Abstract The coastline of the USA is vast and comprises a variety of landform types including barrier islands, mainland beaches, soft bluffed coastlines and hard rocky coasts. The majority of the bluffed and rocky coasts are found in the northeastern part of the country (New England) and along the Pacific coast. Rocky and bluffed landform types are commonly interspersed along the coastline and occur as a result of relative lowering of sea level from tectonic or isostatic forcing, which can occur on timescales ranging from instantaneous to millenia. Recent research on sea cliffs in the contiguous USA has focused on a broad range of topics from documenting erosion rates to identifying processes and controls on morphology to prediction modelling. This chapter provides a detailed synthesis of recent and seminal research on rocky coast geomorphology along open-ocean coasts of the continental United States (USA).

Abstract The Villa Del Monte landslide was one of 20 large and complex landslides triggered by the 1989 Loma Prieta, California, earthquake in a zone of pervasive coseismic ground cracking near the fault rupture. The landslide was ~980 m long, 870 m wide, and encompassed an area of ~68 ha. Drilling data suggested that movement may have extended to depths as great as 85 m below the ground surface. Even though the landslide moved <1 m, it caused substantial damage to numerous dwellings and other structures, primarily as a result of differential displacements and internal Assuring. Surface cracks, scarps, and compression features delineating the Villa Del Monte landslide were discontinuous, probably because coseismic displacements were small; such discontinuous features were also characteristic of the other large, coseismic landslides in the area, which also moved only short distances during the earthquake. Because features marking landslide boundaries were discontinuous and because other types of coseismic ground cracks were widespread in the area, identification of the landslides required detailed mapping and analysis. Recognition that landslides such as that at Villa Del Monte may occur near earthquake-generating fault ruptures should aid in future hazard evaluations of areas along active faults.

Abstract Beach compartments or littoral cells form the framework for our understanding of the sources, transport, sinks, and storage of sand in the nearshore zone. in general, along the California coast, beach sand is derived from rivers or bluff erosion, moves alongshore under the influence of prevailing wave conditions, and ultimately is lost either to a submarine canyon or dune field. The Santa Cruz Littoral Cell appears to extend as far north as San Francisco Bay and terminates downcoast at Monterey Submarine Canyon. Northwesterly waves drive littoral drift at a rate of about 200,000 to 250,000 m 3 /yr at the Santa Cruz Harbor. The major sources of sand within the Santa Cruz cell are coastal streams draining the Santa Cruz Mountains and 130 km of coastal bluffs. On the basis of the grain-size distribution of beach and nearshore sediments, a littoral cutoff diameter (0.18 mm) was established in calculating a sediment budget. Fluvial sediment transport measurements combined with flow-duration curves and grain-size distributions were employed to calculate input from coastal streams to the cell. Cliff height and length, sand content, and average long-term (50 to 75 years of aerial-photograph coverage) erosion rates were utilized to determine the littoral contribution from seacliff and bluff retreat. Coastal streams supply about 75 percent of the total littoral-sand input to the cell, bluff erosion contributes about 20 percent and the remaining 5 percent is from gully erosion and sand-dune deflation. Sediment input to the cell is highly episodic in response to large and infrequent erosional events. The processes that deliver sand to the cell (principally bluff erosion and high stream flow) may operate at different frequencies than those that move sand through the cell (longshore transport). An additional complexity arises from potential changes in sand storage, either on the beach or along the inner shelf, which are capable of producing significant volumes of sand due to the large areas involved.