复合火山构造的高分辨率岸上地震成像:意大利武尔卡诺岛例子

火山口地下构造详细的地震成像对于增进这些高危险火山的构造和火山学的知识是必不可少的。然而,在火山地带,尤其是在岸上,很难获得高质量的地震数据。我们报道了拉福萨火山口(意大利武尔卡诺岛)西部地区的高分辨率地震剖面结果。利用高分辨率的振动源及交替采集和处理技术,我们能够克服由火山煤岩类型带来的大多数困难。本研究提供了火山堆积的地下分布和一些重要内部喷火山口构造的识别。我们确定了埋于拉福萨火山口下面的寄生火山口或玄武碎屑岩丘的位置,它在约1km的深度记录到地震的地方正在消散CO2。此外,在剖面最南部发现的变形模式与穹隆侵入后破火山口塌陷是一致的。结果表明,使用高分辨率振动源结合交替地震采集技术和非常规处理方法,可以帮助恢复火山地区浅层构造的详细信息。     

Hazard assessment of far-range volcanic ash dispersal from a violent Strombolian eruption at Somma-Vesuvius volcano, Naples, Italy: implications on civil aviation

Long-range dispersal of volcanic ash can disrupt civil aviation over large areas, as occurred during the 2010 eruption of Eyjafjallaj?kull volcano in Iceland. Here we assess the hazard for civil aviation posed by volcanic ash from a potential violent Strombolian eruption of Somma-Vesuvius, the most likely scenario if eruptive activity resumed at this volcano. A Somma-Vesuvius eruption is of concern for two main reasons: (1) there is a high probability (38?%) that the eruption will be violent Strombolian, as this activity has been common in the most recent period of activity (between AD 1631 and 1944); and (2) violent Strombolian eruptions typically last longer than higher-magnitude events (from 3 to 7?days for the climactic phases) and, consequently, are likely to cause prolonged air traffic disruption (even at large distances if a substantial amount of fine ash is produced such as is typical during Vesuvius eruptions). We compute probabilistic hazard maps for airborne ash concentration at relevant flight levels using the FALL3D ash dispersal model and a statistically representative set of meteorological conditions. Probabilistic hazard maps are computed for two different ash concentration thresholds, 2 and 0.2?mg/m³, which correspond, respectively, to the no-fly and enhanced procedure conditions defined in Europe during the Eyjafjallaj?kull eruption. The seasonal influence of ash dispersal is also analysed by computing seasonal maps. We define the persistence of ash in the atmosphere as the time that a concentration threshold is exceeded divided by the total duration of the eruption (here the eruption phase producing a sustained eruption column). The maps of averaged persistence give additional information on the expected duration of the conditions leading to flight disruption at a given location. We assess the impact that a violent Strombolian eruption would have on the main airports and aerial corridors of the Central Mediterranean area, and this assessment can help those who devise procedures to minimise the impact of these long-lasting low-intensity volcanic events on civil aviation.     

Procida volcanic history: new insights into the evolution of the Phlegraean Volcanic District (Campania region,Italy)

New stratigraphic, major- and trace-element, and Sr-, Nd- and Pb- isotopic data on volcanic deposits older than 14 ka from the island of Procida, Italy, are presented and compared with published analyses from the rest of the Phlegraean Volcanic District (PVD). Procida rocks range in composition from basalt to shoshonite and trachyte and show ⁸⁷Sr/⁸⁶Sr, ¹⁴³Nd/¹⁴⁴Nd, ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios varying within the ranges 0.70523–0.70678, 0.512539–0.512630, 18.99–19.29, 15.67–15.69 and 39.10–39.39, respectively. The presence of a compositional gap in the range SiO₂=54–59 wt % is evidence of magma bimodality, and suggests that the feeding magmatic system was formed by at least two different reservoirs located at different depths. Geochemical and isotopic variations with increasing differentiation can be explained by fractional crystallization mechanisms, that in some cases were associated with crustal contamination that occurred in both deeper and shallower reservoirs; the most evolved magmas formed in the shallower one. Mixing/mingling processes also occurred. The variation of isotopic composition through time observed both for Procida and for Campi Flegrei and Ischia rocks is evidence of strong affinity between magmas that erupted on the entire PVD until about 40 ka. This indicates that they share a common origin and a common plumbing system. Most of the PVD eruptive centers active until about 40 ka lie within a NE-SW-oriented volcano-tectonic belt extending from the southeastern part of Ischia, through Procida and Torregaveta volcano to the northeastern sector of the present Campi Flegrei caldera. This not only indicates the existence of a link between regional structures and volcanism in the area, but also suggests that PVD magma genesis and evolution were strongly regulated by extensional tectonics. In the last 40 ka the mafic rocks erupted along this extensional structure – from Torregaveta and the islands of Ischia and Procida – indicate that it still represents an important crustal discontinuity that focuses mantle-derived magmas. Procida trachybasalts are enriched in large ion lithophile elements (LILE) and light and middle rare earth elements (LREE and MREE), and show slight negative anomalies in the high field strength elements (HFSE) relative to average MORB. A slight depletion in HREE is present. Trace element and isotope systematics can be referred to a lithospheric mantle source. The lithospheric mantle source carries intra-plate and slab-derived components, the latter probably inherited from a previous subduction event.     

Intensity attenuation in the Campania region,Southern Italy

Ground motion prediction equations (GMPE) in terms of macroseismic intensity are a prerequisite for intensity-based shake maps and seismic hazard assessment and have the advantage of direct relation to earthquake damage and good data availability also for historical events. In this study, we derive GMPE for macroseismic intensity for the Campania region in southern Italy. This region is highly exposed to the seismic hazard related to the high seismicity with moderate- to large-magnitude earthquakes in the Appenninic belt. The relations are based on physical considerations and are easy to implement for the user. The uncertainties in earthquake source parameters are accounted for through a Monte Carlo approach and results are compared to those obtained through a standard regression scheme. One relation takes into account the finite dimensions of the fault plane and describes the site intensity as a function of Joyner–Boore distance. Additionally, a relation describing the intensity as a function of epicentral distance is derived for implementation in cases where the dimensions of the fault plane are unknown. The relations are based on an extensive dataset of macroseismic intensities for large earthquakes in the Campania region and are valid in the magnitude range M _w = 6.3–7.0 for shallow crustal earthquakes. Results indicate that the uncertainties in earthquake source parameters are negligible in comparison to the spread in the intensity data. The GMPE provide a good overall fit to historical earthquakes in the region and can provide the intensities for a future earthquake within 1 intensity unit.     

Hazard assessment at volcanic fields: the Campi Flegrei case history

Volcanological analysis of the 10 000 yr –1538 explosive activity at Campi Flegrei shows that the most common explosive eruptions are characterized by the emplacement of flow or surge deposits, originating from the interaction between magma and shallow and/or sea water. The minimum volumes of pyroclastic products range between 0.04 and 0.7 km³; the proximal areas covered by these products range from 3–4 to 40–50 km². The pyroclastic flow and surge deposits occurring inside the caldera have been strongly controlled by pre-existent morphology; because of this, the area of present Napoli city was blanketed by approximately 5 m of pyroclastic deposits, during the last 5000 yr.Previous analysis suggests that the presence of even very low topographic obstacles may influence pyroclastic density current run out such that future eruptive deposits would mainly be confined inside the caldera rim. We suggest that a future eruption at Campi Flegrei would not seriously involve the urbanized area of Napoli city located on the hills. On the contrary, the plains located on the eastern side of the caldera (Fuorigrotta, Bagnoli) would be the most damaged area.     

Modelling of surface ground deformations in the Phlegraean Fields volcanic area,Italy

A preliminary finite elements model of the ground deformations observed at Phlegraean Fields is proposed. The model assumes an oblate-spheroid magma chamber at the depth of 5.4 km with major semiaxis of 1.5 km and minor semiaxis of 0.75 km. The dimensions of the magma chamber have been evaluated by using a thermal model based on the assumptions that a progressively cooling huge magmatic body is responsible for the volcanic activity at Phlegraean Fields in the last 35,000 years. Surface deformations caused by an over-pressure of 30 MPa in the magma chamber have been calculated. Constant, and temperature-dependent elastic parameters of the surrounding medium have been considered. Vertical displacements of the order of those presently observed at Phlegraean Fields can be obtained only with temperature-dependent elastic properties of the medium.     

Post-collapse volcanic history of calderas on a composite volcano: an example from Roccamonfina,southern Italy

Roccamonfina, part of the Roman Potassic Volcanic Province, is an example of a composite volcano with a complex history of caldera development. The main caldera truncates a cone constructed predominantly of this caldera may have been associated with one of the ignimbritic eruptions of the Brown Leucitic Tuff (BLT) around 385 000 yr BP. The Campagnola Tuff, the youngest ignimbrite of the BLT, however, drapes the caldera margin and must postdate at least the initial stages of collapse. During the subsequent history of the caldera there were several major explosive eruptions. The largest of these was that of the Galluccio Tuff at about 300 000 yr BP. It is likely that there was further collapse within the main caldera associated with these eruptions. It is of note that despite these subsequent major explosive eruptions later collapse occurred within the confines of the main caldera. Between eruptions caldera lakes developed producing numerous lacustrine beds within the caldera fill. Extensive phases of phreatomagmatic activity generated thick sequences of pyroclastic surge and fall deposits. Activity within the main caldera ended with the growth of a large complex of basaltic trachyandestite lava domes around 150 000 yr BP. Early in the history of Roccamonfina sector collapse on the northern flank of the volcano formed the northern caldera. One of the youngest major events on Roccamonfina occurred at the head of this northern caldera with explosive activity producing the Conca Ignimbrite and associated caldera. There is no evidence that there was any linkage in the plumbing systems that fed eruptions in the main and northern calderas.     

Mineralogy and geochemistry of the « Low potassium » series of the roccamonfina volcanic suite (Campania,South Italy)

In the Campania area volcanic rocks belonging both to the trachytic (low K) and tephritic (high K) series occur, the high K series being well subordinate to the low K one. Volcanology of the trachytic series shows that: 1) the most widespread products are trachytes and alkali-trachytes, 2) in the stratigraphic sequences the most evolved (salic) volcanics are the oldest. The Roccamonfina trachytic series includes several Hy and Q normative lavas, whereas the majority of the Phlegraean Fields rock samples are Ne normative. In the A F M diagram, the lack of the Fe-rich phases gives a linear trend similar to the calc-alkaline series. An important feature of the Roccamonfina trachytic series is the coexistence of two clinopyroxenes of diopsidic and salitic composition observed in all the studied samples. The phenocrystic assemblage (clinopyroxenes, Mg-olivine, Mg-biotite) indicates that the crystallization of the melt probably occurred under relatively highpH₂O conditions. The crystallization of the diopsidic pyroxene was controlled mainly by a relatively high silica activity of the magma, whereas the salitic pyroxene, which crystallized at a lithostatic pressure lower than the diopside, might be related to the increase of the alumina activity in the final trachytic liquid. The occurrence of two clinoproxenes suggests two main episodes of crystallization of the parental latitic magma, one at a depth of about 15 km producing diopside phenocrysts and the second at a shallower depth where salite was in equilibrium with the residual melt. The volcanic rocks of the Roccamonfina trachytic series (latites, trachytes and alkalitrachytes) have likely been generated by fractionation of a latitic melt, whereas the strongly porphyritic trachybasalts formed by crystal settling of pyroxenes and olivine from a more evolved latitic melt.     

Hazard distribution and risk assessment in the network systems

In the age when transport flows in the railway and road systems, information flows in the internet channels, etc. intensify, hazard distribution in the network systems becomes a more relevant and important issue. In the paper various theoretical hazard type distributions in the network systems are analysed. Conditions and assumptions that hazard in the network system cells would settle and became steady are defined. Cases are analysed, when hazard is initiated in one or several network nodes, while in other nodes hazard is decreased, i.e. they have immunity to the hazard. In all cases hazard distribution equilibrium equations are constructed and their solutions‘ existence conditions are defined. Theoretical results are illustrated by simulation of hazard fuel transportation in the Lithuanian roads. It is shown that using this methodology it is possible to construct an algorithm, which enables to operate and decrease fuel transportation hazard and risk. The novelty of the work is associated with employing Markov process to describe hazard distribution mechanism and to determine limited hazard distribution in the nodes of networks. The hazard of tank trucks in the network of Lithuanian roads has been assessed for the first time.     

The evaluation of volcanic risk in the Vesuvian area

Volcanic Risk has been defined as the product: R = Value × Vulnerability × Hazard, where value is the total amount of lives or properties at risk for a volcani eruption, the vulnerability is the percentage of value at risk for a given volcanic event, and the hazard is the probability that a given area may be affected by a certain volcanic phenomenon.We used this definition to evaluate the Risk of loss of human lives for volcanic eruptions of Vesuvius. Value has been determined based on the total number of inhabitants living in areas that could be affected by an eruption. Vulnerability is based on the relative probability of deaths as a result of different volcanic phenomena (tephra fall, pyroclastic flows, etc.). Hazard is evaluated based on the absolute probability of a given phenomenon in a certain area. This last parameter is the most difficult to evaluate.We subdivided the activity of Vesuvius, that produces risk of loss of human lives, into three classes of eruptions, based on the Volcanic Explosivity Index. We assume that the events of each class are distributed according to a poissonian distribution (this is demonstrated for VEI = 3, and inferred for the other classes), so that we can evaluate the absolute probability of an eruption for each class within a given time span. We use a time window of 10 years and evaluate the probabilities of occurrence of at least one eruption for VEI = 3, 4, 5; the probability is respectively: P₃ = 0.09896, P₄ = 0.01748, P₅ = 0.00298We have made a hazard evaluation for the entire Vesuvian area as well as an evaluation of Volcanic Risk.The obtained map shows that the areas with higher risk are on the southern side of Vesuvius, in the coastal region where each town is characterized by an average Risk of 1000 inhabitants/10 years. The risk regularly decreases with increasing distance from the volcano. The risk is mostly due to the events with VEI = 3 and 4, as the most destructive effects of VEI = 5 are counterbalanced by the lower probability of such events.The map of volcanic risk is not intended to predict the loss of human lives of an eruption, but to give a methodology that permits to identify those areas where it is necessary to operate in order to reduce the risk of an eruption before it occurs.     

The dyke swarm of Mount Calanna (Etna, Italy): an example of the uppermost portion of a volcanic plumbing system

A new multidisciplinary study, combining geology, petrography, and geochemistry, on the rocks of the isolated hill of Mount Calanna (Mount Etna, Italy) has provided evidence for the existence of a dyke swarm, formed by more than 200 dykes distributed over an area of ~0.7 km², with an intensity of intrusion up to 40%. All bodies are deeply altered, and the geological and mesostructural surveying of 132 dykes revealed that they intruded in E–W direction, with an average dip of 60°. The faults affecting the outcrop have in general an E–W strike and dip of ~55°: these have all normal motion and have been interpreted as coeval with the dykes. This interpretation contrasts with the previous hypothesis that considered Mount Calanna as a thrust resulting from compressive deformation resulting from the gravitational spreading of the volcanic edifice. Mount Calanna is here interpreted as the uppermost portion of a vertically extensive magmatic plexus that fed the eruptive activity of one (or more) eruptive center/s sited in the Valle del Bove area. Measurements of the apparent densities on 23 dykes and host rock samples give an average value of 2,420 kg/m³ for the entire complex, ~15% lower than the density expected for hawaiitic magma, placing an important constraint on the geophysical identification of similar structures. Considering that Mount Etna is not an old eroded edifice but an active and growing volcano, the exposure of this subvolcanic structure can be regarded as exceptional. Its geometry and physical characteristics can be thus regarded as an interesting example of the present-day shallow plumbing system of Mount Etna as well as of other basaltic volcanoes.     

Temporal evolution of the Roccamonfina volcanic complex (Pleistocene), Central Italy

The Roccamonfina volcanic complex (RVC), in southern Italy, is an Early to Middle Pleistocene stratovolcano sharing temporal and morphological characteristics with the Somma–Vesuvius and the Alban Hills; both being associated with high volcanic hazard for the cities of Naples and Rome, respectively. The RVC is important for the understanding of volcanic evolution in the Roman and Campanian volcanic provinces. We report a comprehensive study of its evolution based on morphological, geochemical and K–Ar geochronological data.     

Search for strange attractors in magnetic field data: An example from a tertiary volcanic area near Bonn, Germany

Spatial variations of the magnetic field, measured at the Earth's surface, are mainly due to geological inhomogeneities within the crust. The present state of the crust, in turn, reflects its past dynamical processes and evolution. We analyzed the magnetic field intensity along a few but densely sampled profiles in a Tertiary volcanic province near Bonn, Germany. The aim was to find out whether the variation of the magnetic intensity can be related to a deterministic, although chaotic, generating system or to a stochastic one. In the former case, the geodynamical history would depend on a few degrees of freedom, whereas in the latter case, the parameters to take into account were so many that a statistic approach appears to be more suitable. Since strange attractors do not emerge from the analyzed data, we exclude the presence of a chaos generating system. Autocorrelation functions and a rescaled-range analysis, on the other hand, reveal and quantify a certain degree of correlation among successive data points and allow calculation of a range of spectral exponents in log-log diagrams, which are clearly distinct from those of white noise and Brownian motion. Only one of the profiles exhibits similarity to uncorrelated or white noise. In this case, the signal variations do not result from the local geology but from a buried gas pipe-line, aligned subparallel to that profile. If self-organized crustal evolution generally produces signatures that can be described as correlated noise, within a limited bandwidth of spectral exponents, erraneous or disturbed data could eventually be discriminated from records containing purely natural data by applying analysis tools of the dynamic system theory together with autocorrelation tests.     

Petrology of volcanic products younger than 42 ka on the Lipari–Vulcano complex (Aeolian Islands, Italy): an example of volcanism controlled by tectonics

Over the last 42 ka, volcanic activity at Lipari Island (Aeolian Arc, Italy) produced lava domes, flows and pyroclastic deposits with rhyolitic composition, showing in many cases evidence of magma mixing such as latitic enclaves and banding. In this same period, on nearby Vulcano Island, similar rhyolitic lava domes, pyroclastic products and lava flows, ranging in composition from shoshonite to rhyolite, were erupted. As a whole, the post-42 ka products of Lipari and Vulcano show geochemical variations with time, which are well correlated between the two islands and may correspond to a modification of the primary magmas. The rhyolitic products are similar to each other in their major elements composition, but differ in their trace element abundances (e.g. La ranging from 40 to 78 ppm for SiO₂ close to 75 wt%). Their isotopic composition is variable, too. The ⁸⁷Sr/⁸⁶Sr (0.704723–0.705992) and ¹⁴³Nd/¹⁴⁴Nd (0.512575–0.512526) ranges partially overlap those of the more mafic products (latites), having ⁸⁷Sr/⁸⁶Sr from 0.7044 to 0.7047 and ¹⁴³Nd/¹⁴⁴Nd from 0.512672 to 0.512615. ²⁰⁶Pb/²⁰⁴Pb is 19.390–19.450 in latites and 19.350–19.380 in rhyolites. Crystal fractionation and crustal assimilation processes of andesitic to latitic melts, showing an increasing content in incompatible elements in time, may explain the genesis of the different rhyolitic magmas. The rocks of the local crustal basement assimilated may correspond to lithotypes present in the Calabrian Arc. Mixing and mingling processes between latitic and rhyolitic magmas that are not genetically related occur during most of the eruptions. The alignment of vents related to the volcanic activity of the last 40 ka corresponds to the NNW–SSE Tindari–Letojanni strike-slip fault and to the correlated N–S extensional fault system. The mafic magmas erupted along these different directions display evidence of an evolution at different P_H2O conditions. This suggests that the Tindari–Letojanni fault played a relevant role in the ascent, storage and diversification of magmas during the recent volcanic activity.     

Structural evolution of the Pleistocene Cimini trachytic volcanic complex (Central Italy)

Structural, geomorphological, geophysical and volcanological data have been processed for the implementation of a dedicated GIS through which the structural evolution of the Pleistocene trachytic Cimini volcano (central Italy) has been reconstructed. The evolution of the Cimini complex includes three main close-in time phases: (1) intrusion of a shallow laccolith, rising along NW and NE trending faults and stagnating at the contact between the Mesozoic-Cenozoic and the Pliocene-Pleistocene sedimentary units constituting the bedrock of the volcano; (2) emplacement of lava domes along radial and tangential fractures formed by the swelling induced by the laccolith growth; (3) ignimbrite eruptions and final effusion of olivine-latitic lavas. Domes are both of Pelean and low lava dome type and their morphology was controlled by the location on the inclined surface of the swelled area. Some domes show to have uplifted upper Pliocene thermally metamorphosed clay sediments, suggesting a cryptodome-like growth. Comparison of the top of the Mesozoic-Cenozoic units with the top of the upper Pliocene-Pleistocene sedimentary complex, suggests that the laccolith emplaced in a graben of the Mesozoic-Cenozoic sedimentary complex filled by the Pliocene–Pleistocene sediments uplifted by the shallow intrusion. Stress patterns acting on the Cimini area have been deduced analysing the drainage network and the morphotectonic lineaments. Rose diagrams show a large dispersion of the lineaments reflecting the local presence of radial and tangential fractures. The most frequent extensional NW and NE trending lineaments have regional significance and controlled the magma uprise leading to the laccolith emplacement.     

Hazard area and probability of volcanic disruption of the proposed high-level radioactive waste repository at Yucca Mountain, Nevada, USA

Models that calculate the probability that a new volcano or a dike from a nearby eruption will intersect the footprint of the proposed high-level nuclear waste repository are generalized based on a conceptual model developed for the space transportation industry. The proposed hazard area, defined such that every new eruption that occurs there will disrupt the repository, plays a fundamental role in developing probability models. This hazard area is used not only to hedge the uncertainties in predicting patterns of future volcanic activity, but also to account for the characteristics of a new eruption during the post-closure performance period of an underground geologic repository. The paper discusses the advantages of probability comparisons, capabilities of conservativeness measurements and expert-elicitation on model parameters, and the implications to the proposed repository.Paper funded by a contract from the Agency for Nuclear Projects, State of Nevada, USA.     

Evolution of the Vico lavas,Roman volcanic region,Italy

A petrochemical study of representative lavas from Vico, relative to their established stratigraphic succession, shows that the erupted magma was recurrent in composition. The predominant differentiation trend of the lava suite, illustrated by means of a principal component analysis (Le Maitre, 1968), leads to trachytic residual compositions which can be interpreted in terms of crystal fractionation processes under volcanic pressure regime.     

A Probabilistic Tsunami Hazard Study of the Auckland Region, Part II: Inundation Modelling and Hazard Assessment

Regional source tsunamis pose a potentially devastating hazard to communities and infrastructure on the New Zealand coast. But major events are very uncommon. This dichotomy of infrequent but potentially devastating hazards makes realistic assessment of the risk challenging. Here, we describe a method to determine a probabilistic assessment of the tsunami hazard by regional source tsunamis with an “Average Recurrence Interval” of 2,500-years. The method is applied to the east Auckland region of New Zealand. From an assessment of potential regional tsunamigenic events over 100,000 years, the inundation of the Auckland region from the worst 100 events is modelled using a hydrodynamic model and probabilistic inundation depths on a 2,500-year time scale were determined. Tidal effects on the potential inundation were included by coupling the predicted wave heights with the probability density function of tidal heights at the inundation site. Results show that the more exposed northern section of the east coast and outer islands in the Hauraki Gulf face the greatest hazard from regional tsunamis in the Auckland region. Incorporating tidal effects into predictions of inundation reduced the predicted hazard compared to modelling all the tsunamis arriving at high tide giving a more accurate hazard assessment on the specified time scale. This study presents the first probabilistic analysis of dynamic modelling of tsunami inundation for the New Zealand coast and as such provides the most comprehensive assessment of tsunami inundation of the Auckland region from regional source tsunamis available to date.     

The role of the urban system dysfunction in the assessment of seismic risk in the Mt. Etna area (Italy)

A procedure for seismic risk assessment is applied to the Mt. Etna area (eastern Sicily, Italy) through assessment of urban system dysfunction following the occurrence of an earthquake. The tool used is based on the Disruption Index as a concept implemented in Simulator QuakeIST, which defines urban disruption following a natural disaster. The first element of the procedure is the definition of the seismic input, which is based on information about historical seismicity and seismogenic faults. The second element is computation of seismic impact on the building stock and infrastructure in the area considered. Information on urban-scale vulnerability was collected and a geographic information system was used to organise the data relating to buildings and network systems (e.g., building stock, schools, strategic structures, lifelines). The central idea underlying the definition of the Disruption Index is identification and evaluation of the impact on a target community through the physical elements that most contribute to severe disruption. The procedure applied in this study (i.e., software and data) constitutes a very useful operational tool to drive the development of strategies to minimise risks from earthquakes.     

Looking into a volcanic area: An overview on the 350 m scientific drilling at Colli Albani (Rome,Italy)

A 350 m deep borehole was drilled in the Colli Albani volcanic district (Central Italy) in order to: understand the shallow crust structure beneath the volcanic complex; characterize the rock physical properties especially through in-situ measurements and, afterward, laboratory experiments; assess the local present-day stress field; install a broad-band seismometer at depth. The borehole is located adjacent to the western rim of the Tuscolano–Artemisio caldera, where several phenomena of unrest recently occurred. In 1989–90 a seismic swarm affected this area and a related uplift was recognized. In addition, high gas concentrations (mainly CO₂ and H₂S), in aquifers and soils, caused illnesses and casualties among inhabitants and animals in the past.