Publicity waves based on manipulated geoscientific data suggesting climatic trigger for majority of tsunami findings in the Mediterranean – Response to 'Tsunamis in the geological record: Making waves with a cautionary tale from the Mediterranean' by Marriner et al. (2017)

Abstract

This article is a response to the publication by Nick Marriner, David Kaniewski, Christophe Morhange, Clément Flaux, Matthieu Giaime, Matteo Vacchi and James Goff entitled "Tsunamis in the geological record: Making waves with a cautionary tale from the Mediterranean", published in October 2017 in Science Advances. Making use of radiometric data sets published in the context of selected palaeotsunami studies by independent research groups from different countries, Marriner et al. (2017) carried out statistical and time series analyses. They compared their results with an assessment of Mediterranean storminess since the mid-Holocene that was previously published by Kaniewski et al. (2016) based on a single-core study from coastal Croatia. Marriner et al. (2017) now present "previously unrecognized" 1500-year "tsunami megacycles" which they suggest correlating with Mediterranean climate deterioration. They conclude that up to 90% of all the 'tsunamis' identified in original tsunami papers used for their study are "better ascribed to periods of heightened storminess". In this response, we show that (i) the comparison of statistical data describing storm and tsunami events presented by Marriner et al. (2017) is incorrect both from a geographical and a statistical point of view, (ii) the assumed periods of central Mediterranean storminess published by Kaniewski et al. (2016) are missing convincing geological and geochronological evidence and are statistically incorrect, (iii) the palaeotsunami data that was originally collected by different groups of authors were manipulated by Marriner et al. (2017) in a way that the resulting data set – used as a benchmark for the entire study of these authors – is wrong and inaccurate, and that (iv) Marriner et al. (2017) did not address or even negate the original sedimentological studies' presentation of comparative tsunami versus storm deposits for the selected individual localities. Based on a thorough and detailed evaluation of the geoscientific background and the methodological approach of the studies by Kaniewski et al. (2016) and Marriner et al. (2017), we conclude that there is no serious and reliable geoscientific evidence for increased storminess in the (central) Mediterranean Sea between 3400 – 2550, 2000 –1800, 1650 –1450, 1300 – 900 and 400 –100 cal BP. The impact of those storms in the Mediterranean, producing geological traces somewhat comparable to those caused by tsunamis, is insignificantly small. For the period 1902 – 2017, Mediterranean tsunamis make up 73 – 98 % of all combined extreme wave events (EWE) leading to coastal flooding and appeared up to 181 times deadlier than comparable storm effects. This is the reason why coastal Mediterranean research has focused on Holocene records of the tsunami hazard, while research on comparable storm effects is of lower significance. The validity of geological evidence for Mediterranean EWE and their interpretation as caused by palaeotsunami impacts thus remains untouched. Tsunamis, in most cases directly and indirectly induced by seismo-tectonics, have always been a much greater threat to Mediterranean coastal regions than comparable storm effects. ' Tsunami megacycles' as expressions of a 1500-year periodicity centered on the Little Ice Age, 1600 and 3100 cal BP that were correlated with questionable storm data do not exist. Cause and effect relationships work the other way round: Major tsunami events, testified by historical accounts, such as those that occurred in 1908 AD, 1755 AD, 1693 AD and 365 AD, induced numerous studies along Mediterranean coasts. These investigations resulted in a large number of publications that specifically focus on those time periods, suspected by Marriner et al. (2017) to bear signs of increased storminess, namely 200 – 300 BP and 1600 BP. The Mediterranean tsunami record cannot be ascribed to periods of increased storminess. On the contrary, the tsunami record as interpreted by the authors of the original papers cited by Marriner et al. (2017), is due to the outstandingly high seismo-tectonic activity of the region. Mediterranean tsunamis are mostly triggered by earthquakes or by earthquake-related secondary effects such as underwater mass movements. The study by Marriner et al. (2017) is also problematic because it includes simple basic statistical mistakes and major methodological inconsistencies. The geomorphological and sedimentary back-ground of EWE deposits was not taken into account. The 'broad brush' approach used by Marriner et al. (2017) to sweep sedimentary deposits from tsunami origin into the storm bag origin, just on the basis of (false) statistics coupled with very broad and unreliable palaeoclimatic indicators and time frames, is misleading. The distortion of original data collected and interpreted by other research groups by Marriner et al. (2017) is particularly disturbing. Their publication is also bound to question in this case the effectiveness of scientific quality assurance in modern publishing commerce. Marriner et al. (2017: 7) talk down the considerable risk to human settlements and infrastructure along Mediterranean coasts in relation to tsunami and earthquake hazards. Their conclusion is not only wrong as a result of their incorrect data mining and analyses, it is also irresponsible with regard to national and international efforts of tsunami and earthquake risk mitigation.

A Neolithic mega-tsunami event in the eastern Mediterranean: Prehistoric settlement vulnerability along the Carmel coast, Israel

“…Here, we describe a large early Holocene tsunami deposit in coastal sediments from Dor in NW Israel (Fig 2), as well as its probable prehistoric socio-cultural impact. [3,8], submarine landslides as well as tsunami deposits, geomorphological tsunami features and documented tsunami events (Modified from [9]). The name compilation of the sites presented in the figure are: 1 a -2 a (Alexandria); 3 a (Paphos, Polis, Cape, Greco); 4 a -8 a (Caesarea Marittima, Jiser al-Zarka); 9 a (Byblos, Senani Island); 10 a (Elos); 11 a (Gramvousa, Balos, Falasarna, Mavros, Stomiou, Gramenos, Paleochora); 12 a (Western Crete); 13 a (Palaikastro); 14 a (Pounta); 15 a (Limni Moustou); 16 a (Pylos, Porto Gatea, Archangelos, Elaphonisos); 17 a (Limni Divariou); 18 a (Santorini); 19 a (Balos bay); 20 a (Thera); 21 a (Dalaman); 22 a (Didim) for the previously dated tsunami deposits and 1 (Lebanon, Israel, Syria); 2 (levant coast); 3 (Paphos, Polis, Cape, Greco); 4 (S-E Cyprus); 5 (Akko); 6 (Yaffo); 7-8 (S-E Cyprus); 9-11 (Levant coast); 12 (The Nile cone); 13 (Lebanon); 14 (Levant coast); 15 (southern turkey); 16 (Cyprus); 17 (Israel); 18 (Lebanon-Israel) for the previously dated tsunami events.…”

River channel evolution and tsunami impacts recorded in local sedimentary archives – the ‘Fiume Morto’ at Ostia Antica (Tiber River, Italy)

“…For further details on the storm versus tsunami discussion for the central and eastern Mediterranean, see Vött et al . ().…”

Geoarchaeological evidence of Ostia’s river harbour operating until the fourth century AD

“…Similar sedimentological and microfossil evidence in favour of tsunami impact was recently published for Ostia's Fiume Morto river harbour , and is now also generally confirmed for the navalia complex (this paper). An overall assumption by Marriner et al (2017) that most of the tsunami signatures found in geological archives of the eastern Mediterranean are misinterpreted and rather represent climatic signals of increased storm activity was found to be based on incorrect statistical data treatment and rebutted by Vött et al (2019).…”

“…However, catalogues listing historic storm, earthquake, and tsunami events are known to be incomplete (Hadler et al 2012;Vött et al 2019). Even if there are historic reports, their translation and interpretation remain a matter of debate.…”