paleoseismology along the 1980 surface rupture of the irpinia fault implications for earthquake recurrence in the southern apennines italy the irpinia fault was the source of the ms 6 9 1980 irpinia earthquake and produced the first unequivocal historical surface faulting in italy trenching of the 1980 fault scarp at piano di pecore a flat intermontane basin about 5 km south of the 1980 instrumental epicenter provides the first data on earthquake recurrence intervals slip per event and slip rate on a major normal fault in the southern apennines fault zone the trenches exposed evidence of four pre 1980 paleoearthquakes that occurred during the past 8600 years a best estimate average recurrence interval is 2150 years although the time interval between individual events varies by as much as a factor of 2 each paleo earthquake is similar to the 1980 surface rupture in amount of slip and style of deformation which suggests that the 1980 event is characteristic for the irpinia fault slip per event values average 61 cm the net vertical displacement of 2 12 2 36 m since 8600 cal year b p observed in the trenches gives a vertical slip rate of 0 25 0 35 mm yr a dip slip rate of 0 29 0 40 mm yr and an extension rate of 0 14 0 20 mm yr although fault behavior data are only available for the irpinia fault they provide a starting point for evaluating earthquake recurrence and rates of deformation in southern apennines they suggest that 1 fault specific earthquake recurrence intervals based on the historical seismic record overestimates the occurrence of large magnitude m7 earthquakes and 2 the holocene rate of extension across the apennines is 1 mm yr the 1980 earthquake and the paleoseismologic observations show that repeated and localized surface faulting occurs in southern apennines and leaves subtle but distinct geomorphic evidence that can be detected with detailed and careful investigation

polar vortices on earth and mars a comparative study of the climatology and variability from reanalyses polar vortices on mars provide case studies to aid understanding of geophysical vortex dynamics and may help to resolve long standing issues regarding polar vortices on earth due to the recent development of the first publicly available martian reanalysis dataset macda for the first time we are able to characterise thoroughly the structure and evolution of the martian polar vortices and hence perform a systematic comparison with the polar vortices on earth the winter atmospheric circulations of the two planets are compared with a specific focus on the structure and evolution of the polar vortices the martian residual meridional overturning circulation is found to be very similar to the stratospheric residual circulation on earth during winter while on earth this residual circulation is very different from the eulerian circulation on mars it is found to be very similar unlike on earth it is found that the martian polar vortices are annular and that the northern hemisphere vortex is far stronger than its southern counterpart while winter hemisphere differences in vortex strength are also reported on earth the contrast is not as large distinctions between the two planets are also apparent in terms of the climatological vertical structure of the vortices in that the martian polar vortices are observed to decrease in size at higher altitudes whereas on earth the opposite is observed finally it is found that the martian vortices are less variable through the winter than on earth especially in terms of the vortex geometry during one particular major regional dust storm on mars martian year 26 an equatorward displacement of the vortex is observed sharing some qualitative characteristics of sudden stratospheric warmings on earth

unveiling the sources of the catastrophic 1456 multiple earthquake hints to an unexplored tectonic mechanism in southern italy we revisited data related to the 1456 seismic crisis the largest earthquake to have ever occurred in peninsular italy in search of its causative source s data about this earthquake consist solely of historical reports and their intensity assessment because of the age of this multiple earthquake the scarcity and sparseness of the data and the unusually large damage area no previous studies have attempted to attribute the 1456 events to specific faults existing analytical methods to identify a likely source from intensity data also proved inappropriate for such a sparse dataset since historical evidence suggests that the cumulative damage pattern contains at least three widely separated events we subdivided the 1456 damage pattern into three independent mesoseismal areas each of these areas falls onto east west tectonic trends previously identified and marked by deep 10 km right lateral slip earthquakes based on this evidence we propose 1 that the 1456 events were generated by individual segments of regional east west structures and are evidence of a seismogenic style that involves oblique dextral reactivation of east west lower crustal faults 2 that each event may have triggered subsequent but relatively distant events in a cascade fashion as suggested by historical accounts hence 3 that the 1456 sequence reveals a fundamental but unexplored mechanism of tectonic deformation and seismic release in southern italy this style dominates the region that lies between the northwest southeast system of large extensional faults straddling the crest of the southern apennines and the buried outer front of the chain although the quality of the available information concerning the 1456 earthquake is naturally limited we show that the overlap of the damage distribution the orientation and characteristics of regional tectonic structures the seismicity patterns and the focal mechanisms all concur with our interpretations and would be difficult to justify otherwise

defining seismogenic sources from historical earthquake felt reports abstract we present a method that uses macroseismic intensity data to assess the location physical dimensions and orientation of the source of large historical earthquakes intensity data contain a great deal of information that can be used to constrain the essential characteristics of the seismic source in particular both the seismological theory and its practice suggest that the orientation of the source of significant earthquakes is reflected in the elongation of the associated damage pattern a plausible and easily manageable way of describing a seismic source is by representing it as an oriented rectangle the length and width of which are obtained from moment magnitude through empirical relationships this rectangle is meant to represent either the actual surface projection of the seismogenic fault or at least the projection of the portion of the earth crust where a given seismic source is likely to be located the systematic application of this method to all the m 5 5 earthquakes that occurred in the central and southern apennines italy in the past four centuries returned encouraging results that compare well with existing instrumental direct geological and geodynamic evidence the method is quite stable for different choices of the algorithm parameters and provides elongation directions that in most cases can be shown to be statistically significant in particular the resulting pattern of source orientations is rather homogeneous showing a consistent appennines parallel trend that agrees well with the ne sw extension style of deformation active in the central and southern portions of the italian peninsula

from historical seismology to seismogenic source models 20 years on excerpts from the italian experience abstract large earthquakes occur rather orderly in space and time hence they can be somehow anticipated and their effects can be projected into the future the modern practice of seismic hazard assessment rests on these principles and may rely on them but also requires a detailed knowledge of the location and characteristics of individual earthquake sources we discuss how this knowledge base can be constructed with an eye on the geological history which provides a record of the faults capable of generating large earthquakes and one on the human history which supplies evidence for whether where and how these faults have actually caused damaging earthquakes in the past how do these two records interact with each other it is now accepted that identifying active and potentially seismogenic faults in italy is especially hard the geological record may be clear and honest when dealing with processes at the scale of several million years but can be very difficult to decipher if we are concerned with contemporary geological processes such as earthquakes shortening the tim e w indow of observation of earthquake activity is why historical seismology is so crucial for constructing a seismogenic source model to this end we exploited a number of key italian destructive earthquakes each of which illuminates a recent geological process that may not offer a discernible surface signature our findings led us to reconsider the tectonic style of large areas changed our perception of their earthquake potential hinted at the existence of unknown seismogenic zones and even led to downsizing the magnitude of the largest italian historical earthquakes we maintain that the complexity of the geological setting may be counterbalanced by the richness of the historical earthquake record we also believe that our experience in the combined investigation of italy s historical earthquakes and seismogenic sources may be replicated in all earthquake prone countries that exhibit a history of human settlement throughout the millennia

variable winds on venus mapped in three dimensions 1 we present zonal and meridional wind measurements at three altitude levels within the cloud layers of venus from cloud tracking using images taken with the virtis instrument on board venus express at low latitudes zonal winds in the southern hemisphere are nearly constant with latitude with westward velocities of 105 ms 1 at cloud tops altitude 66 km and 60 70 ms 1 at the cloud base altitude 47 km at high latitudes zonal wind speeds decrease linearly with latitude with no detectable vertical wind shear values lower than 15 ms 1 indicating the possibility of a vertically coherent vortex structure meridional winds at the cloud tops are poleward with peak speed of 10 ms 1 at 55 s but below the cloud tops and averaged over the south hemisphere are found to be smaller than 5 ms 1 we also report the detection at subpolar latitudes of wind variability due to the solar tide

south polar features on venus similar to those near the north pole venus has no seasons slow rotation and a very massive atmosphere which is mainly carbon dioxide with clouds primarily of sulphuric acid droplets infrared observations by previous missions to venus revealed a bright dipole feature surrounded by a cold collar at its north pole the polar dipole is a double eye feature at the centre of a vast vortex that rotates around the pole and is possibly associated with rapid downwelling the polar cold collar is a wide shallow river of cold air that circulates around the polar vortex one outstanding question has been whether the global circulation was symmetric such that a dipole feature existed at the south pole here we report observations of venus south polar region where we have seen clouds with morphology much like those around the north pole but rotating somewhat faster than the northern dipole the vortex may extend down to the lower cloud layers that lie at about 50 km height and perhaps deeper the spectroscopic properties of the clouds around the south pole are compatible with a sulphuric acid composition

rise and fall of a hypothesized seismic gap source complexity in the mw 7 0 16 december 1857 southern italy earthquake abstract on 16 december 1857 a strong earthquake m 7 struck a large portion of the southern apennines about 150 km southeast of naples the earthquake was thoroughly investigated by irish engineer robert mallet who wrote an extensive report that is still regarded as a landmark in observational seismology because of the concentration of damage in the high agri valley and contrary to mallet s own findings for many years the earthquake was referred to as the val d agri earthquake and was believed by most investigators to have ruptured the 20 25 km normal fault lying beneath this intermontane basin the magnitude of the earthquake however and evidence for earthquake complexity suggest that the true rupture length has been so far underestimated we contend that the 1857 earthquake ruptured in a cascade fashion two adjacent and relatively well known faults first the smaller melandro pergola fault commonly believed to represent a seismic gap between the causative faults of the 1857 and of the 1980 irpinia m w 6 9 earthquakes and then the larger agri valley fault proper contemporary chronicles reported a time lapse of 2 3 min between the two ruptures thus effectively making them two independent shocks the rupture must have proceeded unilaterally from the northwestern edge of the melandro pergola fault where mallet placed the earthquake epicenter thus explaining the concentration of damage and attention by rescue crews and subsequent investigators in the southeastern portion of the high agri valley

mapping zonal winds at venus s cloud tops from ground based doppler velocimetry abstract the most significant aspect of the general circulation of the atmosphere of venus is its retrograde super rotation a complete characterization of this dynamical phenomenon is crucial for understanding its driving mechanisms here we report on ground based doppler velocimetry measurements of the zonal winds based on high resolution spectra from the uv visual echelle spectrograph uves instrument at eso s very large telescope under the assumption of predominantly zonal flow this method allows the simultaneous direct measurement of the zonal velocity across a range of latitudes and local times in the day side the technique based on long slit spectroscopy combined with the high spatial resolution provided by the vlt has provided the first ground based characterization of the latitudinal profile of zonal wind in the atmosphere of venus the first zonal wind field map in the visible as well as new constraints on wind variations with local time we measured mean zonal wind amplitudes between 106 21 and 127 14 m s at latitudes between 18 n and 34 s with the zonal wind being approximately uniform in 2 6 wide latitude bands 0 3 arcsec at disk center the zonal wind profile retrieved is consistent with previous spacecraft measurements based on cloud tracking but with non negligible variability in local time longitude and in latitude near 50 the presence of moderate jets is apparent in both hemispheres with the southern jet being stronger by 10 m s small scale wind variations with local time are also present at low and mid latitudes

high resolution cloud feature tracking on venus by galileo abstract the venus cloud deck was monitored in february 1990 for 16 hours at 400 nanometers wavelength by the galileo imaging system with a spatial resolution of about 15 km and with image time separations as small as 10 minutes velocities are deduced by following the motion of small cloud features in spite of the high temporal frequencies capable of being detected no dynamical phenomena are apparent in the velocity data except the already well known solar tides possibly altered by the slow 4 day wave and the hadley circulation there is no evidence to a level of approximately 4 m s 1 of eddy or wavelike activity the dominant size of sub global scale albedo features is 200 500 km and their contrast is approximately 5 at low latitudes there are patches of blotchy cell like structures but at most locations the markings are streaky the patterns are similar to those discovered by mariner 10 and pioneer venus m j s belton et al 1976 j atmos sci 33 1383 1393 w b rossow et al 1980 j geophys res 85 8107 8128 scaling arguments are presented to argue that the mesoscale blotchy cell like cloud patterns are caused by local dynamics driven in a shallow layer by differential absorption of sunlight it is also argued that mesoscale albedo features are either streaky or cell like simply depending on whether the horizontal shear of the large scale flow exceeds a certain critical value

solar migrating atmospheric tides in the winds of the polar region of venus we study the effects of migrating solar tides on the winds at the cloud tops of the polar region of venus the winds were measured using cloud tracking on images obtained at wavelengths of 3 9 and 5 0 l mb y the instrument virtis m onboard venus express these wavelengths probe about the same altitude close to the cloud tops allowing for the first time to retrieve winds simultaneously in the day and nightside of the planet we use a dataset with observations from 16 orbits covering a time span of 289 days and a latitude range between 70s and 85s the region where the so called cold collar resides diurnal and quarter diurnal tides wavenumbers 1 and 4 were detected in the wind field with a decoupled influence on the zonal and meridional directions the diurnal tide is the dominant harmonic with amplitudes of about 4 7 m s exclusively affecting the meridional component of the wind and forcing a solar to antisolar circulation at the polar region the quarter diurnal mode is only apparent in the zonal wind in a restricted latitude range with amplitudes 2 2 m s the spatial structure of the diurnal tide has also been investigated obtaining a vertical wavelength of about 8 km in accordance with predictions by models finally a theoretical relation between the amplitudes of tidal temperature and tidal wind has been derived and its validity tested with models and results from previous missions

fault plane solutions and seismicity of the italian peninsula abstract a new fault plane solution map of the italian peninsula is presented in this paper the earthquakes analyzed are included in the period 1905 1980 with magnitudes ranging 4 7 75 earthquakes are located in the crust while 31 are related to the deep and intermediate zone of the calabrian arc the large seismic events of the italian peninsula are generally associated with normal faulting while strike slip motion is mostly related to small earthquakes located along lateral segments of the mountain chain the deep and intermediate earthquakes of the tyrrhenian sea indicate predominant down dip compression and strike slip motion at the boundaries of this benioff zone this last is interpreted as a remnant of a subduction zone active since oligocene extending to 500 km depth with a very small lateral size about 300 km the present tectonics of this benioff zone is strongly conditioned by the lateral bending more so than the gravitational sinking process the coexistence of thrust and normal faulting motion associated to the earthquakes within a few tens of kilometers of each other seems to be explained by the strong lateral inhomogeneities of the crustal rocks present in this region more so than to the depth of the seismogenetic zone and the nature of the faulting process

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

venus s southern polar vortex reveals precessing circulation initial images of venus s south pole by the venus express mission have shown the presence of a bright highly variable vortex similar to that at the planet s north pole using high resolution infrared measurements of polar winds from the venus express visible and infrared thermal imaging spectrometer virtis instrument we show the vortex to have a constantly varying internal structure with a center of rotation displaced from the geographic south pole by 3 degrees of latitude and that drifts around the pole with a period of 5 to 10 earth days this is indicative of a nonsymmetric and varying precession of the polar atmospheric circulation with respect to the planetary axis

a chaotic long lived vortex at the southern pole of venus a whirling vortex has been observed in the atmosphere at the south pole of venus cloud motions tracked by the venus express spacecraft suggest that the south polar vortex is long lived erratic and baroclinic in character

sunlight refraction in the mesosphere of venus during the transit on june 8th 2004 abstract many observers in the past gave detailed descriptions of the telescopic aspect of venus during its extremely rare transits across the solar disk in particular at the ingress and egress the portion of the planet s disk outside the solar photosphere has been repeatedly perceived as outlined by a thin bright arc aureole those historical visual observations allowed inferring the existence of venus atmosphere the bright arc being correctly ascribed to the refraction of light by the outer layers of a dense atmosphere on june 8th 2004 fast photometry based on electronic imaging devices allowed the first quantitative analysis of the phenomenon several observers used a variety of acquisition systems to image the event ranging from amateur sized to professional telescopes and cameras thus collecting for the first time a large amount of quantitative information on this atmospheric phenomenon in this paper after reviewing some elements brought by the historical records we give a detailed report of the ground based observations of the 2004 transit besides confirming the historical descriptions we perform the first photometric analysis of the aureole using various acquisition systems the spatially resolved data provide measurements of the aureole flux as a function of the planetocentric latitude along the limb a new differential refraction model of solar disk through the upper atmosphere allows us to relate the variable photometry to the latitudinal dependency of scale height with temperature in the south polar region as well as the latitudinal variation of the cloud top layer altitude we compare our measurements to recent analysis of the venus express virtis m vmc and spicav soir thermal field and aerosol distribution our results can be used a starting point for new more optimized experiments during the 2012 transit event

insights from the mw 6 3 2009 l aquila earthquake central apennines unveiling new seismogenic sources through their surface signatures the adjacent san pio fault terra nova 23 108 115 2011 abstract we analysed a broad region around l aquila in search of seismogenic faults similar to that responsible for the 6 april 2009 earthquake mw 6 3 having in mind the lessons learned from this earthquake we focused on adjacent areas displaying similar morphotectonic geological and structural features the basin running from barisciano to civitaretenga navelli notably located near the southeastern edge of the 2009 aftershock pattern appears to be one such area we collected morphotectonic and structural data indicating that this basin is underlain by a major active normal fault the san pio fault all the observations are very much reminiscent of the morphotectonic geological and structural setting of the area struck by the l aquila earthquake suggesting that the newly identified fault has the potential for a mw 6 2 shock

assessing the long term variability of venus winds at cloud level from virtis venus express abstract the venus express vex mission has been in orbit to venus for more than 4 years now the visible and infrared thermal imaging spectrometer virtis instrument onboard vex observes venus in two channels visible and infrared obtaining spectra and multi wavelength images of the planet that can be used to sample the atmosphere at different altitudes day side images in the ultraviolet range 380 nm are used to study the dynamics of the upper cloud at 66 72 km while night side images in the near infrared 1 74 m map the opacity of the lower cloud deck at 44 48 km here we present a long term analysis of the global atmospheric dynamics at these levels using a large selection of orbits from the virtis m dataset covering 860 earth days that extends our previous work sanchez lavega a et al 2008 geophys res lett 35 l13204 and allows studying the variability of the global circulation at the two altitude levels the atmospheric superrotation is evident with equatorial to mid latitudes westward velocities of 100 and 60 m s 1 in the upper and lower cloud layers these zonal velocities are almost constant in latitude from the equator to 50 s from 50 s to 90 s the zonal winds at both cloud layers decrease steadily to zero at the pole individual cloud tracked winds have errors of 3 10 m s 1 with a mean of 5 m s 1 and the standard deviations for a given latitude of our zonal and meridional winds are 9 m s 1 the zonal winds in the upper cloud change with the local time in a way that can be interpreted in terms of a solar tide the zonal winds in the lower cloud are stable at mid latitudes to the tropics and present variability at subpolar latitudes apparently linked to the activity of the south polar vortex while the upper cloud presents a net meridional motion consistent with the upper branch of a hadley cell with peak velocity v 10 m s 1 at 50 s the lower cloud meridional motions are less organized with some cloud features moving with intense northwards and southwards motions up to v 15 m s 1 but on average with almost null global meridional motions at all latitudes we also examine the long term behavior of the winds at these two vertical layers by comparing our extended wind tracked data with results from previous missions

possible fault plane in a seismic gap area of the southern apennines italy revealed by receiver function analysis 1 unusual features in teleseismic receiver function computed at a single three component seismic station reveal the presence of a dipping interface in the shallow crust with a pronounced seismic velocity contrast in the campania lucania region southern apennines italy the locus of this finding is the pergola melandro basin situated between the maximum intensity areas of two of the most destructive earthquakes reported in the italian seismic catalogue the m 7 0 val d agri earthquake 1857 and the ms 6 9 irpinia earthquake 1980 this area is not associated with known historical events and for this reason is currently object of investigation as a potential seismic gap where the probability of future ruptures is higher than in surrounding regions also for the static stress increase caused by the two above mentioned earthquakes through an inversion procedure applied to the computed receiver functions we are able to satisfactorily constrain the strike dip depth and velocity contrast of this crustal discontinuity whose geometric characteristics closely match those proposed by some authors for the sources of the two neighboring earthquakes we argue that the detected interface is the seismogenic source which fills the gap the findings of this study could open new perspectives both in the study of seismic gap areas and in the identification of historical earthquake sources offering a new and effective tool to locate investigate and constrain buried or unknown faults

approaching the seismogenic source of the calabria 8 september 1905 earthquake new geophysical geological and biochemical data from the s eufemia gulf s italy abstract recognizing the seismogenic source of major historical earthquakes particularly when these have occurred offshore is a long standing issue across the mediterranean sea and elsewhere the destructive earthquake m 7 that struck western calabria southern italy on the night of 8 september 1905 is one such case having various authors proposed a seismogenic source with apparently diverse hypotheses and without achieving a unique solution to gain novel insight into the crustal volume where the 1905 earthquake took place and to seek a more robust solution for the seismogenic source associated with this destructive event we carried out a well targeted multidisciplinary survey within the gulf of s eufemia se tyrrhenian sea collecting geophysical data oceanographic measurements and biological chemical and sedimentary samples we identified three main tectonic features affecting the sedimentary basin in the gulf of s eufemia 1 a ne sw striking ca 13 km long normal fault here named s eufemia fault 2 a wnw striking polyphased fault system and 3 a likely e w trending lineament among these the normal fault shows evidence of activity witnessed by the deformed recent sediments and by its seabed rupture along which locally fluid leakage occurs features in agreement with the anomalous distribution of prokaryotic abundance and biopolymeric c content resulted from the shallow sediment analyses the numerous seismogenic sources proposed in the literature during the past 15 yr make up a composite framework of this sector of western calabria that we tested against a the geological evidence from the newly acquired dataset and b the regional seismotectonic models such assessment allows us to propose the ne sw striking normal fault as the most probable candidate for the seismogenic source of the 1905 earthquake reappraising a major historical earthquake as the 1905 one enhances the seismotectonic picture of western calabria further understanding of the region and better constraining the location of the seismogenic source may be attained through integrated interpretation of our data together with a on land field evidence and b seismological modeling

a reanalysis of venus winds at two cloud levels from galileo ssi images abstract the global circulation of the venus atmosphere is characterized at cloud level by a zonal super rotation studied over the years with data from a battery of spacecrafts orbiters balloons and probes among them the galileo spacecraft monitored the venus atmosphere in a flyby in february 1990 in its route toward jupiter since the flyby was almost equatorial published analysis of zonal winds obtained from displacements of cloud elements on images obtained by the ssi camera belton m j s and 20 colleagues 1991 science 253 1531 1536 stop at latitudes 50 north and south in this paper we present new results on venus winds based on a reanalysis of an extended set of images obtained at two wavelengths 418 nm violet and 986 nm near infrared that sense different altitude levels in the upper cloud our main result is that we have been able to extend the zonal wind profile up to the polar latitudes 70 n and 70 s at 418 nm and 70 n at 986 nm binned and smoothed profiles are given in tabular form we show that the zonal winds drop in their velocity poleward of latitudes 45 n and 50 s where an intense meridional wind shear develops at the two cloud levels our data confirm the magnitude of this shear retrieved previously from radio occultation data but disagrees with it in the latitudinal location of the sheared region the new wind data can be used to recalibrate the zonal winds retrieved from the previous measurements of the temperature field and the cyclostrophic balance assumption the meridional profiles of the zonal winds at the two cloud levels are used to assess the vertical wind shear in the upper cloud layer as a function of latitude and locate the most unstable region

scale heights and detached haze layers in the mesosphere of venus from spicav ir data abstract spicav ir one channel of spicav soir instrument suite onboard venus express performed solar occultation measurements of the atmosphere at terminators in 0 65 1 7 m spectral range we analyze the properties of the upper part of the venus aerosol layer upper haze 70 95 km altitude from 798 observations performed from may 2006 through november 2014 vertical profiles of slant optical depth extinction coefficient effective radius and number density of haze particles from 222 orbits were analyzed in a previous publication luginin et al 2016 their diurnal latitudinal and interannual variabilities were investigated the present paper is devoted to analysis of scale heights and properties of detached haze layers from 147 orbits at mid to high northern latitudes where the best spatial resolution was obtained scale heights retrieved from 43 orbits were equal to 4 5 5 km at the north pole 82 n 90 n decreasing to 2 4 km at 60 n 80 n latitudes as an explanation of such latitudinal variations we propose a mechanism based on vertical transport driven by winds that are directed upward at the north pole and downward at 60 n 80 n latitudes detached layers were detected in 93 occultations at 58 n 90 n the detached layers are presumably formed through condensation of water vapor on droplets of sulfuric acid water solution they were mostly seen at 80 88 km at the morning terminator and at 84 90 km at the evening one this difference in altitude of the detached layers can be explained by diurnal variations in thermal structure of venusian mesosphere the vertical optical depth of detached layers varies broadly around the mean dl 0 8 3 10 3 no difference between the morning and the evening terminators was observed the effective radius and number density of aerosol particles in the detached layers group around a very wide maximum at the morning terminator 0 65 0 25 m and 0 6 0 4 cm 3 and two maxima at the evening terminator 0 4 0 1 m and 0 85 0 15 m 0 3 0 2 cm 3 and 4 5 2 5 cm 3 this could be explained by differences in initial altitudes at which condensation of particles occurs

global maps of venus nightside mean infrared thermal emissions obtained by virtis on venus express one of the striking features about venus atmosphere is its temporal variability and dynamics with a chaotic polar vortex large scale atmospheric waves sheared features and variable winds that depend on local time and possibly orographic features the aim of this research is to combine data accumulated over several years and obtain a global mean state of the atmosphere focusing in the global structure of the clouds using the cloud opacity and upper cloud temperatures we have first produced global maps using the integrated radiance through the infrared atmospheric windows centred around 1 74 m and 2 25 m that show the spatial variations of the cloud opacity in the lower clouds around 44 48 km altitude and also provide an indirect estimation of the possible particle size we have also produced similar global maps using the brightness temperatures seen in the thermal region at 3 8 m and 5 0 m which provide direct indication of the temperatures at the top of the clouds around 60 70 km altitude these maps have been generated using the complete dataset of the visible and infrared thermal imaging spectrometer mapping channel virtis m on board venus express with a wide spatial and long temporal coverage in the period from may 2006 until october 2008 our results provide a global view of the cloud opacity particle size and upper cloud temperatures at both hemispheres showing the main different dynamical regions of the planet the profiles obtained also provide the detailed dependencies with latitude local time and longitude diagnostic of the global circulation flow and dynamics at various altitude layers from about 44 up to 70 km over the surface

surface rupture of the 1857 southern italian earthquake in october 1862 robert mallet published an extensive study of a large earthquake that occurred on 16 december 1857 150 km south east of naples this event is one of the most destructive ever recorded in italy although continental earthquakes of similar size are almost invariably associated with surface faulting mallet did not identify any surface rupture and subsequent workers have also failed to find surface traces using satellite images and aerial photographs as a guide we examined two prominent quaternary normal fault systems in the field flanking the val d agri and the val di diano both trend nw se and dip to the sw the distribution of damage suggests that one or both moved in 1857 on one fault segment in val d agri we found a 2 5 m high scarp whose youthfulness and height suggest it is due to the 1857 earthquake comparison of the observed slip with rates derived from geomorphic evidence suggests a recurrence time for 1857 type events of about 3000 years while the new data we provide are consistent with the event having a magnitude of ms 7 0 there are also grounds for supposing it might have been bigger

cloud tracked winds from pioneer venus ocpp images abstract analysis of ultraviolet image sequences obtained from the pioneer venus orbiter cloud photopolarimeter and covering five 80 day periods from 1979 1985 provides the first climatological description of the cloud top circulation on venus the average zonal winds can be characterized as a 5 day retrograde rotation of the whole cloud level atmosphere with weak jets at middle to high latitudes both the midlatitude and equatorial zonal winds vary by about 5 8 m s 1 over time spans of 1 6 years the average meridional circulation is poleward in both hemispheres up to at least 60 latitude consistent with the presence of a thermally direct hadley circulation associated with the clouds the strength of the hadley circulation also varies with time four wave modes are clearly identified a diurnal solar tide a semi diurnal solar tide a 4 day equatorial wave and a 5 day midlatitude wave the semidiurnal tide appears to have an amplitude of about 5 m s 1 and to be approximately constant with time

dynamics of saturn s polar regions we analyze data retrieved by the imaging science system onboard the cassini spacecraft to study the horizontal velocity and vorticity fields of saturn s polar regions latitudes 60 90 n in june december 2013 and 60 90 s in october 2006 and july december 2008 including the northern region where the hexagonal wave is prominent with the aid of an automated two dimensional correlation algorithm we determine two dimensional maps of zonal and meridional winds and deduce vorticity maps we extract zonal averages of zonal winds providing wind profiles that reach latitudes as high as 89 5 in the south and 89 9 in the north wind measurements cover the intense polar cyclonic vortices that reach similar peak velocities of 150 m s 1 at 88 5 the hexagonal wave lies in the core of an intense eastward jet at planetocentric latitude 75 8 n with motions that become nonzonal at the hexagonal feature in the south hemisphere the peak of the eastward jet is located at planetocentric latitude 70 4 s a large anticyclone the south polar spot sps similar to the north polar spot nps observed at the voyager times 1980 1981 has been observed in images from april 2008 to january 2009 in the south polar region at latitude 66 1 close to the eastward jet the sps does not apparently excite a wave on the jet we analyze the stability of the zonal jets finding potential instabilities at the flanks of the eastward jets around 70 and we measure the eddy wind components suggesting momentum transfer from eddy motion to the westward jets closer to the poles

complex normal faulting in the apennines thrust and fold belt the 1997 seismic sequence in central italy a long sequence of moderate magnitude earthquakes 5 m 6 struck central italy in september and october 1997 at the end of the sequence a year later the seismogenic area extends for about 60 km along the apennines the analysis of historical seismicity suggests that this seismic sequence filled a 700 year gap in this portion of the chain other historical sequences in the same area are characterized by prolonged seismic release on adjacent fault segments probably due to the in volvement of shallow and complex structures inherited by the compressive tectonics the distribution of seismicity and the fault plane solutions show that the extension in this region is accomplished by normal faults dipping at relatively low angles 40 to the southwest the focal mechanisms of the largest shocks reveal normal faulting with extension perpendicular to the apenninic chain northeast southwest consistently with the quaternary tectonics of the internal sector of the northern apen nine belt and with previous earthquakes in adjacent regions three mainshocks oc curred on distinct 5 to 10 km long fault segments adjacent and slightly offset be tween each other high quality aftershock locations show that seismicity is confined within the sedimentary mesozoic cover in the upper 8 km of the crust and that most of the aftershocks are shallower than the largest shocks which nucleated at 6 km depth faults evidenced by aftershock locations have a planar geometry and show increased complexity toward the surface most of the aftershock focal mechanisms are dominated by normal faulting several strike slip events occurred at shallow depths reactivating portions of pre existing thrust planes that segment the normal fault system the spatiotemporal evolution of seismicity shows a peculiar migration of hypocenters along the strike of the main faults with multiple ruptures and the activation of fault segments before the occurrence of the main rupture episodes

local pattern of stress field and seismogenic sources in the pergola melandro basin and the agri valley southern italy summary our study area is a ca 50 km long section of the central southern apennines tectonic belt that includes the pergola melandro basin pm and the agri valley av this region is located between the areas affected by the 1980 ms 6 9 irpinia and the 1857 m 7 0 val d agri earthquakes and is characterized by rare historical events and very low and sparse background seismicity in this study we provide new seismological and geophysical information to identify the characteristics of the seismotectonics in the area as the prevailing faulting mechanism and the fit of local to regional stress field these data concern focal mechanisms from waveform modelling and p wave polarities analyses of borehole breakouts and detailed investigation of two seismic sequences all the data cover a significantly broad range of magnitudes and depths and suggest that no important local variation in stress orientation seems to affect this area which shows a ne sw direction of extension consistent with that regionally observed in southern italy such local homogeneity in the stress field pattern is peculiar to the study area the variations of orientation and or type of stress observed in the northern apennines or less than only 100 km toward the northwest within the same tectonic belt are absent here furthermore there is a suggestion for a northeastward sense of dip of the seismogenic faults in the region an interesting constraint to the characterization of seismic sources

predominance of unilateral rupture for a global catalog of large earthquakes the manner in which an earthquake rupture propagates across a fault reflects both the initial properties of the fault and the dynamical stresses produced by the rupture we quantify the propagation of an earthquake rupture using the second moments of the earthquake space time distribution in particular the second moments provide a simple way to differentiate between approximately bilateral and predominantly unilateral ruptures we determined the second moments for a catalog of m w 7 earthquakes that have occurred since 1994 the results show that approximately 80 of large shallow ruptures are predominantly unilateral our result agrees well with strong motion inversions from previous studies on moderate and large earthquakes the predominance of unilateral propagation in large earthquakes is explained by a simple characteristic earthquake model in which large events rupture an entire structurally defined fault segment and nucleation points are uniformly distributed along the fault the predominance of unilateral rupture may also be enhanced by the dynamic stress field produced by contrasts in the elastic properties between the two sides of plate boundary faults manuscript received 16 november 2001

late holocene earthquakes in southern apennine paleoseismology of the caggiano fault although southern apennines are characterized by the strongest crustal earthquakes of central western mediterranean region local active tectonics is still poorly known at least for seismogenic fault recognition is concerned research carried out in the maddalena mts southeast of irpinia the region struck by the mw 6 9 1980 earthquake indicates historical ruptures along a 17 km long n120 normal fault system caggiano fault the system is characterized by a bedrock fault scarp carved in carbonate rocks which continues laterally into a retreating and eroded smoothed scarp affecting the clayey siliciclastic units and by smart scarps and discontinuous free faces in holocene cemented slope debris and in modern alluvial fan deposits the geometry of the structure in depth has been depicted by means of electrical resistivity tomography while paleoseismic analysis carried out in three trenches revealed surface faulting events during the past 7 ky bp 14c age the latest occurred in the past 2 ky bp 14c age and probably during after slope debris deposition related to the little ice age 1400 1800 a d preliminary evaluation accounts for minimum slip rates of 0 3 0 4 mm year which is the same order of rates estimated for many active faults along the apennine chain associated earthquakes might be in the order of mw 6 6 to be compared to the historical events occurred in the area e g 1561 and 1857 p p earthquakes

combining seismic reflection with multifold wide aperture profiling an effective strategy for high resolution shallow imaging of active faults 1 shallow imaging of fault zones is a challenging task we investigate if this issue can be successfully addressed by combining reflection seismics with non standard multifold wide aperture profiling a strategy pertaining to crustal scale exploration so far near offset reflection and multifold wide aperture data are simultaneously recorded along two profiles in a small basin crossed by an active fault in southern italy imaging consists of multiscale seismic tomography complemented by cdp processing of near offset reflections and of data spanning a large offset range by combining smooth vp and reflectivity images we pinpoint the fault location and yield a valuable picture of the basin performance of each exploration technique strongly varies in the two surveys depending on the local geology thus the combined exploration strategy not only yields complementary images for enhanced interpretation but also allows extending the range of applicability of shallow seismics for fault detection reducing the risk of unsuccessful investigations

vertical structure of the axi asymmetric temperature disturbance in the venusian polar atmosphere comparison between radio occultation measurements and gcm results vertical temperature profiles at 40 75 km around 80 n in the venus polar vortex are retrieved over 13 earth days almost continuously from radio occultation measurements vera in the venus express mission they show periodical variations with a dominant period of 3 1 earth days these fluctuations are confined in an altitude range of 45 65 km with a local minimum at 58 km altitude where the static stability abruptly increases with height the phase of the temperature fluctuations is almost reversed at the 58 km level and varies little above and below this altitude a numerical simulation of a venusian atmospheric general circulation model gcm shows that the axi asymmetric temperature disturbance with zonal wavenumber 1 is predominant at 50 75 km levels in the model atmosphere the vertical structure of the reproduced disturbance agrees quite well with that retrieved by the radio occultation measurement amplitude of the temperature fluctuation has a local minimum and its phase is reversed at the altitude 65 km in the model where the static stability rapidly changes as in the observations above and below this altitude the phase is almost constant in the vertical direction the relationship among the temperature horizontal winds and geopotential height associated with the simulated disturbance suggests that the axi asymmetric temperature disturbance observed in the venus polar region can be interpreted as neutral barotropic rossby waves related to barotropic instability in the polar region

vortex circulation on venus dynamical similarities with terrestrial hurricanes 1 some dynamical and morphological similarities exist between the vortex organization of the atmosphere in the northern and southern hemispheres of venus and the tropical cyclones hurricanes on earth an s shape feature detected in the center of the vortices on venus from pioneer venus orbiter and venus express observations has also been seen in tropical cyclones this feature can be simulated with an idealized nonlinear and non divergent barotropic model and like in the vortices on venus and in tropical cyclones it is found to be transient given the challenges in measuring the deep atmospheric circulation of venus the morphological similarities provide clues toward understanding the processes involved in the maintenance of venus atmospheric super rotation

cloud level winds from the venus express monitoring camera imaging abstract six years of continuous monitoring of venus by european space agency s venus express orbiter provides an opportunity to study dynamics of the atmosphere our neighbor planet venus monitoring camera vmc on board the orbiter has acquired the longest and the most complete so far set of ultra violet images of venus these images enable a study the cloud level circulation by tracking motion of the cloud features the highly elliptical polar orbit of venus express provides optimal conditions for observations of the southern hemisphere at varying spatial resolution out of the 2300 orbits of venus express over which the images used in the study cover about 10 venus years out of these we tracked cloud features in images obtained in 127 orbits by a manual cloud tracking technique and by a digital correlation method in 576 orbits total number of wind vectors derived in this work is 45 600 for the manual tracking and 391 600 for the digital method this allowed us to determine the mean circulation its long term and diurnal trends orbit to orbit variations and periodicities we also present the first results of tracking features in the vmc near ir images in low latitudes the mean zonal wind at cloud tops 67 2 km following rossow w b del genio a t eichler t 1990 j atmos sci 47 2053 2084 is about 90 m s with a maximum of about 100 m s at 40 50 s poleward of 50 s the average zonal wind speed decreases with latitude the corresponding atmospheric rotation period at cloud tops has a maximum of about 5 days at equator decreases to approximately 3 days in middle latitudes and stays almost constant poleward from 50 s the mean poleward meridional wind slowly increases from zero value at the equator to about 10 m s at 50 s and then decreases to zero at the pole the error of an individual measurement is 7 5 30 m s wind speeds of 70 80 m s were derived from near ir images at low latitudes the vmc observations indicate a long term trend for the zonal wind speed at low latitudes to increase from 85 m s in the beginning of the mission to 110 m s by the middle of 2012 vmc uv observations also showed significant short term variations of the mean flow the velocity difference between consecutive orbits in the region of mid latitude jet could reach 30 m s that likely indicates vacillation of the mean flow between jet like regime and quasi solid body rotation at mid latitudes fourier analysis revealed periodicities in the zonal circulation at low latitudes within the equatorial region up to 35 s the zonal wind show an oscillation with a period of 4 1 5 days 4 83 days on average that is close to the super rotation period at the equator the wave amplitude is 4 17 m s and decreases with latitude a feature of the kelvin wave the vmc observations showed a clear diurnal signature a minimum in the zonal speed was found close to the noon 11 14 h and maxima in the morning 8 9 h and in the evening 16 17 h the meridional component peaks in the early afternoon 13 15 h at around 50 s latitude the minimum of the meridional component is located at low latitudes in the morning 8 11 h the horizontal divergence of the mean cloud motions associated with the diurnal pattern suggests upwelling motions in the morning at low latitudes and downwelling flow in the afternoon in the cold collar region

the database of individual seismogenic sources diss version 3 summarizing 20 years of research on italy s earthquake geology abstract this paper describes the main characteristics the evolution and the structure of the database of individual seismogenic sources diss and particularly of its release of early 2007 the database contains the results of the investigations of the active tectonics in italy during the past 20 years the first two sections of this paper document the recent evolution in mapping and archiving italian active fault data in relation to important achievements in the understanding of italian tectonics some of which were spurred by significant earthquakes the central sections describe the current structure of the database the reasons for its assumptions and data categories its current contents its evolution through several years of improvements the last section describes how the current contents of the database correspond with the existing strain and stress data available from focal mechanism borehole breakout and gps data for the whole of italy the database supplies a fresh and unified view of active and seismogenic processes in italy by building on basic physical constraints concerning rates of crustal deformation on the continuity of deformation belts and on the spatial relationships between adjacent faults both at the surface and at depth

venus cloud tracked and doppler velocimetry winds from cfht espadons and venus express virtis in april 2014 abstract we present new coordinated observations and measurements of the wind amplitude and its variability at venus cloud tops based on the two complementary techniques of ground based doppler velocimetry widemann et al 2007 2008 machado et al 2012 2014 and cloud tracked winds using esa venus express virtis m imaging at 0 38 m drossart et al 2007 sanchez lavega et al 2008 hueso et al 2012 machado et al 2014 cloud tracked winds trace the true atmospheric motion also responsible for the doppler fizeau shift of the solar radiation on the dayside by super rotating moving cloud tops with respect to both the sun and the observer machado et al 2014 and based on this complementarity we performed a new coordinated campaign in april 2014 combining both venus express observations and ground based doppler wind measurements on the dayside of venus cloud tops at canada france hawaii telescope at a phase angle 76 0 3 the analysis and results show 1 additional confirmation of the coherence and complementarity in the results provided by these techniques on both spatial and temporal time scales of the two methods 2 first time estimation of the meridional component of the wind in another planet using the doppler velocimetry technique with evidence of a symmetrical poleward meridional hadley flow in both hemispheres of v m 22 15 5 m s 1 3 spatial and temporal variability of the zonal flow with latitude and local time with a significant increase of wind amplitude near the morning terminator previously reported in feb 2011 observations

the irpinia italy 1980 earthquake detailed analysis of a complex normal faulting a detailed analysis of near source strong motion and leveling data together with the results of teleseismic waveform modeling by westaway and jackson 1987 and aftershock studies by deschamps and king 1984 allows a satisfactory kinematic description of the complex normal faulting associated with the magnitude ms 6 9 november 23 1980 irpinia earthquake southern italy the three main rupture episodes starting at about 0 20 and 40 s are here associated with better constrained source parameters than in previous studies we first evaluated the triggering time for the 11 closest accelerometers by using the well recorded 40 s strong motion phases this gave the absolute time and location of the dominant episodes of faulting the first rupture propagated mainly toward the northwest on a ne dipping normal fault at a mean velocity close to 3 km s for about 20 km and continued 15 km further on smaller subfaults it was associated with surface breakage in the southeastern part the second rupture started from the southeastern end of the first rupture about 18 s after it and propagated about 20 km toward the southeast on a low angle normal fault dipping 20 ne it was associated with secondary faulting on steeper planes reaching the surface the third and last episode at 39 s nucleated near the first hypocenter at shallower depth and the rupture possibly propagated on a 10 to 15 km long normal fault striking se antithetic to the first activated fault a clear correlation appears between the strength of the geological formations and the existence of surface breakage and shallow aftershock activity

a decade of passive seismic monitoring experiments with local networks in four italian regions we report on four seismic monitoring experiments that in the past ten years we carried out with dense local networks in seismically active italian areas where for at least a year tens of three component seismic stations were set up to record microseismicity the areas observed are alpago cansiglio located in the venetian alps citta di castello in the northern apennines marsica in the central apennines and val d agri located in the southern apennines we produced homogeneous catalogues regarding earthquake locations and local magnitudes to investigate seismicity patterns during an inter seismic period the four regions are characterised by different kinematics strain rates and historical recent seismicity we investigate earthquake distribution in space time and size obtaining reference seismic rates and parameters of the gutenberg and richter law we declustered the catalogues to look for coherent signs in the background seismic activity despite a difference in the catalogues magnitudes of completeness due both to the diverse detection threshold of the local networks and different seismic release we detect and observe two common main behaviours a the alpago cansiglio and marsica regions are characterised by a relatively lower rate of seismic release associated to the episodic occurrence of seismic sequences with the largest event being 3 ml 4 in these areas the seismicity is not localised around the main faults b the citta di castello and val d agri regions have a relatively high rate of seismicity release almost continuously with time and the increase in earthquake production is not clearly related to seismic sequences in these areas the seismicity nucleates around defined fault systems and is usually lower than ml 3 we suggest that the presence of over pressured fluids in the citta di castello and val d agri uppermost crustal volume may favour and mould the higher rate of microseismic release

sediment gravity flows triggered by remotely generated earthquake waves recent great earthquakes and tsunamis around the world have heightened awareness of the inevitability of similar events occurring within the cascadia subduction zone of the pacific northwest we analyzed seafloor temperature pressure and seismic signals and of video stills of sediment enveloped instruments recorded during the 2011 2015 cascadia initiative experiment and seafloor morphology our results led us to suggest that thick accretionary prism sediments amplified and extended seismic wave durations from the april 11 2012 mw8 6 indian ocean earthquake located more than 13 500 km away these waves triggered a sequence of small slope failures on the cascadia margin that led to sediment gravity flows culminating in turbidity currents previous studies have related the triggering of sediment laden gravity flows and turbidite deposition to local earthquakes but this is the first study in which the originating seismic event is extremely distant 10 000 km the possibility of remotely triggered slope failures that generate sediment laden gravity flows should be considered in inferences of recurrence intervals of past great cascadia earthquakes from turbidite sequences future similar studies may provide new understanding of submarine slope failures and turbidity currents and the hazards they pose to seafloor infrastructure and tsunami generation in regions both with and without local earthquakes

change of tectono stratigraphic regime in the australian plate during the 99 ma mid cretaceous and 43 ma mid eocene swerves of the pacific the clockwise bend at 99 ma mid cretaceous in linear volcanic chains in the tropical pacific coincides with a change from pre 99 ma head on chilean type subduction of the pacific plate beneath eastern gondwana to 99 43 ma sinistral oblique mariana type subduction and strike slip breakup by simple sea floor spreading between australia and antarctica and by backarc spreading in the southwest pacific the 99 ma breakup of australia from antarctica is documented by a mid cretaceous unconformity this tectono stratigraphic change founded modern australia with a mountain chain along an upper plate margin in the east and lowlands on the lower plate margin in the south the counterclockwise bend at 43 ma mid eocene the emperor hawaiian bend coincides with the onset of structure in the challenger rift of new zealand the eromanga cooper basin of central australia and the oil shale grabens of coastal queensland

potential vorticity of the south polar vortex of venus venus atmosphere shows highly variable warm vortices over both of the planet s poles the nature of the mechanism behind their formation and properties is still unknown potential vorticity is a conserved quantity when advective processes dominate over friction and diabatic heating and is a quantity frequently used to model balanced flows as a step toward understanding the vortices dynamics we present maps of ertel s potential vorticity epv at venus south polar region we analyze three configurations of the south polar vortex at the upper cloud level p 240 mbar z 58 km based on our previous analyses of cloud motions and thermal structure from data acquired by the visual and infrared thermal imaging spectrometer instrument on board venus express additionally we tentatively estimate epv at the lower cloud level p 2200 mbar z 43 km based on our previous wind measurements and on static stability data from pioneer venus and the venus international reference atmosphere vira model values of epv are on the order of 10 6 and 10 8 k m2 kg 1 s 1 at the upper and lower cloud levels respectively being 3 times larger than the estimated errors the morphology observed in epv maps is mainly determined by the structures of the vertical component of the relative vorticity this is in contrast to the vortex s morphology observed in 3 8 or 5 m images which are related to the thermal structure of the atmosphere at the cloud top some of the epv maps point to a weak ringed structure in the upper cloud while a more homogenous epv field is found in the lower cloud

venus atmospheric circulation known and unknown 1 after a pause of more than two decades venus atmosphere is being explored again since april 2006 european space agency s venus express has been acquiring data exploiting the near infrared windows that allow us to peer into the deep night side atmosphere in june 2007 nasa s messenger mission will fly past venus on its way to mercury collecting useful data for a few weeks instruments and experiments on venus express are expected to provide a more comprehensive set of atmospheric observations over three and perhaps more venus days venus express observations are already providing clues about the processes that maintain the rapid circulation of venus atmosphere the early observations show not only that the global circulation is organized into two hemispheric vortices centered over respective poles but also that the vortex organization extends deep into the atmosphere the limited galileo nims near infrared observations in 1989 had revealed the deep circulation in the equatorial regions but because of the spacecraft flyby trajectory could not observe the high latitudes to elucidate the polar circulation and its organization the long hiatus in systematic venus observations has provided an opportunity to perform some new analysis of the previous pioneer venus observations this paper presents a synopsis of the circulation measurements at high latitudes and an analysis of the solar thermal tides seen in the cloud motions and suggests some limitations of previous estimates of transport of angular momentum by eddies

a ten year earthquake occurrence model for italy the recent m w 6 3 destructive l aquila earthquake has further stimulated the improvement of the italian operational earthquake forecasting capability at different time intervals here we describe a medium term 10 year forecast model for m w 5 5 earthquakes in italy that aims at opening new possibilities for risk mitigation purposes while a longer forecast yielded by the national seismic hazard map is the primary component in establishing the building code a medium term earthquake forecast model may be useful to prioritize additional risk mitigation strategies such as the retrofitting of vulnerable structures in particular we have developed an earthquake occurrence model for a 10 year forecast that consists of a weighted average of time independent and different types of available time dependent models based on seismotectonic zonations and regular grids the inclusion of time dependent models marks a difference with the earthquake occurrence model of the national seismic hazard map and it is motivated by the fact that at the 10 year scale the contribution of time dependency in the earthquake occurrence process may play a major role the models are assembled through a simple averaging scheme whereby each model is weighted through the results of a retrospective testing phase similar to the ones carried out in the framework of the collaboratory for the study of earthquake predictability in this way the most hazardous italian areas in the next ten years will arise from a combination of distinct models that place more emphasis on different aspects of the earthquake occurrence process such as earthquake clustering historical seismic rate and the presence of delayed faults capable of large events finally we report new challenges and possible developments for future updating of the model

venus cloud top winds from tracking uv features in venus monitoring camera images 1 to date dynamical observations of the venus clouds have delivered mainly either only short term or long term averaged results with the venus monitoring camera vmc it finally became possible to investigate the global dynamics with a relatively high resolution in space and time on a long term basis our findings from manual cloud feature wind tracking in vmc uv image sequences so far show that the details of the mesospheric dynamics of venus appear to be highly variable although the general rotation of the atmosphere remained relatively stable since mariner 10 more than 30 years ago by now there are indications of short term variations in the general circulation pattern of the venus atmosphere at cloud top level in some cases significant variations in the zonal wind properties occur on a timescale of days in other cases we see rather stable conditions over one atmospheric revolution or longer at cloud top level it remains an interesting question whether the irregularly observed midlatitude jets are indeed variable or simply become shielded from view by higher h2so4 haze layers for varying time intervals winds at latitudes higher than 60 s are still difficult to obtain track because of low contrast and scarcity of features but increasing data is being collected over all it was possible to extend latitudinal coverage of the cloud top winds with vmc observations thermal tides seem to be present in the data but final confirmation still depends on synthesis of visible and infrared thermal imaging spectrometer and vmc observations on night and dayside although poorly resolved meridional wind speed measurements agree mainly with previous observations and with the presence of a hadley cell spanning between equatorial region and about 45 s latitude

altimetry of the venus cloud tops from the venus express observations 1 simultaneous observations of venus by visible and infrared thermal imaging spectrometer and venus monitoring camera onboard the venus express spacecraft are used to map the cloud top altitude and to relate it to the ultraviolet uv markings the cloud top altitude is retrieved from the depth of co2 absorption band at 1 6 m in low and middle latitudes the cloud top is located at 74 1 km it decreases poleward of 50 and reaches 63 69 km in the polar regions this depression coincides with the eye of the planetary vortex at the same latitude and hour angle cloud top can experience fast variations of about 1 km in tens of hours while larger long term variations of several kilometers have been observed only at high latitudes uv markings correlate with the cloud altimetry however the difference between adjacent uv dark and bright regions does not exceed several hundred meters surprisingly co2 absorption bands are often weaker in the dark uv features indicating that these clouds may be a few hundred meters higher or have a larger scale height than neighboring clouds ultraviolet dark spiral arms which are often seen at about 70 correspond to higher altitudes or to the regions with strong latitudinal gradient of the cloud top altitude cloud altimetry in the polar region reveals the structure that correlates with the thermal emission maps but is invisible in uv images this implies that the uv optically thick polar hood is transparent in the near ir

active extension in val d agri area southern apennines italy implications for the geometry of the seismogenic belt summary integration of geologic geomorphologic and seismologic data sets is used to reconstruct the recent tectonic evolution and active deformation pattern in the val d agri area located in the seismically active axial sector of the southern apennines italy the western portion of the apennines thrust belt has been affected by pliocene quaternary extension during easterly roll back and crustal delamination of the adriatic slab the bulk of quaternary extension has been accommodated by sw dipping oblique and normal faults which have attained mature morphologic and structural features and nowadays separate mountain ranges from intermontane basins however in the present seismogenic belt coseismic faulting locally occurs on ne dipping structures which might cut the inherited pleistocene landscape in the val d agri basin in spite of the large early middle pleistocene displacement occurred on sw dipping faults bordering its eastern flank our investigations show that the recent basin evolution has been controlled by a ne dipping fault system monti della maddalena fault system mmfs this fault system cuts across the monti della maddalena range west of the agri valley and has not yet created an evident tectonic landscape notwithstanding fault motion since the middle pleistocene might explain geomorphologic and hydrographic anomalies of the agri river and its valley where fault controlled subsidence has captured the river course and produced an aggrading plain within a regional uplift context recent and ongoing motion is documented by fault scarplets in loose deposits 14c ages of palaeosols and the spatial relation with low to moderate instrumental seismicity results from fault kinematic analysis are compatible with fault plane solutions of local and regional seismic events and indicate ne sw oriented extension recognition of the mmfs as a potential seismogenic fault increases the longitudinal extent of the ne dipping morphologically immature seismic sources in the southern apennines and argues against the range bounding fault model for active extension in the region the regional size of the ne dipping seismogenic belt may result from impingement of a mantle wedge beneath the apenninic chain and possibly track the external front of crustal delamination

morphology and dynamics of the upper cloud layer of venus esa s venus express probe has been in orbit since april 2006 eight research papers in this issue present new results from the mission covering the atmosphere polar features interactions with the solar wind and the controversial matter of venusian lightning hakan svedham et al open the section with a review of the similarities and mostly differences between venus and its twin the earth andrew ingersoll considers the latest results and also how the project teams plan to make the most of the probe s remaining six years of life venus is completely covered by a thick cloud layer with the cloud tops in fast retrograde rotation global and small scale properties of these clouds and their temporal and latitudinal variations are investigated and the wind velocities are derived the southern polar region is highly variable and can change dramatically on time scales as short as one day perhaps arising from the injection of so2 into the mesosphere venus is completely covered by a thick cloud layer of which the upper part is composed of sulphuric acid and some unknown aerosols1 the cloud tops are in fast retrograde rotation super rotation but the factors responsible for this super rotation are unknown2 here we report observations of venus with the venus monitoring camera3 on board the venus express spacecraft we investigate both global and small scale properties of the clouds their temporal and latitudinal variations and derive wind velocities the southern polar region is highly variable and can change dramatically on timescales as short as one day perhaps arising from the injection of so2 into the mesosphere the convective cells in the vicinity of the subsolar point are much smaller than previously inferred4 5 6 which we interpret as indicating that they are confined to the upper cloud layer contrary to previous conclusions7 8 but consistent with more recent study9

atmospheric thermal structure and cloud features in the southern hemisphere of venus as retrieved from virtis vex radiation measurements thermal structure and cloud features in the atmosphere of venus are investigated using spectroscopic nightside measurements recorded by the visible and infrared thermal imaging spectrometer virtis aboard esa s venus express mission in the moderate resolution infrared mapping channel m ir 1 5 m new methodical approaches and retrieval results for the northern hemisphere have been recently described by haus et al haus r kappel d arnold g 2013 planet space sci 89 77 101 http dx doi org 10 1016 j pss 2013 09 020 now southern hemisphere maps of mesospheric temperature and cloud parameter fields are presented that cover variations with altitude latitude local time and mission time measurements from the entire usable data archive are utilized comprising radiation spectra recorded during eight venus solar days between april 2006 and october 2008 zonal averages of retrieved temperature altitude profiles in both hemispheres are very similar and give evidence of global n s axial symmetry of atmospheric temperature structure cold collar and warmer polar vortex regions exhibit the strongest temperature variability with standard deviations up to 8 5 k at 75 s and 63 km altitude compared with about 1 0 k at low and mid latitudes above 75 km the mesospheric temperature field strongly depends on local time at altitudes above about 75 km the atmosphere is warmer in the second half of night while the dawn side at lower altitudes is usually colder than the dusk side by about 8 k local minimum temperature of 220 k occurs at 03 00 h local time at 65 km and 60 s temperature standard deviation at polar latitudes is particularly large near midnight temperature variability with solar longitude is forced by solar thermal tides with a dominating diurnal component the influence of observed cloud parameter changes on retrieved mesospheric zonal average temperature structure is moderate and does not exceed 2 3 k at altitudes between 60 and 75 km the mesospheric thermal structure was essentially stable with julian date between 2006 and 2008 global n s axial symmetry is also observed in cloud structures cloud top altitude at 1 m slowly decreases from 71 km at the equator to 70 km at 45 50 and rapidly drops poleward of 50 it reaches 61 km over both poles average particle size in the vertical cloud column increases from mid latitudes toward the poles and also toward the equator resulting in minimum and maximum zonal average cloud opacities of about 32 and 42 and a planetary average of 36 5 at 1 m zonal averages of cloud features are similar at different solar days but variations with local time are very complex and inseparably associated with the superrotation of the clouds

venus upper atmospheric dynamical structure from ground based observations shortly before and after venus inferior conjunction 2009 abstract investigations on the dynamical structure of venus upper atmosphere were carried out by infrared heterodyne doppler wind measurements shortly before and after the venusian inferior conjunction on march 27 2009 the cologne tuneable heterodyne infrared spectrometer this has been installed at the mcmath pierce solar telescope on kitt peak arizona usa to detect non local thermodynamical equilibrium non lte emission lines of co2 at a wavelength of 10 5 m these solar induced emission lines originate at a pressure level of 1 bar corresponding to an altitude level of 110 10 km from the frequency position of the spectral lines we directly derived doppler winds without any additional information the high spatial resolution with a field of view of 1 6 arcsec compared to an apparent diameter of venus of 57 arcsec allowed to collect information at different latitudes of the illuminated planet line of sight wind velocities between 189 11 m s and 41 14 m s were detected along the illuminated evening western limb in march and along the bright morning eastern limb in april single observations at the evening and morning terminator do not show a systematic difference of wind velocities the measured wind is uniform at low and mid latitudes in march a lower mean value of 134 1 m s was found compared to april where we retrieved a value of 141 1 m s poleward of a latitude of 50 we observed a strong decrease in wind speed down to 41 14 m s in addition to the pure line of sight wind velocities we used the observing geometry for additional interpretations regarding a global flow from the subsolar point to the antisolar point ss as flow and a global retrograde superrotational zonal wind rsz the estimations indicate a dominating ss as flow with a maximum wind velocity at the terminator of 138 1 m s at low and mid latitudes no indication of a global rsz component was found corresponding wind values for the latter yield wind velocities in the zonal direction between 20 m s retrograde direction and 20 m s prograde direction at different latitudes an inversion of the wind direction is in disagreement with a global rsz behavior the comprehensive dataset was used to investigate short term wind variabilities and changes up to 58 m s within few days were found we included a detailed comparison of concurrent single position observations with sub millimeter measurements clancy r t sandor b j moriarty schieven g 2012 icarus 217 794 812 suggesting a cross terminator gradient at certain latitudes a detailed interpretation of the observed time dependent behavior by global circulation models including wave activities will be addressed in future work

evidence of low magnitude continued reservoir induced seismicity associated with the pertusillo artificial lake southern italy the most common observations of reservoir induced seismicity ris by filling artificial lakes are generally associated with the initial impoundment of the lake or the lake level increase above a previous maximum rarely ris persists for many years without a decrease in frequency or magnitude if this occurs it is called protracted or continued seismicity pertusillo artificial lake in high agri valley southern italy is a small reservoir with a water column that fluctuates yearly by about 10 15 m on average corresponding to a pressure perturbation at the bottom of the lake of 0 10 0 15 mpa although the reservoir was filled in 1963 the microearthquake activity still occurring around the lake allows the categorization of such ris as continued seismicity we collected all microearthquakes m l 2 7 recorded near the reservoir by two different seismic networks from january 2005 to june 2012 and analyzed their frequency magnitude distribution which showed a b value b 1 40 much higher than that expected for the investigated area even though the spatial seismicity pattern shows two distinct clusters to the northeast and southwest of the lake we found that only the southwest seismicity is significantly correlated with the water level the findings suggest that the physical driving mechanism is the 1d pore fluid pressure diffusion along the northeast southwest fault zones connecting the reservoir to the southern termination of the monti della maddalena fault system with an average hydraulic diffusivity of 7 8 m2 s online material figures of magnitude comparisons between catalogs temporal occurrence of events rainfall versus number of earthquakes and number of events versus water level and animated 3d views of seismicity and reservoir

late quaternary tectonics of the vallo di diano basin southern apennines italy italian ministry of university and research project firb research and development of new technologies for protection and defence of territory from natural risks w p c3 crustal imaging in italy

faulting and earthquake triggering during the 1783 calabria seismic sequence summary between the 1783 february 5 and 1783 march 28 five earthquakes struck the southern part of calabria the main shock february 5 and the first aftershock february 6 devastated the region ene of the messina strait the greatest damage occurred along the foot of the aspromonte mountains south of san giorgio morgeto and along the tyrrhenian coast south of palmi a surface break about 18 km long with several feet of downthrow to the west formed along the cittanova santa cristina fault as a result of the main shock on february 7 a third large shock ruined villages at the foot of the serre mountains north of san giorgio morgeto morphological and structural evidence combined with a reassessment of observations made at the time of the earthquakes suggest that these three shocks were shallow 20 km and related to slip on the west dipping ne striking cittanova sant eufemia palmi scilla and serre normal faults respectively which juxtapose the basement of the aspromonte and serre mountains with the pleistocene deposits of the gioia tauro and mesima basins and border the palmi coastal high the three faults belong to an active rift that stretches from northern calabria to offshore the ionian coast of sicily the spatial coupling between the 1783 events is investigated by resolving changes of coulomb failure stress the main shock 1783 february 5 m 7 on the cittanova and sant eufemia faults increased that stress by several bars on the scilla fault triggering the 1783 february 6 earthquake m 6 5 the cumulative effect of these two shocks was to raise the coulomb stress by more than 1 bar on the sw part of the serre fault which was subsequently the site of the 1783 february 7 shock m 6 5 in turn the first three events increased the stress by about 1 bar on the ne part of this latter fault leading to the 1783 march 1 shock m 5 7 the gap between the 1783 february 7 and 1783 march 1 events may be related to the previous occurrence of an earthquake 124 yr before 1659 november 5 m 6 which had already released stress locally the occurrence of the last 1783 event 28 march is not as simply accounted for by coulomb modelling in part because it remains unclear which fault slipped and how deep this event was overall the 1783 sequence increased the coulomb failure stress by several bars south of the messina strait and north of the epicentral region of the 1693 se sicily catania noto earthquakes 125 yr later this same region was the site of the 1908 messina earthquake also a normal faulting event our study thus provides one convincing example in which coulomb stress modelling brings insight into the spatial dynamics of seismic sequences