Apennine Region Research Articles

Possible Location of the Next Major Earthquakes in the Northern Apennines: Present Key Role of the Romagna-Marche-Umbria Wedge

It is argued that in some zones of the Northern Apennines, in particular the Rimini-Ancona thrust system, the Romagna Apennines and the Alta Valtiberina trough, the probability of major earthquakes is now higher than in other Apennine zones. This hypothesis is suggested by the comparison of the present short-term kinematics of the Romagna-Marche-Umbria wedge in the Northern Apennines, deduced by the distribution of major shocks in the last tens of years, with the previous repeated behavior of the same wedge, evidenced by the distribution of major earthquakes in the last seven centuries. The seismotectonics of the Apennine region here considered is closely connected with the larger context that involves the progressive migration (from south to north) of seismicity along the peri-Adriatic zones. The information provided by this study can be used to better manage the resources for prevention in Italy.

Paleoenvironmental conditions across the Cretaceous–Paleogene transition at the Apennines sections (Italy): An integrated geochemical and ichnological approach

Two distal Cretaceous–Paleogene (K/Pg) boundary sections in the Central Apennine region (Italy) have been studied: Bottaccione Gorge and Contessa Highway. Geochemical and carbon isotope analyses on the infilling of trace fossils and on the host sedimentary rocks were performed to determine paleoenvironmental conditions during the Cretaceous–Paleogene transition. Major and trace element contents were measured in a 63 cm-thick interval at Bottaccione Gorge (from 22 cm below to 41 cm above the K/Pg boundary) and in a 72 cm-thick interval at Contessa Highway (from 43 cm below to 29 cm above the K/Pg boundary). Even though the K/Pg ejecta layer is now depleted at these sections due to continuous oversampling, the uppermost Maastrichtian and lowermost Danian deposits record the paleoenvironmental conditions prior to and after the K/Pg event. We used redox-sensitive element ratios (V/Al, Cr/Al, Co/Al, Ni/Al Cu/Al, Zn/Al, Mo/Al Pb/Al and U/Mo) and detrital element ratios (K/Al, Rb/Al, Zr/Al and ƩREE/Al) as proxies of certain environmental parameters, used for paleoenvironmental reconstruction. In general, similar values for elemental ratios are registered within Maastrichtian and Danian deposits, which supports similar paleoenvironmental conditions prior to and after the K/Pg event as well as the rapid reestablishment of the pre-impact conditions (i.e., oxygenation, nutrient availability, and/or sedimentary input). An enrichment in certain redox-sensitive elements above the K/Pg at the Bottaccione Gorge section suggests lower oxygenation, as also evidenced by the tracemaker community. Carbon isotope composition data from the infilling material of trace fossils furthermore reveals values similar to those of the host rocks at the corresponding depth, which supports an active infilling by nearly contemporaneous bioturbation during sediment deposition.

Hydrogeological monitoring to assess possible pre-seismic correlations of groundwater changes with seismic activity in central Italy

This paper presents the preliminary results of a multidisciplinary study to determine a possible hydrogeological survey methodology to be applied in the seismic field.In fact in case of earthquakes, variations of the stress involving a migration of fluids occur, with consequent changes in the flow and geochemistry of groundwater. For this reason, it was identified a study site at Bussi sul Tirino (Central Italy); multiple hydrogeological and geophysical parameters including water level, temperature, electrical conductivity, crustal deformation, geochemical and isotopic composition of water are examined together to investigate possible pre-earthquake anomalous signals.Continuous monitoring of the aquifer has been performed in the period July 2014 to March 2015 in a deep well in order to detect changes in the hydrogeological parameters due to seismic activities. The recorded data was subsequently filtered to: i) separate the typical seasonal trends of the aquifer; ii) identify the piezometric variations due to intense rainfall events; iii) distinguish the tides, solid or liquid, recognized using the frequency of recorded oscillations; iv) identify changes in water level due to river-aquifer relationship. After filtering, the data have been correlated with the seismic events recorded by the national seismic network in a distance range of 30 km from the monitoring well. The comparison, for the selected time interval, shows a clear correlation between the changes in groundwater features and the seismic signal. The short time series does not allow to clarify the processes, but the obtained results are encouraging and confirm the applicability of the method in the Central Apennine region.

The role of the wolf in endemic sylvatic Trichinella britovi infection in the Abruzzi region of Central Italy

During the period 2004–2014 in the Abruzzi region (Central Italy), muscle samples gathered from hunted wild boars (n=16,323) and retrieved from carcasses of other susceptible wild mammals (n=838) and birds (n=438) were tested for Trichinella larvae according to European Union regulations. Although no positive samples were found from wild birds, 91 wild mammals tested positive. Six species were found to harbor Trichinella spp. infections, namely wolf (Canis lupus, 59 positive samples out of 218), red fox (Vulpes vulpes, 24/480), wild boar (Sus scrofa, 3/16,323), stone marten (Martes foina, 2/27), pine marten (Martes martes, 2/6) and wildcat (Felis silvestris, 1/8). All isolates tested for species attribution belonged to Trichinella britovi. The overall prevalence was 0.52% (IC 95%: 0.4–0.6). The higher frequency of positive samples in wolf, compared to red fox, was statistically significant (p=0.001). In spite of the limited geographical area of investigation and the random nature of sampling, this study provides new data on the circulation of T. britovi in Italy. In particular, the highest prevalence being found among wolves allows us to consider this species as a sentinel for T. britovi infection in the investigated area, and probably also in other apennine regions, which is different from the alpine regions where the red fox was reputed as the primary reservoir of Trichinella spp. infection.

Concordance between macrophytes and macroinvertebrates in a Mediterranean river of central Apennine region.

The main aim of this study was to improve the knowledge about the concordance among macrophytes and macroinvertebrates to provide complementary information and facilitate the procedures for quality assessment of river ecosystems. Macrophytes and macroinvertebrates were collected in 11 sampling sites along a central Apennine calcareous river in October 2008 and June 2009. The concordance between the two biomonitoring groups was tested according to several environmental parameters. The comparison of data matrix similarities by Mantel test showed differences in the assemblage of macrophytes and macroinvertebrates along the river since correlation values were 0.04, p > 0.05 in October 2008 and 0.39, p > 0.05 in June 2009. The study revealed lack of concordance between the two groups, emphasizing that the information provided by macrophytes and macroinvertebrates does not overlap in terms of response to environmental parameters. Indeed, the two different biological groups resulted useful descriptors of different parameters. Together, they could represent a complementary tool to reflect the river environmental quality.

Quaternary, catastrophic rock avalanches in the Central Apennines (Italy): Relationships with inherited tectonic features, gravity-driven deformations and the geodynamic frame

Five cases of Quaternary rock avalanches detached from carbonate mountain ridges in the Central Apennines are presented. Due to the large amount of rock masses involved, the width of accumulation and detachment areas and the damming in the host environment, the analysed rock avalanches can be considered as catastrophic rock slope failures, sporadic events in a mountain region characterized by low elevation but where mountain ridges can have a relative elevation of up to 1km above the lowermost valley floors.The geological setting of tectonic structures that originated during the Apennine orogenesis influenced rock avalanche characteristics, determining the location and shape of detachment areas, the kind of rock mass involved, and the failure mechanisms. Two main types have been identified: i) forelimb rock-slide avalanches (FRSA) such as the Lettopalena and Mt. Arezzo rock avalanche which involved Cenozoic, heterogeneous sequences of carbonate ramp deposits detached from box-shaped source areas according to a rock sliding mechanism; and ii) backlimb slide-wedge rock avalanches (BSWRA) such as the Campo di Giove, Scanno and Celano rock avalanches that detached from sub-circular source areas carved on fault-bounded ridges and involving Meso-Cenozoic carbonate rocks with a combined sliding and rock wedge failure mechanism.The Campo di Giove, Lettopalena and Scanno rock avalanches originated from mountain ridges bounded by inactive fault zones and undergoing deep-seated gravitational slope deformations (DSGSDs) at the mountain scale. These three rock slope failures are considered as isolated events of long-lasting deformative processes featuring creep deformation. Gravity-driven deformations firstly generated as a response to stacking processes and synchronous normal faulting during the Neogene–Early Pleistocene Apennine tectonics. In particular, the Caramanico Fault System (CFS) and the Genzana Fault (GF), bordering the carbonate ridges from which the Campo di Giove and Scanno rock avalanches originated respectively, are here considered as backlimb collapse structures accommodating the passive uplift and deformation of positive tectonic structures. Gravity-driven deformations persisted during the post-Early Pleistocene dome-like uplift of the whole Apennine region. The regional uplift created the first-order (200km) topographic wave-length of the belt, i.e. a periodic loading which has been balanced by the deflection of the Apennine crust and lithosphere. On the contrary, shorter topographic wave-lengths inherited from former thrusting and synchronous normal faulting determined local isostatic imbalances bearing a large potential for the mature development of DSGSDs on mountain ridges, favoured also by lateral unloading due to linear erosion and increase of topographic stress. Thus, a cause–effect relationship is hypothesized between the geodynamic evolution of the belt and mountain-sized gravity-driven deformations including large rock slope failures.

On Men and Bears: a Forgotten Migration in Nineteenth-Century Italy

This article centres on a unique type of migration: the seasonal travels of animal-trainers, mainly orsanti (bear-trainers), from the Italian Apennine region to the rest of Europe in the mid nineteenth century. These migrants set out from the walled mountain towns of Bedonia and Compiano and from surrounding villages in the province of Parma, at the intersection of Liguria, Tuscany and Emilia-Romagna. They roamed Italy and Europe, reaching as far as Turkey, Russia and Scandinavia, with their carts and their animals: a strange company of men, boys, bears, camels and monkeys. The article is based on material recently acquired by the Archivio Ligure della Scrittura Popolare of Genoa (henceforth ALSP) and the Museo degli Orsanti in Compiano, Parma (henceforth Compiano Museum). 1 Primary materials from these collections – personal documents, private journals, objects and yellowed pictures – have been tackled by borrowing from an unusual body of criticism that extends from the mythological implications of bears to visual semiotics and art history. This interdisciplinary synergy responds to the call by Felix Driver and Bill Schwarz for a widening of the circle of historical production – ‘breaking down the barriers between historians, and ... encouraging greater communication between different fields of historical practice’. 2 Such a wider outlook is especially necessary when dealing with marginal subjects for whom sources are scarce. In my research I followed the orsanti back to their hometowns, tracking the faded traces of bears and men who travelled a narrow path at the periphery of society and historiography. 3 These animal-trainers, usually travelling in small groups but also sometimes alone or with a larger performing company, were part of a large movement of people that for centuries animated the entire European continent. The lower classes had hardly been immobile. Waves of local, circular, chain and career migrations had corrugated the European landscape since the 1600s, belonging to a long history of poverty and charity. 4 For the peasant classes, as Leslie Moch notes in her Moving Europeans, ‘stability was a privilege’. 5 Various migrant groups played a part in the developing European economy. Teams of seasonal workers were hired to reclaim and fertilize potential agricultural land, as in the unhealthy swamps of the Tuscan Maremma. In winter men from the poor mountain villages of the

Social Network Analysis in Encouraging Role-Players in the Beef Market to Take Breeding Decisions: A Methodological Study

The aim of the research is to apply the social network analysis (SNA) to the Italian Romagnola beef meat market in order to better understand the interrelationships of the supply chain. Knowledge of the market exchange system is very important in order to be able to choose the most suitable breeding approach. The analysis was carried out using data concerning the heifers exchanged during the year 2008 within the framework of the activities of the Italian consortium of white bullock producers of the central Apennine region of Italy (Vitellone Bianco dell’Appennino Centrale). The social network analysis shows that very few of the possible links between the agents are used and that this leads to a lack of competitiveness. At the same time, the agents have shown to be able to place themselves at the most important points along the supply chain. Furthermore, the results of the analysis show the need for a stronger farming phase with a greater emphasis on the farmers, given that, from an economic point of view, they are the most important role-players.

Late Quaternary soil erosion and landscape development in the Apennine region (central Italy)

This study on past soil erosion processes focuses on a catchment located in a mountainous sector of the Central Apennines, 60 km northeast of Rome. Humans are known to have interacted with the landscape in this region at least since the early Iron Age. The area is highly sensitive to climatic changes and human intervention and thus is susceptible to soil erosion. The environmental impact of past human activities has been examined by geomorphological and sedimentological investigations and supported by modelling operations.Percussion drillings in the floodplains reveal up to 10 m thick alluvial deposits. Combined sedimentological and geomorphological analysis suggests that the total sediment volume of the valley infill totals about 300,000 m3 of sediments. Radiocarbon dating documents that this alluvial sedimentation started during the sub-Atlantic period (between the 1st and 2nd centuries BC) and coincides with a shift from a flood-quiescent to a flood-prone phase. According to historical sources, the flood phase correlates chronologically with the Roman occupation of the area, when they practiced extensive logging in their territories. GIS modelling operations show a loss of soil surface of about 71 cm on average for the entire catchment (1,600,000 m3 loss of soil), if long-term land exploitation for wood supply is assumed. The modeling showed that approximately 80% of the eroded soil has been fluvially transported out of the catchment, so the present alluvial plains may represent only about 20% of the overall lost soil mass.

Collapse sinkholes in the carbonate massifs of Central and Southern Apennines

This study focuses on karst collapse sinkholes of the southern and central Apennines region (Italy), and has the aim of outlining and discussing the factors whichcontribute to the occurrence of collapse phenomena. By the analysis of the morphometrical/morphological features of the about 600 initially identified sinkholes, about 50% were interpreted as collapse sinkholes related to karst phenomena, whichare the object of this study. These were geo-referred and organised in a data base, in whichinformation on the geological-structural and hydrogeological features of areas affected by the collapses was also reported. The collapse sinkhole inventory was paralleled by an analysis of the distribution of the main mineral springs (H2S- and CO2- richwaters), of travertine bodies and of extensional faults withlate Quaternary activity, whichwere all considered significant to the study due to the interrelations linking travertines, karst solution processes, CO2- richwaters and faults. Furthermore, withthe aim of investigating the role of seismic shaking in the occurrence of the collapses, the karst collapse sinkhole distribution was compared withthe distribution of stronger historical earthquake epicentres. The results of this regional scale synthesis suggests a possible key to the interpretation of karst collapse phenomena. The latter, in fact, appear correlated to the combination of peculiar conditions, whichmay be envisaged in the presence of active faults and mineral waters. The study, in particular, suggests that karst collapse sinkholes result from enhanced dissolution phenomena related to the rising of fluids of deep origin, for which active faults represent preferred pathways, and favoured by the presence of a relatively shallow water table. In the collapse events, an important role is possibly played by seismic shaking.

Provenance signatures for the Miocene volcaniclastic succession of the Tufiti di Tusa Formation, southern Apennines, Italy

AbstractThe Tufiti di Tusa Formation, a siliciclastic turbidite system of lower Miocene age in southern Italy, is mainly composed of volcaniclastic and quartzolithic sandstones interbedded with mudrocks. Sandstones are subdivided into four distinctive petrofacies, evolving from quartzolithic to volcaniclastic lithofeldspathic and feldspatholithic, reflecting detrital evolution from growing orogen (quartzolithic petrofacies) to active volcanism (volcaniclastic petrofacies). The mineralogical composition of the associated mudrocks is predominantly characterized by phyllosilicates, mainly illite/smectite mixed layers (I/S R1 associated with minor amounts of I/S R0 in the lower part of the succession, and I/S R3 in its upper part), together with illite, detrital micas and chlorite, and minor amounts of chlorite/smectite mixed layers and kaolinite, in addition to quartz, calcite and feldspars. The most abundant phyllosilicates are I/S mixed layers, 10-Å minerals (illite and micas) and chlorite, while kaolinite and chlorite–smectite mixed layers are present as a few per cent or in trace amounts. X-ray diffraction patterns show the occurrence of the ordered I/S R1 mixed layers in most samples but, at the top of the succession, some samples are characterized by I/S R3 mixed layers, whilst in the lower part of the succession I/S R1 is associated with a lower amount of I/S R0. These features suggest that the Tufiti di Tusa Formation experienced a medium diagenetic grade, and the occurrence of I/S R3 could be explained by K-availability in samples in the upper part of the succession. The lithic fragments in sandstones are metasedimentary rocks of Palaeozoic age, and andesite to dacite volcanic rocks of early Miocene age. The associated mudrocks also contain trace element ratios (Cr/V, Y/Ni, La/Sc, Th/Sc, Th/Co, Th/Cr, Cr/Th and Eu/Eu*) consistent with a provenance containing intermediate to silicic sources with scarce or absent basic rocks. The chemical index of alteration (63.2 to 71.6) suggests a moderate degree of weathering in the source. Furthermore, the K/Cs ratios of sediments confirm likely moderate rather than intense weathering. The index of compositional variability (ICV) values (from 1.2 to 2.5) are high enough to suggest the mudrocks are first-cycle sediments with little recycling. The Al–Ti–Zr diagram and the Th/Sc v. Zr/Sc plot indicate poor sorting and rapid deposition of the sediments. Detrital and sedimentary evolution of the Tufiti di Tusa Formation provides constraints, in terms of relations between a growing orogenic system and active volcanism in the Central Mediterranean, to contribute to geodynamic and palaeogeographic reconstructions of the earliest collision in the southern Apennines region.

Conservation genetics of small relic populations of silver fir (Abies alba Mill.) in the northern Apennines

Small and isolated silver fir populations from the Emilian Apennines (northern Italy) were studied to assess their level of genetic variation and their relationship with Alpine populations. We investigated the variability of two chloroplast microsatellites to analyse the within‐population genetic variability of four peripheral and fragmented Apennine populations and to determine their phylogenetic relatedness to seven Alpine populations covering the entire distribution of silver fir in the Alps. Haplotypic richness and haplotype diversity as well as the fraction of private haplotypes were lower in Apennine populations, evidencing the genetic impoverishment of these stands. The among‐population genetic variability analysis revealed the genetic peculiarity of Apennine populations. Analysis of molecular variance showed that the highest level of the among‐population variation occurs between Alpine and Apennine regions. A neighbour‐joining dendrogram revealed a distinct Apennine cluster that included the closest Alpine population. Our genetic analysis supports a common origin for Emilian Apennine populations, suggesting that these populations are relicts of past large silver fir populations in the northern Apennines. Our results point to a relevant conservation value for these stands, to be considered in their management.

Seismic attenuation and mantle wedge temperature in the northern Apennines subduction zone (Italy) from teleseismic body wave spectra

We analyze P and S wave spectra from moderate‐ to deep‐focus teleseisms recorded at the Retreating‐Trench, Extension, and Accretion Tectonics (RETREAT) temporary broadband seismic network to assess the variations of the Earth mantle attenuation in the northern Apennines region (Italy). For each earthquake, we compute the ratio between the spectrum at each station and the average spectrum, in order to estimate t* residuals (Δt*) from the spectral ratio decay. The number and distribution of the teleseisms useable for the P wave t* calculation allow for a gross azimuthal analysis; although the (Δt*) values at single station display, in most cases, azimuthal‐dependent fluctuations, their overall distribution shows a partition of the study region into two main areas, whose gross features remain almost unchanged over the whole azimuthal range. This partition is confirmed by the S wave t* mean values, computed for each station over the set of useable events. We distinguish a relatively high attenuation area on the western, Tyrrhenian side and a relatively low attenuation area on the eastern, Adriatic side. By correlating our Δt* estimates and the velocity structure derived from the existing tomographic models, we compute the ranges of possible P and S wave Q values in the mantle wedge above the Apennines slab (on the Tyrrhenian side) and in the asthenosphere below the Adriatic region. Furthermore, the determined attenuation properties are used to draw some inferences on the thermal state of the uppermost mantle and on the physical properties of the tectonic elements, which constitute the subduction system in the region.

Does lake age affect zooplankton diversity in Mediterranean lakes and reservoirs? A case study from southern Italy

Zooplankton assemblages of 51 lacustrine environments located in the middle of the Mediterranean Region were analysed to evaluate the existence of an ‘age effect’ in determining their structure. The analysed datasets refer to two different geographic areas, one comprising 30 natural and artificial lakes in Sicily and the other an arrangement of 21 analogous aquatic ecosystems located at the bottom of the Italian Peninsula, a more pristine area called Southern Apennine region. Most of the natural lakes are of post-glacial origin. The artificial lakes in both datasets were built in the last century and offer the opportunity to evaluate the possible short-term effects of ageing on the structure of their zooplankton. A comparison of assemblages in the two regions by PERMANOVA and nMDS revealed that they are quite different; therefore they were analysed separately. An explorative analysis on the possible relationship between biological data and environmental data (including lake age) was performed on both datasets using DISTLM. The presence of an ‘age effect’ emerged only in the subset of artificial lakes of the Southern Apennine region; accordingly it was tested more in detail with an a posteriori PERMANOVA analysis in the subset of reservoirs that resulted positive in the first test. SIMPER allowed us to single out the main species responsible of changes in the zooplankton along the selected age groups. No age effect was evident in the Sicilian water bodies, where other variables, such as conductivity, trophic state, urbanisation and water level fluctuations proved to have a major role in shaping zooplankton assemblages. The results showed that the age effect is: (i) detectable only at a time scale of decades; (ii) masked by the human impact in the watershed.

Uncertainty analysis for seismic hazard in Northern and Central Italy

In this study we examine uncertainty and parametric sensitivity of Peak Ground Acceleration (PGA) and 1-Hz Spectral Acceleration (1-Hz SA) in probabilistic seismic hazard maps (10% probability of exceedance in 50 years) of Northern and Central Italy. The uncertainty in hazard is estimated using a Monte Carlo approach to randomly sample a logic tree that has three input-variables branch points representing alternative values for bvalue, maximum magnitude (Mmax) and attenuation relationships. Uncertainty is expressed in terms of 95% confidence band and Coefficient Of Variation (COV). The overall variability of ground motions and their sensitivity to each parameter of the logic tree are investigated. The largest values of the overall 95% confidence band are around 0.15 g for PGA in the Friuli and Northern Apennines regions and around 0.35 g for 1-Hz SA in the Central Apennines. The sensitivity analysis shows that the largest contributor to seismic hazard variability is uncertainty in the choice of ground-motion attenuation relationships, especially in the Friuli Region (?0.10 g) for PGA and in the Friuli and Central Apennines regions (?0.15 g) for 1-Hz SA. This is followed by the variability of the b-value: its main contribution is evident in the Friuli and Central Apennines regions for both 1-Hz SA (?0.15 g) and PGA (?0.10 g). We observe that the contribution of Mmax to seismic hazard variability is negligible, at least for 10% exceedance in 50-years hazard. The overall COV map for PGA shows that the uncertainty in the hazard is larger in the Friuli and Northern Apennine regions, around 20-30%, than the Central Apennines and Northwestern Italy, around 10-20%. The overall uncertainty is larger for the 1-Hz SA map and reaches 50- 60% in the Central Apennines and Western Alps.

Volcanic hazard at Vesuvius: An analysis for the revision of the current emergency plan

Mt Somma-Vesuvius is a composite volcano on the southern margin of the Campanian Plain which has been active since 39 ka BP and which poses a hazard and risk for the people living around its base. The volcano last erupted in 1944, and since this date has been in repose. As the level of volcanic risk perception is very high in the scientific community, in 1995 a hazard and risk evaluation, and evacuation plan, was published by the Italian Department of Civil Protection ( Dipartimento della Protezione Civile) . The plan considered the response to a worst-case scenario, taken to be a subplinian eruption on the scale of the 1631 AD eruption, and based on a volcanological reconstruction of this eruption, assumes that a future eruption will be preceded by about two weeks of ground uplift at the volcano's summit, and about one week of locally perceptible seismic activity. Moreover, by analogy with the 1631 events, the plan assumes that ash fall and pyroclastic flow should be recognized as the primary volcanic hazard. To design the response to this subplinian eruption, the emergency plan divided the Somma-Vesuvius region into three hazard zones affected by pyroclastic flows (Red Zone), tephra fall (Yellow and Green Zone), and floods (Blue Zone). The plan at present is the subject of much controversy, and, in our opinion, several assumptions need to be modified according to the following arguments: a) For the precursory unrest problem, recent scientific studies show that at present neither forecast capability is realistic, so that the assumption that a future eruption will be preceded by about two weeks of forecasts need to be modified; b) Regarding the exposure of the Vesuvius region to flow phenomena, the Red Zone presents much inconsistency near the outer border as it has been defined by the administrative limits of the eighteen municipality area lying on the volcano. As this outer limit shows no uniformity, a pressing need exists to define appropriately the flow hazard zone, since there are some important public structures not considered in the current Red Zone that could be exposed to flow risk; c) Modern wind records clearly indicate that at the time of a future eruption winds could blow not only from the west, but also from the east, so that the Yellow Zone (the area with the potential to be affected by significant tephra fall deposits) must be redefined. As a result the relationship between the Yellow Zone and Green Zone (the area within and beyond which the impact of tephra fall is expected to be insignificant) must be reconsidered mainly in the Naples area; d) The May 1998 landslide, caused in the Apennine region east of the volcano by continuous rain fall, led to the definition of a zone affected by re-mobilisation of tephra (Blue Zone), confined in the Nola valley. However, as described in the 1631 chronicles of the eruption, if generation of debris flows occurs during and after a future eruption, a much wider region east of the Somma-Vesuvius must be affected by events of this type.

SKS splitting measurements beneath Northern Apennines region: A case of oblique trench-retreat

We present here the new observations of seismic anisotropy obtained from SKS birefringence analysis. We studied 27 teleseismic earthquakes recorded by the temporary seismic network of RETREAT project in the Northern Apennines region. For each station–event couple we calculate the anisotropic parameters (delay time and fast-polarization direction) by minimizing the energy in the transverse component. Our measurements confirm the existence of two domains. The Tuscany domain, on the south-west with respect to the Apennines, shows mostly NW–SE fast axes directions, with a rotation toward E–W direction moving toward the Tyrrhenian Sea. The Adria domain, north-east of the Apennines orogen, shows more scattered measurements, with prevailing N–S to NNE–SSW directions, also with back-azimuthal dependence. The transition between the two domains is abrupt in the northern part of the study region but more gradual in the southern part. Measured delay times (1.8 s on average) suggest that the detected anisotropy is located principally in the asthenosphere. Beneath the Adria domain, where the presence of a double-layer structure seems consistent, a lithospheric contribution is plausible. An interpretation in terms of ongoing mantle deformation suggests a differential evolution of the trench-retreat process along the Northern Apennines orogen. The orogen-parallel anisotropy in the study region is beneath the inner part of the belt instead of beneath its crest and no orogen-normal measurements are found in the Tuscany side. Compared to the anisotropy pattern of the typical slab retreat seen in southern part of the Northern Apennines, in the northernmost one the anisotropy suggests that an oblique trench-retreat has occurred, possibly linked to Northern Apennines retreat since 5 Ma.

Stress interaction effect on the occurrence probability of characteristic earthquakes in Central Apennines

In this study, we compute the effect of stress change due to previous historical earthquakes on the probability of occurrence of future earthquakes on neighboring faults. Following a methodology developed in the last decade, we start from the estimate of the probability of occurrence in the next 50 years for a characteristic earthquake on known seismogenic structures, based on a time‐dependent renewal model. Then a physical model for the Coulomb stress change caused by previous earthquakes on these structures is applied. The influence of this stress change on the occurrence rate of characteristic earthquakes is computed, taking into account both permanent (clock advance) and temporary (rate‐and‐state) perturbations. We apply this method to the computation of earthquake hazard of the main seismogenic structures recognized in the Central and Southern Apennines region, for which both historical and paleoseismological data are available. This study provides the opportunity of reviewing the problems connected with the estimate of the parameters of a renewal model in case of characteristic earthquakes characterized by return times longer than the time spanned by the available catalogues and the applicability of the concept of characteristic earthquake itself. The results show that the estimated effect of earthquake interaction in this region is small compared with the uncertainties affecting the statistical model used for the basic time‐dependent hazard assessment.

Market Makers and Market Takers: A History of Natural Fibres Textiles in the Central Apennine Region (the Marche and Umbria). By Robert S. DuPlessis. Bari: Mario Adda Editore, 2005. Pp. 172.

Market Makers and Market Takers: A History of Natural Fibres Textiles in the Central Apennine Region (the Marche and Umbria). By Robert S. DuPlessis. Bari: Mario Adda Editore, 2005. Pp. 172.

Sedimentology, palynology and new geochronological constraints on Quaternary deposits of the Corvaro intermontane basin (central Italy)

Two main depositional phases are recognized in the Middle-Late Pleistocene sedimentary sequences of the Corvaro tectonic depression (Latium, central Italy). To improve the chronological, palaeoenvironmental and palaeoclimatic frame of the area two boreholes were drilled. They allowed to estimate the thickness of deposits, to define the stratigraphy and to establish the presence, during the second phase, of a palustrine/lacustrine environment limited to the marginal sector of the Amara valley alluvial fan. The Corvaro 2 core was palynologically investigated. Pollen of nonarboreal plants dominates the assemblages, suggesting that a steppe characterized the environment during a glacial phase. Pollen of arboreal plants is scarce, and represented mainly by gymnosperm trees and shrubs. A slight expansion of deciduous oaks together with sparse occurrences of some other mesophilous trees is radiocarbon dated at around 30,000 years BP. These arboreal oscillations of the last glacial period are found for the first time in a mountain area of the Apennine region. Our results suggest that intermontane valleys, such as Valle del Salto, have probably played an important role in preserving biodiversity.