GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 1.2 167 quadricopters and ground based reconnaissance and photos was performed for several weeks after the main event of August 24. This make possible to records few thousands aerial and terrestrial images of the faults scarps useful to compare with larger ruptures of the main event of October 30. ��� ������������ �� ������� ����������� ������� ����� ������ �� ���������� The improvements in digital technology, allowed small groups of geologists working in the short window of time following the late quarter 2016 earthquakes to document structural relationships in unprecedented detail over large regions. The digital images has been processed using Structure fromMotion algorithms obtaining 3D clouds of more than 3*10 7 points for each area. These point clouds, permitted to generate a fully rendered 3D geological model making the extraction of the fractures geometries possible. Comparison of the multi-temporal point clouds permitted to define the kinematics of the fault strands. Digital surface models and orthophotos mosaics, allowed to detect displacements of several centimetres where the faults and fractures can be easily traced. The attitude of these discontinuities, expressed by offset, dip direction and dip, was measured using a combination of GIS tools, integrated and verified with the digital field survey checks, and subsequently processed via the traditional geometrical spatial methods using structural statistical tools. The along-strike displacement versus distance of the fault planes and ground ruptures was analysed along several cross sections orthogonal to the fault strikes. ��� �� ��� ���� ���������� �� ������� ���� ���������� ������� ��� �� �������� One of the main challenges of mapping this particular rupture was to identify and locate the primary rupture paths through a complex network of faults outcrop in the Sibillini and Laga Mountains. �������� ���������� ������������� �� ��� ������� ��������� ��� �������������� Detailed structural relationships of the surface ruptures, are systematically mapped at scales finer than 1:500, and documented the distribution of all fractures with >2 cm of vertical offset, which totalled more than 5,000 individual scarps. The surface ruptures generally crossing many of the already known normal faults. They have a continuous extent of more than 25 km and consist of open cracks and vertical dislocations or warps (2 m maximum throw) orientated NW-SE. The cross sections highlight slip accommodation through linkage, which shows to be a common fault growth mechanism. A very good structural detail of the fault scarp arrays map is observable especially where primary rupture became distributed across multiple faults in the stepover region of the Mt. Vettore and Pian Grande di Castelluccio. Complex sections of the ruptures are located in the Mt. Vettore - Mt. Porche - Mt. Bove sectors especially because locate in the steep mountainous slopes with high relief. These ruptures typically occurs as multiple overlapping scarps that can be divided into kinematic sets that occur throughout the width of the pre-existing fault zones. The distribution and internal configuration of shearing in the rupture zone and the map-view width is one of the most important and easiest to systematically document parameters together with the way in which fracture sets are arranged relative to each other. The main factors that define the different aspects of rupture zone fabric include: a) the length and architecture of the rupture zone; b) rupture zone thickness; c) kinematics and magnitude of the coseismic slip within the rupture; d) geometric arrangement and relationship of different fracture sets, patterns of splaying, and their degree of interconnectivity. Moreover the rheology of the ruptures materials (rock, soil, debris), overburned thickness of the rupture zone width and magnitude of tectonic loading, play an important role in the rupture zone fabric. These coseismic structures are an exceptional example of the complex geological evolution of a region, where at least three tectonic phases are overprinted. The last active extensional phase affecting central Italy, highlighted by the recent seismic activity and the development of coeseismic surface ruptures, permits us to bear witness to the geological evolution of the region.