Eastern Thessaly region (Central Greece) shows numerous evidences of seismic activity ranging from structural, morphological, palaeoseismological, archaeological and historical. In the present note, we focus on the latter two aspects. A fundamental source of historic data are the "Chronicles" of the monasteries of the area. Doubtless, the most important ones are those located in the Meteora region (western Thessaly). In the "Chronicles" of these monasteries few events are reported relative to the investigated region and particularly the August 1668, occurred in the area of Larissa, the 1731, the November 9, 1766 and the August 28, 1781. Maximum inferred intensity of the three latter earthquakes has been estimated of the VIII degree. Based on the tectonic setting of the possible seismogenic structures, these events are tentatively located in the Tyrnavos Basin, while no other events are known in this sector neither before the 16th century nor in more recent times, except the March 1941 earthquake occurred East of Larissa. Archaeological information from the broader area concerns several sectors. i) Along the Rodià Fault, which is the major antithetic structure bordering to the north the Tyrnavos Basin, near the Arghyropouli village, the ancient site of Leimoné has been occupied since Neolithic times but it also represents an important Mycenaean site (13th-10th century BC). According to the historian Rhianos (3rd century BC), the town was still there during the Classical Period (5th-4th century BC) but according to Strabo it was disappeared at the end of the 1st century BC. ii) In Larissa, an inscription of the end of the 3rd century BC ascertain the bad conditions of a certain number of shrines and public buildings, reporting several damages like fallen columns. iii) Along the Tyrnavos Fault, the ancient settlement and ruins found on the rocky hill of the present-day Damasi village has been correlated to the ancient town of Phalanna and the alluvial plain extending to the north with its exploitable territory bordered by the western segment of the Tyrnavos Fault that generates a damming effect. As a consequence, frequent flooding events have continuously enriched the soil and probably enhanced the productivity of the area thus making it particularly appealing for farming. iv) At Pythion, 50 km N of Tyrnavos at the foothills of the Mount Olympus, the temple of Apollo Pythios has been rebuilt during the middle Imperial Epoch (Roman times 1st-4th century AD), probably at the beginning of the 2nd century AD. The first excavations revealed that many blocks belonging to former buildings and stones with inscriptions were chaotically accumulated in hollows. On the other hand, the existence of this temple is documented during the third Macedonian War (first half of the 2nd century BC) without any doubt and consequently the destruction of the buildings must have occurred during this time window and they were rebuilt at some distance from its original location. v) In Larissa, some blocks belonging to former buildings have been used as grave-steles during the second half of the 1st century BC thus suggesting the probable destruction of these buildings and the consequent dereliction. vi) The more important evidences of historical seismic activity producing important damaging effects have been obtained from the excavations of the great theatre of Larissa. The theatre was built at the beginning of the 3rd century BC during the Early Hellenistic times but following the traditional plan and architecture of the Classical time (koilon, orchestra and scenic building). During the II century BC was added a Doric style proscenium in front of the scenic building. During the Imperial time (last 10 years of the first century BC), the theatre underwent a deep re-handling due to a different use as arena. In particular, a new and larger proscenium was built as a monumental decoration holding three frontispice with dedications of the Larissa people to the Emperor August, to Tiberius as "benefactor and founder". During the excavations of the theatre, several evidences of damages of the building have been observed. Probably the most important and more impressive damages are represented by the displacement of some of the blocks of the walls and the rupture of some of the blocks. For example, some of the blocks show a typical concoid fracture clearly induced by a strong mechanical shock occurred in one of its corners. These rupture conditions are likely to be associated to the dynamic motion of the overlying block which acted as a hammer due to a strong acceleration. Numerous blocks are also dislocated and rotated. According to the size of the shifted blocks, their weight and the amount of displacement they suffered, we can tentatively estimate the peak acceleration occurred in the area and possibly the direction of the seismic waves. The collected archaeological and historical data, have been also compared with the available palaeoseismological data, while possible inferences for the seismic hazard of the region will be discussed.
Archaeological evidences of past earthquakes from Eastern Thessaly, Central Greece: inferences for the seismic hazard of the region
CAPUTO, Riccardo;
2004
Abstract
Eastern Thessaly region (Central Greece) shows numerous evidences of seismic activity ranging from structural, morphological, palaeoseismological, archaeological and historical. In the present note, we focus on the latter two aspects. A fundamental source of historic data are the "Chronicles" of the monasteries of the area. Doubtless, the most important ones are those located in the Meteora region (western Thessaly). In the "Chronicles" of these monasteries few events are reported relative to the investigated region and particularly the August 1668, occurred in the area of Larissa, the 1731, the November 9, 1766 and the August 28, 1781. Maximum inferred intensity of the three latter earthquakes has been estimated of the VIII degree. Based on the tectonic setting of the possible seismogenic structures, these events are tentatively located in the Tyrnavos Basin, while no other events are known in this sector neither before the 16th century nor in more recent times, except the March 1941 earthquake occurred East of Larissa. Archaeological information from the broader area concerns several sectors. i) Along the Rodià Fault, which is the major antithetic structure bordering to the north the Tyrnavos Basin, near the Arghyropouli village, the ancient site of Leimoné has been occupied since Neolithic times but it also represents an important Mycenaean site (13th-10th century BC). According to the historian Rhianos (3rd century BC), the town was still there during the Classical Period (5th-4th century BC) but according to Strabo it was disappeared at the end of the 1st century BC. ii) In Larissa, an inscription of the end of the 3rd century BC ascertain the bad conditions of a certain number of shrines and public buildings, reporting several damages like fallen columns. iii) Along the Tyrnavos Fault, the ancient settlement and ruins found on the rocky hill of the present-day Damasi village has been correlated to the ancient town of Phalanna and the alluvial plain extending to the north with its exploitable territory bordered by the western segment of the Tyrnavos Fault that generates a damming effect. As a consequence, frequent flooding events have continuously enriched the soil and probably enhanced the productivity of the area thus making it particularly appealing for farming. iv) At Pythion, 50 km N of Tyrnavos at the foothills of the Mount Olympus, the temple of Apollo Pythios has been rebuilt during the middle Imperial Epoch (Roman times 1st-4th century AD), probably at the beginning of the 2nd century AD. The first excavations revealed that many blocks belonging to former buildings and stones with inscriptions were chaotically accumulated in hollows. On the other hand, the existence of this temple is documented during the third Macedonian War (first half of the 2nd century BC) without any doubt and consequently the destruction of the buildings must have occurred during this time window and they were rebuilt at some distance from its original location. v) In Larissa, some blocks belonging to former buildings have been used as grave-steles during the second half of the 1st century BC thus suggesting the probable destruction of these buildings and the consequent dereliction. vi) The more important evidences of historical seismic activity producing important damaging effects have been obtained from the excavations of the great theatre of Larissa. The theatre was built at the beginning of the 3rd century BC during the Early Hellenistic times but following the traditional plan and architecture of the Classical time (koilon, orchestra and scenic building). During the II century BC was added a Doric style proscenium in front of the scenic building. During the Imperial time (last 10 years of the first century BC), the theatre underwent a deep re-handling due to a different use as arena. In particular, a new and larger proscenium was built as a monumental decoration holding three frontispice with dedications of the Larissa people to the Emperor August, to Tiberius as "benefactor and founder". During the excavations of the theatre, several evidences of damages of the building have been observed. Probably the most important and more impressive damages are represented by the displacement of some of the blocks of the walls and the rupture of some of the blocks. For example, some of the blocks show a typical concoid fracture clearly induced by a strong mechanical shock occurred in one of its corners. These rupture conditions are likely to be associated to the dynamic motion of the overlying block which acted as a hammer due to a strong acceleration. Numerous blocks are also dislocated and rotated. According to the size of the shifted blocks, their weight and the amount of displacement they suffered, we can tentatively estimate the peak acceleration occurred in the area and possibly the direction of the seismic waves. The collected archaeological and historical data, have been also compared with the available palaeoseismological data, while possible inferences for the seismic hazard of the region will be discussed.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
