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This study used sedimentary archives obtained from a high-standing terrace along the coastal zone of the Coquimbo region to reconstruct past extreme events (floods and tsunamis). Using sedimentological (grain size), geochemical (XRF), and geochronological (14C and 137Cs) analyses, we identified nine flood deposits (1957, 1965, 1984, 1987, 1991, 1997, 2002, 2015, and 2017) and one tsunami deposit (1922). The sedimentary flood record appears complete for the last 70 years and is useful for reconstructing paleoflood events, highlighting the relevance of coastal high-standing terraces to improve our understanding of the frequency of floods in Chilean coastal areas. [ABSTRACT FROM AUTHOR]

The Moroccan coasts are occasionally inundated by storm surges and tsunamis. Local historical archives recorded some of these events, such as the storm surge of 1913 CE and the tsunami of 1755 CE. The latter remains the most destructive event the country has ever faced, with major human and economic losses recorded mainly between the two cities of Tangier and Safi. The privileged way to prevent any hazard related to these events is to study their past occurrences and impacts. However, historical evidences about these natural hazards are often very scarce to determine their return periods and evaluate their intensities. The scientific community increasingly uses sedimentary archives from coastal environments, since they offer a viable complement to historical archives. Several studies using this approach have been conducted on the Moroccan coast in recent years; however, until now, there has been no review dealing with these studies, which is the main objective of this paper. Twenty sites with traces of coastal inundation deposits have been inventoried during this work, and most of them are located along the Atlantic coast. The Mediterranean side remains poorly studied despite the presence of tsunami and storm surge risks. The review draws attention also to the absence of chronological data for most of the coastal inundation deposits recognized up to now along the Moroccan coasts, which is a major issue that prevents the determination of the return period of these events. [ABSTRACT FROM AUTHOR]

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Presents research into biogenic silica production rates, opal rain rates in the water column and opal sediment burial rates for the Indian Ocean sector of the Southern Ocean which show that the assumed opal paradox is a result of underestimated opal production rates and overestimated opal accumulation rates. Methods; Results; Conclusions.

The Atlantic coast of Morocco has been exposed to marine submersion events from storm surges and tsunamis which have resulted in human and economic losses. The absence of long term records for these hazards makes it difficult to trace their behavior through time, which is the first step to prepare proactive adaptation strategies for events that may happen in the future. In this paper, we present a late Holocene record of marine submersion events along the Atlantic coast of Morocco using a 2.7 m sediment core sampled from the Tahaddart estuary. The sedimentological and geochemical analyses conducted on this geological archive showed a mud-dominated sequence with 14 allochthonous sandy layers (E1-E14) left by marine high-energy events. The deposition age of three layers (E1, E13 and E14) has been determined using conventional dating methods (210Pbex, 137Cs and 14C). The first layer, introduced as E1 seems to fit with the great Lisbon tsunami in 1755 CE (Common Era), an event dated for the first time along the Atlantic coast of Morocco. The other two layers, referred to as E13 and E14, were dated between 3464 and 2837 cal BP (calibrated years Before Present) and chronologically correlated with marine high-energy deposits found on the Spanish Atlantic coast. This correlation confirms the existence of another regional event around 3200 BP. [ABSTRACT FROM AUTHOR]