Search results for "Ambient noise"

Effect of Local Geology on Ground Motion in the City of Palermo, Italy, as Inferred from Aftershocks of the 6 September 2002 Mw 5.9 Earthquake

2005

On 6 September 2002 a M w 5.9 earthquake occurred in the southern Tyrrhenian sea, 40 km off the coast of Palermo (Italy). In the days after the mainshock, eight temporary stations were installed in the city to record aftershocks on different geological formations. Seismograms of about 30 earthquakes with magnitude ≥2.8 are analyzed. The data analysis confirms the role of near-surface geology in causing locally significant variations of the ground-shaking level as already inferred by Guidoboni et al. (2003) from historical damage scenario studies. The largest spectral variations estimated through aftershock recordings result in a factor of 10 difference between stiff and soft sites, in frequ…

Temporal weights in loudness: Investigation of the effects of background noise and sound level

2019

Previous research has consistently shown that for sounds varying in intensity over time, the beginning of the sound is of higher importance for the perception of loudness than later parts (primacy effect). However, in all previous studies, the target sounds were presented in quiet, and at a fixed average sound level. In the present study, temporal loudness weights for a time-varying narrowband noise were investigated in the presence of a continuous bandpass-filtered background noise and the average sound levels of the target stimuli were varied across a range of 60 dB. Pronounced primacy effects were observed in all conditions and there were no significant differences between the temporal w…

Automatic Acoustic Target Detecting and Tracking on the Azimuth Recording Diagram with Image Processing Methods

2019

International audience; Passive acoustic target detection has been a hot research topic for a few decades. Azimuth recording diagram is one of the most promising techniques to estimate the arrival direction of the interested signal by visualizing the sound wave information. However, this method is challenged by the random ambient noise, resulting in low reliability and short effective distance. This paper presents a real-time postprocessing framework for passive acoustic target detection modalities by using a sonar array, in which image processing methods are used to automate the target detecting and tracking on the azimuth recording diagram. The simulation results demonstrate that the prop…

Alteraciones del sueño producidas por el ruido ambiental*

1989

ResumenEste articulo presenta los resultados de una encuesta realizada con el objetivo de valorar distintos aspectos relacionados con el ruido ambiental y sus efectos sobre determinadas comunidades urbanas. Un total de 263 residentes en 5 emplazamientos diferentes de la ciudad de Valencia fueron entrevistados. En estos 5 emplazamientos se realizaron de manera independiente una serie de medidas de los niveles de ruido durante las 24 horas del dia y en distintos días de la semana.:El 400%0 de los encuestados manifestó tener alguna dificultad para dormirse y el 59% de ellos lo atribuyó al ruido causado por el tráfico. Asimismo, un 49% de los encuestados declaró despertarse durante la noche (el…

Seismo-stratigraphic model of “La Bandita” area in the Palermo Plain (Sicily, Italy) through HVSR inversion constrained by stratigraphic data

2018

Ambient noise Horizontal-to-Vertical Spectral Ratio (HVSR) technique is commonly used approach to obtain 1D models of the shear-wave velocity in the shallow surface of an investigated area. However, obtained models can have a wide margin of uncertainty if inversions have not been appropriately constrained by detailed stratigraphic information. An application of HVSR inversion constrained by lithostratigraphic data is presented in order to verify the effectiveness of this technique for purposes of geological and geophysical reconstruction of a sedimentary basin in a densely urbanized area. This is often the case of seismic microzonation studies, in which almost all the information derives fr…

AMADEUS-The acoustic neutrino detection test system of the ANTARES deep-sea neutrino telescope

2011

The AMADEUS (ANTARES Modules for the Acoustic Detection Under the Sea) system which is described in this article aims at the investigation of techniques for acoustic detection of neutrinos in the deep sea. It is integrated into the ANTARES neutrino telescope in the Mediterranean Sea. Its acoustic sensors, installed at water depths between 2050 and 2300 m, employ piezo-electric elements for the broad-band recording of signals with frequencies ranging up to 125 kHz. The typical sensitivity of the sensors is around - 145 dB re 1 V/mu Pa (including preamplifier). Completed in May 2008, AMADEUS consists of six "acoustic clusters", each comprising six acoustic sensors that are arranged at distanc…

Ambient Noise Effect on Auditory Threshold

1966

Road traffic noise around schools: a risk for pupil's performance?

1993

Noise levels around educational centres can negatively affect the performance of both teachers and pupils. Two public schools in Valencia, Spain, were selected for study. One of these schools was exposed to excessively high road traffic noise levels while the other was located in a relatively quiet area. The socioeconomic level of those attending the schools was very similar. A set of external and internal noise measurements were carried out, along with two different attention tests among the children. Test results were consistently better (both for tests and for children from different classrooms in each school) in the quiet school. Exposure to high traffic noise levels in the noisy school…

Microtremor Measurements in the City of Palermo, Italy: Analysis of the Correlation between Local Geology and Damage

2008

Abstract This study presents the results of 90 seismic ambient noise measurements in Palermo, the main city of Sicily (Italy). The dataset has been processed using the horizontal-to-vertical spectral ratio (HVNSR) technique and interpreted in terms of local geology, which is characterized by the presence of alluvial sediments of two riverbeds masked by urbanization since the seventeenth century. HVNSRs show significant variations in the study area: when the transition stiff to soft is crossed, a typical spectral peak appears in the HVNSRs, mostly in the frequency band 1–2 Hz, and exceeding a factor of 3 in amplitude. Using available information on subsurface geological structure, we compute…

Effect of boat noise on the behaviour of bluefin tuna Thunnus thynnus in the Mediterranean Sea

2007

The effect of boat noise on the behaviour of bluefin tuna Thunnus thynnus was investi- gated in the Egadi Islands, Sicily, during spring 2005 using a fixed tuna trap set near shipping routes. Tuna behaviour was observed when exposed to both natural ambient sound and sound generated by hydrofoil passenger ferries, small boats and large car ferries. Acoustical and behavioural analyses were conducted with and without extraneous sound to define a list of behavioural categories. Each vessel produced different engine sounds with regard to their composition and bandwidth, and all were distinctly different from ambient sound levels. In the absence of boat noise, tuna assumed a con- centrated coordi…