Returning to the facts: Response to the refusal of tsunami traces in the ancient harbour of Lechaion (Gulf of Corinth, Greece) by 'non-catastrophists' - Reaffirmed evidence of harbour destruction by historical earthquakes and tsunamis in AD 69-79 and the 6(th) cent. AD and a preceding pre-historical event in the early 8(th) cent. BC

摘要

The ancient harbour of Lechaion supposedly was one of the most important harbours of the ancient world Representing the western harbour of Connth at the eastern end of the Gulf of Corinth, it was of major importance for commercial trade and military purposes This paper is a response to the article by Kolaiti et al (2017) who reject recent findings by Hadler et al. (2011, 2013) and Koster et al. (2013). The latter presented evidence of multiple tsunami impact on the harbour. Kolaiti et al. (2017) reassessed and interpreted historical, archaeological and climatological data concluding that there is no evidence that tsunami waves inundated the Lechaion site and that the overall tsunami potential in the eastern Gulf of Corinth is comparatively low. Instead, environmental changes in and around the ancient harbour are supposed to have been controlled by climatological factors, such as wind, swell and sea currents as well as human interventions. In this paper, we re-evaluate and synthesize geomorphological, stratigraphical and geochronological data published by Stiros et al.(1996), Morhange et al.(2012) and Hadler et al. (2013) and consider seismo-histoncal information collected by Mourtzas et al.(2014) and palaeoseismological data by Mmos-Mmopoulos et al.(2015). Based on geoscientific facts, the main statements of Kolaiti et al.(2017) are evaluated. From an epistemological point of view, the rationale brought forward by Kolaiti et al.(2017) that tsunami impact is not acceptable as long as historical evidence is missing, is untenable. Tsunami traces in geological archives dated by means of absolute dating techniques must not be rejected because they are not included m existing catalogues summarizing historical data. Earthquake and tsunami catalogues are known to be incomplete (Hadler et al.2012, Papadopoulos 2015: 150). Based on original grain size data, we show that the sediment core from the central harbour basin drilled by Morhange et al.(2012) includes two tsunami candidate layers so far unrecognized Moreover, the re-interpretation of vibracore data from Hadler et al.(2013) by Kolaiti et al.2017) in terms of manmade intervention instead of tsunami-related impact is not consistent with available macro- and microfossil signatures. In order to achieve a consistent set of comparable radiocarbon data, we calculated the best-fit approximation of the local manne reservoir effect (MRE) for the Lechaion area as Delta R = 133 +/- 75 for marine samples and used this new Delta R to re-calibrate all available radiocarbon ages published by Stiros et al. 1996), Morhange et al. (012), Campos et al.(2013a, 2013b) and Hadler eta l .2013) . ringing together ancient harbour chrono-stratigraphies and the seismo-tectomc history of Lechaion and its environs, the timing of tsunami event I identified by Hadler et al .(2013) can be refined to the 770s cal BC, li.e.the early 8(th) cent .BC .This age is well consistent with the age of a homogemte-turbidite sequence described by Campos et al .(2013a, 2013b) from c .42 km distant from Lechaion at 867 m water depth indicating an earthquake-triggered tsunami/seiche effect .The age of tsunami event II detected at Lechaion by Hadler et al. (2013) can now be specified more precisely, namely to c. 44 cal BC-73 cal AD. This age is in close agreement with the age of an older tsunami candidate layer discovered in the core from Morhange et al.(2012) dated to the time before 88-215 cal AD (terminus ante quem).