The coastal cities of Gwadar and Pasni, situated along the Arabian Sea in the northwestern region of the Indian Ocean, are subjected to thorough investigation for inundation and vulnerability analysis. The estimation of maximum tsunami wave potential in the Arabian Sea involves evaluating paleomorphodynamic records of tsunamites found along its coastlines, with a focus on the most severe case for modeling to determine the maximum wave potential. Subsequently, based on this assessment, three distinct wave scenarios (7, 10, and 15 m) are projected onto Pasni and Gwadar and their surrounding coastal areas. The results reveal the high vulnerability of both cities to wave heights ≥7 m and wavelengths ≥15 km, with the 15 m scenario posing a near-complete disaster for both cities and adjoining towns. Furthermore, simulation results demonstrate that the coastal orientation and morphology contribute to the devastating impact of reflection, integration, and amplification phenomena in the region, with their intensity escalating with larger approaching waveforms. The reflection-amplification phenomenon notably and variably impacts inundation extents and depths. The installed tsunami early warning system's effectiveness is also evaluated based on the modeling and simulated results and the recent practices of early warning alerts issued.

Abstract. The coastal cities and areas of Gwadar and Pasni in Pakistan, being highly vulnerable to tsunamis, are investigated for inundation and risk analysis. For modelling, both dynamic and static approaches are used for better understanding and for their comparative analysis. The tsunami wave potential in the Arabian Sea is estimated by compiling and assessing the palaeo-morphodynamics of tsunamite record discovered so far along its coastlines. The dynamic model is calibrated and validated with the inundation limits of the 1945 tsunami in the Pasni area. Further, for risk estimation, three different wave scenarios (7 m, 10 m, and 15 m) are projected on Pasni and Gwadar. Results show that both cities are highly vulnerable to wave heights ≥7 m and wave lengths ≥ 15 km. The 15 m scenario would be almost a complete disaster for both cities and adjoining towns. Results of simulation and comparative analysis also show that due to coastal orientation and morphology, the reflection, integration, and amplification phenomena have a devastating effect on the region, and their intensity increases with the increasing size of the approaching waveform. It variably but significantly affects the inundation extents and depths. At the end, based on the simulated results, the utility of the installed early warning system is assessed.

The Arabian Peninsula is surrounded by seismically highly active plate margins, while the interior seems to be free from destructive earthquakes. We report two historical earthquakes in Qalhat, Oman, >300 km from any plate boundary and provide archaeoseismological analysis of ruined buildings. The first quake hit the city in 1497 AD with an intensity VII at most; the community survived and damage was repaired. The second event caused total devastation (intensity X-XI), sometime between 1580 and 1592. The city never recovered from the latter; it has been a field of ruins ever since. ShakeMap modeling yielded magnitude Mw 5.5 for the first and Mw 6.5-7.0 for the second earthquake. We suggest that the strike-slip Tiwi Fault or the reverse Qalhat Fault caused the first, while the reverse Qalhat Fault might have caused the second earthquake.

A sedimentological, geochronological, and geodynamic investigation of detailed micro- and meso-scale soft-sediment deformation structures (SSDS) within internally deformed layers on Gnitz Peninsula, Usedom Island, Germany, was performed in the last years. Five layers with SSDS were described of which four were possibly caused by glacial isostatic adjustment (GIA)-triggered earthquakes mirrored in liquefaction and reliquefaction phenomena (Pisarska-Jamroży et al., 2022). Hence, in line with earlier investigations and suggestions by Hoffmann and Reicherter (2012), the SSDS generation is related to oscillation of the Scandinavian Ice Sheet whose loading cycle caused stress changes likely releasing local earthquakes along pre-existing faults.Optically stimulated luminescence dating indicates a most probable time span of corresponding earthquake occurrence between 23.2 and 14.6 ka (including uncertainty). For the first time, glacially induced Coulomb failure stress changes were modelled for this area with a set of commonly accepted GIA models. They strongly support the interpretation of SSDS trapped in layers as seismites during that time. Using reliable fault parameters of faults in near vicinity of Gnitz Peninsula and suggested stress regimes and directions for northern Germany, the modelling can help indicate the most probable reactivated pre-Quaternary fault(s). If they can be confirmed after detailed palaeoseismological, geomorphological, geophysical, and structural investigations as so-called glacially induced fault(s), this would add another puzzle piece to a geodynamic scenario of glacially triggered faulting having affected an area from northern central Europe to northern Fennoscandia in the Late Pleistocene and Early Holocene.Our presentation will focus on the geodynamic setting of NE Germany, how it was changed during the last glaciation and how potentially reactivated faults can be determined.ReferencesHoffmann, G., Reicherter, K., 2012. Soft-sediment deformation of late Pleistocene sediments along the southwestern coast of the Baltic Sea (NE Germany). Int. J. Earth Sci. 101, 351-363, doi:10.1007/s00531-010-0633-z.Pisarska-Jamroży, M., Belzyt, S., Börner, A., Hoffmann, G., Kenzler, M., Rother, H., Steffen, R., Steffen, H., 2022. Late Pleistocene earthquakes imprinted on glaciolacustrine sediments at Gnitz Peninsula (Usedom Island, NE Germany). Quat. Sci. Rev. 296C, 107807, doi:10.1016/j.quascirev.2022.107807.

Tsunamis and cyclones are sea-borne hazards capable of inundating vast coastal areas. This study aims at an extreme wave hazard assessment with a preliminary inundation analysis along the Makran Coast, Pakistan. The coastal hazard, particularly tsunamis, is evaluated by integrating five approaches: (i) probabilistic tsunami hazard assessment (PTHA); (ii) deterministic tsunami hazard assessment (DTHA); (iii) geophysical-seismic (2-D thermal modelling), (iv) sedimentary tsunami deposits (tsunamis); and (v) the historical record. The recurrence interval for a mega-tsunami event (& GE;12 m) is between 500 and 1000 years in the Arabian Sea. Of these mega-tsunamis, about 60% are generated by seismic sources, while the remaining 40% are attributed to secondary (co-seismic submarine landslides) and other non-seismic sources. Based on the above five approaches, the hazard analysis helped to shortlist four wave scenarios (3, 7, 10, and 15 m). Which were further used to demarcate risk areas through static inundation analysis. The results indicated that the damage potential at the coast is minor to negligible with 3 m waves and moderate with 7 m waves. Whereas the 10 m and 15 m waves will severely disrupt the study area. In addition to tsunami risk, cyclone risk is assessed by interpolating storm tracks dating back to 1842 CE. In the last 64 years, cyclone frequency has jumped from 1 cyclone per 10 years to 20 cyclones per 10 years, and the intensity has increased by two levels from Tropical Storm (TS) to Category-3.

Beachrocks are a common characteristic of tropical and subtropical coastlines. It is known that they have a substantial influence on beach morphodynamics and they are commonly utilised as indicators of palaeo‐sea levels. At the same time, facies variability in beachrocks is understudied and their effect on shoreline evolution is poorly understood. At Mission Rocks on the KwaZulu‐Natal coastline of South Africa a narrow beach with isolated sand patches occupies low points of an otherwise continuous 3 m thick, raised shore platform of sandy and gravelly beachrocks. These beachrocks are in the process of disintegrating into megagravel deposits through chemical and mechanical weathering in a wave‐dominated, high‐energy setting. The breakdown is potentially slowed by a contemporary, fast‐forming beachrock facies, that blankets the surface and fills fractures and potholes within the older platform. The accumulation and cementation of this recent beachrock is the focus of this study. The beachrock is dated by historical evidence to post‐World War II. Data from field observations, petrographic and geochemical methods reveal that the cementing agents of the beachrock were precipitated from marine water in a phreatic setting despite its position above the intertidal zone. Not only does this facies have implications for the interpretation of palaeo‐beachrock as a sea‐level indicator, it also raises further questions regarding modelling of coastal erosion of beaches associated with outcrops of beachrock.

Oscillation of an ice sheet can be accompanied by earthquakes due to local reactivation of pre-existing faults related to the ice loading. A sufficiently large magnitude of an earthquake can trigger seismic waves that may strongly deform susceptible sediment layers and can cause the development of soft -sediment deformation structures (SSDS). Morphological and structural features of SSDS within a gla-ciolacustrine succession exposed at the coastal cliff on Gnitz Peninsula (Usedom Island) in NE Germany indicate that they must have developed due to glacial isostatic adjustment, which was suggested earlier by Hoffmann and Reicherter (2012).Here we present detailed micro-and meso-scale SSDS within internally deformed layers interpreted as seismites, liquefaction and re-liquefaction sedimentological imprints on Gnitz Peninsula. New optically stimulated luminescence dating results indicate that the most probable time span of corresponding earthquake occurrence is between 23.2 and 14.6 ka. The interpretation of SSDS 'trapped' in layers as seismites is strongly supported by modelling of glacially induced Coulomb failure stress changes in this region. Our results point to a set of probably pre-Quaternary faults which were locally reactivated in the area of Gnitz Peninsula during the last glacial maximum.(c) 2022 Elsevier Ltd. All rights reserved.

In this paper, we demonstrate how subfossil mangrove wood can be used to elucidate the timing of past tsunami events. Although tsunamis generated by submarine earthquakes along the Makran subduction zone in the Arabian Sea are not unusual, rigorous age documentation is generally lacking. The best known is the only instrument-recorded tsunami, which affected the coastlines of Iran, Pakistan, India, and Oman in November 1945. Eyewitness accounts of the effect along the Oman coastline assert that this tsunami was not destructive. However, a 25-cm-thick shell layer in the lagoon adjacent to the city of Sur was attributed to the 1945 tsunami, although dating of the shell deposit proved difficult, and the radiocarbon dates of mollusk shells were regarded as unreliable. Here, we reinterpret the age of this tsunamigenic layer based on the new discovery of parallel-oriented woody axes in the sedimentological context of the tsunami shell layer in the Sur lagoon. The woody axes were analyzed anatomically and identified as pertaining to the gray mangrove Avicennia. Radiocarbon dating of the wood (905–722 cal BP), along with sedimentological investigations, suggests that the deposition of the woody axes should be attributed to an older tsunami event that occurred ca. 1000 years ago, which has been documented at other locations along the Arabian Sea coastline. From this, we conclude that mangroves grew in this lagoon at that time. Very little is known about ancient mangrove distribution in this region and, so far, no records have been provided for this time window at this site. We also deduce that the tsunami event that occurred one millennium ago must have been substantially more severe than the one in 1945. More accurate dating of tsunamigenic events will aid in calculating the recurrence intervals and magnitude of tsunamis generated along the Makran subduction zone.

AbstractPalaeolandscape reconstructions at the German North Sea coast are essential for the understanding of coastal changes and dynamic landscape-forming processes. This study contributes to reconstructing Holocene coastal changes in the back-barrier area of the East Frisian island of Norderney and draws conclusions on the local palaeogeography. Five sediment cores were analysed in terms of sedimentology (grain-size distribution), geochemistry (TOC, TIC, N, C/N), microfauna (foraminifers and ostracods) and 13 radiocarbon dates. In order to identify driving environmental factors and support the facies interpretation, multivariate statistics (PCA) were carried out. Additional cores from the surrounding area (WASA Project and ‘Landesamt für Bergbau, Energie und Geologie’ (LBEG) Hannover) enabled correlation of the investigated cores over a transect of ~6 km, showing six depositional environments, which can be used for landscape reconstruction. Deposition starts with periglacial (aeolian and glaciofluvial) Pleistocene sediments, with subsequent pedogenesis followed by swamp conditions that develop into a salt marsh. The overlying tidal-flat sediments are partially cut by (fossil and recent) channel deposits. A hiatus at the base of the tidal-flat deposits that spans some 3000 years hints at their reworking caused by a combination of antrophogenic coastal protection measures and the impact of storms. Furthermore, based on the profile correlation and the age data, a widespread salt-marsh area with a minimum age of ~4000 cal BP is defined for the ‘Hohes Riff’ in the southwestern back-barrier of Norderney Island.

Quaternary Research is an international journal devoted to the advancement of the interdisciplinary understanding of the Quaternary Period.We aim to publish articles of broad interest with relevance to more than one discipline,

© University of Washington. Published by Cambridge University Press, 2021 Cite this article: Decker V, Falkenroth M, Lindauer S, Landgraf J, Al-Lawati Z, AlRahbi H, Franz SO, Hoffmann G (2021). Collapse of Holocene mangrove ecosystems along the coastline of Oman – Corrigendum. Quaternary Research 100, 260–262. https://doi.org/10.1017/qua.2021.6 Quaternary Research (2021), 100, 260–262 doi:10.1017/qua.2021.6

Beachrocks are coastal sediments that are lithified through the precipitation of carbonate cements. It is widely acknowledged that lithofacies in beachrocks are variable and their interpretation is useful when using beachrock as a sea level indicator or when studying shoreline evolution over the centurial to millennial scales. Surprisingly however, the facies variability of beachrocks remains understudied as they are almost exclusively described as seaward dipping, slab-shaped outcrop forming in low energy dissipative beach environments. The Mission Rocks coastline of north-eastern South Africa is in stark contrast. Here the coast comprises an up to 3 m thick raised shore platform of beachrock, where a variety of sedimentological facies are observed. These comprise seaward-dipping planar bedded sandstones and conglomeratic units, often interbedded with bimodally-orientated trough cross bedded sandstones. In our study we aim to use sedimentological facies analysis, petrography and cathodoluminescence to unravel the deposition- and cementation processes of this beachrock facies. In particular, an unusual beachrock breccia interposed amongst the breakdown remnants of the platform forms the basis of this paper. The breccia documents a cycle of simultaneous erosional breakdown and depositional buildup of the beachrock platform, a yet undescribed process for the development of beachrock. Since it forms as a thin veneer (< 0.10 m), with a slightly thicker infill (≤ 0.5 m) amidst erosional hollows and gullies of the + 2 m high rocky platform, it raises into question the necessity of a thick sedimentary overburden, that is typically considered the requirement for beachrock cementation in the mixing zone. Timing of beachrock formation is constrained by recent anthropogenic activities, as the underlaying platform was mined for building purposes during WWII and it is in these quarry slots and crack that the beachrock is found. While it is generally suspected that beachrocks may form at the centennial scale, evidence for this remains weak. Not only can the interpretation of this facies contribute to our understanding of the long term processes that form and break down beachrocks on high energetic coastlines, it provides insight into rapid beachrock formation and as such its utility as a sea level index point.

Crustal movement along the coastline of the Arabian Sea in Oman is quantified along a 72 km long coastal section characterised by staircases of marine terraces. An extensive topographic, geomorphological and geological survey was conducted on these terraces and an age model based on cosmogenic nuclide (Be-10, Cl-36) and optically stimulated luminescence dating is presented, together with a new approach to extract palaeo-shorelines from a high-resolution digital elevation model. The uplifting crustal block is fault bounded and is composed of obduction related peridotites overlain by shallow marine limestone. Nine distinct terrace levels are identified and the results indicate continuous uplift between Marine Isotope Stage (MIS) 5a and MIS 19. The calculated uplift rates vary along the coastline and a northward tilting of the uplifted coastal block is interpreted as evidence for differential uplift. The geomorphology of the terraces proves that the tilting must have taken place after the last interglacial. Tectonic forcing of the uplift by a crustal forebulge associated with the Makran Subduction Zone is discussed. It is also concluded that the uplift involves processes of serpentinisation of the peridotites in combination with karstification of the overlying limestone formations. As water is essential for both processes, climate change during the Quaternary apparently played a significant role in the uplift process as well as hydro-isostasy. (C) 2019 Elsevier B.V. All rights reserved.

In this study we aim to document various coastal notches in Sur Lagoon (Oman) and interpret them regarding their use as sea-level indicator. We also unravel any short-term sea-level fluctuations, which are potentially preserved within the trace fossil assemblages of some of the notches. The oldest paleo notches stem from the last interglacial sea-level highstand of MIS 5e. This is concluded from cosmogenic nuclide dating of the fanglomerate bedrock in Sur Lagoon as presented in this study. All outcrops of paleo notches around Sur Lagoon were investigated in regards to the faunal distribution and notch shape. Furthermore, the absolute elevation of the notches and biological markers relative to msl were measured with a differential GPS. The bioerosional notch occurs at the same height around Sur Lagoon indicating that the area remained tectonically stable over the last 125 kyr. According to the elevation of the notch-apex, msl was 3.93 ± 0.12 m higher than today during the last interglacial. The distribution of boring and bioconstructing organisms relative to the notch shape displays at least one phase of short-term sea-level rise subsequent to the notch formation. The beachrocks that are associated with the bioerosion notches in Sur Lagoon show a larger grainsize than any sediment that is deposited in the lagoon nowadays. This, in combination with the occurrence of exceptionally high and deep abrasion notches, indicates that the coastline was more openly exposed and thus experienced a higher wave energy during the notch formation.

The medieval city of Qalhat was an important trade town along the sea routes in the Indian Ocean. The reasons for the decline of the city are unclear, as the archaeological evidence is inconclusive. Geological field work was conducted and a digital elevation model analysed to test the hypothesis that the city was destroyed by an earthquake. The study area is located along the passive continental margin of the Arabian Plate. The coast shows a set of Pleistocene marine terraces. These landforms are in indication of lithosphere uplift. Faulted terrace fill deposits and deviating fluvial streams indicate rather recent lithosphere deformation. Processes responsible for the deformation are seen as subduction related forebulge uplift, serpentinite diapirism as well as isostatic response to karstification of limestone. We conclude that earthquake activity along the most prominent structural element, the Qalhat Fault, is a plausible reason for the decline of the medieval city.