GNGTS 2014 - Atti del 33° Convegno Nazionale

104 GNGTS 2014 S essione 1.1 Some well documented examples of Greek earthquakes (Serva e Michetti, 2010) are sintetically reported as follows�: - the August 27, 1886 earthquake (epicenter in Peloponnesus, Greece) ������������ ����� (Margottini, 1982) was felt in Salento area with very high values of intensity (I=VII MCS); - the May 28, 1897 earthquake (epicenter in Creta - Cyprus) reached I=VI MCS in Salento area; - the August 28, 1962 earthquake (epicenter in Ionian Sea) was felt in Salento with I= VI MCS. - the June 26, 1926 earthquake (epicenter between Creta and Cipro, Imax=X MCS) was well felt all over the Southern Italy. The intensity in the town of Taranto (western Salento) was IV- V MCS (Castanetto et al. , 1985). It is noteworthy that earthquakes located in the southern Apennines were powerfully felt in the whole Apulia region; among the strongest historical events of the Campania-Lucania Apennines, the 1456 (Imax =XI MCS), 1694 (Imax =XI MCS) and 1857 (Imax =XI MCS) earthquakes caused effects of intensity I=VI MCS in some localities of Salento area. More recently, the July 23, 1930 (Imax =XMCS) and the November 23, 1980 (Imax =XMCS) Irpinia earthquakes gave rise to several ������ �������� ������ ������������ ����������� �� ��� ������� ground effects, mostly hydrological variations, in the Apulian region. In details, I=������ ��� ��� ������� ��� �� ��� ���� ������� ����� ����� ���� ��� VI-VII MCS was reached due to the 1930 seismic event while I=VI MSK was estimated for the 1980 earthquakes (Porfido et al,. 2002, 2007, Serva et al. , 2007). Environmental effects of the 1743 earthquake. The most severe damage in the Salento peninsula was caused by the Mw = 6.9, 1743 strong earthquake; the casualties were about 180, of which 150 in the town of Nardò. Heavy damage affected particularly the towns of Nardò (Lecce) and Francavilla Fontana (Brindisi) (Margottini, 1981, 1985). ��� ������� ����� ��� The seismic event was also felt on the western coast of Greece, on the Malta island, in southern Italy and in some localities of central and northern Italy. The 1743 earthquake also generated a tsunami, which deposits are distributed along the southern Adriatic coastline of Salento (Mastronuzzi et al. , 2007� ����� ��� ����� ������ ; Galli and Naso, 2008��). This earthquake is described in a large amount of ���������� ��������� ��� ������� historical documents and seismic catalogues, however ��� �������� ��� �������� �� ��� ������������� ������ �� ����� � ������� �� the location and geometry of the seismogenetic source is still a subject of scientific debate. In this paper a revaluation of the 1743 MCS intensity for the damaged localities, on the basis of recent scientific literature (Margottini, 1981, 1985; Ferrari, 1987; De Simone, 1993; Boschi et al. , 1995; Galli and Naso, 2008) has been carried out. The most damaged town was Nardò, where X MCS intensity value was assigned. Accordingly, it was possible to attribute values of IX MCS to the town of Francavilla Fontana, VIII MCS to the towns of Brindisi, Castrignano del Capo, Leverano, Mesagne, Tuturano, Manduria, Racale, Salve, and VII MCS to Calimera, Copertino, Lecce, Oria, Ostuni, Seclì. Furthermore, a critical review of historical sources, especially archival documents coeval to the 1743 earthquake, found in different National Archives in Italy and in local ������ ��������� church archives�, has been performed. F�� � ���� �������� ���������� �� ��� ���������� ���� � ������������ or a more complete evaluation of the earthquake from a macroseismic point of view, it is of fundamental importance to take into account both the direct information derived from archival and historiographical sources and also ��� �������� �������������� ���� the  indirect geomorphologic data referable to environmental earthquake effects. The environmental effects triggered by the 1743 seismic event, mostly consisting in secondary effects, have been also documented by coeval reports: • in the town of Brindisi a tsunami was described, with fractures in the sea floor: “…. è stato così spaventoso, che ritirandosi il mare, faceansi vedere aperture della terra, et il molo di porta Reale diviso in tre parti…” (Ascoli F., in De Simone, 1993). • in the neighbouring of the Butrinto fortress (Albania) ruptures and probably liquefaction phenomena in the ground were observed: “….the ground opened, and it was rising up, and water and smoke come through the cracks...” (ASV b.988, in Ambraseys, 2009)