The report describes a recent landslide occurred in San Leo (northern Italy), an outstanding village from the historical, architectural and landscape point of view. On February 27, 2014, around 6 pm local time, about 0.30 Mm3 of rock detached from a sub-vertical cliff and fell into the facing valley, producing a roar and a shake, which was initially perceived by the inhabitants as an earthquake, then followed by a dust cloud produced by the fragmentation of material during the collapse. Fortunately, nobody was injured, neither the landslide damaged any relevant structure; anyhow, it is still posing a severe threat to the village and, above all, to the fortress that represents an architectural masterpiece dating back to the middle ages. An outlook of the event will be given, along with the description of the peculiar geological and geomorphological features driving the slope instability phenomena, which indeed are widely diffused in the entire region. Lastly, an overview of the landslides, which historically affected the village, is also given, showing how natural hazards can influence the history of a site
The ancient fortified city of San Leo is built on a limestone plateau. The rock slab is tectonized and crossed by several families of joints and faults, while the underlying foundation of the rocky cliff is composed of gentle clay slopes, modelled in the so-called “Argille Scagliose” geological units. The differential weathering of the upper rock formation with respect to the ductile clays has produced ledges and overhangs on the cliff face. Furthermore, weathering and/or movement of the underlying clays has caused the opening and widening of vertical fractures in the brittle limestone rock masses, diffused over the entire rock mass. The evolution of plastic movements (slides and flows) in the underlying clay units might undermine the limestone slab and endanger the stability of the rocky cliff, thus posing risk to the fortified city of San Leo and its notable cultural heritage. In this paper, historical and recent slope instability events are described, on the basis of historical documents and modern investigations
The purpose of this report is to develop a mathematical model for a pressure transducer mounted in a fluid filled cavity (a system) and examine the pressure "measurement" error of the cavity and transducer by computing the dynamic response (output pressure) of the system to a specified pressure time history (input pressure). The "measurement" error is determined by comparing the calculated output pressure to the specified input pressure. The dynamic response of a transducer mounted at one end of a one-dimensional acoustical cavity is determined. The cavity is filled with a compressible isentropic fluid, and the fluid at the open end of the cavity (i.e., the boundary at x = 0) is subjected to a specified uniform axial input pressure. At the other end of the cavity the transducer is represented as a mass, spring, and damper system. Consequently, the boundary condition at x = 4! is also time dependent. for periodic excitation, is obtained by integrating a coupled set of ordinary differential equations. The general solution to the boundary value problem, as well as the steady state solution *This work was supported by the U. S. Department of Energy under Contract Number DE-AC04-94AL850a).
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