Massimo Moretti

Modelling seismites with a digital shaking table

Abstract Soft-sediment deformation structures induced by seismically triggered liquefaction and/or fluidization (seismites) have been reproduced with a digital shaking table. We have used natural sediments with variable granulometric ranges (clay, silt and sand) and an earthquake simulator that is able to reproduce real tridimensional seismograms. Acceleration and pore pressure recording allowed us to follow liquefaction and/or fluidization processes in unconsolidated sediments during earthquakes. Different types of seismites were produced by variations in the tested sedimentary column.

Soft-sediment deformation structures interpreted as seismites in middle-late Pleistocene aeolian deposits (Apulian foreland, southern Italy)

Abstract Soft-sediment deformation structures in middle-late Pleistocene deposits of Torre San Gennaro (Brindisi—southern Italy) have been analysed. From a morphologic point of view, the deformational structures are represented by deformed cross-bedding and large injection structures. They are restricted to aeolian sediments, and the mechanism of deformation is related to liquefaction and/or fluidization processes. The liquefaction and/or fluidization processes have been interpreted as seismic-induced after consideration of all other possible trigger agents. The discussion about the possible source areas of the palaeoseismic event was carried out through the analysis both of the general magnitude/distance relations and the main structural features of the study zone. In conclusion we consider the key criteria for trigger mechanism interpretation of soft-sediment deformation structures in aeolian deposits and the actual feasibility of using aeolian sediments for the palaeoseismic studies.

Asymmetrical soft-sediment deformation structures triggered by rapid sedimentation in turbiditic deposits (Late Miocene, Guadix Basin, southern Spain)

SummarySoft-sediment deformation structures in Tortonian turbiditic deposits of the Guadix Basin (southern Spain) have been described. The most common structures are asymmetrical pillow structures and elongated sets of loadcasts. The structures are metric in scale and have been interpreted as the result of liquefaction and/or fluidization processes triggered by the rapid sedimentation of single high concentration turbidites.Final morphology of soft-sediment deformation structures is related to two main driving force systems: unstable density gradient and lateral shear stress. The latter is probably induced by the downslope component of the sediment weight. The asymmetry of deformational structures (in horizontal and vertical cross-section) allows a clarification of the relationship between morphology of deformation and direction of lateral shear stress: this relationship seems ambiguous and confused in the literature. The interpretations both of deformation mechanism and trigger agent have been supported with:-field analyses;-calculations on the liquefaction processes induced by rapid sedimentation;-qualitative models in laboratory.

Structures sédimentaires de déformation interprétées comme séismites clans le quaternaire du bassin du bas segura (cordillère bétique orientale)

The Quaternary alluvial and coastal sediments from the Low Segura Basin show sedimentary deformation structures produced by liquefaction and fluidization processes described in this study. From the morphological point of view, they are load structures (sagging load-casts and drop structures), developed in a sediment with a reverse density gradient. They have been interpreted as seismites after elimination of any other possible genetic process related to the sedimentary environment. These structures indicate the existence of seismic events of moderate to high magnitude in the area during the Quaternary.

Geology of the middle and upper Pleistocene marine and continental terraces of the northern Tavoliere di Puglia plain (Apulia, southern Italy)

The Tavoliere di Puglia is a large alluvial plain located in southern Italy (Foggia Province, Apulia Region). From a geological perspective view, it represents the northern part of the Bradanic trough located between the southern Apennine Chain and the Apulian Foreland. A detailed geological survey of the middle-late Pleistocene terraces has been performed in this area and a new geologic map, at 1:150,000 scale, is here described. Criteria to distinguish these units are based on the recognition of basal unconformity surfaces: seven different synthems (UBSU, Unconformity-bounded Stratigraphic Units) have been discriminated. The data are presented in a synthesis map in which the geometrical relationships between the different sedimentary units are shown. New results for this sector of the Bradanic trough are significantly different from previous literature data. Furthermore, the map allows a reliable reconstruction of the Tavoliere di Puglia paleogeography during the Late Quaternary. Moreover, a detailed map of the Pleistocene terraces is fundamental to analyze and solve environmental problems associated with soil loss and desertification processes and river flood events.

Geology of Mar Piccolo, Taranto (southern Italy): the physical basis for remediation of a polluted marine area

Four 1:15,000 maps for the coastal area of Mar Piccolo (Taranto, southern Italy) are presented. The study area is a small, sheltered shallow marine basin of about 20 km2, located north of Taranto town. It contains some submarine, karstic freshwater springs (citri) that have determined the development of intensive aquaculture in the past. Now, the Mar Piccolo is a highly polluted area due to the presence of both military and industrial navy docks and various heavy industries located in proximal areas: (i) the ILVA steel plant in Taranto, the largest in Europe; (ii) the ENI oil refinery and (iii) the CEMENTIR, the largest cement and concrete plant in southern Italy. Many studies show that water and sediments are contaminated (heavy metals, isopropyl alcohol, polychlorinated biphenyl [PCB], etc.), and various remediation projects are now in preparation. In this study, we analyze the physical characteristics of the Mar Piccolo environment by producing several maps: a geological map; a geomorphological map; a bathy-morphological map and a map of the thickness of surficial sediment. All these maps are original products focused on the realization of a reliable geological picture for the Mar Piccolo area. They represent the first steps toward the detailed knowledge of the Mar Piccolo physical environment, which we consider to be a fundamental requirement for developing the most appropriate remediation techniques.

Flooding scenario for four Italian coastal plains using three relative sea level rise models

ABSTRACT The coastal areas of the central Mediterranean Sea are sensitive to climate change and the consequent relative sea level rise. Both phenomena may affect densely urbanized and populated areas, causing severe damages. Our maps show the land-marine flooding projections as effects of the expected relative sea level rise for four Italian coastal plains using (i) IPCC AR5 estimations, based on the IPCC RCP 8.5 emission scenarios and (ii) the Rahmstorf 2007 model. Isostatic and tectonic data were added to the global projections to estimate the relative sea changes expected along the coastline by 2100, as well as sea-flooding. The northern Adriatic map shows the study area, extending for about 5500 km2, and is presented at a scale of 1:300,000 with two inset maps at a scale of 1:150,000. The Oristano coastal plain is about 125 km2; the map scale is at 1:60,000 with an inset map scale at 1:33,000. The Cagliari coastal study area extends for 61 km2; the map scale is at 1:60,000 with two inset maps at 1:30,000. The Taranto area extends for 4.2 km2 and is represented at a scale map of 1:30,000, while the three inset maps are at a scale of 1:10,000.

Texture and composition of the Rosa Marina beach sands (Adriatic coast, southern Italy): a sedimentological/ecological approach

Abstract Beach sands from the Rosa Marina locality (Adriatic coast, southern Italy) were analysed mainly microscopically in order to trace the source areas of their lithoclastic and bioclastic components. The main cropping out sedimentary units were also studied with the objective to identify the potential source areas of lithoclasts. This allowed to establish how the various rock units contribute to the formation of beach sands. The analysis of the bioclastic components allows to estimate the actual role of organisms regarding the supply of this material to the beach. Identification of taxa that are present in the beach sands as shell fragments or other remains was carried out at the genus or family level. Ecological investigation of the same beach and the recognition of sub-environments (mainly distinguished on the basis of the nature of the substrate and of the water depth) was the key topic that allowed to establish the actual source areas of bioclasts in the Rosa Marina beach sands. The sedimentological analysis (including a physical study of the beach and the calculation of some statistical parameters concerning the grain-size curves) shows that the Rosa Marina beach is nowadays subject to erosion.

Contained-reflected turbidites and Slurry Beds in the Tufiti di Tusa Formation.Examples from Lucanian Apennines (Southern Italy) and their significance

Abstract from 88th Congress of the Italian Geological Society, 2016-09-07 - 2016-09-09, NaplesAbstract from 88th Congress of the Italian Geological Society, 2016-09-07, 2016-09-09, Naplesbook Edited by D. Calcaterra, S. Mazzoli, F.M. Petti, B. Carmina & A. Zuccari doi: 10.3301/ROL.2016.79