the interaction of the madden julian oscillation with the maritime continent in a gcm previous studies using the hadley centre coupled model hadcm3 have shown that the islands of the maritime continent act as an unrealistic block to the eastward propagation of the madden julian oscillation mjo this blocking effect is investigated using a simplified aqua planet version of this gcm with various idealized configurations of the maritime continent islands placed on the equator and an mjo like convective signal forced by a propagating sea surface temperature anomaly dipole results suggest that it is the orography of the islands rather than the presence of the islands themselves which results in the blocking of the mjo although the peak elevation of the orography in the gcm is very much lower than in reality it appears to act as effective block to the eastward propagation of the low level kelvin wave signal which accompanies the mjo in particular the representation of sumatra in the gcm as a north south oriented ridge straddling the equator seems to be particularly effective at blocking the kelvin wave signal which in a full gcm would result in the weakening or complete extinction of the mjo signal to the east of the maritime continent

contemporaneous extension and compression in the northern apennines from earthquake fault plane solutions summary the northern apenninic arc belongs to the deformation zones surrounding the adriatic plate which behaves as a rigid block it is a ne verging fold and thrust belt which developed since the miocene with the migration of an extensional compressional pair previous seismological data are roughly in agreement with this deformation picture although the outer compressional front was not clearly defined by the few available solutions in this work we confirm the existence of two adjacent zones of contemporaneous extension and compression in the northern apennines defining the extent of these two zones and their interim1 deformation better than was previously done this is accomplished through the analysis of 125 new focal mechanisms of earthquakes 2 6 md 4 8 recorded by the national network of the lstituto nazionale di geofisica in the period 1988 1995 the two deformation zones are clearly separated and lie very close to each other with a partial overlapping in the emilian tuscan apennines strikeslip events are scattered in most of the study area thrust faulting earthquakes are located in the internal part of the most recently active thrust front middle upper pleistocene there is a general trend of the compressional p axes of thrust fault and strike slip solutions to be perpendicular to the apenninic direction in the external zone while the tensional axes of the normal fault and strike slip solutions in the belt do not show a uniform orientation however clearly evident is the ene direction of extension in the peri tyrrhenian region consistent with the direction of shmln in the quaternary volcanoes of this region inferred from borehole breakouts and microearthquake fault plane solutions we determined the orientation of the stress tensor in the two main deformation zones by inversion of the 125 fault plane solutions determined in this study we found that the external belt is characterized by ne sw compression ol horizontal oriented n45 e while a normal faulting regime with o3 e w oriented is characteristic of the umbria tuscany back arc region

the sealing capacity of the cap rock above the torre alfina geothermal reservoir central italy revealed by soil co2 flux investigations abstract torre alfina is a medium enthalpy t 140 c geothermal field in central italy hosted in buried fractured mesozoic limestones extensively explored in the 1970s and 1980s but which so far has not been exploited a detailed diffuse soil co2 flux investigation 1336 measurements over a surface of 12 6 km2 and the periodic monitoring of soil co2 flux from target areas indicate that in most of the area even above a pressurized gas cap existing at the reservoir top the soil co2 flux is low and mostly within the background threshold 48 g m 2 day 1 and is likely generated by biological soil respiration anomalous values up to 30 250 g m 2 day 1 are found only in the proximity of a small zone with gas vents whose composition is identical to that of the gas produced by the geothermal wells tapping the reservoir this is the only zone where a fault connecting the deep geothermal reservoir with the surface does exist these data are compared with those of the near latera high enthalpy geothermal field t 210 c where anomalous soil co2 flux is recorded above the productive reservoir the difference of soil co2 release in the two fields is attributed to the differences in the impervious cover allochthonous flysch deposits above the carbonate reservoir which is thin and locally lacking at latera and continuous and thick 400 m at torre alfina results demonstrate that soil co2 flux investigations are useful in geothermal exploration but only high flux values likely indicate the presence of a geothermal reservoir at depth whereas low flux values can indicate either the lack of an active geothermal reservoir at depth or the presence of a very effective impervious cover above the reservoir

active tectonics and seismic zonation of the urban area of florence italy the city of florence possesses a concentration of cultural and artistic treasures which is unique in the world in this sense it has a particularly high seismic exposure and a potentially high vulnerability in order to better evaluate its seismic hazard and risk we analyzed the seismic response of the urban area of florence by performing a multidisciplinary study on the effects of earthquakes on the city by a computer aided methodology we re evaluated the seismic intensity reports of the may 18 and june 6 1895 earthquakes in different parts of the city and compared these data with recent studies on surface geology active tectonics and actual fault movements in the florence basin we concluded that more detailed studies of soil response are needed to form a basis for public policy

tectono sedimentary analysis of a complex extensional neogene basin formed on thrust faulted northern apennines hinterland radicofani basin italy abstract large nw se oriented neogene quaternary structural depressions up to about 200 km long and 25 km wide have developed on the western side hinterland of the northern apennines over thrust substrate the depressions are now for the most part laterally bounded by normal faults and are longitudinally separated into basins by transfer zones a debate exists in the literature as to whether these basins have developed as half graben under a predominantly extensional regime since late miocene or as thrust top basins under a predominantly compressional regime that has continued until the pleistocene the radicofani basin is one of the best preserved basins it developed mainly during the late miocene early pliocene in the southern half of the siena radicofani structural depression and is now bounded on the east by normal faults that transect a thrust anticline nose in the substrate to the north by a substrate high or transfer zone and to the south and west by quaternary igneous volcanic edifices the basin experienced variable differential tectonic and associated sedimentation along linking normal boundary faults along its eastern margin it shows the development of thick 600 m alluvial fans that developed in relay areas between boundary faults and transverse faults and transfer zones well exposed sections generally show upward transitions from conglomeratic alluvial fans to shoreface sandstone to offshore mudstones locally the transition is marked by deltas primarily characterised by thick gravelly sandy stacked cross sets the thicker sandy gravel to gravelly sand cross sets 5 8 m thick are interpreted as gilbert type deltas interstratified thinner 0 5 1 m thick generally openwork gravelly strata are part of delta topset assemblages and probably represent prograding fluvial bars tectonic movements provided the accommodation space for the total 2700 m thick basin fill sea level fluctuations that led to the repeated development of the cross sets may also have been influenced by climatic or eustatic changes possibly related to the effects of early antarctic glaciations some features of the radicofani basin can be found in both extensional and compressional basins however the position of the basin in the mountain chain and the development of alluvial fans fandeltas and associated deposits along the main boundary fault combined with structural evidence from seismic lines show that during the early pliocene this basin best conforms to existing models of half graben

a new view of italian seismicity using 20 years of instrumental recordings in this paper we show the seismicity of the past 20 years that occurred in italy and surrounding regions hypocentral locations have been obtained by using p and s wave arrival times from the ingv national and several regional permanent seismic networks more than 48 000 events selected from an original data set of about 99 780 are used to reconstruct the most complete seismic picture of the italian region so far the seismicity distribution allows inference on seismotectonics of this complex region of subduction versus continental collision our results clearly reveal the geometry of the adria and the ionian subduction and a continuous normal fault belt in the upper crust following the apennines mountain range the depth of the seismogenic layer is computed from the cut off of seismicity at depth and shows large variations along and across the seismic active regions earthquakes are generated by the different velocity of slab retreat and the subsequent asthenospheric upwelling d 2004 elsevier b v all rights reserved

extensional and strike slip tectonics across the monte amiata monte cetona transect northern apennines italy and seismotectonic implications abstract this paper deals with the structural evolution along a transect across the inner northern apennines monte amiata volcano geothermal area monte cetona mainly focussing on the post orogenic middle miocene quaternary structures the tectonic setting of the study area derives from the superimposition of three main faulting events the first and second events developed during the middle late miocene and early middle pliocene respectively and took place in response to extensional tectonics the third faulting event developed in a transcurrent transtensional setting during the quaternary quaternary faults mainly strike ne sw and show left lateral kinematics with a minor dip slip normal component they caused the monte amiata volcanic eruptions 300 190 ka and controlled the widespread pleistocene and present hydrothermal fluids circulation quaternary strike slip faults have been documented in the monte amiata monte cetona area for the first time in this paper correlation with the adjoining areas e g vulsini region identifies the quaternary strike slip faulting recognised in the study area as a feasible source for the seismic activity in the monte amiata region where the origin of diffuse low magnitude seismicity is still under debate and poorly understood

geological structure of a long living geothermal system larderello italy we have examined the data of 600 geothermal wells and re interpreted approximately 500 km seismic profiles through the field of larderello italy we conclude that the two main seismic reflectors present below the geothermal area host two different fluids 1 superheated steam in the upper h horizon reached by drillholes and 2 supercritical fluid in the deeper k horizon reached by few unproductive or damaged wells the superheated steam has the physical and chemical connotation of the geothermal fluid exploited so far at larderello whereas the supercritical fluid represents a potential unconventional deep seated resource still to be assessed the high temperatures existing in correspondence of the k horizon suggest that the silica rich rocks are close to a plastic state and the fluids should remain confined in a medium sealed to the confining rocks unless occasional fluid overpressure and abrupt high strain rates occur

earthquake triggered soft sediment deformation structures seismites in travertine deposits abstract earthquakes related soft sediment deformations seismites are relevant structures to help reconstructing the palaeoseismicity in a region nevertheless although seismites have been described for a large variety of palaeo environments and stratigraphic settings they are rare and in some cases ambiguous structures in this paper we document for the first time impressive seismites affecting a latest quaternary travertine deposit located in southern tuscany serre di rapolano italy these structures are extremely relevant as seismites have been never described for this kind of terrestrial deposits the seismites developed within a 2 5 m thick stratigraphic succession made of alternating terrigenous and carbonate sediments embedded within the travertine deposits earthquake produced liquefaction and fluidization of some terrigenous levels and the injection of fluidized silty sediments dykes and sills into carbonate and terrigenous levels slumped levels and associated decollement surfaces produced highly non cylindrical folds overall induced by the loss of brittle shear strength along the basin slopes the occurrence of these soft sediment deformations implies an important seismic event that took place in a time spam encompassed between 84 8 and 48 92 5 08 ka in an area characterized by low seismicity and scarce knowledge of its seismotectonic setting their spectacular exposition and preservation in saw cuts of an abandoned quarry cava oliviera quarry highlights their relevance and importance

considerations on the seismotectonics of the northern apennines abstract the northern apennines have been subdivided into homogeneous zones on the basis of recent structural evolution and crustal structure in which the earthquake distribution can find a coherent framework these zones whose physiography is in strict connection with their structure are the internal peri tyrrhenian belt the external or main belt the buried belt and the pede alpine homocline earthquake activity has a tendency to cluster along well defined bands particularly in the easternmost border of the peri tyrrhenian belt as well as along the zone between the external belt and the buried belt i e along the padanian margin of the northern apennines a minimum of seismic activity seems to be correlated with some zones of the external belt as well as with the late tertiary and quaternary magmatic province of tyrrhenian southern tuscany the fault plane solutions are coherent with the structural picture a tentative seismotectonic model of the northern apennines is discussed

the 1846 orciano pisa earthquake in published sources and government survey documents abstract according to the catalogue postpischl 1985 the 1846 orciano earthquake is a very important high intensity x mcs event located in a moderately seismic area southwestern tuscany after a critical revision of the information available from published sources the documents of the government survey were located and processed for macroseismic purposes the data contained in the administrative forms required an original interpretative method aiming to supply information suitable for intensity assessment the intensity values generally come out lower than those previously assessed only by means of the interpretation of the published sources though the intensity distribution pattern does not appear to be substantially modified a preliminary investigation on the far field area reveals that the event was felt over an area coherent with the size of the event suggested by the epicentral intensity

correlation between seismic reflectivity and rheology in extended lithosphere southern tuscany inner northern apennines italy abstract in southern tuscany inner zone of the northern apennines the lithosphere has been affected by extensional deformation since the middle miocene and is characterized by high heat flow 120 mw m 2 both local shallow and regional deep seismic reflection profiles clearly show the occurrence of a sharp reflector k horizon within the upper crust which is probably located at the top of a shear zone acting as the decollement horizon for the latest pliocene quaternary normal faults its depth varies between 3 and 6 km in geothermal areas and 9 and 12 km elsewhere borehole control in the geothermal areas shows that it occurs at a temperature of approximately 450 c the hypothesis that the k horizon represents the top of the brittle ductile transition agrees with two lines of evidence a it approximately follows the same isotherm over the whole region and b its depth coincides with rheological predictions of the brittle ductile transition for the range of high pore fluid pressures and strain rates estimated for southern tuscany it appears therefore that at least under specific conditions very high pore fluid pressures strain concentration the brittle ductile transition may have a seismic signature

considerations on the significance of some post glacial fault scarps in the abruzzo apennines central italy abstract in this paper the tectonic and palaeoseismological significance of the fault scarps present in the massifs of the velino and of mount greco and in the plains adjacent to these massifs forming part of the abruzzo apennines is discussed the basic features of post glacial fault scarps already mentioned in the literature are illustrated found in the fucino plain in the ovindoli piani di pezza area on the mount magnola in the valle majelama alluvial fan and in the piano di aremogna others not previously mentioned surveyed by the author in the mount ocre cefalone area in the piana di corvaro and on the mount greco toppe del tesoro are also discussed on the basis of the characteristics of these scarps and of the chronological framework of the last phases of activity of the faults which gave rise to the scarps described the reliability of the assumptions made for palaeoseismological studies in other places is discussed for the abruzzo area the studies performed in the area of the velino and greco massifs suggest that to establish the possible co seismical activity of the faults the use of morphological indices and also of the results obtained with the excavation of trenches has to be very cautiously applied it is considered that the following can be stated it is probable that the majority of the mentioned fault scarps are co seismic in view of the height of some fault scarps it cannot be excluded that they were formed during the course of earthquake sequences lasting not more that 2 3000 years it is possible that some of the above mentioned scarps were produced during seismic events of great magnitude it does not seem possible at present to calculate a precise slip rate the amount of the offset often changes along the same fault even over short distances moreover there are many horst and graben type structures produced by local effects which contribute towards making an assessment of the fault offsets complicated it is also clear that erosion can change the aspect of the scarps an evaluation of the displacements caused by the faults producing them must therefore be made extremely cautiously caution is needed in assessing the magnitude of past earthquakes and in assuming recurrence intervals the dating of the phases of fault activity is approximate and there is great difficulty in recognizing with any certainty the duration the sort of activity and the length of the fault segment concerned in the activity moreover the existence in the past of aseismic creep and of movements linked to post glacial isostatic rebound cannot be excluded with any certainty these considerations must be regarded for the two massifs examined since there have been the epicentres of rare earthquakes of low intensity the only large earthquake known in history which caused surface ruptures occurred in the fucino area in 1915 the fault scarps reported in this paper seem however interpretable in general as indications of post glacial tectonic activity the intensity of which was unsuspected until a few years ago

a review on the driving mechanism of the tyrrhenian apennines system implications for the present seismotectonic setting in the central northern apennines abstract the formation of the tyrrhenian apennines system has been characterized by a complex distribution of major tectonic events such as opening of basins migration and distortion of orogenic belts retreat of trench zones stopping of consuming processes and starting of new subductions the various aspects of each event such as timing location dimension and deformation style impose important constraints on the genetic mechanism in this work we argue that the numerous constraints implied by all events together may be plausibly and coherently explained as effects of the convergence of the confining africa arabia and eurasia plates crucial evidence for discriminating among the various geodynamic hypotheses so far advanced is provided by the structural tectonic information recently provided by crop seismic sections in the study area the proposed evolutionary history is illustrated by several paleogeographic maps which provide a more detailed reconstruction than previous attempts particular attention is paid to describing the tectonic setting developed since the middle pleistocene in the apennines belt and its connection with seismic activity

propagating and nonpropagating mjo events over maritime continent abstractthe observed outgoing longwave radiation olr and era interim data during 1979 2008 from november to april were analyzed to reveal fundamental differences between eastward propagating ep and nonpropagating np mjo events across the maritime continent mc it was found that when the maximum mjo convection arrives near 120 e a positive moisture tendency lies in a longitudinal zone 10 s 10 n 130 170 e for the ep cases whereas a negative tendency appears in the same region for the np cases in the latter cases there are clearly detectable westward propagating rossby wave type dry signals over the equatorial central western pacific the dry rossby wave signal may hinder the development of new convection to the east of the mjo convective center preventing the eastward propagation of the mjo a moisture budget analysis shows that the positive tendency of specific humidity in the ep composite is mainly attributed to the advection of the mean moisture by an intraseasonal ascending motion ano

geochemical and petrological evidence of the subduction of delaminated adriatic continental lithosphere in the genesis of the neogene quaternary magmatism of central italy abstract serri g innocenti f and manetti p 1993 geochemical and petrological evidence of the subduction of delaminated adriatic continental lithosphere in the genesis of the neogene quaternary magmatism of central italy in m j r wortel u hansen and r sabadini editors relationships between mantle processes and geological processes at or near the earth s surface tectonophysics 223 117 147 the neogene quaternary magmatism of the northern apenninic arc took place in four phases separated in space and time which become progressively younger from west to east phase i 14 ma phase ii 7 3 6 0 ma phase iii 5 1 2 2 ma phase iv 1 3 0 1 ma this magmatism is the result of the activation of three physically separate sources 1 the adriatic continental crust extracted from the mantle in the late proterozoic 2 a strongly refractory recently k enriched harzburgitic mantle located in the mechanical boundary layer mbl of the lithosphere and 3 a recently metasomatized cpx rich mantle compositionally variable from iherzolite to wehrlite clinopyroxenite interpreted as an ephemerally k enriched asthenosphere the adriatic continental crust is the dominant source of the acid plutonic and volcanic rocks of the tuscan region the acid magmatism is mostly found inside an ellipsoidal area about 150 300 km centred on giglio island here defined as the tuscan crustal dome within this area mantle derived magmas unaffected by important crustal contamination processes and mixing with crustal anatectic melts have so far not been found pure crustal magmas are rare but are represented for example by some of the san vincenzo and roccastrada rhyolites virtually all the tuscan acid centres show evidence of mixing with potassic mantle derived magmas major and trace elements as well as 87 sr 86 sr and 143 nd 144 nd data on primitive rocks mg 65 reveal two groups of mantle derived magmas these define two distinct mantle enrichment trends both essentially due to the additions of k rich components which metasomatized separate compositionally diverse upper mantle sectors in both cases the most remarkable mineralogical effect of these enrichment processes is the production of variable amount of phlogopite through reaction between fluids and or melts with the mantle the rocks of group i ol hy and q normative lamproites ultrapotassic high mg latites ultrapotassic shoshonites and shoshonites saturated trend are considered to be derived by partial melting at low pressure 87 sr 86 sr 0 717 ce sr 0 3 and k 2 o na 2 o 6 7 and low ratios of 143 nd 144 nd 0 5121 0 5120 and ba la 87 sr 86 sr 0 712 and k 2 o na 2 o 8 9 values and low 143 nd 144 nd ba la 0 10 ratios these constraints do not allow to exclude a complete identity between the k rich components which metasomatized the mantle sources of the saturated and undersaturated trend magmas the geochemical and isotopic features of the components that metasomatized the mantle sources of the northern apenninic arc magmatism can be explained by a geodynamic process which causes a large amount of crustal materials to be incorporated within the upper mantle we propose that the delamination and subduction of the adriatic continental lithosphere related to the still ongoing northern apennine continental collision provide a viable mechanism to explain the genesis and eastward discontinuous migration of the magmatism in central italy the subduction of delaminated lithospheric mantle with lower crustal slivers would have exposed uppermost mantle adriatic mbl and crustal units previously imbricated in the apennine chain to the heating advected by the upwelling of a recently and ephemerally k enriched asthenospheric mantle wedge and by the underplating of magmas derived from it we consider that the diapiric uprising of a hot crustally contaminated asthenosphere occurs in the wake left above the sinking of the adriatic delaminated subducting continental lithosphere the delamination subduction process of the adriatic lithosphere has probably started in the early middle miocene but earlier than 15 14 ma ago as indicated by the age and petrologic characteristics of the first magmatic episode sisco lamproite of the northern apennine orogenesis

volcanic spreading forcing and feedback in geothermal reservoir development amiata volcano italia abstract we made a stratigraphic structural and morphologic study of the amiata volcano in italy we find that the edifice is dissected by intersecting grabens that accommodate the collapse of the higher sectors of the volcano in turn a number of compressive structures and diapirs exist around the margin of the volcano these structures create an angular drainage pattern with stream damming and captures and a set of lakes within and around the volcano we interpret these structures as the result of volcanic spreading of amiata on its weak substratum formed by the late triassic evaporites burano anhydrites and the middle jurassic to early cretaceous clayey chaotic complexes ligurian complex regional doming created a slope in the basement facilitating the outward flow and spreading of the ductile layers forced by the volcanic load we model the dynamics of spreading with a scaled lubrication approximation of the navier stokes equations and numerically study a set of solutions in the model we include simple functions for volcanic deposition and surface erosion that change the topography over time scaling indicates that spreading at amiata could still be active the numerical solution shows that as the central part of the edifice sinks into the weak basement diapiric structures of the underlying formations form around the base of the volcano deposition of volcanic rocks within the volcano and surface erosion away from it both enhance spreading in addition a sloping basement may constitute a trigger for spreading and formation of trains of adjacent diapirs as a feedback the hot hydrothermal fluids decrease the shear strength of the anhydrites facilitating the spreading process finally we observe that volcanic spreading has created ideal heat traps that constitute todays exploited geothermal fields at amiata normal faults generated by volcanic spreading volcanic conduits and direct contact between volcanic rocks which host an extensive fresh water aquifer and the rocks of the geothermal field constitute ideal pathways for water recharge during vapour extraction for geothermal energy production we think that volcanic spreading could maintain faults in a critically stressed state facilitating the occurrence of induced and triggered seismicity

mapping capable faulting hazard in a moderate seismicity high heat flow environment the tuscia province southern tuscany northern latium italy abstract this study is focused on potential evidence of capable faulting affecting southern tuscany northern latium a region of high heat flow and moderate to low seismicity here we refer to this region as tuscia the latin name for the land of the etruscans the review of the evidence for active tectonics in this area has allowed us to identify several potentially active capable faults mapped using a combination of analysis of digital terrain models with remote sensing and local geological information derived from bibliographic data and different scale maps active and capable faulting is certainly more evident in the eastern sector of tuscia chianti cetona ridge pienza amiata and bolsena caldera however even in the western tuscia e g colline metallifere and tyrrhenian coast capable faulting may be hypothesized along numerous structural elements the characterization of active faulting potential in terms of geometry slip types and rates in such a high heat flow environment beyond its usefulness in improving the assessment of fault displacement and earthquake hazard also helps to improve knowledge of the stress field and structural setting of the many geothermal fields in the area this allows new useful insights into geothermal exploitation and hazard e g induced triggered seismicity moreover this new knowledge of active tectonics and capable faults of the hinterland sector of the northern apennines may also provide useful insights into the siting processes of highly hazardous and strategic structures and more generally in land use planning and management of infrastructures especially during emergencies

an idealized semi empirical framework for modeling the madden julian oscillation abstractthe authors present a simple semi empirical model to explore the hypothesis that the madden julian oscillation can be represented as a moisture mode destabilized by surface flux and cloud radiative feedbacks the model is one dimensional in longitude the vertical and meridional structure is entirely implicit the only prognostic variable is column water vapor w the zonal wind field is an instantaneous diagnostic function of the precipitation field the linearized version of the model has only westward propagating relative to the mean flow unstable modes because wind induced surface latent heat flux anomalies occur to the west of precipitation anomalies the maximum growth rate occurs at the wavelength at which the correlation between precipitation and surface latent heat flux is maximized this wavelength lies in the synoptic to planetary scale range and is proportional to the horizontal scale associated with the assumed diagnostic wind response to precipitation anomalies the nonlinear version

a unified moisture mode framework for seasonality of the madden julian oscillation abstractthe madden julian oscillation mjo exhibits pronounced seasonality while it is largely characterized by equatorially eastward propagation during the boreal winter mjo convection undergoes marked poleward movement over the asian monsoon region during summer producing a significant modulation of monsoon rainfall in classical mjo theories that seek to interpret the distinct seasonality in mjo propagation features the role of equatorial wave dynamics has been emphasized for its eastward propagation whereas coupling between mjo convection and the mean monsoon flow is considered essential for its northward propagation in this study a unified physical framework based on the moisture mode theory is offered to explain the seasonality in mjo propagation moistening and drying caused by horizontal advection of the lower tropospheric mean moisture by mjo winds which was recently found to be critical for the eastward propagation of the winter mjo is also shown to play a dominant role in operating t

seasonality in the madden julian oscillation abstract this study using observational data and global reanalysis products synthesizes existing knowledge on the seasonality in the madden julian oscillation mjo and discusses its possible dependence on the mean background state the seasonality in the mjo is documented in terms of its components in low level zonal wind and precipitation a single peak season boreal winter exists near the equator in the indian and western pacific oceans for the broad tropical region however the seasonality in the mjo is featured by a latitudinal migration across the equator between two peak seasons the primary peak season is in boreal winter december march during which mjo signals are mainly confined to the indian and western pacific ocean and reach their maxima in the south pacific convergence zone the secondary peak season is boreal summer june september during which the strongest mjo occurs north of the equator from the bay of bengal to the south china sea and another separated region of strong mjo

crustal models of the geothermal areas of southern tuscany italy abstract geological and geophysical data gathered in the geothermal areas of southern tuscany located in the inner part of the northern apennines indicate the presence of granite intrusions the most relevant data are 1 regional asthenospheric ascent to a depth of 40 50 km 2 granitic dykes as old as 3 8 2 9 ma and a widespread contact aureole found in several deep geothermal wells 3 very high heat flow values interpreted as the result of convective circulation of hot fluids above shallow magmatic bodies 4 the presence of low density bodies inferred from low gravity values often correlated with positive heat flow anomalies 5 the occurrence of a highly reflective horizon named k in a depth range of 3 12 km in the geothermal areas as shown by seismic reflection data 6 a 30 40 km wide low velocity body below the k horizon whose existence is supported by local earthquake tomography and teleseismic studies 7 the presence of a conductive body which correlates well with the anomalous tomographic and teleseismic body as revealed by magnetotelluric surveys the goal of the paper is to test different alternative crustal models by using these data the models are 1 granite intrusion 2 geopressurized fluids below impervious layers 3 contact metamorphic aureole 4 mylonite layers at the upper lower crust transition and 5 some combination of the four the occurrence of shallow intrusive bodies still partially molten and associated with saline brines is considered the most tenable model

upper crustal structure of the larderello geothermal field as a feature of post collisional extensional tectonics southern tuscany italy abstract reflection seismic profiles crossing the larderello geothermal field permit the distinction of three different seismic facies units in the upper continental crust the upper 3 4 km of the crust is characterized by low reflectivity its base corresponding to a reflector referred to as the k horizon and recognized in many other areas of southern tuscany beneath this reflector a seismic facies of 0 8 1 0 twt thickness is characterized by strong convergent and divergent reflections forming a lozange shaped geometry the lowermost seismic facies is characterized by almost horizontal reflections based on the distribution of the hypocentral microearthquakes temperature data recorded in deep boreholes and the geometry of normal faults the k horizon is explained here as a kinematically active rheological boundary which separates a brittle upper part from a ductile lower part according to this hypothesis the k horizon and the lozange reflections could originate from a mylonite band located at the contact between two geological bodies characterized by different rheological behavior it is inferred that this horizon acts as a decoupling plane in the upper continental crust it developed as a consequence of the extensional tectonics and the high heat flow which characterize southern tuscany

synoptic disturbances over the equatorial south china sea and western maritime continent during boreal winter abstract during boreal winter the maritime continent is a region of deep cumulus convection and heavy precipitation systems that play a major role in several global and regional scale processes over the western part of this region the synoptic scale borneo vortex the northeast cold surge and the intraseasonal madden julian oscillation mjo contribute to the variability in deep convection this work studies the impact on deep convection due to interactions among these three different motion systems furthermore the role of the unique topography of the region is examined with respect to the variability in the synoptic scale cold surge and borneo vortex on the synoptic scale the interaction of northeast winds with local topography and the dynamic response to the change in latitude contribute to the turning of the winds and localized patterns of deep convection in days without a borneo vortex deep convection tends to be suppressed over the south china sea and borneo and enhanced downstream over th

the italian cmt dataset from 1977 to the present abstract the ingv harvard european mediterranean regional centroid moment tensor rcmt catalog collects solutions routinely computed since 1997 for earthquakes with moderate magnitude 4 5 m 5 5 in the mediterranean region the database represents an extension to smaller magnitudes of the harvard global cmt catalog based on analysis of seismograms recorded at regional distance and modeling of intermediate period surface waves the catalog includes about 600 events 200 of which in the italian region this study extends the catalog back in time for the italian region as long as made possible by available digital data i e since 1977 with the same analysis and inversion method used for current seismicity as a result we present here 65 new moment tensors for years between 1977 and 1997 these solutions represent 45 of the total number of events analyzed the existing seismograms being often too scarce to allow a stable solution the new dataset includes events in many seismic zones where moderate seismicity had previously been scarcely documented e g the po plain the central to southern apennines and the adriatic sea the complete dataset including previously determined rcmts and cmts represents the seismic deformation in the italian area during the last 25 years

a proposal for the kinematic modelling of w dipping subductions possible applications to the tyrrhenian apennines system in w dipping subduction zones there is a general eastward progression of the back arc basin accretionary wedge foredeep complex with the forward progression early stages of the complex are revealed by slices of upper crust and sedimentary cover abandoned to the west left floating above a new section of mantle a major shear zone should form at the new moho separating upper crust slices of earlier accretionary stages and the eastward flowing mantle the mantle wedging at the top of the subduction plane could be responsible for the uplift of the central parts of the belt the retreating of the subduction hinge is interpreted as due to the push generated by the eastward mantle flow detected in the hot spot reference frame the foredeep depth is mainly a function of the radius of curvature of the subduction hinge the frontal wedge is constructed from the stacking of the upper layers of the subducting plate and the syntectonic clastics that fill the foredeep which are progressively involved in thrusting and later by extension in order to preserve volume balance the lithosphere of the eastern plate before subduction has to be the same size as that which has been subducted due to the longer length of the arc with respect to the original length of the linear margin between the two converging plates laterally stretched subducted lithosphere is predicted at depth w dipping subductions usually have a short life probably due to their inherent capability to produce new lateral heterogeneities of the lithosphere the thin back arc which are a key factor in controlling and generating new subductions both e and w dipping this model is applied to the apennines tyrrhenian sea system

transtensional shear zones controlling volcanic eruptions the middle pleistocene mt amiata volcano inner northern apennines italy terra nova 00 1 10 2010 abstract the mt amiata volcano is characterized by the sw ne alignment of the eruption centres as well as other italian pleistocene volcanoes we carried out a structural and kinematic analysis in a broad stripe comprehending the eruption centres and the substratum towards ne and sw the results point out that a transtensional left lateral brittle shear zone affects the pre neogene substratum the middle pleistocene volcanic rocks and the late pleistocene travertines this transtensional structure is active since the early pliocene it controlled the location of the eruption centres through pull apart structures thus providing the deep structural channels for the uprising of magma to the surface the mt amiata volcano represents a key study area to investigate the pleistocene to present relationships between tectonics and magmatism in the tyrrhenian area

propagating versus nonpropagating madden julian oscillation events abstractbasinwide convective anomalies over the indian ocean io associated with the madden julian oscillation mjo sometimes propagate eastward and reach the west pacific wp but sometimes do not long term observations and reanalysis products are used to investigate the difference between the propagating and nonpropagating mjo events io convection onset events associated with the mjo are grouped into three categories based on the strengths of the simultaneous dry anomalies over the eastern maritime continent and wp the io convection anomaly preferentially makes eastward propagation and reaches the wp when the dry anomaly is stronger analysis of the column integrated moist static energy mse budget shows that horizontal advection moistens the atmosphere to the east of the positive mse anomaly associated with the active convection over the io and is of sufficient magnitude to explain the eastward propagation of the positive mse anomaly interpretation is complicated however by lack of closure in

the deep structure of the larderello travale geothermal field from 3d microearthquake traveltime tomography 1 with the aim of exploring the deep structure of the larderello travale lt geothermal field a high resolution 3 d tomographic inversion of microearthquake traveltimes has been performed results show that the deep part of the larderello travale field is characterized by the presence of a structure having a velocity range of 6 0 6 5 km s and a convex shape deepening towards the northeastern and the southeastern sides of the field earthquakes are mostly concentrated on the top of the high velocity structure and below the k horizon implying a transition of rheological properties at depth the reported dependence on time of ts tp observed at one station located above an earthquake cluster suggests that the variation in pore fluid pressure might be responsible for the transition of rheological properties along the contact in such an area changes in pore fluid pressure might be related to time dependent hydraulic mechanisms that are very effective in crustal rocks at elevated temperatures index terms 7215 seismology earthquake parameters 7280 seismology volcano seismology 8045 structural geology role of fluids 8180 tectonophysics tomography 8424 volcanology hydrothermal systems citation vanorio t r de matteis a zollo f batini a fiordelisi and b ciulli 2004 the deep structure of the larderello travale geothermal field from 3d microearthquake traveltime tomography geophys res lett 31 l07613

tertiary extensional tectonics in tuscany northern apennines italy abstract two extensional events have been recognized in the tertiary evolution of tuscany the first event occurred in the period between the late oligocene and late tortonian and caused a stretching of 120 or greater the second event occurred between the late tortonian and quaternary periods and caused a stretching not greater than 10 the first event is characterized by the exhumation of middle crust rocks and therefore by the development of core complexes the most significant structures of the first event are low angle normal faults which characterize the upper plate of the core complexes and ductile shear zones which characterize the lower plate the low angle normal faults tend to die out in the late triassic evaporite level which constitutes the main detachment of the core complexes the main structures of the second extensional event are high angle normal faults which dissect all the previous tectonic features these faults border tectonic depressions which were the site of clastic sedimentation from late tortonian to quaternary time these normal faults may tend to flatten in a seismic lozenge shaped band explained as an active extensional shear zone which is located at the brittle ductile boundary a similar explanation is given for the detachment located in the late triassic evaporite level during the first extensional event while the first extensional event is in the framework of the northern apennine post collisional evolution the second extensional event because it affects an already stretched crust could be attributed to the southern tyrrhenian opening which began during late tortonian

caldera structure amount of collapse and erupted volumes the case of bolsena caldera italy calderas are common on volcanoes but their structure is seldom visible the 19 km wide bolsena caldera italy formed between 0 6 and 0 2 ma the largely preserved structural rim and subsurface data make bolsena ideal to investigate caldera structure in relation to the subsidence and erupted volume in this paper we use remote sensing field analysis and available subsurface data at the surface the caldera passes from a downsag south rim to a narrow and densely faulted area north rim with outer normal and inner reverse faults the caldera structure on the widely faulted east rim appears to be scale dependent with a staircase like fault zone larger scale horst and graben like structures intermediate scale and domino like structures smaller scale subsurface data indicate asymmetric collapse with a northward increase in subsidence ranging from diffuse to the south to focused to the north deformation at the surface the collapse rate constant between ca 490 and 175 ka was more than magma output between ca 330 and 130 ka highlighting significant 200 m and prolonged 200 ka posteruptive subsidence as the nearby latera caldera west rim of bolsena was mostly active between ca 265 and 160 ka much of the subsidence at bolsena may be related to this activity suggesting a common magmatic reservoir the subsidence related structural variations along the caldera rim and the significant posteruptive subsidence found at bolsena have not been found in other calderas

extension and compression in the northern apennines italy hinterland evidence from the late miocene pliocene siena radicofani basin and relations with basement structures 1 the northern apennines na hinterland area is characterized by a complex neogene quaternary tectonics where both crustal extension associated with the tyrrhenian basin opening and crustal shortening in the onshore area took part in the deformation analysis of synorogenic deposits preserved in the nnw trending siena radicofani basin srb extending along a large part of the na hinterland documents the evolution of deformation of this sector during the last 9 ma information from subsurface geology deep seismic lines commercial seismic lines and deep wells surface geology mapping and structural analysis and from analogue modeling was integrated and used to infer the tectono sedimentary history of the srb and its relation with structures in the substratum as well as the possible implications for the evolution of the na hinterland the results we obtain indicate that the srb and the adjoining hinterland basins were bounded by thrust anticlines controlling basin development and deformation seismic lines across the srb display various examples of compressional structures affecting the basin fill and the substratum such as thrust anticlines and reverse faults notably these basin scale structures exhibit a good correlation with those observed in the field and are consistent with the kinematics of the outcrop scale compressional structures the thrust anticlines bounding the basins are often cored by triassic evaporites burano formation suggesting that this weak layer decoupling the sedimentary cover from the underlying crystalline basement controlled their evolution in this circumstance three series of scaled brittle ductile physical models have been used to investigate the development of a basement cover system with a decollement ductile layer at the base of the sedimentary cover these models simulate the evolution of the northern apennines hinterland where the basement is involved in the thrusting and the sedimentary cover is shortened above a basal ductile layer given by the burano formation longitudinal models cross sections display similar deformation patterns to those observed in the na hinterland such as characteristic wavelength of both basement and cover structures as well as detachment and fault propagation folding in the cover extensional tectonics is instead found to control sedimentation in the southern part of the srb at 8 ma or representing recent deformation the older extensional event is here related to the forelandward propagation of tyrrhenian related extension that could reactivate suitably oriented basement thrusts transfer zones produced a differential propagation of extension such that along strike sectors of the hinterland were eventually deformed by different stress fields analysis of the srb and of other adjoining basins reveals that the na hinterland experienced alternated periods of forward and backward migration of the compression extension transition in our interpretation the competition between extension and compression in the hinterland is related to the nnw directed africa pelagian indentation responsible for the lateral extrusion of the na and the contemporaneous opening of the tyrrhenian basin in the inner zone increased marginal loading at the foreland promoting reactivation of hinterland thrusts may have influenced this process as well

reduction of environmental risk from capable faults the case of the eastern etna region eastern sicily italy abstract on the eastern flank of etna volcano movements along the nnw sse trending normal faults of the timpe system generate recurrent low magnitude very shallow seismic events that induce noteworthy ground surface effects the timpe system is the on land extension of the hyblean malta fault system which is the likely source of the 1693 maw 7 4 earthquake frequent creep phenomena occur both associated with seismic events and or volcanic eruptions and independent from them these surface deformations are mainly confined in the eastern sector of the volcano apparatus and result from the interaction between regional tectonics and local volcano tectonic processes the widespread diffusion of cultural sites in this region even before the greek civilisation testifies to the complex relationship of humans with a restless violent nature many greek authors and myths refer to the frightening eruptions and earthquakes of etna but at the same time strabo underlines the extreme fertility of the land due to the volcanic ash and the quality of the local wine so notwithstanding the evident risk this region is one of the most densely inhabited regions of sicily coseismic surface ruptures and creep are responsible for damaging effects on buildings roads railways and lifelines including the water supply network to reduce the environmental risk from faulting apat italian agency for environment protection and for technical services has compiled a georeferenced database where capable faults extract from ithaca italy hazard from capable faults catalogue and water supply and other environmentally sensible networks are overlapped to pinpoint zones of expected damage this tool is fundamental in land planning and during an emergency as seen during the 2002 santa venerina earthquake when the environmental agency needed to quickly verify the integrity of the water distribution and sewage networks

contrasting characteristics between the northward and eastward propagation of the intraseasonal oscillation during the boreal summer abstract this study investigates the structural and evolutionary characteristics of the eastward and northward propagating intraseasonal oscillation iso in the indian ocean and western pacific during the boreal summer along the equator the near surface moisture convergence located to the east of the deep convection region appears to result in the eastward propagation of the iso consistent with the frictional wave cisk conditional instability of the second kind mechanism proposed in previous studies the eastward propagation is characterized by sequentially downstream development of deep convection occuring mainly in certain regions such as 60 95 120 and 145 e and the date line the northward propagation of deep convection can be attributed to the low level moisture convergence located to the north this convergence is a deep structure extending from the surface to the middle troposphere near surface convergence appears only after the systems approach the landmass in the north it is sugges

dynamic basis of volcanic spreading the established models of the structure and dynamics of a typical hawaiian volcano lead inevitably to a paradox finite element viscoelastic calculations using tecton melosh and raefsky 1980 1981 predict that a compressional stress field should characterize their upper flanks instead extension is observed the paradox is solved by postulating that volcanic evolution is determined by feedback processes related to growth and spreading of the volcanic edifice many examples of the process of spreading are documented in the geologic literature on volcanoes of a very broad size range and very different geologic settings the process is similar across many orders of magnitude in size the deformation of the substratum related to magma intrusion during lava dome building events is at the lower end of the scale the spreading of seafloor at oceanic ridges is at the higher end of the scale volcanoes may evolve from small constructs into huge shield volcanoes and perhaps into ocean plates key elements for volcanic spreading are 1 the existence of a weak basal layer and 2 a sufficiently high mass and magma influx to drive the process as the mass of a volcano grows it passes through five phases which may overlap repeat or be omitted building compressing thrusting intruding and spreading during the building phase the mass of a volcano does not significantly affect the stress field of the substratum primitive magmas are likely to be erupted as the mass increases the volcano subsides and becomes characterized by a compressional stress field which inhibits any further intrusion of magma into the volcanic edifice magma may differentiate in the crust allowing for large caldera forming eruptions to occur in the next phase thrusting begins on a decollement usually located at the foot of the edifice while the stress field on the upper slopes of the volcano remains compressional the stress at the base close to the center becomes extensional allowing the magma to intrude and differentiate at the base of the edifice a basal intrusive complex begins to grow explosive eruptions may be expected finally spreading of this complex creates an extensional stress field on the upper flanks of the volcano confining compression to the lower slopes of the edifice the extension allows primitive magma to erupt again at the summit the process of spreading seems to have a fundamental influence on the structural and magmatic evolution of volcanoes at every scale this process results from coupling and feedback between the gravitational and thermal fields thus studying this process may improve our understanding of the relation between structural dynamics and magma evolution and of the origin and evolution of volcanic seismicity and eruptions

structures and mechanisms of the northward propagating boreal summer intraseasonal oscillation abstract the spatial and temporal structures of the northward propagating boreal summer intraseasonal oscillation bsiso are revealed based on the analysis of both the echam4 model simulation and the ncep ncar reanalysis the bsiso structure and evolution characteristics simulated by the model bear many similarities to those derived from the ncep ncar reanalysis the most notable features are the remarkable meridional asymmetries relative to the bsiso convection in the vorticity and specific humidity fields a positive vorticity perturbation with an equivalent barotropic structure appears a few latitude degrees north of the convection center the maximum specific humidity also shows a clear northward shift in the lower troposphere two internal atmospheric dynamics mechanisms are proposed to understand the cause of the northward propagation of the bsiso the first is the vertical shear mechanism the key process associated with this mechanism is the generation of barotropic vorticity due to the couplin

the structure of the monte amiata volcano geothermal area northern apennines italy neogene quaternary compression versus extension the tectonic evolution of the mt amiata volcano geothermal area is under discussion some authors state that this region as well as the hinterland of the northern apennines were affected by compression from the cretaceous to the quaternary in contrast most authors believe that extension drove the tectonic evolution of the northern apennines from the early miocene to the quaternary field data seismic analyses and borehole logs have been integrated in order to better define the structural features of the continental crust in the mt amiata geothermal area in this paper i propose the hypothesis that the structure of the crust in the mt amiata volcano geothermal area derives from two main geological processes 1 contractional tectonics related to the stacking of the northern apennines cretaceous early miocene 2 subsequent extensional collapse of the hinterland of the mountain chain and related opening of the northern tyrrhenian sea early miocene quaternary compressional and extensional structures characterise the mt amiata region although extensional structures dominate its geological framework in particular the extension produced a middle late miocene boudinage of the previously stacked tectonic units b pliocene quaternary normal faulting which favoured the emplacement of a magmatic body in the middle upper crust and c the eruption of the mt amiata volcano which gave rise to an acid and intermediate volcanic complex 0 3 0 19 ma the extension produced the space necessary to accommodate the middle late miocene marine and continental sediments pliocene and quaternary normal and transtensional faults dissected the previous structures and influenced the early middle pliocene marine sedimentation within the structural depressions neighbouring the mt amiata volcano the magmatic body was emplaced at depth about 6 7 km during the pliocene extension and produced the eruption of the mt amiata volcano during the late pleistocene this gave rise to local uplift presently reaching about 3 000 m as well as a negative bouguer anomaly 16 mgal both centred on the mt amiata area the crustal dome shows a good correspondence with the convex shape of the regional seismic marker known as the k horizon which corresponds to the 450 c isotherm and the areas with greatest heat flow this is probably a consequence of the above cited magmatic body presently in the process of solidification a late pleistocene eruption occurred along a crustal fissure striking n50 mt amiata fault which crosscuts the crustal dome hydrothermal circulation proven by the occurrence of thermal springs and gas vents mainly co2 and h2s mainly occurs along the mt amiata fault both in the northeastern ans southwestern sides of the volcano

topographic effects on the eastward propagation and initiation of the madden julian oscillation abstract this study investigates the relationship between deep convection and heating anomaly in the madden julian oscillation mjo and the tropical topography the eastward propagation of the deep heating anomalies is confined to two regions the indian ocean and the western pacific warm pool superimposed on the eastward propagation is a series of quasi stationary deep heating anomalies that occur sequentially and discretely downstream in a leapfrog manner in the central indian ocean the maritime continent tropical south america and tropical africa the deep heating anomaly usually preceded by near surface moisture convergence and shallow heating anomalies tends to occur on the windward side of the tropical topography in these regions except the central indian ocean under the prevailing surface easterly anomaly of the mjo it is suggested that the lifting and frictional effects of the tropical topography and landmass induce the near surface moisture convergence anomaly which in turn triggers

geothermal problems in mountain ranges alps abstract an attempt has been made to model the temperature distribution taking into account simultaneously the effects of regional uplift and erosion present topography development of topography with time and paleoclimatic variations two time intervals were considered a long period 30 m y for the uplift history and a relatively short period 200 000 y for the surface history topography climate the calculations were based on finite differences in space and time an example is presented for an area in the swiss alps where observed rock temperatures in a tunnel and paleotemperature data are available a simple uplift history can fit the paleotemperatures but leads to unrealistic high temperatures in greater depths to improve the model frictional heat sources due to crustal overthrusting were introduced

tectonothermal processes and mechanical strength in a recent orogenic belt northern apennines 1 this paper investigates the seismic cutoff temperature at the maximum depth of seismicity across a young orogenic belt the northern apennines by attempting to take account of the different tectonothermal processes which have occurred in the region since the last 20 myr the analysis of seismicity over a period of 20 years 1981 2002 in combination with the thermal regime shows that the western part of the northern apennines peri tyrrhenian zone is characterized by extensional tectonics few earthquakes generally shallow and of low magnitude and high surface heat flux the entire crust of the eastern part of the orogenic belt external zone is affected by seismic activity of moderate magnitude and low heat flux earthquakes increase both in number and energy released in the inner portion of the belt internal zone where events with larger focal depth indicate subduction the cutoff potential temperature at the largest depth of seismicity is 550 c for the internal zone in the external zone of the orogen the temperature at the maximum depth of seismicity is about 550 c this result agrees with recent work on the thermal structure and seismicity of several continental areas the limiting temperature in the peri tyrrhenian zone can instead exceed 750 c a possible explanation is that the deepest earthquakes might be associated to magma movement the overall earthquake spatial distribution across the orogen appears related to the long term rheology which varies roughly in the same direction of tectonic transport of the chain this consistency appears also from the b value of the frequency magnitude relation which can be interpreted in relation to the rheological properties of the medium the b value seems to be inversely correlated to the expected mechanical strength of the crust and increases eastward in the direction of tectonic transport the largest number of shocks and magnitude of the internal zone happen where a sharp lateral change of strength should occur

convectively coupled equatorial waves 1 convectively coupled equatorial waves ccews control a substantial fraction of tropical rainfall variability their horizontal structures and dispersion characteristics correspond to matsuno s 1966 solutions of the shallow water equations on an equatorial beta plane namely kelvin equatorial rossby mixed rossby gravity and inertio gravity waves because of moist processes the tilted vertical structures of ccews are complex and their scales do not correspond to that expected from the linear theory of dry waves the dynamical structures and cloud morphology of ccews display a large degree of self similarity over a surprisingly wide range of scales with shallow convection at their leading edge followed by deep convection and then stratiform precipitation mirroring that of individual mesoscale convective complexes ccews have broad impacts within the tropics and their simulation in general circulation models is still problematic although progress has been made using simpler models a complete understanding of ccews remains a challenge in tropical meteorology

carbon dioxide degassing and thermal energy release in the monte amiata volcanic geothermal area italy abstract the quaternary volcanic complex of mount amiata is located in southern tuscany italy and represents the most recent manifestation of the tuscan magmatic province the region is characterised by a large thermal anomaly and by the presence of numerous co2 rich gas emissions and geothermal features mainly located at the periphery of the volcanic complex two geothermal systems are located at increasing depths in the carbonate and metamorphic formations beneath the volcanic complex the shallow volcanic aquifer is separated from the deep geothermal systems by a low permeability unit ligurian unit a measured co2 discharge through soils of 1 8 109 mol a 1 shows that large amounts of co2 move from the deep reservoir to the surface a large range in 13ctdic 21 07 to 3 65 characterises the waters circulating in the aquifers of the region and the mass and isotopic balance of tdic allows distinguishing a discharge of 0 3 109 mol a 1 of deeply sourced co2 in spring waters the total natural co2 discharge 2 1 109 mol a 1 is slightly less than minimum co2 output estimated by an indirect method 2 8 109 mol a 1 but present day release of 5 8 109 mol a 1 co2 from deep geothermal wells may have reduced natural co2 discharge the heat transported by groundwater computed considering the increase in temperature from the infiltration area to the discharge from springs is of the same order of magnitude or higher than the regional conductive heat flow 200 mw m 2 and reaches extremely high values up to 2700 mw m 2 in the north eastern part of the study area heat transfer occurs mainly by conductive heating in the volcanic aquifer and by uprising gas and vapor along fault zones and in those areas where low permeability cover is lacking the comparison of co2 flux heat flow and geological setting shows that near surface geology and hydrogeological setting play a central role in determining co2 degassing and heat transfer patterns

late quaternary sea level changes along the tyrrhenian coast near orbetello tuscany central italy palaeoenvironmental reconstruction using ostracods abstract a multidisciplinary study has been carried out on a 51 m long core drilled on coastal lowlands near the albegna river tuscany central italy both sedimentological and faunal analyses ostracods and molluscs indicate a coastal lagoon environment repeatedly influenced both by the rising holocene sea and the albegna river alluvial inflow 13c 18o mg ca sr ca and 87sr 86sr analyses were performed on cyprideis torosa shells in order to detail the influence of albegna river freshwater on the coastal lagoon water the analytical data illustrate the difficulties of using geochemical proxies in marginal marine settings four radiocarbon dates provide a chronostratigraphy for the early holocene part of the core the data are used to reconstruct late pleistocene to early holocene palaeoenvironments along this part of the coast and show the development of freshwater environments followed by a coastal brackish lagoon formed in response to the initial holocene rapid rise in relative sea level an attempt is made to relate sediments and age data from the core to the relative sea level curve for the tyrrhenian sea

new gps constraints on the kinematics of the apennines subduction abstract we present the velocity field of the italian area derived from continuous gps observations from 2003 to 2007 the gps sites were installed by different institutions and for different purposes they cover the whole country with a mean inter site distance of about 60 km and provide a valuable source of data to map the present day kinematics of the region the absolute itrf2005 rotation poles and rates of eurasia africa and adriatic plates are estimated to study the kinematics along their boundaries in the apennines belt the corsica sardinia block coherently moving as the eurasia plate is used as reference of the upper plate for the apennines subduction zone we apply a simple kinematic model to estimate the rates and spatial pattern of the subduction along the apennines we identify at least four different independently moving lower plates i e the adriatic diverging and internally segmented ionian sicily and africa converging plates with different subduction rates the conservative estimates of the subduction rate are 5 mm yr in the calabrian arc 1 5 mm yr in sicily and 0 9 mm yr in the northern apennines this variegate mixture of behaviors seems to reflect the variable lithospheric thickness and composition of the lower plates inherited from the mesozoic rifting an unexpected along strike contraction is observed along the western side of the central northern apennines velocities are estimated both relative to eurasia and relative to the deep and shallow hotspot reference frames hsrf the hotspot representation seems more coherent with the geophysical and geological constraints along the subduction system in which the adriatic and ionian plates move sw ward and their deeper slab portions provide an obstacle to the opposite relative mantle flow all these patterns better reconcile if the subduction process is conceived as a passive feature controlled by the far field plate velocities and the relative eastward mantle flow acting on a disrupted slab

highly extended terrains lateral segmentation of the substratum and basin development the middle late miocene radicondoli basin inner northern apennines italy 1 this paper deals with the evolution of sedimentary basins not delimited by normal faults with a substratum characterized by an upward concave shape and with infilling sediments synclinally deformed we describe the middle late miocene radicondoli basin representing an example of such bowl shaped basins its tectonic origin is controversial being related both to compression and extension these opposite interpretations bear significant consequences on the geodynamic context in which the inner northern apennines developed during the middle late miocene the results of our structural studies carried out in the substratum and infilling sediments indicate that the radicondoli basin is an example of a hanging wall basin developed in an extensional setting extensional tectonics determined the lateral segmentation of the substratum competent levels i e tuscan nappe and verrucano group and the consequent collapse of overlying less competent levels i e the ligurian units with the formation of a bowl shaped tectonic depression here the syntectonic sediments serravallian late messinian are deformed in a large syncline characterized by minor gravity driven folds with vergences toward the depocenter and traces of their axial planes parallel to the basin margins this paper highlights the role of the competence contrast during the postcollisional tectonic evolution and the influence of substratum lateral segmentation for the accommodation of syntectonic sediments

deformation of the 125 ka marine terrace in italy tectonic implications in peninsular italy marine terraces and shorelines created during oxygenisotope substage 5e known historically as the tyrrhenian highstand provide a reliable and homogeneous datum of vertical motions during the past 125 000 years published accounts of 121 locations on the tyrrhenian inner edge were reinterpreted and used to calculate both local and regional uplift rates the data show arching of southern italy between the tyrrhenian and the adriatic coasts and of the calabrian arc between the sangineto and the longi taormina tectonic lineaments at rates of up to 1 2 mm yr for the past 125 ka they also suggest that the present configuration of the southern apennines is the product of post early pleistocene regional uplift superimposed on tortonian to early pleistocene thrusting uplift patterns are characterised by different wavelength in different geodynamic settings suggesting a close link with the depth of the causative tectonic sources

coastal deformation between the versilia and the garigliano plains italy since the last interglacial stage the opening of the north central tyrrhenian sea is the result of the cretaceous paleogene alpine collision which triggered a series of regional uplift subsidence and transcurrent tectonic mechanisms along the coastal tyrrhenian sectors of peninsular italy these tectonic pro cesses in conjunction with the effects of glacio and hydro isostasy during the quaternary produced substantial crustal responses that in some cases reached metres in extent in the study of coastal neotectonics geomorphological markers of the last interglacial maximum corresponding to marine isotope stage 5 5 are generally used to quantify the magnitude of the vertical crustal displacements that have occurred since 125 kyr through altimetrical palaeoenvironmental and chronological reinterpretation of the most significant works published since 1913 combined with an additional set of data reported here a detailed reconstruction of the shoreline displacements evident along 500 km of coast between northern tuscany and southern latium is presented the reconstruction was carried out by quantifying the vertical movement since the last interglacial period and by identifying the tectonic behaviour of different coastal sectors this has been done by carefully choosing the eustatic marker among those available at each study site in order to minimize the margin of error associated with the measurements copyright 2003 john wiley sons ltd

topographic influence on the mjo in the maritime continent abstract this study demonstrates that during the passage of the mjo through the maritime continent in the boreal winter the corresponding deep convection and near surface wind anomalies tend to skirt around mountainous islands flow bifurcation around elongated mountainous islands such as new guinea is clearly seen topographic blocking generates distinctive vorticity and convergence distributions in this specific domain mountain wave like structures are also observed throughout the maritime continent with a clear spatial relationship with the high terrains in sumatra sulawesi and new guinea the existence of topography seems to create extra lifting and sinking within the large scale circulation and thus the convective system exhibits quasi stationary features near the major topography during the mjo passage through the maritime continent it is suggested that resolving the detailed topographic effects may play a key role in simulating realistic characteristics of the mjo in the maritime continent

why does the mjo detour the maritime continent during austral summer eastward propagation of the madden julian oscillation mjo detours the maritime continent mc region southward during austral summer exhibiting enhanced convective activity preferentially in the southern part of the mc area with much weaker anomalies in the central mc area column integrated moist static energy budget of the mjo is analyzed to understand the processes responsible for the mjo detouring results show that zonal and meridional moisture advection is the essential process to the mjo detouring causing the difference between the southern and central mc regions in the moisture recharge before and during the mjo onset further analysis reveals that moisture advection by mjo perturbation winds acting upon the background moisture gradient has the dominant contribution to the regional contrast between the central and southern mc areas the zonal moisture advection is greater in the southern mc region because the zonal gradient of the background moisture field is much steeper in the southern mc area than in the central mc area the onset of the australian monsoon in austral summer contributes to the establishment of the sharp zonal moisture gradient in the southern mc region the meridional moisture advection is weaker in the central mc area because meridional wind anomalies associated with the mjo vary regionally presumably through interactions with the topography and land sea contrast

key processes for the eastward propagation of the madden julian oscillation based on multimodel simulations as a prominent climate variability mode with widespread influences on global weather extremes the madden julian oscillation mjo remains poorly represented in the latest generation of general circulation models gcms with a particular challenge in simulating its eastward propagating convective signals in this study by analyzing multi model simulations from a recent global mjo model evaluation project an effort is made to identify key processes for the eastward propagation of the mjo through analyses of moisture entropy me processes under a moisture mode framework for the mjo the column integrated horizontal me advection is found to play a critical role for the eastward propagation of the mjo in both observations and good mjo models with a primary contribution through advection of the lower tropospheric seasonal mean me by the mjo anomalous circulations by contrast the horizontal me advection effect for the eastward propagation is greatly underestimated in poor mjo gcms due to model deficiencies in simulating both the seasonal mean me pattern and mjo circulations leading to a largely stationary mjo mode in these gcms these results thus pinpoint an important guidance towards improved representation of the mjo in climate and weather forecast models while this study mainly focuses on fundamental physics for the mjo propagation over the indian ocean complex influences by the maritime continent on the mjo and also me processes associated with the mjo over the western pacific warrant further investigations

neogene and quaternary rollback evolution of the tyrrhenian sea the apennines and the sicilian maghrebides reconstruction of the evolution of the tyrrhenian sea shows that the major stage of rifting associated with the opening of this basin began at similar to10 ma it involved two episodes of back arc extension which were induced by the rollback of a west dipping subducting slab the first period of extension 10 6 ma was prominent in the northern tyrrhenian sea and in the western part of the southern tyrrhenian sea the second period of extension mainly affected the southern tyrrhenian sea began in the latest messinian 6 5 ma and has been accompanied by subduction rollback at rates of 60 100 km myr 1 slab reconstruction combined with paleomagnetic and paleogeographic constraints indicates that in the central apennines the latest messinian 6 5 ma arrival of a carbonate platform at the subduction zone impeded subduction and initiated a slab tear and major strike slip faults these processes resulted in the formation of a narrow subducting slab beneath the ionian sea that has undergone faster subduction rollback and induced extreme rates of back arc extension

tectonic control on travertine and calcareous tufa deposition in a low temperature geothermal system sarteano central italy this paper presents an integrated study directed toward an understanding of the tectonic control on the hydrothermal circulation and resulting deposition of middle late pleistocene travertine in a low temperature geothermal field of southern tuscany located in the sarteano area central italy the study area is characterized by thermal springs c 25 c and related continental carbonate deposits structurally controlled by sw ne trending oblique to strike slip faults dissecting previous normal faults sedimentological stratigraphical data and 230 th 234 u radiometric age determination for the travertine indicate that continental carbonates were deposited in a tectonically controlled perched spring system from 268 22 ka at least to the present the hydrothermal system is and was characterized by meteoric waters with a minor contribution from fluids of deeper origin meteoric waters infiltrated to depth through tectonically damaged zones of mesozoic and cenozoic carbonate rocks and overheated as a result of localized anomalous geothermal gradient then fluids enriched in bicarbonate sulphate moved up along highly fractured rock masses at the intersection between strike slip faults and normal faults this paper highlights the use of continental carbonates in the reconstruction of palaeohydrothermal systems in terms of the location of the main conduits for hydrothermal fluid flow age of faulting and physical properties of hydrothermal fluids

heat flow deep temperatures and extensional structures in the larderello geothermal field italy constraints on geothermal fluid flow the larderello geothermal field is located in the inner northern apennines southern tuscany an area which has been affected by extensional tectonics since the early middle miocene the structure of the larderello field is characterised by nw trending ne dipping pliocene to present normal faults their geometry down to depths of 4 5 km is constrained by field borehole and reflection seismic data an association between extensional structures and heat flow maxima up to 1000 mw m2 is recognisable from detailed surface heat flow mapping in order to investigate the relationships among extensional structures and heat flow subsurface isotherms were traced subject to borehole control along variously oriented geological cross sections the isotherms show vertical displacements associated with the recent normal faults and related deformation zones which reach the brittle ductile transition estimates of the relative importance of convective and conductive components of heat flow suggest that fluid circulation is particularly important in correspondence with the normal faults accounting for the correlation between isotherm perturbations and extensional structures in this view extensional shear zones are interpreted as the main structural pathways for the flow of hot geothermal fluids

subcrustal earthquakes in the northern apennines italy evidence for a still active subduction previously unreported subcrustal earthquakes have been located up to 90 km depth beneath the northern apennines italy these earthquakes occur beneath a zone of abundant upper crustal seismicity mostly confined to the upper 20 km of the crust although there are relatively few well located subcrustal earthquakes there appears to be a general southwestward deepening of the hypocenters from the adriatic to the tyrrhenian sea consistent with other geophysical data which suggest that the adriatic lithosphere is presently subducting beneath the northern apennines

active oblique extension in the central apennines italy evidence from the fucino region the fucino basin is a flat quaternary depression within the central apennines it is surrounded by active normal faults with small oblique slip components surface faulting was observed along the east side of the basin during the ms 7 0 avezzano earthquake of 1915 in order to understand the kinematics of recent strain better and to assess the seismic hazard of this region we carried out a detailed geomorphic and structural study of the faults around the basin fault scarp heights were accurately measured with total station profiles and vertical slip rates were estimated assuming slope offsets to post date the end of periglacial abrasion 14 4 kyr bp to the north the most prominent fault the magnola fault appears to have an average postglacial throw rate of 0 7 0 3 mm yr 1 and together with the velino fault to be capable of generating earthquakes of maximum magnitudes of 6 9 7 3 with recurrence intervals of 1000 3000 yr east of the basin the serrone parasano and ventrino faults form a right stepping horsetail of the giovenco fault current vertical slip rates on the three former faults appear to be between 0 5 and 1 4 0 5 and 1 0 and 0 3 and 1 1 mm yr 1 respectively infrequent maximum magnitude earthquakes on them may also exceed 7 particularly in the case of coupled rupture with loosely constrained recurrence intervals up to several thousand years the right lateral slip components implied by the most recent slickensides and by geomorphic offsets on the nw se trending normal faults of the area suggest that the blocks they bound rotate counterclockwise consistent with oblique left slip on the nnw sse trending giovenco and ovindoli faults to the east sinistral shear parallel to the latter faults the maximum relief across the magnola fault and the postglacial slope offsets measured suggest that the extension rate across the central apennines might be of the order of 6 3 mm yr 1 in a n20 10 e direction more northerly than hitherto inferred

anatomy of an unstable volcano from insar multiple processes affecting flank instability at mt etna 1994 2008 1 volcano deformation may occur under different conditions to understand how a volcano deforms as well as relations with magmatic activity we studied mt etna in detail using interferometric synthetic aperture radar insar data from 1994 to 2008 from 1994 to 2000 the volcano inflated with a linear behavior the inflation was accompanied by eastward and westward slip on the eastern and western flanks respectively the portions proximal to the summit showed higher inflation rates whereas the distal portions showed several sectors bounded by faults in some cases behaving as rigid blocks from 2000 to 2003 the deformation became nonlinear especially on the proximal eastern and western flanks showing marked eastward and westward displacements respectively this behavior resulted from the deformation induced by the emplacement of feeder dikes during the 2001 and 2002 2003 eruptions from 2003 to 2008 the deformation approached linearity again even though the overall pattern continued to be influenced by the emplacement of the dikes from 2001 to 2002 the eastward velocity on the eastern flank showed a marked asymmetry between the faster sectors to the north and those largely inactive to the south in addition from 1994 to 2008 part of the volcano base south west and north lower slopes experienced a consistent trend of uplift on the order of 0 5 cm yr this study reveals that the flanks of etna have undergone a complex instability resulting from three main processes in the long term 103 104 years the load of the volcano is responsible for the development of a peripheral bulge in the intermediate term 101 years observed from 1994 to 2000 inflation due to the accumulation of magma induces a moderate and linear uplift and outward slip of the flanks in the short term 1 year observed from 2001 to 2002 the emplacement of feeder dikes along the ne and south rifts results in a nonlinear focused and asymmetric deformation on the eastern and western flanks deformation due to flank instability is widespread at mt etna regardless of volcanic activity and remains by far the predominant type of deformation on the volcano

earthquake hazard and the environmental seismic intensity esi scale the main objective of this paper was to introduce the environmental seismic intensity scale esi a new scale developed and tested by an interdisciplinary group of scientists geologists geophysicists and seismologists in the frame of the international union for quaternary research inqua activities to the widest community of earth scientists and engineers dealing with seismic hazard assessment this scale defines earthquake intensity by taking into consideration the occurrence size and areal distribution of earthquake environmental effects eee including surface faulting tectonic uplift and subsidence landslides rock falls liquefaction ground collapse and tsunami waves indeed eees can significantly improve the evaluation of seismic intensity which still remains a critical parameter for a realistic seismic hazard assessment allowing to compare historical and modern earthquakes moreover as shown by recent moderate to large earthquakes geological effects often cause severe damage therefore their consideration in the earthquake risk scenario is crucial for all stakeholders especially urban planners geotechnical and structural engineers hazard analysts civil protection agencies and insurance companies the paper describes background and construction principles of the scale and presents some case studies in different continents and tectonic settings to illustrate its relevant benefits esi is normally used together with traditional intensity scales which unfortunately tend to saturate in the highest degrees in this case and in unpopulated areas esi offers a unique way for assessing a reliable earthquake intensity finally yet importantly the esi scale also provides a very convenient guideline for the survey of eees in earthquake stricken areas ensuring they are catalogued in a complete and homogeneous manner

barrier effect of the indo pacific maritime continent on mjo propagation in observations and cmip5 models abstractthis study explores possible mechanisms for the barrier effect of the indo pacific maritime continent mc on mjo propagation in particular this study examines whether similar mechanisms