## 7 Secondary Environmental Effects Induced by the 1953 Ionian Sea Earthquakes
### Secondary Effects Induced by the 9 August 1953 Earthquake in Cephalonia and Ithaki  
The 9 August 1953 earthquake triggered slope failures, ground cracks and dust clouds. In Cephalonia, slope failures and, in particular, rockfalls occurred in the quarries of Argostoli town (ETHNIKOS KIRIX, 10.08.1953), which were located close to the beach (Figure 7). Similar effects have occurred along the road network between Argostoli and the northern part of the island and, in particular, along the western slopes of Ayia Dynati Mt (NEOLOOS PATRON, 11.08.1953; PELOPONNISOS, 11.08.1953; EMPROS, 11.08.1953; Figure 7). Dust clouds were induced by the 9 August earthquake and they were attributed not only to collapse of buildings and slope failures, but also to the intense ground motion (I IMERA, 11.08.1953; NEOLOG PATRON, 11.08.1953; EMPROS, 11.08.1953; Figure 7). These clouds covered the Erissos and Pylaros provinces in northern Cephalonia (I IMERA, 11.08.1953). In Ithaki Island, the 9 August 1953 earthquake triggered slope failures (ELEFTHERIA, 11.08.1953) as well as ground cracks and related subsidence (TA NEA, 10.08.1953; ETHNIKOS KIRIX, 10.08.1953; I MERA, 11.08.1953; NEOLOG PATRON, 11.08.1953; Figure 7). More specifically, large and extensive ground cracks and related subsidence were generated along the main road leading from the Vathi area, located in the southern fault block, to the Stavros area, located in the northern fault block of the island (ETHNIKOS KIRIX, 10.08.1953; I IMERA, 11.08.1953; NEOLOG PATRON, 11.08.1953; Figure 7). These effects resulted in damage in several sites along the main road network, itself resulting in temporary traffic disruption between the northern and the southern part of the island (ETHNIKOS KIRIX, 10.08.1953; NEOLOG PATRON, 11.08.1953). Moreover,  
Figure 7: Secondary environmental effects induced by the 9 August 1953 Ionian Sea earthquake in Cephalonia and Ithaki islands. slope failures, including rockfalls and slides, in several sites along the road network of Ithaki Island resulted in similar damage. No additional data for the exact location of the earthquakes' effects in Ithaki Island are available. Moreover, no related quantitative information for the detected ground cracks and slope failures were obtained from the aforementioned sources. Secondary Effects Induced by the 11 August 1953 Ionian Sea Earthquake in Cephalonia, Ithaki and Zakythos  
The 11 August 1953 earthquake triggered slope failures, comprised of mainly rockfalls and slides, anomalous waves/tsunami, hydrological anomalies, ground cracks attributed to liquefaction phenomena and hydrocarbon-related effects. Slope failures were induced by the 11 August 1953 earthquake in Cephalonia Island (TO VIMA, 12.08.1953; IIMERA, 12.08.1953; NEOLOGO's PATRON, 12.08.1953; PELOPONNISOS, 12.08.1953; Figure 8). More specifically, rockfalls were generated along the road network leading to Chionata, Skala and Poros villages in the southeastern Cephalonia (TO VIMA, 12.08.1953), in the Sami area (NEOLOGO's PATRON, 12.08.1953), along the road network leading from Sami to Argosoti's town (TO VIMA, 12.08.1953), along the slopes over Tzamata village (PELOPONNISOS, 12.08.1953) and along the road leading from the Argostoti's to Eleios-Promori area ( I IIMERA, 12.08.1953; Figure 8). The detachment of scree from bedrock and subsequent slides and rockfalls were also triggered in Lourdata village (TO VIMA, 12.08.1953; I IMERA, 12.08.1953; Figure 8), based on [PERSON] reports published in newspapers. The aforementioned slope failures resulted in the destruction of the road network and temporary traffic and communication disruption, which are vital in the first hours and days of a response to an earthquake emergency. Slope failures also affected residential areas in Cephalonia and resulted in very heavy structural damage to buildings, fatalities and injuries. In the case of Tzamata village, rockfalls caused the complete destruction of buildings, the uprooting of trees and 14 fatalities (PELOPONNISOS, 12.08.1953).