Abstract: Following the 2009 L'Aquila earthquake, the Dipartimento della Protezione Civile Italiana (DPC), appointed an International Commission on Earthquake Forecasting for Civil Protection (ICEF) to report on the current state of knowledge of short-term prediction and forecasting of tectonic earthquakes and indicate guidelines for utilization of possible forerunners of large earthquakes to drive civil protection actions, including the use of probabilistic seismic hazard analysis in the wake of a large earthquake. The ICEF reviewed research on earthquake prediction and forecasting, drawing from developments in seismically active regions worldwide. A prediction is defined as a deterministic statement that a future earthquake will or will not occur in a particular geographic region, time window, and magnitude range, whereas a forecast gives a probability (greater than zero but less than one) that such an event will occur. Earthquake predictability, the degree to which the future occurrence of earthquakes can be determined from the observable behavior of earthquake systems, is poorly understood. This lack of understanding is reflected in the inability to reliably predict large earthquakes in seismically active regions on short time scales. Most proposed prediction methods rely on the concept of a diagnostic precursor; i.e., some kind of signal observable before earthquakes that indicates with high probability the location, time, and magnitude of an impending event. Precursor methods reviewed here include changes in strain rates, seismic wave speeds, and electrical conductivity; variations of radon concentrations in groundwater, soil, and air; fluctuations in groundwater levels; electromagnetic variations near and above Earth's surface; thermal anomalies; anomalous animal behavior; and seismicity patterns. The search for diagnostic precursors has not yet produced a successful short-term prediction scheme. Therefore, this report focuses on operational earthquake forecasting as the principle means for gathering and disseminating authoritative information about time-dependent seismic hazards to help communities prepare for potentially destructive earthquakes. On short time scales of days and weeks, earthquake sequences show clustering in space and time, as indicated by the aftershocks triggered by large events. Statistical descriptions of clustering explain many features observed in seismicity catalogs, and they can be used to construct forecasts that indicate how earthquake probabilities change over the short term. Properly applied, short-term forecasts have operational utility; for example, in anticipating aftershocks that follow large earthquakes. Although the value of long-term forecasts for ensuring seismic safety is clear, the interpretation of short-term forecasts is problematic, because earthquake probabilities may vary over orders of magnitude but typically remain low in an absolute sense (< 1% per day). Translating such low-probability forecasts into effective decision-making is a difficult challenge. Reports on the current utilization operational forecasting in earthquake risk management were compiled for six countries with high seismic risk: China, Greece, Italy, Japan, Russia, United States. Long-term models are currently the most important forecasting tools for civil protection against earthquake damage, because they guide earthquake safety provisions of building codes, performance-based seismic design, and other risk-reducing engineering practices, such as retrofitting to correct design flaws in older buildings. Short-term forecasting of aftershocks is practiced by several countries among those surveyed, but operational earthquake forecasting has not been fully implemented (i.e., regularly updated and on a national scale) in any of them. Based on the experience accumulated in seismically active regions, the ICEF has provided to DPC a set of recommendations on the utilization of operational forecasting in Italy, which may also be useful in other countries. The public should be provided with open sources of information about the short-term probabilities of future earthquakes that are authoritative, scientific, consistent, and timely. Advisories should be based on operationally qualified, regularly updated seismicity forecasting systems that have been rigorously reviewed and updated by experts in the creation, delivery, and utility of earthquake information. The quality of all operational models should be evaluated for reliability and skill by retrospective testing, and they should be under continuous prospective testing against established long-term forecasts and alternative time-dependent models. Alert procedures should be standardized to facilitate decisions at different levels of government and among the public. Earthquake probability thresholds should be established to guide alert levels based on objective analysis of costs and benefits, as well as the less tangible aspects of value-of-information, such as gains in psychological preparedness and resilience. The principles of effective public communication established by social science research should be applied to the delivery of seismic hazard information.

Abstract: Data acquisition by seismic centers relies on real-time systems, like SeisComP3, Antelope and Earthworm. However, these are complex systems that are designed for fast and precisely defined standard real-time analyses. Therefore, it is not a simple task to access or modify internal routines, and to integrate them into custom-processing workflows or to perform in-depth data analyses. Often a library is necessary that provides convenient access to data and allows easy control over all of the operations that are to be performed on the data. ObsPy is such a library, which is designed to access and process seismological waveform data and metadata. We use short and simple examples here to demonstrate how effective it is to use Python for seismological data analysis. Then, we illustrate the general capabilities of ObsPy, and highlight some of its specific aspects that are relevant for seismological data centers and observatories, through presentation of real-world examples. Finally, we demonstrate how the ObsPy library can be used to develop custom graphical user interface applications.

Abstract: An effort is made to improve Benioff's method for investigation of strain release in aftershock sequences. The improvement may be summarized as follows: 1. Earthquake volume increases with magnitude, instead of being constant. A relation is given, relating volume to magnitude. 2. A revised energy-magnitude formula is used. 3. The seismic gain ratio, i. e. the ratio between seismic energy and elastic strain energy, probably increases with magnitude, instead of being constant. Likewise, the ratio of fault plane area of the main shock to the vertical section through the aftershock volume increases with magnitude. 4. The seismic energy density, the elastic strain energy density as well as strain are independent of magnitude. 5. The deformation, i. e. the total strain in the aftershock zone, increases with magnitude at the same rate as seismic energy and volume do. As a consequence of these improvements some earlier published strain release characteristics are reconstructed, this time as deformation characteristics instead.

Abstract: In comparison with the great number of disastrous earthquakeswhich have occurred from antiquity to the present time in Greece, largetsunamis are very rare on the coasts of Greece. A really great tsunamimay have started in the Aegean Sea after the tremendous explosion ofSantorin volcano, which occurred 3370 ± 100 years ago (13). After thedeposit of a layer of pumice 20-30 m thick and the emptying of thevolcanic focus, the roof of the cavern thus formed collapsed. Thecentrai part, consisting of an area of 83 sq km, of the former islandStronghyb tlius became a gigantic caldera 300-400 m deep.Tliere is no evidence indicating whether the cobapse took placegraduaby or ab at once. In the second case a huge tsunami should havestarted greater by far than that generated by the explosion of Krakatoa,on August 27, 1883. At that time depths of 200-300 m were formed bythe sinking (24) of 2/3 of the former island of an area of 33 1/2 sq km.Thus the cavity formed by the explosion of Santorin is about 4 timesgreater than that of the Krakatoa.

Abstract: Spaceborne remote sensing of high-temperature volcanic features offers an excellent opportunity to monitor the onset and development of new eruptive activity. To provide a basis for real-time response during eruptive events, we designed and developed the volcano monitoring system that we call HOTSAT. This multiplatform system can elaborate both Moderate Resolution Imaging Spectroradiometer (MODIS) and Spinning Enhanced Visible and Infrared Imager (SEVIRI) data, and it is here applied to the monitoring of the Etna volcano. The main advantage of this approach is that the different features of both of these sensors can be used. It can be refreshed every 15 min due to the high frequency of the SEVIRI acquisition, and it can detect smaller and/or less intense thermal anomalies through the MODIS data. The system consists of data preprocessing, detection of volcano hotspots, and radiative power estimation. To locate thermal anomalies, a new contextual algorithm is introduced that takes advantage of both the spectral and spatial comparison methods. The derivation of the radiative power is carried out at all ‘hot’ pixels using the middle infrared radiance technique. The whole processing chain was tested during the 2008 Etna eruption. The results show the robustness of the system after it detected the lava fountain that occurred on May 10 through the SEVIRI data, and the very beginning of the eruption on May 13 through the MODIS data analysis.

Abstract: Long time series of fluid pressure and temperature within a hydrothermal system feeding the Solfatara fumaroles are investigated here, on the basis of the chemical equilibria within the CO2–H2O–H2–CO gas system. The Pisciarelli fumarole external to Solfatara crater shows an annual cycle of CO contents that indicates the occurrence of shallow secondary processes that mask the deep signals. In contrast, the Bocca Grande and Bocca Nova fumaroles located inside Solfatara crater do not show evidence of secondary processes, and their compositional variations are linked to the temperature–pressure changes within the hydrothermal system. The agreement between geochemical signals and the ground movements of the area (bradyseismic phenomena) suggests a direct relationship between the pressurization process and the ground uplift. Since 2007, the gas geoindicators have indicated pressurization of the system, which is most probably caused by the arrival of deep gases with high CO2 contents in the shallow parts of the hydrothermal system. This pressurization process causes critical conditions in the hydrothermal system, as highlighted by the increase in the fumarole temperature, the opening of new vents, and the localized seismic activity. If the pressurization process continues with time, it is not possible to rule out the occurrence of phreatic explosions.

Abstract: Mount Etna produces frequent eruptions from its summit craters and from fissures on its flanks. The flank fissures trend approximately radially to the summit, and are mainly concentrated in three rift zones that are located on the NE, S and W flanks. Many flank eruptions result from lateral magma transfer from the central conduit into fractures intersecting the flanks, although some eruptions are fed through newly formed conduits that are not directly linked to the central conduit. We analyzed the structural features of eruptions from 1900 to the present, one of the most active periods in the documented eruptive history of Etna, which comprised 35 summit and 33 flank events. Except for a small eruption on the W flank in 1974, all of the flank eruptions in this interval occurred on or near the NE and S rifts. Eruptions in the NE sector were generally shorter, but their fissure systems developed more rapidly and were longer than those in the S sector. In contrast, summit eruptions had longer mean durations, but generally lower effusion rates (excluding paroxysmal events characterized by very high effusion rates that lasted only a few hours). This database was examined considering the main parameters (frequency and strike) of the eruptive fissures that were active over the last ~2 ka. The distribution in time and space of summit and flank eruptions appears to be closely linked to the dynamics of the unstable E to S flank sector of Etna, which is undergoing periodic displacements induced by subvolcanic magma accumulation and gravitational pull. In this framework, magma accumulation below Etna exerts pressure against the unbuttressed E and S flanks, which have moved away from the rest of the volcano. This has caused an extension to the detachment zones, and has facilitated magma transfer from the central conduit into the flanks.

Abstract: Tlie long-period seismic records at Umea (Sweden) of an intermediate-depth earthquake in Burma 011 27 February, 1964, exhibit an exceptionally clear case of 8-P conversion at the Mohorovicie discontinuity. The records are examined from various points of view (arrival times, amplitude ratios, particle motions) and comparisons are made for each test between observations and theory. General aspects of mode conversions at the base of the crust are discussed, both their importance and why they are so seldom observed.

Abstract: For mapping the seismic activity tlie earthquake energy releaseil per square degree per liundred years was determined, and tlie values obtained were used for drawing isoenergetical lines. Two maps constructed in this way for the periods 1710-1959 and 1841-1959 show clearly tliat the earthquake activity in the Greek area is concentrated, for the most part, along the large fault zone bordering the western and southern coasts of Greece. It is believed tliat this fault zone marks the trend of a marginai geosyncline, which is now in the course of development in the Eastern Mediterranean. Tlie map of earthquake efflciency in Greece sliows clearly tliat the main part of the earthquake energy released in the Greek area comes frolli two well developed centres of higher seismic activity, located along the abovementioned large fault zone.

Abstract: QuakeML is an XML-based data exchange standard for seismology that is in its fourth year of active community-driven development. Its development was motivated by the need to consolidate existing data formats for applications in statistical seismology, as well as setting a cutting-edge, community-agreed standard to foster interoperability of distributed infrastructures. The current release (version 1.2) is based on a public Request for Comments process and accounts for suggestions and comments provided by a broad international user community. QuakeML is designed as an umbrella schema under which several sub-packages are collected. The present scope of QuakeML 1.2 covers a basic description of seismic events including picks, arrivals, amplitudes, magnitudes, origins, focal mechanisms, and moment tensors. Work on additional packages (macroseismic information, ground motion, seismic inventory, and resource metadata) has been started, but is at an early stage. Several applications based on the QuakeML data model have been created so far. Among these are earthquake catalog web services at the European Mediterranean Seismological Centre (EMSC), GNS Science, and the Southern California Earthquake Data Center (SCEDC), and QuakePy, an open-source Python-based seismicity analysis toolkit. Furthermore, QuakeML is being used in the SeisComP3 system from GFZ Potsdam, and in the Collaboratory for the Study of Earthquake Predictability (CSEP) testing center installations, developed by Southern California Earthquake Center (SCEC). QuakeML is still under active and dynamic development. Further contributions from the community are crucial to its success and are highly welcome.

Abstract: Investigation of the time and magnitude distribution of the fore- and aftershocks of the Cremasta lake earthquake which occurred on February 5, 1966 is made. The deformation characteristics and spatial distribution of these shocks is also studied. Strong evidence is presented that the foreshocks and the main shock have been triggered by the waterloading of the Cremasta artificial lake.

Abstract: Deformation characteristics, magnitude and time distribution of the aftershocks of the large earthquakes, occurred in the region of Greece from 1926 till 1964 are investigated. An approximate relation between the number of aftershocks and the magnitude and focal depth of the main shock has been found. Also, an approximate relation has been derived between the magnitude of the largest aftershock and the magnitude and focal depth of the main sliok. The largest aftershock occurs within fourteen days after the main shock. In many cases large " late aftershocks " occur one or more months after the main shock. One or more foreshocks of magnitude larger than 3.5 occurred in forty per cent of the cases. The probability for an earthquake to be preceded l>y a large foreshoek not much smaller than the main shock is 10%. It is shown that some properties of the Earth's material in the aftershock region can be derived by studying the magnitude distribution and deformation characteristics of the aftershocks.

Abstract: Satellite data, radiative power of hot spots as measured with remote sensing, historical records, on site geological surveys, digital elevation model data, and simulation results together provide a massive data source to investigate the behavior of active volcanoes like Mount Etna (Sicily, Italy) over recent times The integration of these heterogeneous data into a coherent visualization framework is important for their practical exploitation It is crucial to fill in the gap between experimental and numerical data, and the direct human perception of their meaning Indeed, the people in charge of safety planning of an area need to be able to quickly assess hazards and other relevant issues even during critical situations With this in mind, we developed LAV@HAZARD, a web-based geographic information system that provides an interface for the collection of all of the products coming from the LAVA project research activities LAV@HAZARD is based on Google Maps application programming interface, a choice motivated by its ease of use and the user-friendly interactive environment it provides In particular, the web structure consists of four modules for satellite applications (time-space evolution of hot spots, radiant flux and effusion rate), hazard map visualization, a database of ca 30,000 lava-flow simulations, and real-time scenario forecasting by MAGFLOW on Compute Unified Device Architecture

Abstract: We analyzed gas samples collected from fumaroles and bubbling pools at Irruputuncu, Putana, Olca and Alitar volcanoes located in the central Andes volcanic zone (northern Chile). The Irruputuncu and Putana fumarolic discharges showed outlet temperatures ranging from 83 ˚C to 240 ˚C and from 82 ˚C to 88 ˚C, respectively. The chemical and isotopic ( 3 He/ 4 He, d 13 C-CO 2 , d 18 O-H 2 O and dD-H 2 O) compositions of these discharges were similar to medium-to-high temperature volcanic gases from other active volcanoes in this sector of the Andean volcanic chain (e.g. Lascar volcano). Inorganic and organic gas geothermometers for the H 2 O-CO 2 -CO-H 2 , CO 2 -CH 4 and C 2 -C 3 alkenes-alkanes systems indicated equilibrium temperatures that exceed 500 ˚C at the gas sources. These relatively high temperatures are in agreement with the presence of relevantly high concentrations of magmatic gas emissions, including SO 2 . Olca and Alitar volcano fluid chemistries indicated lower amounts of magmatic-derived gas species, while both the helium and the water isotopic compositions suggested significant fractions of shallow, crustal/meteoric-originated fluids. These indicate contributions from a hydrothermal environment with temperatures <400 ˚C. The geochemical and isotopic features derived from the present study show that the Irruputuncu, Putana, Olca and Alitar volcanoes should be considered as active and thus warrant periodic geochemical monitoring to determine the evolution of these systems and their potential hazards.

Abstract: The results of geodynamic investigations, in a space of ten years (1953-1963) obtained in the Vajont's gorge during and after construction of the « Carlo Semenza » dam, they are here resumed. On their basis, it is examined the probable reasons of the October 9th 1963 tragic event. It is taken into consideration the seismic activity's awaking -towards the eastern zone of the dam- in the first ten days of September 1965 occurred.

Abstract: This report presents a retrospective methodology to validate a long-term hazard map related to lava-flow invasion at Mount Etna, the most active volcano in Europe. A lava-flow hazard map provides the probability that a specific point will be affected by potential destructive volcanic processes over the time period considered. We constructed this lava-flow hazard map for Mount Etna volcano through the identification of the emission regions with the highest probabilities of eruptive vents and through characterization of the event types for the numerical simulations and the computation of the eruptive probabilities. Numerical simulations of lava-flow paths were carried out using the MAGFLOW cellular automata model. To validate the methodology developed, a hazard map was built by considering only the eruptions that occurred at Mount Etna before 1981. On the basis of the probability of coverage by lava flows, the map was divided into ten classes, and two fitting scores were calculated to measure the overlap between the hazard classes and the actual shapes of the lava flows that occurred after 1981.

Abstract: We report here on Vulcamera, a stand-alone program for the determination of volcanic SO2 fluxes using ultraviolet cameras. The code enables field image acquisition and all the required post-processing operations.

Abstract: The MAGFLOW lava simulation model is a cellular automaton developed by the Sezione di Catania of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and it represents the peak of the evolution of cell-based models for lava-flow simulation. The accuracy and adherence to reality achieved by the physics-based cell evolution of MAGFLOW comes at the cost of significant computational times for long-running simulations. The present study describes the efforts and results obtained by porting the original serial code to the parallel computational platforms offered by modern video cards, and in particular to the NVIDIA Compute Unified Device Architecture (CUDA). A number of optimization strategies that have been used to achieve optimal performance on a graphic processing units (GPU) are also discussed. The actual benefits of running on the GPU rather than the central processing unit depends on the extent and duration of the simulated event; for large, long-running simulations, the GPU can be 70-to-80-times faster, while for short-lived eruptions with a small extents the speed improvements obtained are 40-to-50 times.

Abstract: In the past, variations in the chemical contents (SO42−, Cl−, cations) of crater lake water have not systematically demonstrated any relationships with eruptive activity. Intensive parameters (i.e., concentrations, temperature, pH, salinity) should be converted into extensive parameters (i.e., fluxes, changes with time of mass and solutes), taking into account all the internal and external chemical–physical factors that affect the crater lake system. This study presents a generalized box model approach that can be useful for geochemical monitoring of active crater lakes, as highly dynamic natural systems. The mass budget of a lake is based on observations of physical variations over a certain period of time: lake volume (level, surface area), lake water temperature, meteorological precipitation, air humidity, wind velocity, input of spring water, and overflow of the lake. This first approach leads to quantification of the input and output fluxes that contribute to the actual crater lake volume. Estimating the input flux of the "volcanic" fluid (Qf- kg/s) –– an unmeasurable subsurface parameter –– and tracing its variations with time is the major focus during crater lake monitoring. Through expanding the mass budget into an isotope and chemical budget of the lake, the box model helps to qualitatively characterize the fluids involved. The (calculated) Cl− content and dD ratio of the rising "volcanic" fluid defines its origin. With reference to continuous monitoring of crater lakes, the present study provides tips that allow better calculation of Qf in the future. At present, this study offers the most comprehensive and up-to-date literature review on active crater lakes.

Abstract: After the 1976 Friuli earthquake (Ms = 65) in north-eastern Italy that caused about 1,000 casualties and widespread destruction in the Friuli area, the Italian government established the Centro di Ricerche Sismologiche (CRS) This is now a department of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), and it is specifically devoted to the monitoring of the seismicity of north-eastern Italy Since its inception, the North-East Italy Seismic Network has grown enormously Currently, it consists of 14 broad-band and 20 short-period seismic stations, all of which are telemetered to and acquired in real time at the OGS-CRS data center in Udine Data exchange agreements in place with other Italian, Slovenian, Austrian and Swiss seismological institutes lead to a total number of 94 seismic stations acquired in real time, which confirms that the OGS is the reference institute for seismic monitoring of north-eastern Italy Since 2002, CRS has been using the Antelope software suite as the main tool for collecting, analyzing, archiving and exchanging seismic data SeisComP is also used as a real-time data exchange server tool A customized webaccessible server is used to manually relocate earthquakes, and automatic procedures have been set-up for moment-tensor determination, shaking-map computation, web publishing of earthquake parametric data, waveform drumplots, state-of-health parameters, and quality checks of the station by spectra analysis Scripts for email/SMS/fax alerting to public institutions have also been customized Recently, a real-time seismology website was designed and set-up (http://rtscrsinogsit/)

Abstract: In the first paper (Galanopoulos, 1961), it was assumed that there is a linear relation of the earthquake intensity to the acceleratimi at the epicenter. On this assumption the magnitude formula: M = Oi log I0r + C2 [1] was derived from the empiri cai equation: ara„ R = GE [2] found by Gutenberg and Ricliter (1942). The formula [1] was proved to be appropriate for M-determination from macroseismic data. By using the basic relation: I = p log a + q [3] applied in ali macroseismic computations, the magnitude formula:

Abstract: Evidence is presented which favours the theory that the earthquake activity in the area of Greece should bo ascribed to horizontal currents flowing off to the side of the secondary sedimentary arc, from a minor mantle current rising under the primary volcanic arc of the Southeastern section of the Dinaric Alps.

Abstract: The radioelement concentrations of uranium (238U), thorium (232Th) and potassium (40K), as their radionuclides eU, eTh and K, of Cunur Hill in the city of Isparta (Turkey) and its surroundings were measured using gamma-ray spectrometry with a NaI(Tl) detector. The measurements were performed over an area of 2 km × 8 km around Cunur Hill, which forms part of the Isparta volcanic region that has a trachyandesitic composition, and which included the limestone outcrops east of Cunur. The results are mapped as combined radioelement concentrations. The radioelement concentrations of eU, eTh and K measured for Cunur Hill are high because of its trachyandesitic composition, while those measured in the limestone area were low, as would be expected.

Abstract: The largest dataset ever recorded during a normal fault seismic sequence was acquired during the 2009 seismic emergency triggered by the damaging earthquake in L'Aquila (Italy) This was possible through the coordination of different rapid-response seismic networks in Italy, France and Germany A seismic network of more than 60 stations recorded up to 70,000 earthquakes Here, we describe the different open-data archives where it is possible to find this unique set of data for studies related to hazard, seismotectonics and earthquake physics Moreover, we briefly describe some immediate and direct applications of emergency seismic networks At the same time, we note the absence of communication platforms between the different European networks Rapid-response networks need to agree on common strategies for network operations Hopefully, over the next few years, the European Rapid-Response Seismic Network will became a reality

Abstract: A great number of temperature measurements in deep bore-holes are made on the territory of the Soviet Union. The results of these measurements are partly systematized in the work " Problems of Geothermie " t1). However they can be hardly used for the calculations of heat flow because of the absence of the corresponding determinations of the thermal conductivity of rock cores taken directly from these boreholes. In the present paper the temperature gradient and the thermal conductivity of samples of rocks for the same place are determined and by means of these data the value of the thermal flow is estimated. For temperature measurements the electric resistance thermometer was used that is designed by Dergunov I. D. and improved for the conditions of work in deep bore-holes (up to 4-5 km) at rather high pressures and temperatures. The electrical resistance was measured by means of the compensation methods by a special potentiometer and a high sensitive mirror galvanometer. Four bringing wires are used for doing away with the erratic currents and the influence of the wires. As a result of it the accuracy of the temperature measurements is about 0.01°C. Fig. 1 represents the exterior of the apparatus and the thermometer. The thermometer is a hollow cylinder on the surface of which a copper wire is winded bifllarily, whose resistance is measured. When the cylinder is buried into a bore-hole it is washed by a solution from outside and inside. Together with the application of ftorplast isolation this decreases the thermal inertia of the thermometer down to 1.5 sec. For the sake of strength annular justs are made on the cylinder. The thermometer stands the pressure up to 600 atm and the temperature up to 200°C.

Abstract: The Earth expansion problem has attracted great interest, and the present study demonstrates that the Earth has been expanding, at least over the recent several decades. Space-geodetic data recorded at stations distributed globally were used (including global positioning system data, very-long-baseline interferometry, satellite laser ranging stations, and stations for Doppler orbitography and radiopositioning integrated by satellite), which covered a period of more than 10 years in the International Terrestrial Reference Frame 2008. A triangular network covering the surface of the Earth was thus constructed based on the spherical Delaunay approach, and average-weighted vertical variations in the Earth surface were estimated. Calculations show that the Earth is expanding at present at a rate of 0.24 ± 0.04 mm/yr. Furthermore, based on the Earth Gravitational Model 2008 and the secular variation rates of the second-degree coefficients estimated by satellite laser ranging and Earth mean-pole data, the principal inertia moments of the Earth (A, B, C) and in particular their temporal variations, were determined: the simple mean value of the three principal inertia moments (i.e., [A+B+C]/3) is gradually increasing. This clearly demonstrates that the Earth has been expanding, at least over the recent decades, and the data show that the Earth is expanding at a rate ranging from 0.17 ± 0.02 mm/yr to 0.21 ± 0.02 mm/yr, which coincides with the space geodetic evidence. Hence, based on both space geodetic observations and gravimetric data, we conclude that the Earth has been expanding at a rate of about 0.2 mm/yr over recent decades.

Abstract: The use of a lava-flow simulation (DOWNFLOW) probabilistic code and airborne light detection and ranging (LIDAR) technology are combined to analyze the emplacement of compound lava flow fields at Mount Etna (Sicily, Italy). The goal was to assess the hazard posed by lava flows. The LIDAR-derived time series acquired during the 2006 Mount Etna eruption records the changing topography of an active lava-flow field. These short-time-interval, high-resolution topographic surveys provide a detailed quantitative picture of the topographic changes. The results highlight how the flow field evolves as a number of narrow (5-15 m wide) disjointed flow units that are fed simultaneously by uneven lava pulses that advance within formed channels. These flow units have widely ranging advance velocities (3-90 m/h). Overflows, bifurcations and braiding are also clearly displayed. In such a complex scenario, the suitability of deterministic codes for lava-flow simulation can be hampered by the fundamental difficulty of measuring the flow parameters (e.g. the lava discharge rate, or the lava viscosity of a single flow unit). However, the DOWNFLOW probabilistic code approaches this point statistically and needs no direct knowledge of flow parameters. DOWNFLOW intrinsically accounts for complexities and perturbations of lava flows by randomly varying the pre-eruption topography. This DOWNFLOW code is systematically applied here over Mount Etna, to derive a lava-flow hazard map based on: (i) the topography of the volcano; (ii) the probability density function for vent opening; and (iii) a law for the expected lava-flow length for all of the computational vents considered. Changes in the hazard due to the recent morphological evolution of Mount Etna have also been addressed.

Abstract: A geological section of the Volturno Basin (northern Campania, continental margin, Italy) has been constructed based on new multichannel seismic data, to show the stratigraphic relationships between the filling in the Quaternary basin and the Meso-Cenozoic acoustic basement The new seismic sections presented here outline the underlying structures of the basin and their relationships to the filling in the Quaternary basin Deep exploration wells in Campania and Latium on the Tyrrhenian margin have gathered litho-stratigraphic and commercial multi-channel seismic data that can be used for better integration of the geological data for the area under study The trending of the seismic units is controlled by the Massico Structural High, which forms the boundary of the Volturno Basin towards the north-west This produces a geometry that is characteristic of a fan complex, with NE-SW trending This qualitative calibration of the seismic sequences that fill the sedimentary basin was carried out through the litho-stratigraphic data of the «Castelvolturno 2» well, which highlights the pyroclastic layers and conglomeratic strata of the lagoon and delta environments as they evolve upwards towards marine sediments Seismo-stratigraphic analysis shows the complex depositional geometries of the filling in the Volturno Basin, which overlie the Meso-Cenozoic carbonatic basement and the related flysch deposits Coupled with regional geological evidence, the data interpretation here suggests that the Volturno Basin represents a half-graben structure that is characterized by down-thrown blocks along normal faults