Abstract The NE Sicilian continental margin is largely affected by canyons and related landslide scars. Two main types of submarine canyons are recognizable: the first type carves the shelf up to depths <20 m, a few hundred metres from the coast, acting as a main collector for sediments transported by hyperpycnal flows and/or littoral drift. These canyons mostly have a V-shaped cross-section and are characterized by a strong axial incision, where a network of dendritic gullies carving the canyon flanks converges. The second type of canyon occurs where the shelf is wider, hindering the direct connection between the subaerial and submarine drainage system. This setting exhibits canyon heads mostly confined to the shelf break, characterized by a weaker axial incision of the canyon and U-shaped cross-section. A total of 280 landslide scars are recognized in the study area and these are divided into three groups according to their morphology and location. A morphometric analysis of these scars is performed to investigate which parameters might be key factors in controlling instability processes and how they correlate with each other. We also try to assess the possible tsunamigenic potential associated with these landslide events by coupling the morphometric analysis with semi-empirical relationships available in the literature.

The purpose of the study is to (1) identify the sources of sediment in various environments, (2) define the history and transport processes of the sediments, and (3) better understand the erosion and potential replenishment of the local beaches along the southern coast of the Baja California peninsula. For the purpose of this study, six naturally defined areas were studied separately: El Cardonal, El Arco, San Lucas, El Tiburón, El Tule, and San José. Two main sedimentary provinces were identified via Fourier grain-shape analysis, El Médano and Los Cabos. El Médano sedimentary province includes the El Cardonal and El Arco areas, which are influenced by the dynamics associated with the Pacific Ocean dominated by northwesterly winds, waves, and longshore transport. Beaches from this province have a source mostly from marine material from the shallow shelf, and they are dominantly affected by longshore transport. Secondarily, they are dominated by old and recent aeolian material dissected by intermittent arroyos and local arroyo material from intrusive rocks. The Los Cabos sedimentary province includes the other four areas, and it is influenced by the dynamics of the Gulf of California. In this province, dominant southerly waves are present. Sediment transport occurs along the coast from southwest to northeast; although, some beaches contain material from northern areas, probably related to the direction of waves and sediment transport direction during meteoric events such as hurricanes. Beaches from this province have a source mostly from local arroyo material from intrusive rocks. Other beach material results from longshore transport and some material comes from the El Médano sedimentary province in the El Arco boundary area. Grain-shape data and the information associated with elongation (harmonic 2) show that marine samples (beach, shallow, and deep inner continental shelf) from Los Médanos sedimentary province contain high frequencies of grains with low elongation, opposite of the arroyo samples. This suggests that the low elongation grain source may be farther north of this province. In the Los Cabos sedimentary province, the local arroyos and the longshore transport have been identified as the major factors that nourish and distribute the beach material along the coast. The results of this study parallel those found in similar geographic regions where storms rather than steady currents dominant.

Abstract The Columbia River empties into the Pacific Ocean near latitude 46° N. Much of the detrital load of the river is distributed over a 165 km long littoral cell between Tillamook Head, Oregon, and Point Grenville, Washington. The cell is characterized by north-directed littoral drift in response to dominant southwest winter storms, yet it experiences a summer drift reversal in response to more modest northwest winds and seas. The result has been development of extensive barrier beaches during the late Holocene, which define the major embayments of Willapa Bay and Grays Harbor. The mouth of the Columbia River was modified by jetties beginning late in the nineteenth century. The entrance to Grays Harbor has been jettied since early in the twentieth century. This article discusses changes resulting from these modifications. Dams on the Columbia River and its tributaries built during the twentieth century appear to have significantly reduced the detrital load available to the littoral cell, resulting in the onset of changes in the deposition-erosion regimen.