic monitoring system with a total of 53 channels of accelerometers is now operating in and at the nearby free-field site of the 20-story steel-framed Atwood Building in highly seismic Anchorage, Alaska. The building has a single-story basement and a reinforced concrete foundation without piles. The monitoring system comprises a 32-channel structural array and a 21-channel site array. Accelerometers are deployed on 10 levels of the building to assess translational, torsional, and rocking motions, interstory drift (displacement) between selected pairs of adjacent floors, and average drift between floors. The site array, located approximately a city block from the building, comprises seven triaxial accelerometers, one at the surface and six in boreholes ranging in depths from 15 to 200 feet (∼5–60 meters). The arrays have already recorded low-amplitude shaking responses of the building and the site caused by numerous earthquakes at distances ranging from tens to a couple of hundred kilometers. Data from an earthquake that occurred 186 km away traces the propagation of waves from the deepest borehole to the roof of the building in approximately 0.5 seconds. Fundamental structural frequencies [0.58 Hz (NS) and 0.47 Hz (EW)], low damping percentages (2–4%), mode coupling, and beating effects are identified. The fundamental site frequency at approximately 1.5 Hz is close to the second modal frequencies (1.83 Hz NS and 1.43 EW) of the building, which may cause resonance of the building. Additional earthquakes prove repeatability of these characteristics; however, stronger shaking may alter these conclusions.

The current state of the seismic monitoring system in Kabardino-Balkaria

2012 ◽  
Vol 48 (3) ◽  
pp. 256-269 ◽  
Author(s):  
A. A. Malovichko ◽  
I. P. Gabsatarova ◽  
R. R. Kashirgova ◽  
S. M. Dolov
Keyword(s):  
Monitoring System ◽  
Seismic Monitoring ◽  
Current State

Italians and others: some quattrocento views of nationality and the church

1982 ◽  
Vol 18 ◽  
pp. 243-260
Author(s):  
Diana M. Webb
Keyword(s):  
Central Italy ◽  
Italian Society ◽  
Self Awareness ◽  
The Past ◽  
Renaissance Period ◽  
The Church

In his excellent study of medieval Italian society, Hyde makes a thought-provoking comparison of ‘the Italians of the age of Dante’ with the humanists of a later generation. The former he sees as distinguished by ‘a sense of continuity with the past and with other parts of the Catholic world’ from the humanists who ‘concentrated on what was close at hand, digging deep rather than spreading wide, so that their world revolved around central Italy.’ It is not my intention here to dispute this assertion, but to use it to stimulate reflection on the nature of Italian self-awareness in the early renaissance period, in the light of a further contrast between Hyde’s two ages which he does not himself emphasise.

NEW APPROACHES TO THE SYNTHESIS OF AUTOMATIC SEISMIC MONITORING SYSTEMS

2020 ◽  
pp. 73-81
Author(s):  
B. M. Shubik ◽  
Keyword(s):  
Monitoring System ◽  
Traditional Approach ◽  
Automatic Monitoring ◽  
Seismic Monitoring ◽  
Monitoring Systems ◽  
Computational Techniques ◽  
Frequency Model ◽  
Complexity Of Algorithms ◽  
New Approaches ◽  
Detection And Localization

The processes of development of hydrocarbon deposits are accompanied, as a rule, by an increase in the level of seismicity and, in particular, by the occurrence of technogenic earthquakes and other deformation phenomena associated with changes in the geodynamic regime. To monitor deformation and geodynamic processes, a seismic monitoring service should be organized. A similar monitoring system is also required for the analysis of aftershock and volcanic activity. Monitoring technology should be based on the use of reliable and fast methods of automatic detection and localization of seismic events of various scales. Traditional approaches to the detection and localization of earthquake epicenters and hypocenters are based on the analysis of data recorded by one or more single seismic stations. In that case, seismic event coordinates are estimated by means of signal extraction from noise and accurately measuring arrival times of a number of specific phases of the seismic signal at each recording point. Existing computational techniques have inherited this traditional approach. However, automatic procedures based on the ideology of manual processing turn out to be extremely laborious and ineffective due to the complexity of algorithms adequate to the actions of an experienced geophysicist-interpreter. The article contains a description of new approaches to the synthesis of automatic monitoring systems, which are based on the principles of emission tomography, use of spatial registration systems, energy analysis of wave fields and methods of converting real waveforms into low-frequency model signals (so-called filter masks/templates). The monitoring system was successfully tested in the process of detecting and locating the epicenters and hypocenters of 19 weak local earthquakes in Israel, as well as a quarry explosion.

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