## 7 Secondary Environmental Effects Induced by the 1953 Ionian Sea Earthquakes
### Secondary Effects Induced by the 12 August 1953 Ionian Sea Earthquake in Cephalonia Island
#### 7.3.2 Hydrological Anomalies  
The earthquake of 12 August 1953 triggered also hydrological anomalies in various sites of Cephalonia. Related information was extracted by the official report of the IGUR [20] and by several local and national newspapers and local journals, comprising TAXYDROMOS, TO VIMA, TA NEA, ETHNIKOS KIRIX and NEOLOGOS PATRON. They were generated in (Figure 11):  
* the northern end of Erissos peninsula (Antipata village)
* the eastern coastal part of Paliki peninsula (Lixouri town)
* the northwestern part of Argostoli peninsula (Argostoli town)
* the eastern part of the Aenos Mt fault block (Chaliotata village)
* the southeastern Cephalonia (Tzanata and Pastra villages)
* They included:
* water turbidity in wells, which were destroyed by the earthquake ground motion, and the water of which turned into mud
* variations in the water level in wells; wells were completely drained
* variations in the flow rates of springs; some springs ran dry and new springs appeared close to the old ones.  
In Antipata village, hydrological anomalies were reported in wells. Wells with depths of up to 5 m were completely drained, resulting in a drinking water shortage in the affected local population [20].  
In Lixouri town, hydrological anomalies and especially water turbidity were reported in wells (TAXYDROMOS, 19.08.1953). The wells, from which Lixouri sourced its potable water, were either destroyed by collapses of the adjacent buildings or filled with muddy waters [47], attributed to the intense earthquake ground motion (TAXYDROMOS, 19.08.1953). Shortly after the earthquake, a shortage of potable water was reported in Lixouri, due to these hydrological anomalies. The problem was temporarily addressed by using open wells, constructed before the earthquake for agricultural purposes. This approach carried the risk of an outbreak of water-borne infections and gastrointestinal diseases. More effective measures were applied by hygiene services, organized in the meantime and reinforced with staff from Athens. The staff involved in the disaster management used water purification tablets and chlorination sachets in the affected wells in Cephalonia Island [47].  
In Argostoli town, similar hydrological anomalies were triggered by the 12 August earthquake (TO VIMA, 18.08.1953). The water in wells turned into mud, resulting in shortage of drinking water.  
In Chaliotata village, in the same spring, which was affected by the 11 August earthquake, the water stopped running after the mainshock.  
In Tzanata village, located east of Poros and southeast of Sami, ejection of water was reported after the earthquake in a site with no vegetation (NEOLOGOS PATRON, 14.08.1953, 18.08.1953; TA NEA, 17.08.1953; ETHNIKOS KIRIX, 17.08.1953). This effect could be attributed to changes in the groundwater and, in particular, to decrease in the groundwater-table depth, leading to the release of water to the surface.  
In Pastra village, located at the Eleios-Pronnoi area, hydrological anomalies comprised discharge increase in springs (NEOLOGOS PATRON, 14.08.1953), unprecedented for the area.  
A lake in the Pyrgi area of Sami dried up and the watermmills on its shores stopped working (AVGI, 1953). Its water was poured into an adjacent lake called Avythos, located close to Ayios Nikolaos village.