2D electrical resistivity tomographies for investigating recent activation landslides in Basilicata Region (Southern Italy)

The results of a geoelectrical survey in the study of recent activation landslides in the Lucanian Apennine chain (Southern Italy) are discussed in this paper. During the last two years, after meteorological conditions which affected Southern Italy and in particular Basilicata Region, many landslides occurred in this area as reactivations of old movements. These reactivations seriously damaged buildings and infrastructure and they threatened the safety of the people living in the area. Taking into account the complexity and danger of the phenomena, some evacuation decrees for a few houses were adopted. In a short time and at low cost, by using the Mobile Laboratory of IMAA for geophysical measurements, active geoelectrical investigations were carried out and data processing performed using innovative techniques for data inversion. The results represent a valid cognitive support to choose the most appropriate technical solution for strengthening of the slopes and an example of best practice for the cooperation between the Civil Protection of Basilicata Region and IMAA-CN

Stability analysis of apparent resistivity measurement in the seismically active area of Val d'Agri (southern Italy)

International audienceA magnetotelluric monitoring station has been installed in the Val d'Agri area (southern Italy), to investigate the physics underlying the generation mechanisms of the electrokinetic effect, due to rapid pore pressure changes and fluid flows near the focal area of incoming earthquakes. It is well known that the magnetotelluric method reveals variations in electrical resistivity within the Earth at large depths, reaching within appropriate frequency bands the Earth's mantle. Depth sounding is performed by measuring the ratio between the mutually perpendicular horizontal electric and magnetic fields at the earth's surface, furnishing the apparent resistivity, which describes the electrical properties of subsoil as function of depth. The selected site of Val d'Agri has been struck by strong seismic events in past and recent years, this suggesting the investigation of possible changes in apparent resistivity correlated with the local tectonic activity. We analyzed the stability of the measurement of apparent resistivity and phase of the impedance tensor Z(?) during time. Our findings suggest that the measure of apparent resistivity during night-time is more stable. Therefore, we identified the characteristic apparent resistivity curve of the subsoil of the Val d'Agri site, which could be considered as a reference

2D electrical resistivity tomographies for investigating recent activation landslides in Basilicata Region (Southern Italy)

The results of a geoelectrical survey in the study of recent activation landslides in the Lucanian Apennine chain (Southern Italy) are discussed in this paper. During the last two years, after meteorological conditions which affected Southern Italy and in particular Basilicata Region, many landslides occurred in this area as reactivations of old movements. These reactivations seriously damaged buildings and infrastructure and they threatened the safety of the people living in the area. Taking into account the complexity and danger of the phenomena, some evacuation decrees for a few houses were adopted. In a short time and at low cost, by using the Mobile Laboratory of IMAA for geophysical measurements, active geoelectrical investigations were carried out and data processing performed using innovative techniques for data inversion. The results represent a valid cognitive support to choose the most appropriate technical solution for strengthening of the slopes and an example of best practice for the cooperation between the Civil Protection of Basilicata Region and IMAA-CN

Reconfigurable nanoelectronics using graphene based spintronic logic gates

This paper presents a novel design concept for spintronic nanoelectronics that emphasizes a seamless integration of spin-based memory and logic circuits. The building blocks are magneto-logic gates based on a hybrid graphene/ferromagnet material system. We use network search engines as a technology demonstration vehicle and present a spin-based circuit design with smaller area, faster speed, and lower energy consumption than the state-of-the-art CMOS counterparts. This design can also be applied in applications such as data compression, coding and image recognition. In the proposed scheme, over 100 spin-based logic operations are carried out before any need for a spin-charge conversion. Consequently, supporting CMOS electronics requires little power consumption. The spintronic-CMOS integrated system can be implemented on a single 3-D chip. These nonvolatile logic circuits hold potential for a paradigm shift in computing applications.Comment: 14 pages (single column), 6 figure

Performance optimization of InGaAs/InP SPADs for either low noise or high photon detection efficiency applications

InGaAs/InP Single-Photon Avalanche Diodes ( SPADs) can achieve high photon detection efficiency (PDE) with a thick absorber, but at the expense of higher dark count rate ( DCR). PDE and DCR also depend on the electric field inside the structure, which can be tailored in the design phase and influences the overall performance. We present the design and the experimental characterization of two different 10 mu m-diameter InGaAs/InP SPADs. The first one is intended for applications where low noise is the key requirement: at 225 K and 5 V excess bias, it features 1 kcps DCR, 25% PDE at 1550 nm and a timing jitter of 100 ps (FWHM). The second device is an InGaAs/InP SPAD optimized for PDE-enhanced applications, having a PDE up to 50% at 1550 nm, with a DCR of 20 kcps and a timing jitter of 70 ps (FWHM) at 225 K. Alternatively, it features a PDE of 37% at 1550 nm, with a DCR of just 3 kcps and a timing jitter of 100 ps (FWHM). When combined with a custom integrated circuit we developed, both devices show an afterpulsing probability as low as few percent with a gating frequency of 1 MHz and hold-off time of few microseconds at 225 K, allowing to achieve a photon count rate towards 1 Mcps

A new magnetotelluric monitoring network operating in Agri Valley (Southern Italy): study of stability of apparent resistivity estimates

Variations detected in geophysical, especially electromagnetic, parameters in seismic active areas have been sometimes attributed to modifications of the stress field. Among the different geophysical methods, magnetotellurics (MT) could be one of the most effective because it allows us to explore down to seismogenic depths. Continuous MT recording could allow us to evaluate whether possible variations are significantly correlated with the seismic activity of investigated area. To assess the significance of such observations we must be able to say how well an apparent resistivity curve should be reproduced when measurements are repeated at a later time. To do this properly it is essential to know that the estimated error bars accurately represent the true uncertainties in comparing the transfer functions. In this work we will show the preliminary results obtained from the analysis of the data coming from the new MT monitoring network installed in Agri Valley. This analysis gives us the possibility: i) to better study the temporal stability of the signals, ii) to better discriminate the noise affecting the measures by remote reference estimation. The performed analysis disclosed a relatively low degree of noise in the investigated area, which is a promising condition for monitoring

A new magnetotelluric monitoring network operating in Agri Valley (Southern Italy): study of stability of apparent resistivity estimates

Variations detected in geophysical, especially electromagnetic, parameters in seismic active areas have been sometimes attributed to modifications of the stress field. Among the different geophysical methods, magnetotellurics (MT) could be one of the most effective because it allows us to explore down to seismogenic depths. Continuous MT recording could allow us to evaluate whether possible variations are significantly correlated with the seismic activity of investigated area. To assess the significance of such observations we must be able to say how well an apparent resistivity curve should be reproduced when measurements are repeated at a later time. To do this properly it is essential to know that the estimated error bars accurately represent the true uncertainties in comparing the transfer functions. In this work we will show the preliminary results obtained from the analysis of the data coming from the new MT monitoring network installed in Agri Valley. This analysis gives us the possibility: i) to better study the temporal stability of the signals, ii) to better discriminate the noise affecting the measures by remote reference estimation. The performed analysis disclosed a relatively low degree of noise in the investigated area, which is a promising condition for monitoring