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GEOHAZARD IN ROCKY COASTAL AREAS, edited by C. Violante. Geological Society Special Publication, 322, 2009. No. of pages: 208. Price: £80-00 (hardback). ISBN 978-86239-282-3.

David J. Miller*, * Department of Geography and Geology, University of the West Indies, Mona, Kingston 7, Jamaica.

Coastal hazard research has concentrated on the vulnerability of populations in lowland coastal areas. These communities are under threat from climate-change induced sea-level rise, coastal erosion and inundation related to extreme meteorological events, and tsunami hazards. Rocky coasts and shorelines have attracted relatively little attention from workers interested in coastal hazards compared to low-lying shorelines. Geohazard in Rocky Coastal Areas addresses this imbalance by using case studies entirely from the Italian peninsula, a coastline which is characterised by the largest number of landslide and flood-related hazards in Europe. At first glance, therefore, the title appears somewhat misleading, but the papers provide a number of research methods and approaches for characterising and modelling land degradation and erosion in rocky coastal areas. These are appropriate not only to the Italian coast, but to a wide range of geographical and geological settings. As such, the book has a potentially wide audience, although primarily directed to research scientists, academics and postgraduate students.

Many of the case studies in the volume examine the geological and hydro-geomorphological processes that deliver sediment to the coast at intermittent time intervals, and the consequences of coastal flooding, combining field studies, geophysical surveys and evidence from historical documents. The research presented also includes investigations of large slope failures on both volcanic and non-volcanic coastal areas, and cliff recession. The publication also seeks to establish sea-land correlations based on marine geophysical and borehole investigations and field analyses, and emphasises the importance of historical documentary sources for hazard assessment.

The book includes nine papers, mostly related to the Neapolitan coastal area of the Tyrrhenian Sea, including the Gulf of Naples, the Sorrento Peninsula, the Gulf of Salerno, and the offshore islands of Capri and Ischia. Violante's introduction provides a definition of rocky coastlines, and examines their common geological settings and constraints. The paper also reviews the main processes and hazards at rocky coasts in general, focusing on the processes that regulate rapid sediment transfer into coastal areas. It further emphasises the critical importance of marine and historical investigations, and the recognition of geologically sensitive coastal areas to coastal hazard studies, illustrated by the use of hazard maps and examples drawn from the Campanian coast.

The other papers consider three broad subject categories: the volcanic influence on coastal sedimentary systems through the remobilisation of pyroclastic fall-out deposits and volcanic flank collapse; the type and distribution of coastal landslides and coastal retreat mechanisms; and methods to assess coastal hazards. Saachi et al. examine flood dominated fan-deltas along the Amalfi coast, associated with steep drainage basins of the Sorrento peninsula. Their development phases relate to high sediment supply where eruption products from Vesuvius are delivered rapidly to the coast and offshore shelf. The paper further examines the internal structure of the fan-deltas and discusses the mechanisms controlling underwater sediment dispersal. The importance of landscape-mantling volcaniclastic deposits is emphasised in the development of the fan-deltas, as well as the possible role of climate forcing.

Marine geophysical and geological investigations by de Alteriis and Violante provide new data on the submarine mass movements around the island of Ischia associated with volcanic flank collapse. They discuss the origin and behaviour of the catastrophic collapses by an examination of three main debris avalanche deposits around the island, and attempt to assess the geological hazards affecting Ischia and its surrounding coastlines. The paper does not examine the tsunamigenic possibility of such collapses, a potentially interesting area for future research.

Milia et al. provide a preliminary interpretation and discussion related to slope instability and tsunami-generation associated with a 3.5 Ka year eruption of the Somma-Vesuvius volcano. High resolution seismic profile data and boreholes recognise volcaniclastic debris avalanche deposits overlain by pyroclastic density current deposits, the latter interpreted as tsunamigenic in origin, which was also linked to erosion of older deposits. The paper further emphasises the importance of incorporating the future volcanigenic tsunami hazard to risk assessment and disaster planning within the region around the Somma-Vesuvius volcano.

The paper by Iadanza et al. reviews coastal landslides based on data derived from the Italian Landslide Inventory Archive (http://www.sinanet.apat.it/progettoiffi). It summarises their distribution, landslide types, activity levels, common damage to infrastructure and typical mitigation measures used. A further examination of coastal landslides is presented by three case studies from the Adriatic Coast, and the Salento and Sorrento Peninsulas.

Brandolini et al. present a case history of five coastal landslides from eastern Liguria, northern Italy. Their geological and geotechnical setting, geomorphological features and landslide evolution processes are discussed, as well as the natural and anthropogenic factors which lead to their occurrence. The paper calls for detailed further studies to assist in mitigation planning.

The geomorphic consequences and long-range effects of the A.D. 79 Plinian eruptions of Somma-Vesuvius on the drainage basins and coastal areas of the Lattari Mountains, Sorrento Peninsula, are examined by Cinque and Robustelli. Landslide activity following the eruption led to valley floor aggradation, alluvial fan reactivation and the growth of new fan-deltas, leading to localised coastal progradation followed by dissection and erosion due to wave activity. Dating of the events and reconstruction of the coast is made by reference to associated Roman ruins. The paper further evaluates potential hazards from pyroclastic fall-out due to the geomorphic response of hillslope and fluvial systems at the coast.

Porfido et al. provide a retrospective reconstruction of past flood events affecting the Amalfi coast using historical and other documentary sources. The paper outlines the research methods, types and sources of archival data from the 16th Century to present, and provides details of 106 flood events. The authors conclude that such information may provide a sounder basis for reliable risk assessment and safer land-use planning on flood-prone areas by determining the severity and recurrence intervals of large floods, though they need to address whether the extent to which flood frequency appears to increase in recent times is a reflection of improved documentation and reporting.

De Pippo et al. apply a systematic method to quantify, rank and map the distribution of hazards associated with coastal cliffs. Six primary hazards are considered including cliff retreat, riverine flooding, storm events, landslides, seismicity and volcanism, and anthropogenic factors. An overall hazard assessment is applied by ranking the scores of each hazard into an interaction matrix, which is illustrated by classifying the hazard potential along the Sorrento Peninsula and Capri coastlines.

Many of the papers are lavishly illustrated with colour plates, maps and diagrams, while multi-beam bathymetric survey, seismic profile survey and side-scan sonar imagery also compliment the text. A four page geographical and subject index appears at the end of the book.