correlation of fluvial sequences in the mediterranean basin over the last 200 ka and their relationship to climate change macklin mark fuller i c lewin j maas g a 2002 correlation of fluvial sequences in the mediterranean basin over the last 200 ka and their relationship to climate change quaternary science reviews 21 14 15 pp 1633 1641 rae2008

lower crustal erosion induced by mantle diapiric upwelling constraints from sedimentary basin formation followed by voluminous basalt volcanism in northwest kyushu japan abstract a sequence of geological events beginning with basement subsidence to form a shallow water sedimentary basin and subsequent voluminous basalt volcanism and uplift of land has been observed in the back arc region of northwestern kyushu japan the basin consists of a succession of marine and non marine sediments with a total thickness of 1000 1500 m which range in age from 43 to 10 ma the basalt volcanism commenced at 10 ma and continued until 1 ma uplift started at around 30 ma and continued after the cessation of the basalt volcanism these geological phenomena may be explained by the convective coupling between the ductile lower crust and upper mantle induced by mantle diapiric upwelling thus surface subsidence leading to sedimentary basin formation is attributed to lower crustal erosion by mantle diapiric upwelling for an earth model with lower crustal and upper mantle viscosities of 10 19 10 20 pa s 5 km of lower crust can be eroded 10 20 myr after the start of convective coupling between the ductile lower crust and upper mantle compatible with the period estimated by observations in this process the melt due to adiabatic mantle diapiric upwelling accumulates beneath the lower crust the accumulation of low density melt in the space originally occupied by mantle material causes crustal uplift when the stress state became extensional as inferred from the extension of okinawa trough during the middle to late miocene 1 the melt filling the eroded lower crustal area may have reached the surface leading to voluminous basalt volcanism

a recent tectonic reorganization in the south central mediterranean abstract new geodetic data combined with seismicity geologic and geochemical information document a major tectonic reorganization in the central mediterranean around 0 8 0 5 ma when rapid trench migration and consequent tyrrhenian back arc extension which dominated the region s evolution since the tortonian 10 8 ma essentially stopped in response the african convergence in sicily was transferred to a back thrust in the southern tyrrhenian characterized by frequent m5 6 earthquakes in the last 20 years a diffuse transform boundary formed across northeastern sicily to connect the sicilian and calabrian plate boundaries causing opening of the messina straits home to large historical earthquakes and unusual volcanism in the aeolian island arc and the intraplate mount etna a divergence of the ionian region from the main part of africa with northeastward motions that reflect the joint influence of african push and hellenic slab pull and are transmitted to calabria and adria could explain motions observed in the sicily channel calabria and apulia as well as the high level of southeastern sicilian seismic activity

evidence for high velocity in koyna seismic zone from p wave teleseismic imaging three dimensional p wave velocity structure of the crust and upper most mantle beneath the koyna seismic zone ksz was determined by inverting 780 p wave teleseismic travel times recorded by a 20 station digital network the velocity image obtained through damped least square was tested for its resolution using checkerboard approach the results of the inversion show strong lateral velocity variations of 6 to 7 within the study region a high velocity anomaly 2 to 5 in the upper and lower crust beneath the ksz is flanked by lower velocity 2 to 5 anomalies on either side the correlation of high velocity with the seismic zone suggests that the earthquakes are occurring in more rigid rocks with increasing ability to store strain energy and release it as brittle failure

geohazards monitoring in roma from insar and in situ data outcomes of the pangeo project within the pangeo project financed by the european commission under the 7th framework program the geological survey of italy ispra and the urban planning department of the city of roma developed a geodatabase and map of the geological hazards for the territory of roma integrating remotely sensed data psinsar permanent scatterer interferometry synthetic aperture radar and in situ geological information numerous thematic layers maps and inventories of hazards e g landslides sinkholes cavities geological and hydrogeological data added to historical and recent urbanization information were compared to the permanent scatterer ps data from the european remote sensing satellites ers 1 2 1992 2000 and envisat 2002 2005 descending scenes in order to produce a ground stability layer gsl based on the ps data most of the territory appears stable almost 70 of ps velocities are within 1 mm year about 14 of the pss show positive line of sight los velocities measured along the los of the satellite between 1 and 3 mm year and more than 2 exceed 3 mm year more than 11 of pss show negative los velocities between 1 and 3 mm year while about 3 exceed 3 mm year with tens of the pss showing velocities over 20 mm year the gsl is comprised of polygons or multi polygons multipart polygons grouping individual polygons under a single identifier geohazard enclosing areas where geohazards have been pointed out by ps data and or in situ surveys observed instabilities and by polygons enclosing areas potentially affected by geohazards based on the available knowledge of the territory potential instabilities in roma s gsl 18 multi polygons covering ca 600 km2 related to observed instabilities have been outlined where ground movements could be detected through insar data or where landslides and sinkholes are known to have occurred other 13 multi polygons covering nearly 900 km2 concern areas where the potential occurrence of geohazards was inferred by combining geological and or geothematic data potential instabilities the geohazards mapped in roma have been landslides collapsible grounds compressible grounds groundwater abstraction mining man made ground tectonic movements and volcanic inflation deflation the lattermost is the likely cause of the significant uplift observed in the alban hills area however this paper focuses on two more currently impending hazards subsidence and sinkholes in general sinkhole prone areas areas of dense underground cavities are hard to discern from satellite data but can be revealed by ruling out other potential causes of observed ground movement based on in situ data subsiding zones are effectively detected by the available psinsar dataset over a total extent of about 60 km2 mostly overlapping the recent alluvial areas of the tiber and its tributaries pss show a very different behaviour inside and outside the historical centre inside loading by anthropogenic construction and man made ground since ancient times has led to an almost complete consolidation of the recent river deposits marked by modest to absent subsidence in contrast outside subsidence clearly stands out with negative los velocities that although generally within several mm year can locally exceed 25 mm year ps data have provided motion information at both a regional and local scale up to the scale of a single building closer to the sea in the tiber delta area velocities increase especially above recently reclaimed marsh areas rich in peat and organic clays velocities can change significantly over short distances as in the international airport area reflecting the local stratigraphic setting the same occurs in the two subsiding areas located within the alban hills volcanic complex which is generally affected by ground uplift as a whole psinsar ground motion velocities offer a significant contribution to susceptibility and hazard recognition studies in particular such a method provides a fast and effective tool available to local authorities to monitor ground and building behaviour possibly allowing for timely prevention activities especially when coupled with appropriate in situ knowledge

effect of asperity order on the shear response of three dimensional joints by focusing on damage area the shear resistance of rock joints has always been of paramount importance in stability analysis of surface and underground rock structures many parameters influence the shear strength of rock joints among which surface asperity is highly crucial that has encouraged many researchers to work on among the pioneers working on the subject patton 1 was the first researcher who systematically studied the effect of joint asperity using simple physical models with two dimensional toothshaped asperity patton proposed the following bilinear shear strength criterion

insolation values for the climate of the last 10 million years new values for the astronomical parameters of the earth s orbit and rotation eccentricity obliquity and precession are proposed for paleoclimatic research related to the late miocene the pliocene and the quaternary they have been obtained from a numerical solution of the lagrangian system of the planetary point masses and from an analytical solution of the poisson equations of the earth moon system the analytical expansion allows the direct determination of the main frequencies with their phase and amplitude numerical and analytical comparisons with the former astronomical solution ber78 are performed so that the accuracy and the interval of time over which the new solution is valid can be estimated the corresponding insolation values have also been computed this analysis leads to the conclusion that the new values are expected to be reliable over the last 5 ma in the time domain and at least over the last 10 ma in the frequency domain

a revision of the 1693 eastern sicily earthquake and tsunami the 1693 earthquake was a disastrous event affecting eastern sicily southern italy where it caused over 60 000 victims and total destruction of several villages and towns in the districts of siracusa ragusa and catania the earthquake was followed by a tsunami that struck the ionian coasts of sicily and the messina strait and was probably observed even in the aeolian islands historical documents on sea waves and flooding though not abundant allow us to form a picture of the tsunami first attack and inundation the first water movement all along the sicilian coastline was a strong sea withdrawal followed by a violent sea return and coastal flooding the main purpose of this research is to put constraints on the focal mechanism of this earthquake on the basis of the available documents on the tsunami 1 by simulating tsunami from different possible sources via numerical modeling based on finite element technique and shallow water approximation and 2 by choosing the source best fitting the tsunami data as the most plausible cause for this tsunami the relevance of this study should also be evaluated in light of the circumstance that no certain indication on the earthquake fault can be deduced from the available macroseismic data alone solving the source problem for this event one of the largest occurring in southeastern sicily in historical times is a significant contribution to understanding the seismotectonic regime of the region and to assessing the related earthquake and tsunami hazard risk with implications on mitigation policies

late quaternary slip rates on the acireale piedimonte normal faults and tectonic origin of mt etna sicily abstract mt etna is located along the east coast of sicily near the boundary between the continental crust of the hyblean plateau and the mesozoic oceanic crust of the ionian basin the main active faults near mt etna cut the base of its eastern flank forming a 30 km long system of nne and nnw trending ene chelon fault segments the acireale piedimonte system showing dip slip and oblique right lateral motion most segments are associated with shallow depth seismicity and all have late pleistocene to holocene vertical slip rates ranging between 1 and 2 mm yr typical of major active normal faults worldwide eruptive fissures arranged in nne to ne trending zones cut the highest slopes of the volcano on the footwall of the normal fault system structural analysis suggests that current motions along both the active faults and eruptive fissures are kinematically compatible and simply linked with ongoing wnw ese directed regional extension such extension characterizes at a greater scale the active tectonics of southern italy where all large shallow historical earthquakes have remained confined within a narrow normal fault belt or rift zone stretching from the northern calabrian arc to southeastern sicily the southernmost west dipping faults of that rift zone in calabria aspromonte cut across the calabro peloritan thrust belt to join the mostly east dipping acireale piedimonte faults along the western boundary of ionian oceanic lithosphere which continues southwards as the malta escarpment we thus relate magmatism at etna to dilational strain on the footwall of an east facing crustal scale normal fault at the bend where the siculo calabrian rift zone veers 60 eastwards as it begins to cross the calabrian arc leaving the east facing margin of the ionian sea to catch up with the west facing margin of the tyrrhenian sea farther north

seismic imaging crustal stress and gps data analyses implications for the generation of the 2008 wenchuan earthquake m7 9 china abstract seismic imaging together with global positioning system gps and crustal stress data analyses show that the mw7 9 2008 wenchuan earthquake occurred within a distinct area of high crustal stress 17 5 mpa and high poisson s ratio 7 10 anomalies centered on the longmen shan shan means mountain in chinese tectonic fault belt low p wave and s wave velocities in the southwest sw segment contrast with high velocity anomalies in the central portion cp and northeast ne segment within the uppermost 15 km depths along the tectonic fault belt though a presumably ductile zone with low velocity anomalies separates the cp and ne segment the rupture initiated near the southwestern end of the cp at a zone of high poisson s ratio which extends down into the lower crust these low velocity and high anomalies immediately below the source hypocenter together with the high crustal stress indicate the presence of high pressure fluids from the lower crust which might have reduced the mechanical strength of the fractured rock matrix and triggered the earthquake our study suggests that the structural heterogeneity and high crustal stress played an important role in the nucleation of the wenchuan earthquake and its rupture process

suboceanic earthquake location and seismic structure in the kanto district central japan abstract we present a combined method using sp depth phase data and double difference arrival times to determine the precise hypocenter locations of earthquakes that occur under the pacific ocean outside of the area covered by the land based seismic network we assess the effectiveness of the combined method using a data set of p and s wave arrival times and sp depth phase from suboceanic earthquakes recorded by both land based seismic stations and offshore seismic stations ofs the hypocenters of the offshore earthquakes relocated using the combined method are consistent with those determined using the standard location method and ofs data the differences in the hypocenters relocated by the two methods are less than 4 km we applied the method to the subduction region that underlies the kanto district central japan and located a large number of earthquakes that occurred beneath the pacific ocean we then determined the detailed 3d seismic velocity structure by inverting a large number of arrival times of p and s waves and sp depth phase from the relocated earthquakes in the study region high velocity anomalies related to the cold subducting pacific slab and low velocity anomalies related to the hot mantle wedge are clearly imaged beneath active volcanoes low velocity zones are visible from the surface to a depth of 100 km reflecting fluids released by dehydration of the subducting pacific slab strong lateral heterogeneities are revealed on the upper boundary of the pacific slab beneath the forearc region the low velocity areas under the offshore region are associated with low seismicity and weak interplate coupling a low velocity layer is imaged along the upper boundary of the philippine sea slab in the northern part of kanto district which may reflect dehydration of the slab our tomographic images indicate that the overlaying philippine sea plate has effects on the spatial distribution of active volcanoes related to the subducting pacific slab in the study region

variations of seismic velocities in the kachchh rift zone gujarat india during 2001 2013 abstract we herein study variations of seismic velocities in the main rupture zone mrz of the mw 7 7 2001 bhuj earthquake for the time periods 2001 05 2006 08 2009 10 and 2011 13 by constructing dvp dvs and d vp vs tomograms using high quality arrival times of 28 902 p and 28 696 s waves from 4644 precise jhd joint hypocentral determination relocations of local events differential tomograms for 2001 05 reveal a marked decrease in seismic velocities low dvp low dvs and high d vp vs in the mrz at 5 35 km depths during 2001 10 which is attributed to an increase in crack fracture density higher pore fluid pressure resulted from the intense fracturing that occurred during the mainshock and post seismic periods while we observe a slight recovery or increase in seismic velocities 2011 13 this could be related to the healing process lower pore fluid pressure due to sealing of cracks of the causative fault zone of the 2001 bhuj mainshock the temporal reduction in seismic velocities is observed to be higher at deeper levels more fluid enrichment under near lithostatic pressure than that at shallower levels fluid source for low velocity zone lvz at 0 10 km depths with high d vp vs could be attributed to the presence of meteoric water or soft alluvium sediments with higher water content while fluid source for lvz at 10 35 km depths could be due to the presence of brine fluids released from the metamorphic dewatering and volatile co2 emanating from the crystallization of carbonatite melts in the asthenosphere in fractures and pores we also imaged two prominent lvzs associated with the katrol hill fault zone and island belt fault zone extending from shallow upper crust to sub crustal depth which might be facilitating the deeper circulation of metamorphic fluids volatile co2 thereby the generation of lower crustal earthquakes occurring in the kachchh rift zone

geochemical investigation of a sediment core from the trajan basin at portus the harbor of ancient rome a journal published by elsevier the attached copy is furnished to the author for internal non commercial research and education use including for instruction at the authors institution and sharing with colleagues other uses including reproduction and distribution or selling or licensing copies or posting to personal institutional or third party websites are prohibited in most cases authors are permitted to post their version of the article e g in word or tex form to their personal website or institutional repository authors requiring further information regarding elsevier s archiving and manuscript policies are encouraged to visit a b s t r a c t from the 1st century ad and for the duration of the roman empire the portus complex was the main harbor of rome its location on the tiber delta next to the tyrrhenian sea produced rapid environmental changes that together with historical vicissitudes largely determined the fate of the harbor we have assembled data on the mineralogy sedimentology geochemistry and ostracod populations of a sediment core drilled in the access channel of the hexagonal basin of trajan with the expectation that such a combined data set will shed new light on how the connections of the inland trajan basin with the tiber river the earlier claudius harbor on the nearby shoreline and the sea evolved through the centuries the data define four distinct periods which geochemistry characterizes by different conditions of salinity and oxygenation these in turn can be related to historical periods and events by means of 14

holocene evolution and sea level changes in the battaglia basin area eastern gargano coast apulia italy abstract the battaglia basin east gargano southern italy is a former waterbody represented as a lake on historical maps the detailed study of two cores bat1 and bat2 and additional information obtained from several other drill holes allowed reconstruction of the holocene evolution of the basin the earlier phases date back to before 7000 cal bp when a high energy beach developed around 6900 cal bp a shallow freshwater body was established before 5950 cal bp sea water flooded the area initially creating a sheltered bay followed by the hydrobiidae and abra segmentum lagoon around 2700 cal bp freshwater conditions were re established the battaglia basin phase lasted until recent times paleoenvironmental information in combination with 14c dating made possible the reconstruction of a local holocene relative sea level curve showing a continuous rise interrupted around 2730 yr bp by an abrupt drop after that sea level started again to rise this evolutionary pattern rise fast drop rise matches results obtained in other apulian areas although it has not been ascertained that the holocene battaglia evolution has been driven by tectonic movements considering the historical gargano activity the tectonic hypothesis looks reasonable

seismic evidence for the influence of fluids on the 2005 west off fukuoka prefecture earthquake in southwest japan abstract high resolution 3 d seismic velocity vp and vs and poisson s ratio structures in the epicentral area of the 2005 west off fukuoka prefecture earthquake were determined by inverting a large number of high quality p and s wave arrival times and sp depth phase data to better understand the genesis of the main shock and its aftershock sequence the hypocenters of the earthquakes used in this study were relocated with a combined method which enables to accurately relocate the earthquakes occurred outside the seismic network by using sp depth phase data together with double difference travel time data this new approach of earthquake location can be applied to other offshore regions of subduction zones where few seismic stations exist while numerous suboceanic earthquakes occur strong crustal velocity heterogeneities were revealed in the hypocentral area which might reflect the existence of fluids geometrical irregularities of the fault zone and geothermal anomalies in the region the main shock hypocenter was located near a distinct zone characterized by low velocity high poisson s ratio and high conductivity anomalies being considered to be associated with the existence of fluids in and around the source area such fluids might have reduced the seismic velocity of the crustal materials around the main shock hypocenter and weakened the mechanic strength of the fractured rock matrix in the source area and thus triggered the 2005 west off fukuoka prefecture earthquake

long term behaviour of the late quaternary normal faults in the straits of messina area calabrian arc structural and morphological constraints abstract the calabrian arc is located in the peri tyrrhenian orogenic belt of southern italy and is characterised by intense post collision dynamics this consists of rapid regional uplifting combined with active normal faulting affecting the tyrrhenian side of calabria and the ionian coast of sicily the siculo calabrian rift zone the effects of the two combined processes are well exposed in the straits of messina area that represent a major transfer zone located between two opposing sets of normal faults characterising the southern calabria and the northeastern sicily branches of the rift in the straits of messina region the distribution and elevation of the upper quaternary marine terraces suggest a southward propagation of the normal fault belt from calabria to sicily it occurred at about 125 ka after a long period of tectonic quiescence and was triggered by huge elastic releases in southern calabria the long term behaviour recorded on the distinct fault segments of the rift is to relate to the presence of a crustal barrier that influenced both the geometry and the fault propagation along the rift zone

elevation of the last interglacial highstand in sicily italy a benchmark of coastal tectonics well preserved mis 5 5 terraces in sicily are identified primarily by the index fossil strombus bubonius and dated by amino acid racemization aar electron spin resonance esr uranium thorium u th and thermo luminescence tl methods this review of published data and new results for the island of sicily and neighbouring small islands of egadi ustica and lampedusa identifies areas of rapid uplift in the east up to 175 m elevation above sea level slower uplift in the north 29 m and relative stability in the northwest 2 18 m in contrast about 250 km of the southern coastline of sicily does not appear to contain mis 5 5 outcrops in eastern sicily correlation of mis 5 5 highstands is based on strombus bubonius discovered at 86 m and correlated with the inner margin terrace at 110 m in the taormina area a fossiliferous marine conglomerate on a terrace with an inner margin at 115 m occurs in an area with undated terrace morphology and elevation data based on esr methodology applied to fossils sampled at 105 m in taormina we attribute this terrace to mis 5 probably 5 5 this age allows us to constrain the date of one point along a very long coastline that is otherwise undated a newly discovered fossil beach between 7 and 9 m at cefalu north central sicily attributed to mis 5 1 5 3 using aar analysis permits correlation of mis 5 5 to a 29 m high tidal notch geomorphologically related to a terrace at the same elevation cefalu lies in an important position between the uplifted coastline of northeastern sicily and the more stable coastline of western sicily this compilation of mis 5 5 data for all of sicily reflects the active tectonics of eastern sicily in contrast to the rest of the island

new insights into the generation of the 2013 lushan earthquake ms 7 0 china global seismic waveform inversion can provide information on where the 2013 ms 7 0 lushan earthquake occurred in sichuan province china and how its aftershock sequence expanded to investigate the generation mechanism of the lushan earthquake and its relation to the 2008 wenchuan earthquake ms 8 0 50 temporary seismic stations were installed in the source area following the lushan earthquake crustal stress data were also collected along the longmen shan fault zone lmfz to reveal its influence on the generation of the lushan earthquake seismic imaging and crustal stress analysis have revealed that the lushan earthquake occurred in a distinct area with high velocity vp vs low poisson s ratio and high crustal stress the high velocity zone at the lushan source may reflect precambrian metasedimentary or igneous rock in the seismogenic layer which enables the accumulation of high crustal stress to generate large earthquakes however a sharply contrasting gap zone with low velocity high anomalies is clearly imaged in the upper crust under the concatenated area between the lushan and wenchuan earthquakes seismic images indicate that the low velocity gap zone is associated with fluid bearing ductile flow from the lower crustal materials of tibet being pushed into a weakened segment of the lmfz this study suggests that the 2013 lushan earthquake may have been triggered by high crustal stress accumulation together with high coseismic stress further increased by the wenchuan earthquake in the metamafic seismogenic layer contrasting rheological variations in the crust and crustal stress changes along the lmfz control the rupture processes that generated the lushan and wenchuan earthquakes as well as the generation of new earthquakes in the future

the use of scenarios to evaluate the tsunami impact in southern italy this paper outlines the main contributions to the definition and evaluation of tsunami hazard and risk resulting from studies undertaken in italy in recent years and emphasises that adopting characteristic cases or scenarios is a very useful and advantageous technique three main cases are given as valuable examples that is the 1627 gargano tsunami the 1693 eastern sicily tsunami and the 1908 messina straits tsunami since 1 they characterise three distinct tsunamigenic regions 2 they are instances of destructive events and 3 they have been extensively studied in the last decade the paper elucidates the state of the art of the research on these events clarifies the chief points of agreement and disagreement among scientists and illustrates the main issues that are to be addressed by future research to provide reliable assessment of tsunami risk and to implement efficient countermeasures to defend the life of people coastal structures and the coastal environment against the attacks of tsunamis

influence of fluids and magma on earthquakes seismological evidence abstract in this paper we present seismological evidence for the influence of fluids and magma on the generation of large earthquakes in the crust and the subducting oceanic slabs under the japan islands the relationship between seismic tomography and large crustal earthquakes m 5 7 8 0 in japan during a period of 116 years from 1885 to 2000 is investigated and it is found that most of the large crustal earthquakes occurred in or around the areas of low seismic velocity the low velocity zones represent weak sections of the seismogenic crust the crustal weakening is closely related to the subduction process in this region along the volcanic front and in back arc areas the crustal weakening is caused by active volcanoes and arc magma resulting from the convective circulation process in the mantle wedge and dehydration reactions in the subducting slab in the forearc region of southwest japan fluids are suggested in the 1995 kobe earthquake source zone which have contributed to the rupture nucleation the fluids originate from the dehydration of the subducting philippine sea slab the recent 2001 geiyo earthquake m 6 8 occurred at 50 km depth within the subducting philippine sea slab and it was also related to the slab dehydration process a detailed 3d velocity structure is determined for the northeast japan forearc region using data from 598 earthquakes that occurred under the pacific ocean with hypocenters well located with sp depth phases the results show that strong lateral heterogeneities exist along the slab boundary which represent asperities and results of slab dehydration and affect the degree and extent of the interplate seismic coupling these results indicate that large earthquakes do not strike anywhere but only anomalous areas which can be detected with geophysical methods the generation of a large earthquake is not a pure mechanical process but is closely related to physical and chemical properties of materials in the crust and upper mantle such as magma fluids etc

submerged archaeological sites along the ionian coast of southeastern sicily italy and implications for the holocene relative sea level change abstract precise measurements of submerged archaeological markers in the siracusa coast southeastern sicily italy provide new data on relative sea level change during the late holocene four submerged archaeological sites have been studied and investigated through direct observations two of them are greek archaic in age 2 5 2 7 ka and are now 0 98 1 48 m below sea level the other two developed during the bronze age 3 2 3 8 ka and are now 1 03 1 97 m below sea level these archaeological data have been integrated with information derived from a submerged speleothem collected in a cave located along the siracusa coast at 20 m depth the positions of the archaeological markers have been measured with respect to present sea level corrected for tide and pressure at the time of surveys these data were compared with predicted sea level rise curves for the holocene using a glacio hydro isostatic model the comparison with the curve for the southeastern sicily coast yields a tectonic component of relative sea level change related to regional uplift uplift rates between 0 3 and 0 8 mm yr have been estimated

seismic imaging of the 2001 bhuj mw7 7 earthquake source zone b value fractal dimension and seismic velocity tomography studies abstract we use precisely located aftershocks of the 2001 mw7 7 bhuj earthquake 2001 2009 to explore the structure of the kachchh seismic zone by mapping the 3 d distributions of b value fractal dimension d and seismic velocities from frequency magnitude analysis we find that the catalog is complete above mw 3 0 thus we analyze 2159 aftershocks with mw 3 0 to estimate the 3 d distribution of b value and fractal dimensions using maximum likelihood and spatial correlation dimension approaches respectively our results show an area of high b d and vp vs ratio values at 15 35 km depth in the main rupture zone mrz while relatively low b and d values characterize the surrounding rigid regions and gedi fault gf zone we propose that higher material heterogeneities in the vicinity of the mrz and or circulation of deep aqueous fluid volatile co2 is the main cause of the increased b d and vp vs ratio values at 15 35 km depth seismic velocity images also show some low velocity zones continuing in to the deep lower crust supporting the existence of circulation of deep aqueous fluid volatile co2 in the region probably released from the eclogitasation of olivine rich lower crustal rocks the presence of number of high and low velocity patches further reveals the heterogeneous and fractured nature of the mrz interestingly we observe that aki 1981 s relation d 2b is not valid for the spatial b d correlation of the events in the gf d2 1 2b zone however the events in the mrz d2 1 7b show a fair agreement with the d 2b relationship while the earthquakes associated with the remaining parts of the aftershock zone d2 1 95b show a strong correlation with the aki 1981 s relationship thus we infer that the remaining parts of the aftershock zone are probably behaving like locked un ruptured zones where larger stresses accumulate we also propose that deep fluid involvement may play a key role in generating seismic activity in the mrz therefore a similar episode of deep fluid inflow could play a crucial role in causing the next strong earthquakes in the surrounding blocks of nwf

the contribution of geochemistry to ancient harbor geoarcheology the example of ostia antica abstract once trapped in ancient harbor basins sediments form environmental archives that have been widely studied by geoarcheologists in recent decades especially to help reconstruct fluvio marine landscapes of the last millennia in some cases classic environmental markers cannot be used for this purpose either because of their scarcity in the sedimentary deposits or because analytical costs limit the resolution that can be achieved in order to remedy these shortcomings and to complement the more commonly used proxies elemental and isotopic geochemistry has been added to the geoarcheological toolkit here we show how to read the evolution of the paleo environmental dynamics in the water column of ostia antica rome s first maritime harbor using the geochemical and isotopic record of a 3000 year old sediment core drilled in the ancient harbor basin a comparison of the results obtained from ostia antica with those of other ancient mediterranean harbors reveals the nature of the main environmental processes operating during the formation of sedimentary deposits in harbor basins from this comparative approach it appears that the respective weight of each control factor is dependent on the coastal geomorphological context of the sites where the harbors were established since the discovery of the harbor of ostia antica in 2014 this method has provided the means for the first time to identify two distinct harbor basin regimes an initial marine dominated regime from the middle of the 4th c bc to the 3rd c bc and a later freshwater dominated regime up to the 2nd c bc more generally we observe the effects of the dynamics of the deltaic progradation of the tiber which very early on was subject to a hydro climatic component on the processes of alluviation of the harbor basin additionally and also for the first time in harbor geoarcheology pb isotope compositions measured specifically on uncontaminated sediments demonstrate their utility for both identifying the geological sources of the sediments of the tiber delta and discriminating finer from larger particles the present study further provides an opportunity to test the validity of two hypotheses recently put forward 1 that a series of three tsunamis is recorded in the harbor silts and 2 that an initial lagoon type harbor was constructed at ostia antica which later evolved into a fluvial harbor neither of these hypotheses are supported by the present data

dendropoma lower intertidal reef formations and their palaeoclimatological significance nw sicily abstract most carbonate rocky shores of nw sicily are marked by a coalescence of shells of the gastropod dendropoma in a construction that is variably developed as a response to wave impact here we review all the available information on these constructions and find that the fossil reefs are reliable sea level indicators the thickness of the reef samples never exceeds 30 40 cm below sea level whereas all 14 c dates fall within a range of few centuries some small fragments ejected by violent sea storms date back to 2500 years cal bp no samples older than 6200 years cal bp have been detected so far the present distribution of mediterranean vermetid platforms should result from a northward migration related to the long term effect of the holocene sea surface temperature sst warming some consideration on the morphology of the reefs and the comparison with the available data point out that dendropoma reefs are excellent biological indicators of sea level fluctuations especially when detected and sampled in tectonically stable areas as those in nw sicily

sedimentary and tectonic evolution of the eastern hyblean plateau southeastern sicily during late cretaceous to quaternary time abstract two palaeogeographic domains have been distinguished in the cretaceous quaternary sequences which crop out in the hyblean region of southeastern sicily in the northeast shallow water algal bryozoan calcarenites of oligocene miocene age overlie either cretaceous rudist limestones or volcanics further to the northeast the stratigraphic gap increases as the miocene limestone thins and in the a g i p well catania 10 plio pleistocene sediments and volcanics directly overlie upper jurassic rocks in the southwestern part of the hyblean plateau pelagic sediments occupy the cretaceous miocene interval they were deposited in a shallow basin dipping gently towards the southwest the transition between the two zones is marked by much evidence of synsedimentary tectonic activity such as widespread slumping and the development of megabreccias composed of cretaceous and eocene blocks the palaeogeographic picture is one of carbonate reefs and volcanic seamounts developing in the upper cretaceous they formed platforms fault bounded to the west and southwest from which were derived the detrital sediments found in the basin and occasional spectacular gravity slides in present day terms the structural high probably corresponds to the northeastern margin of the hyblean plateau and in part to the siracusa syracuse malta escarpment the pattern is little changed in the upper miocene with volcanoclastics of phreatomagmatic origin intercalated with coral bioherms overlying algal bryozoan calcarenites upper tortonian lower messinian limestones with a restricted fauna indicate a shallow water environment which grades up into continental conditions in the eastern hyblean plateau the tertiary sequence is capped by pliocene submarine to subaerial mafic lava flows lower pleistocene sediments consist of biocalcarenites and clays which fill deep graben delimited by plio pleistocene faults the inshore continuation of the malta syracuse escarpment system of faults from a tectonic standpoint the hyblean region a gently deformed segment of the african continental margin acted as a foreland during tertiary times a cretaceous eocene tectonic phase was responsible for the palaeogeographic pattern which existed during most of the cenozoic the present pattern is the result of three main tectonic phases following the regional upper miocene uplift of early middle pliocene plio pleistocene and middle pleistocene recent age which influenced the tectonic evolution of the present ionian coast and the malta syracuse escarpment

from river to shelf anatomy of a high frequency depositional sequence the late pleistocene to holocene tiber depositional sequence the late pleistocene holocene tiber delta succession represents the most recent and one of the best preserved high frequency low rank depositional sequences developed along the latium continental margin of the italian peninsula several previous studies have established a robust data set from which it has been possible to describe the stratigraphic architecture of the entire tiber depositional sequence from the landward to seaward sectors and over a distance of 60 km the tiber depositional sequence shows many characteristics found in other late pleistocene to holocene deltaic and coastal successions of the mediterranean area the stratigraphic architecture of the tiber depositional sequence is controlled mainly by glacioeustasy although factors such as tectonic uplift volcanism and subsidence exert an influence at a local scale the resulting depositional model allowed discussion of some important points such as 1 the genesis of the tiber mixed bedrock alluvial valley extending from the coastal plain to the innermost portion of the shelf recording i multiple episodes of incision during relative sea level fall and ii a downstream increase of depth and width of the valley during the base level fall and the subsequent base level rise 2 the different physical expression of the tiber depositional sequence boundary from landward to seaward and its diachronous and composite character 3 the maximum depth reached by the tiber early lowstand delta at the end of the sea level fall is estimated at ca 90 m below the present sea level and not at 120 m as suggested by previous works 4 the backward position of the tiber late lowstand delta relative to the deposit of early lowstand 5 the change of the channel pattern and of the stacking pattern of fluvial deposits within the lowstand systems tract transgressive systems tract and highstand systems tract all of these features indicate that the late pleistocene holocene tiber delta succession even if deposited in a short period of time from a geological point of view represents the result of the close interaction among many autogenic and allogenic factors however global eustatic variations and sediment supply under the control of climatic changes can be considered the main factors responsible for the stratigraphic architecture of this sedimentary succession which has been heavily modified by human activity only in the last 3000 years

the motion of crustal blocks driven by flow of the lower lithosphere and implications for slip rates of continental strike slip faults geodetic measurements in actively deforming areas of the continents reveal the pattern of deformation in the lithosphere if the dominant forces acting on crustal blocks are tractions at their bases then the long term motion of each block will be given by the average velocity of the underlying lithosphere slip rates between blocks estimated in this way from recent geodetic measurements across fault zones in the south island of new zealand and southern california are in good agreement with slip rates estimated geologically

late holocene alluvial events in the central apennines italy a stratigraphic sequence wasidentified inthegransassomassif central apennines italy consisting ofalluvial sediments andburied soils thesoils dated bytheradiocarbon method enabled various alluvial phases that haveoccurred inthelast 2500years tobechronologically framed these phases werethencorrelated withthefrequency ofthetiber floods atromeandwiththeprogradation ofits delta thephases ofsoil burial byalluvial sediments coincide withtheperiods ofintense flooding ofthetiber at rome between thesecond century bc andthesecond century ad between thesixth andtheninth centuries ad andbetween thefifteenth andthenineteenth centuries ad andwithperiods ofstrong progradation oftheriver delta onthebasis ofthechronological correlation between alluvial phases glacial variations andoscillations inthelevels oflakesfucino andtrasimeno itwasthenpossible to establish that corresponding tothealluvial phases thehydrological balance ofthelakes waspositive and intwoofthethree cases theincreased flood frequency coincided withthephases ofadvance oftheonly glacier located intheapennines

a 125 kyr long geological record of seismic source repeatability the messina straits southern italy and the 1908 earthquake ms7 2 the occurrence of characteristic earthquakes along segments of major active belts has been described as early as the beginning of the century the large 1908 messina straits blind normal faulting earthquake provides an opportunity to investigate the repetition of characteristic earthquakes and the persistency of the main features of the fault zone over a time scale in the order of 100 kyr we have compared seismological and geodetic descriptions of the 1908 rupture process with long term crustal deformation recorded at different stratigraphic levels by marine terraces marine sedimentary units and landscape features the wealth of elevated coastal features in and around a region affected by large normal faulting earthquakes indicates that coseismic strain is superimposed on much faster uplift on a regional scale we investigated in detail the pattern of deformation of the 125 kyr old lowest emergent terrace and found that it mimics the pattern of elevation changes observed following the earthquake this suggests 1 that the 1908 earthquake is characteristic 2 that its segment boundaries have been stationary during the past 125 kyr and 3 that even the locations of the regions of largest coseismic release do not change through many seismic cycles based on a comparison between observed heights of the 125 kyr terrace and 1908 displacements we estimated an average repeat time of 1000 yr for a 1908 type earthquake we also investigated the height position age and state of deformation of older terraces and found 1 that uplift of the region started about 1 ma and has since continued rather uniformly at 0 9 1 4 mm yr 1 2 that during this time the straits have narrowed at a rate of 10 20 mm yr 1 and 3 that all the main geomorphic features of the messina straits result from the interaction of fast regional uplift 1908 type coseismic subsidence and global sea level fluctuations

close range terrestrial digital photogrammetry and terrestrial laser scanning for discontinuity characterization on rock cuts this paper reviews the application of close range terrestrial digital photogrammetry and terrestrial laser scanning for discontinuity characterization on rock cuts terrestrial remote sensing techniques are being increasingly used as a complement to traditional scanline and window mapping methods they provide more comprehensive information on rock cuts allow surveying of inaccessible outcrops and increase user safety selected case studies are used to estimate the accuracy of several 3d model registration approaches and the most time effort and cost effective methods are highlighted it is shown that simple registration networks are able to provide adequate measurement of discontinuity orientation for engineering purposes the case studies presented also illustrate the effects of sampling bias and limitations related to discontinuity characterization using remote sensing techniques vertical orientation bias and occlusion can be of particular concern when persistent discontinuities dip at the same angle as the camera scanner line of sight major advantages of the techniques are presented illustrating how terrestrial remote sensing techniques provide rapid spatial measurements of discontinuity location orientation and curvature and are well suited to the quantification of persistence magnitudes greater than 3 m

tiber delta co2 ch4 degassing a possible hybrid tectonically active sediment hosted geothermal system near rome fiumicino town in the tiber river delta near rome international airport italy is historically affected by large amounts of carbon dioxide co2 in the ground and gas eruptions triggered by shallow drilling while it is known that co2 originates from carbonate thermometamorphism and or mantle degassing the origin of methane ch4 associated with co2 is uncertain and the outgassing spatial distribution is unknown combining isotope gas geochemistry soil gas and structural stratigraphic analyses we provide evidence for a hybrid fluid source system classifiable as sediment hosted geothermal system shgs where biotic ch4 from sedimentary rocks is carried by deep geothermic co2 through active segments of a half graben molecular and isotopic composition of ch4 and concentration of heavier alkanes ethane and propane obtained from gas vents and soil gas throughout the delta area reveal that thermogenic ch4 up to 3 7 vol in soil gas 13cch4 37 to 40 vpdb vienna peedee belemnite and 2hch4 162 to 203 vsmow vienna standard mean ocean water in gas vents prevails over possible microbial and abiotic components the hydrocarbons likely result from known meso cenozoic petroleum systems of the latium tyrrhenian coast overmaturation of source rocks or molecular fractionation induced by gas migration are likely responsible for increased c1 c2 ratios co2 and ch4 soil gas anomalies are scattered along nw se and w e alignments which based on borehole geomorphologic and structural stratigraphic analyses coincide with active faults of a half graben that seems to have controlled the recent evolution of the tiber delta this shgs can be a source of considerable greenhouse gas emissions to the atmosphere and hazards for humans and buildings

resistivity structure of a seismic gap along the atotsugawa fault japan abstract seismicity along the atotsugawa fault located in central japan shows a clear heterogeneity the central segment of the fault with low seismicity is recognized as a seismic gap although a lot of micro earthquakes occur along this fault in order to elucidate the cause of the heterogeneity in seismicity the electrical resistivity structure was investigated around the atotsugawa fault by using the magnetotelluric mt method the regional geoelectrical strikes are approximately parallel to the fault in a low frequency range we constructed two dimensional resistivity models across the fault using tm mode mt responses to minimize three dimensional effects on the modeling process a smooth inversion algorithm was used and the static shifts on the apparent resistivity were corrected in the inversion process a shallow low resistivity zone along the fault is found from the surface to a depth of 1 2 km in the best fit model across the high seismicity segment of the fault on the other hand the corresponding low resistivity zone along the low seismicity segment is limited to a shallower depth less than 1 km the low resistivity zone along the atotsugawa fault is possibly due to fluid in the fracture zone the segment with higher levels of seismicity may have higher fluid content in the fault zone compared with the lower seismicity segment on a view of the crustal structure a lateral resistivity variation in a depth range of 3 12 km is found below the fault trace in the high seismicity segment while a resistive layer of wide extent is found at a depth of about 5 km below the fault trace in the low seismicity segment the resistive layer is explained by less fluid condition and possibly characterized as high rigidity differences in the resistivity structures between low and high seismicity segments of the fault suggest that the seismic gap in the central part of the atotsugawa fault may be interpreted as a locked segment thus mt is an effective method in evaluating a cause and future activity of seismic gaps along active faults the lower crust appears as a conductive zone beneath the low seismicity segment less conductive beneath the high seismicity segment fluid is inferred as a preferable cause of the conductive zone in this study it is suggested that the conductive lower crust beneath the low seismicity segment is recognized where fluid is trapped by an impermeable layer in the upper crust on the other hand fluid in the lower crust may upwell to the surface along the high seismicity segment of the fault

structural heterogeneity in northeast japan and its implications for the genesis of the 2004 and 2007 niigata earthquakes abstract we utilized 188 766 p wave and 179 328 s wave high quality arrival time data from 14 666 local earthquakes to determine the three dimensional 3d seismic velocity v p v s v p v s ratio crack density e and bulk velocity v structures in and around the source areas of the 2004 and 2007 niigata earthquakes japan meteorological agency magnitude m j 6 8 in japan in order to understand the generation mechanisms of the niigata mainshocks the aftershock hypocenters were relocated by applying the double difference location method simultaneously with the tomographic inversion indicating a complicated fault system that includes not only two parallel dominant faults dipping to the northeast but also some conjugate faults crossing the niigata mainshock hypocenters in general high velocity v p v s with low e at 11 km depth is visible in the southeastern part of this area in contrast to anomalous low velocity with high crack density in the northwestern part along the niigata kobe tectonic zone nktz these characteristics of the velocity and crack density are consistent with the spatial distribution of active faults along the nktz the surface geological features that indurated pre neogene rock outcrops were observed in the southeastern area whereas deep sedimentary basins were observed on the opposite side low v p and low v s zones with high v p v s anomalies were imaged in and or under the source areas showing agreement with those revealed by previous studies all the features of the velocity and v p v s structures together with the images of the crack density and bulk velocity suggest the presence of fluids under the source areas such fluids might have weakened the mechanical strength of the fault zone of the source areas thus triggering the 2004 and 2007 niigata earthquakes our present study together with other recent tomographic images reveals that fluids penetrated into the source rocks from the lower crust and uppermost mantle as a result of dehydration of the subducting pacific slab and thus may play a key role in the genesis of these large crustal earthquakes

multicentury glacier fluctuations in the swiss alps during the holocene subfossil remains of wood and peat from six swiss glaciers found in proglacial fluvial sediments indicate that glaciers were smaller than the 1985 reference level and climatic conditions allowed vegetation growth in now glaciated basins an extended data set of swiss glacier recessions consisting of 143 radiocarbon dates is presented to improve the chronology of glacier fluctuations a comparison with other archives and dated glacier advances suggests 12 major recession periods occurring at 9850 9600 93008650 85508050 77007550 74506550 61505950 57005500 52004400 43003400 28002700 21501850 14001200 cal yr bp it is proposed that major glacier fluctuations occurred on a multicentennial scale with a changing pattern during the course of the holocene after the younger dryas glaciers receded to a smaller extent and prolonged recessions occurred repeatedly culminating around 7 cal kyr bp after a transition around 6 cal kyr bp weak fluctuations around the present level dominated after 3 6 cal kyr bp less frequent recessions interrupted the trend to advanced glaciers peaking with the prominent little ice age this trend is in line with a continuous decrease of summer insolation during the holocene

a new spectral analysis method for determining the joint roughness coefficient of rock joints abstract we propose a new spectral analysis method for accurate jrc determination to do this we first propose an average power index pf to present the amplitude height of a rock joint profile which considers both the low and high frequency components of the profile secondly the modified root mean square of the first deviation of the profile z 2 is adopted to better capture the effects of shear direction and the inclination angle of the profile on the rock joint s roughness finally we propose a new roughness parameter pz which combines the pf and the z 2 the pz considers the shear direction the inclination angle and the amplitude height of a rock joint profile simultaneously we derived correlations with upper suggested and lower bounds between jrc and pz using 102 rock joint profiles at the sampling interval of 0 4 mm and compared them with barton s 10 standard rock joint profiles we analyzed five sandstone joints from the field to validate the proposed method both laser scanning and direct shear tests were conducted on the sandstone joints comparing the peak shear strength obtained from experimental tests the proposed method and the z2 method verified that the proposed method can determine the jrc accurately in addition the shear direction influence and sampling interval effect on the rock joint roughness were discussed the correlations between jrc and pz were also derived at the sampling intervals of 0 8 mm and 1 2 mm

the sediments of the stagno di maccarese marsh tiber river delta central italy a late holocene record of natural and human induced environmental changes the environmental evolution inferred from the sedimentary sequence that has occurred during the last three millennia in a drained coastal marsh in the tiber delta is presented the stratigraphy o

the plant landscape of the imperial harbour of rome abstract the research concerns the tiber delta area about 3 km far from the present seacoast where the remains of the ancient harbour of rome are located in 42 ad claudius started the construction of the harbour and nero completed it in 64 ad then the emperor trajan went on to add a hexagonal basin to the former structure which had gradually silted up the imperial harbour was connected to the tiber river and ultimately to the city of rome through the trajan channel during the imperial period most of the supplies imported from the mediterranean provinces reached the city of rome through portus this study applies detailed pollen microcharcoal and ostracod analyses together with radiocarbon dating to the sediments recovered from two cores drilled in the area of the claudius harbour the objective of the drillings was to identify morphological and environmental features of the tiber delta dating back to the roman period and to characterize the landscape of the harbour the chronological framing of the records is based on stratigraphical criteria radiocarbon dates historical data and on the typology of pottery fragments pollen plant macroremains and ostracod assemblages indicate that the two cores record different periods of time the dock core shows the first phases of the harbour activities recording first a marine and then a brackish environment the plant landscape is typical of a coastal environment and appears rather preserved the human presence is clear but not of great impact the channel core records mainly a brackish water environment and a strong human impact related to the presence of portus the port town anthropic indicators such as cultivated and synanthropic taxa as well as strong fire use occurrence are evidence of a high human pressure increasing in the first centuries ad

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

glacier and lake level variations in west central europe over the last 3500 years on the basis of glacier and lake level records this paper attempts for the first time a comparison between high resolution palaeohydrological and palaeoglaciological data in west central europe over the past 3500 years a data set of tree ring width radiocarbon and archaeological data in addition to historical sources were used to reconstruct fluctuations of the great aletsch the gorner and the lower grindelwald glaciers in the swiss alps the three ice streams experienced nearly synchronous advances at c 1000 600 bc and ad 500 600 800 900 1100 1200 and 1300 1860 these glacier fluctuations show strong correspondence with lake level variations reconstructed in eastern france jura mountains and pre alps and on the swiss plateau this supports the hypothesis of climatically driven fluctuations historical data available for the period since ad 1550 reveal in detail various meteorological conditions behind the successive glacier advances however in agreement with the general trend shown by th

seismic images under the beijing region inferred from p and pmp data abstract in this study a new tomographic method is applied to over 1500 high quality pmp moho reflected wave travel time data as well as over 38 500 high quality first p wave arrivals to determine a detailed 3d crustal velocity structure under beijing and adjacent areas results of detailed resolution analyses show that the pmp data can significantly improve the resolution of the model in the middle and lower crust after the pmp data are included in the tomographic inversion our new model not only displays the tectonic feature appeared in the previous studies but also reveals some new features the zhangjiakou bohai sea fault zone zhang bo zone is imaged as prominent and continuous low velocity low v anomalies in the shallower crust while in the middle and lower crust it shows intermittent low v anomalies extending down to the uppermost mantle furthermore the pattern of low v anomalies is different along the zhang bo zone from the southeast to the northwest indicating that there exist large differences in the dynamic evolution of taihangshan and yanshan uplifts and north china depression basin prominent low v anomalies are visible under the source area of the 4 july 2006 wen an earthquake m 5 1 suggesting that the occurrence of the wen an earthquake is possibly related to the effect of the crustal fluids probably caused by the upwelling of the hot and wet asthenospheric materials due to the deep dehydration of the stagnant pacific slab in the mantle transition zone the fluids in the lower crust may cause the weakening of the seismogenic layer in the upper and middle crust and thus contribute to the initiation of the wen an earthquake this is somewhat similar to the cause of the 1695 sanhe pinggu earthquake and the 1976 tangshan earthquake in the region as well as the 1995 kobe earthquake in japan and the 2001 bhuj earthquake in india

fault activity and marine terracing in the capo vaticano area southern calabria during the middle late quaternary abstract the capo vaticano peninsula is a structural high bordered by several normal fault segments mainly striking ne sw and wnw ese and belonging to the so called siculo calabrian rift zone both the two fault systems extend in the tyrrhenian offshore and show recent activity in the capo vaticano peninsula six orders of marine terraces with their preserved paleoshorelines and a top surface have been recognised they form a continuous set of morphological elements ascribed to the last seven principal high stands of the eustatic curve occurred from 330 to 60 kyr on the basis of new chronological data available in the recent literature the morphotectonic analysis of the paleoshorelines allowed recognition of a deformation pattern characterised by a northeastward tilting of the area and to quantify the uplift rates moreover vertical slip rates ranging between 0 25 and 2 5 mm yr have been calculated for a wnw ese trending fault segment the coccorino fault in this structural framework the late quaternary uplift of the capo vaticano peninsula can be related to the activity of both the ne sw and wnw ese striking normal fault systems added to the regional component of uplift the recent activity of these structures is also suggested by the 1905 seismic event that occurred offshore of the capo vaticano peninsula

roots of etna volcano in faults of great earthquakes abstract results from several seismic methods allow us to sketch the deep structure of etna and its ionian margin under etna a volume of high velocity material is found in a structurally high position the emplacement of this suggests spreading of the surrounding medium just offshore down to the east normal faults penetrate through the upper crust the deeper crustal structure beneath appears upwarped from the basin towards etna juxtaposed with the crust of sicily a thinner crust reaches from the ionian basin under etna and the mantle is upwarped in such a structure magma can then be viewed as a melted lens capping a mantle upwarp at shallow depth rather than in an intracrustal chamber this reduces the conflict between estimates of its volume from excess output of volatiles and short residence times a link in time is indicated between volcanic and seismic activity at a large scale over the millennium the reported ends of episodes of high output rates of magma are followed by the reported occurrences of magnitude 7 earthquakes which caused destruction in southeastern sicily several steep active normal fault have been imaged to a depth of 10 km the crust up to 30 km offshore of the cities of catania and augusta which may be fault planes for such large earthquakes they expand and prolongate the system of the timpe faults on the eastern flank of etna thus linking large scale tectonics offshore with the volcano etna developed together with normal faulting upwarp and spreading during the recent evolution of the former ionian subduction activation of the material at depth at the lateral edge of the slab by vertical motion with extension above could produce the peculiar type of etna magmatism

coarse sediments in northern apennine peat bogs and lakes new data for the record of holocene alluvial phases in peninsular italy this research was conducted in the northern apennines in the upper valleys of the cedra river and parma river occupied by glaciers during the last glacial maximum the stratigraphy the dating and the interpretation of the environmental significance of alluvial deposits interbedded between lacustrine sediments are reported the data provide an overview of the periods of enhanced alluvial activity that occurred after the glacial retreat in the apennine chain the alluvial phases and the periods of environmental stability varied in frequency and length during the holocene in particular starting from the beginning of the apennine neoglacial about 4 2 kyr bp the events became much more frequent but shorter the elapsed time between alluvial phases i e the length of the phases of stability was greater during the early holocene probably because of the values of insolation when the insolation in july was lower the length of the phases of stability was greater despite the uncertainty in the dating o

late holocene climatic variability south of the alps as recorded by lake level fluctuations at lake ledro trentino italy a lake level record for the late holocene at lake ledro trentino northeastern italy is presented it is based on the sediment and pollen analysis of a 1 75 m high stratigraphic section observed on the southern shore site ledro i and a 3 2 m long sediment core taken from a littoral mire on the southeastern shore site ledro ii the chronology is derived from 15 radiocarbon dates and pollen stratigraphy the late holocene composite record established from these two sediment sequences gives evidence of centennial scale fluctuations with highstands at c 3400 2600 1700 1200 and 400 cal bp in agreement with various palaeohydro logical records established in central and northern italy as well as north of the alps in addition high lake level conditions at c 2000 cal bp may be the equivalent of stronger river discharge observed at the same time in central italy s rivers in agreement with the lake level record of accesa tuscany the ledro record also suggests a relatively complex palaeohydrological pattern for the period around 4000 cal bp on a millennial scale sediment hiatuses observed in the lower part of the ledro i sediment sequence indicate that except for a high stand occurring just after 7500 cal bp lower lake levels generally prevailed rather before c 4000 cal bp than afterwards finally the lake level data obtained at lake ledro indicate that the relative continuity of settlements in humid areas of northern italy during the bronze age in contrast to their general abandonment north of the alps between c 3450 and 3150 cal bp does not reflect different regional patterns of climatic and palaeohy drological conditions in contrast the rise in lake level dated to c 3400 cal bp at ledro appears to coincide with a worldwide climate reversal observed in both the hemispheres while palaeoenvironmental and archaeological data collected at lake ledro may suggest as a working hypothesis a relative emancipation of proto historic societies from climatic conditions

the holocene record of environmental changes in the stagno di maccarese marsh tiber river delta central italy the stratigraphic study of the stagno di maccarese carried out on the sediments exposed in about 7 km of trenches excavated in an area of approximately 1 5 km2 has shown that in the course of the holocene many environmental variations have taken place the complex evolution of the marsh is demonstrated by the variations in water salinity and the presence of erosion surfaces and soils between the sediments in the early holocene the area studied was an isolated marsh with water having variable salinity and it was only about 6000 cal yr bp that it was encompassed in the system of inner delta marshes in the delta environment the water of the marsh was oligohaline until about 9th 8th centuries bc brackish from 9th 8th centuries bc to about 600 yr bp and later oligohaline until the 19th century drainage a number of environmental variations are connected with local phenomena such as erosion of the beach ridges and tiber floods but the others can be correlated chronologically with climatic events rec

possible mechanisms of dynamic nucleation and arresting of shallow earthquake faulting abstract the nucleation and arresting mechanisms of large shallow earthquakes are investigated from both observational and theoretical viewpoints we show that two distinct phases are commonly observed at the initial part of seismograms of large shallow earthquakes the first phase denotes the onset of the p wave which shows a very gradual increase in amplitude with time this gradual change is interrupted by the arrival of the second phase which causes an abrupt change in the amplitude our seismological observation shows that the time interval between the onset of the two phases is strongly correlated with the magnitude of the earthquake it is probable that the above two phases are related to some aspect of inhomogeneities in the earth s crust one of the important sources of such inhomogeneities is known to be preexisting cracks and their interactions we theoretically show in this paper that a rupture occurring in a zone of densely distributed cracks radiates elastic waves that can simulate the features of the above two phases note that such a rupture is considerably affected by crack interactions theoretical calculation is also carried out to investigate the effect of crack interactions on the arresting of rupture propagation a propagating crack can excite subsidiary cracks ahead of its crack tip which gives rise to crack interactions we show that these interactions sometimes facilitate the arresting of rupture propagation

crustal heterogeneity in the 2000 western tottori earthquake region effect of fluids from slab dehydration abstract in order to understand the generating mechanism of the western tottori earthquake m 7 3 that occurred on 6 october 2000 in southwest japan we determined high resolution 3d p and s wave velocity and poisson s ratio structures in the epicentral area we used 17 542 p and 13 831 s wave high quality arrival times from 721 tottori aftershocks and other local microearthquakes recorded by the dense high sensitivity seismic network hi net installed recently on the japan islands significant variations of up to 4 for seismic velocity and 9 for poisson s ratio are revealed in the aftershock area areas with large coseismic slips and high aftershock activity are associated with high p wave velocity v p high poisson s ratio and high electrical conductivity which may represent strong and competent parts of the fault zone containing fluids the western tottori mainshock hypocenter is located in a boundary zone where both velocity and poisson s ratio change drastically both p and s wave velocities are slower in the lower crust under the mainshock hypocenter and low frequency microearthquakes were detected within the slow anomalies around the moho discontinuity before and after the occurrence of the 2000 western tottori earthquake these results and other related evidence suggest that the strong crustal heterogeneity in the western tottori source area is associated with fluids and arc magma under nearby the daisen volcano which may have influenced the nucleation and rupture process of the western tottori earthquake the arc magma and fluids are thought to result from the dehydration reactions of the subducting philippine sea slab in this region these results suggest that the nucleation of shallow earthquakes could be controlled by a deep structure and regime and so it is important to study the deeper crust and upper mantle structure and processes for clarifying the generating mechanism of large crustal earthquakes

sea level change during the holocene in sardinia and in the northeastern adriatic central mediterranean sea from archaeological and geomorphological data abstract we provide new data on relative sea level change from the late holocene for two locations in the central mediterranean sardinia and ne adriatico they are based on precise measures of submerged archaeological and tide notch markers that are good indicators of past sea level elevation twelve submerged archaeological sites were studied six aged between 2 5 and 1 6 ka bp located along the sardinia coast and a further six dated 2 0 ka bp located along the ne adriatic coast italy slovenia and croatia for sardinia we also use beach rock and core data that can be related to holocene sea level the elevations of selected significant archaeological markers were measured with respect to the present sea level applying corrections for tide and atmospheric pressure values at the time of surveys the interpretation of the functional heights related to sea level at the time of their construction provides data on the relative changes between land and sea these data are compared with predictions derived from a new glacio hydro isostatic model associated with the last glacial cycle sardinia is tectonically relatively stable and we use the sea level data from this island to calibrate our models for eustatic and glacio hydro isostatic change the results are consistent with those from another tectonically stable site the versilia plain of italy the northeast adriatic italy slovenia and croatia is an area of subsidence and we use the calibrated model results to separate out the isostatic from the tectonic contributions this indicates that the adriatic coast from the gulf of trieste to the southern end of istria has tectonically subsided by 1 5 m since roman times

pgq model for nepal himalaya abstract we investigate the spatial variations of pg attenuation structure in nepal himalaya we implement the two station method on 2325 waveforms obtained from 435 events recorded at 151 stations deployed across nepal himalaya to measure the pg wave quality factor q these station station measurements are inverted further for investigating the spatial variations of pg attenuation using a back projection algorithm the model contains variations across the region with much of the region being dominated by high attenuation it is observed that the areas around the existing faults and lineaments exhibit very low q values a few exceptional high q pockets are observed to be limited predominantly in the north western side of our study area we hypothesize that intrinsic attenuation plays a major role in causing the high apparent pg attenuation in the crust of nepal himalaya this may be mainly caused by highly pressurized fluids trapped within a thin low velocity layer lvl at shallow depths moreover it is interesting to observe that all the past earthquakes of m w 7 since 1934 fall into the regions of low q values but not the lowest it may be anticipated that the very low q areas are too weak to sustain the accumulation of high energy release during a large magnitude earthquake therefore the observed low q structures across the study area may imply a weak crust and subsequently a favorable zone for future rupture

late holocene emergence in calabria italy abstract a field survey along the coasts of calabria has found little evidence of holocene emergence the greatest being no more than 1 0 1 5 m in elevation a former shoreline a thick crust of calcareous algae in growth position at about 0 6 m capping an elevated beachrock slab was dated 2990 60 yr b p this emergence is recent if compared to the time of the climatic optimum and relatively slight if late pleistocene uplift rates which in some cases exceed 1 mm yr are considered this apparent discrepancy can be explained by taking into account glacio and hydroisostatic effects of the last glaciation which have produced subsidence at decreasing rates during the late holocene in a wide area around the former scandinavian ice sheet which includes most of the mediterranean according to isostatic modelling the average subsidence rate during the last 6000 5000 years was between 0 4 and 1 mm yr near the coasts of calabria if global sea level changes can be neglected it is only when the subsidence rate of glaciohydro isostatic origin became slower than the local uplift that emergence at a slower rate than that of the tectonic uplift trend could have begun such emergence is therefore a recent phenomenon in the holocene and its rate is still much slower than that of tectonic uplift predominating in calabria over a longer time scale

sequence stratigraphy and depositional setting of the tiber delta integration of high resolution seismics well logs and archeological data abstract using archeological evidence radiocarbon data well logs and high resolution seismic profiles we applied sequence stratigraphic analysis to sediments deposited during the last glacio eustatic cycle on the tyrrhenian continental margin embracing the tiber river months these sediments form a high frequency sequence of fifth order that has developed over the last 20 000 yr since the last lowstand hereafter referred to as the tiber depositional sequence tds the tds is still evolving and lies on a type 1 sequence boundary that has been identified both on the shelf and below the present delta plain this sequence consists of lowstand transgressive and highstand systems tracts the lowstand deposits are not present on the shelf but are found on the continental slope where they constitute the last progradation set of the continental margin a network of gullies active when the river mouth was at the shelf break is present within the lowstand deposits the transgressive systems tract tst deposits lie directly on the basal unconformity landwards the tst is represented by a retrogradational parasequence set of fluvial coastal barrier lagoon and lagoonal delta facies seaward on the shelf these parasequences merge into a seismically transparent deposit that forms a condensed section the flooding surfaces that bound the parasequences are marked by peat layers that were dated by 14c the radiometric ages were used to draw a carve of sea level rise for the last 11 000 yr the top of the transgressive systems tract maximum flooding surface is represented by the last peat layer which was formed about 4700 5000 yr bp and buried 4 5 m below the present upper delta plain the highstand systems tract is made up of deposits of the present tiber wave dominated delta i e upper and lower delta plain delta front and prodelta slope the aligned beach ridges mark the position of the prograding coastline which for the last 2500 yr can be dated by archeological and historical data the recent very fast progradation of the tiber delta during the last 500 years is consistent with historical data on floods of the city of rome and the suspended load of the tiber river

a source to sink compositional model of a present highstand an example in the low rank tiber depositional sequence latium tyrrhenian margin italy abstract our source to sink compositional model of sediment distribution in the present highstand of the tiber depositional sequence has important implications for sediment source lithology generation transport and deposition in the tiber river system sand compositional trends reflect provenance mixing anthropic intervention and the effects of local autogenic factors in continental to marine depositional environments fluvial feldspatho quartzo lithic sand results from the contribution of the major tributaries of the tiber drainage basin which can be divided into two sub basins separated by the corbara dam built in the 1950s upstream drainage basin sand has a siliciclastic sedimentary lithic signature whereas carbonate and volcanic lithic fragments dominate downstream drainage basin sand downstream sand is further modified in the coastal environment by hydraulic sorting and mixed with detritus derived from the recycling of coastal dune sand and altered volcaniclastic paleosols the latter are associated with lower course floodplain and channel deposits which produce a quartzo feldspatho lithic sand sediment grain size zonation in the marine environment is influenced by coastal hydrodynamics which in turn produce two detrital populations with distinct compositional signatures and hydraulic behavior coarser minerals essentially pyroxene phenocrysts and finer feldspar grains are progressively concentrated in higher energy and lower energy environments respectively biogenic continental shelf and slope deposits off the tiber river mouth show very little riverine influence this study of the last highstand system tract in the tiber depositional sequence clarifies the effects of hydraulic sorting grain size dependence and sediment reworking in controlling the final composition of modern sand this knowledge can be used to better understand detrital modes of ancient sedimentary successions

coastal elevation changes in eastern sicily implications for volcano instability at mount etna the eastern flank of mount etna sicily has been recognised as being unstable and three contrasting models have been proposed to account for this phenomenon these being deep seated spreading shallow sliding and tectonic block movements these models are examined by making reference to the rates and patterns of crustal movement along the eastern coastline of sicily as determined from palaeoshoreline data the south eastern coastline of sicily portopalo to catania provides no evidence of holocene emergence in contrast the volcanic coastline catania to capo schiso and the northeastern shoreline taormina to milazzo display widespread evidence of coastal emergence radiocarbon dated remains indicate that both the volcano and northeastern sicily have been uplifted at a rate exceeding 1 5mm yr during holocene times although more recent rates of uplift may have been greater the pattern of uplift suggests that the northeastern coastline of sicily including the volcanic ediface is apparently uplifting as a coherent unit with superficial flank movements being superimposed on a regionally uplifting sub volcanic basement

physical stratigraphy and sedimentology of the late pleistocene holocene tiber delta depositional sequence the tiber delta lies on the passive continental margin of central western italy the tiber delta is a late pleistocene holocene sedimentary succession and constitutes an incomplete high frequency depositional sequence 4th or 5th order which developed from the last post glacial rise in sea level to the present stillstand it is bound by a type 1 basal unconformity which cuts pleistocene deposits five depositional systems have been identified 1 coastal barrier lagoon 2 shelf transition 3 fluvial braided 4 tiber lagoonal deltas t1 t2 t3 and 5 tiber wave dominated delta the first four systems constitute the transgressive system tract tst which is characterized by a retrogradational parasequences set while the fifth system represents the highstand system tract hst characterized by only one parasequence progradational the evolution of these depositional systems has been mostly controlled by sea level rise which was not continuous but punctuated by eight minor stillstands and rapid rises this mechanism of sea level change led to the formation of parasequences that developed within the depositional systems from a palaeogeographical point of view the present tiber delta area was mainly characterized by a coastal barrier lagoon and tiber lagoonal deltas t1 t2 t3 which migrated landwards during the sea level rise throughout the time of the present stillstand the t3 lagoonal delta prograded rapidly into the lagoon reaching the coastal barrier and the lagoon was replaced first by marshes and then by the alluvial plain finally the tiber river overcame the littoral barrier supplying the coast giving rise to the present wave dominated delta

estimation of the joint roughness coefficient of rock joints by consideration of two order asperity and its application in double joint shear tests abstract joint roughness has a significant influence on the shear behavior of rock joints many different statistical parameters have been used to estimate the joint roughness coefficient jrc of rock joints depending on what is most easily available and convenient six statistical parameters z2 sf rp 1 log z2 logsf and r p 1 of ten typical roughness profiles were calculated at different sampling intervals si the results indicate that the jrc of rock joints could not be accurately estimated by using only a single statistical parameter because the first order and second order asperities of joints have different effects on shear behavior a classified and weighted fitting formula jrc 16 09 logz21st 12 70 logz22nd 33 75 si 5 0 mm 0 5 mm is proposed to estimate the jrc shear tests on sandstone joints indicate that the maximum jrc along the shear direction is appropriate to represent the total joint surface and estimate the shear strength this formula was adopted to estimate the jrc in double joint shear tests and the results show that the mechanical behavior of double parallel joints is closely related to the interlayer rock and the weaker joint under lower normal stress the interlayer rock does not fracture and the weaker joint determines the peak shear strength of the rock specimen in contrast under higher normal stress the peak shear strength is attained when the tensile fractures initiate in the interlayer rock and it has also relevancy to the jrc of double joints and interlayer thickness

middle to late holocene glacial variations periglacial processes and alluvial sedimentation on the higher apennine massifs italy the major climatic variations that have affected the summit slopes of the higher apennine massifs in the last 6000 yr are shown in alternating layers of organic matter rich soils and alluvial glacial and periglacial sediments the burial of the soils triggered by environmental climatic variations took place in several phases for the last 3000 yr chronological correlations can be drawn between phases of glacial advance scree and alluvial sedimentation and development of periglacial features during some periods the slopes were covered by vegetation up to 2700 m and beyond while in other phases the same slopes were subject to glacial advances and periglacial processes and alluvial sediments were deposited on the high plateaus around 5740 5590 1560 1370 and 1300 970 cal yr b p organic matter rich soils formed on slopes currently subject to periglacial and glacial processes the mean annual temperature must therefore have been higher than at present furthermore on the basis of the variations in the elevation of the lower limit reached by gelifraction it can be concluded that the oscillations in the minimum winter temperatures could have ranged between 3 0 c lower ca 790 150 cal yr b p and 1 2 c higher ca 5740 5590 cal yr b p than present minimum winter temperatures during the last 3000 yr the cold phases recorded by the calderone glacier advance in the apennines essentially match basically the phases of glacial advance in the alps

the role of foraminifera as indicators of the late pleistocene holocene palaeoclimatic fluctuations on the deltaic environment the example of tiber delta succession tyrrhenian margin italy abstract the palaeoclimatic and palaeoenvironmental reconstruction of the last 39 0 kyr of the central tyrrhenian shelf are presented in this paper micropalaeontological sedimentological and stable isotopic data integrated by radiocarbon dates were determined from three cores drilled in the tiber delta sequence tds which constitutes one of the most complete late quaternary high frequency depositional sequences in the mediterranean area short period climate variations that induced short period events caused changes in the tiber run off and increased the sediment supply and grain size in the delta system the three cores with different thicknesses record all the system tracts forming the tds three intervals corresponding to the early and late lowstand transgressive and highstand system tracts tst and hst were recognised the first is characterised by shoreface inner shelf deposits and corresponds to a general cooling period characterised by short warmer periods approximately 1 0 kyr confirming the climatic variability of mis 3 mis 2 a very condensed deposition affected the second interval which is characterised by a very low sedimentation rate corresponding to the tst of tds the third interval corresponding to holocene shelf deposits shows small climatic oscillations that mark an enhanced seasonality typical of the modern tyrrhenian regime at the millennial scale two warm intervals copper age and late bronze age ii century ac alternating with two cold humid intervals bond cycle b3 rcc 4 2 3 8 kyr bp of mayewski events and the little ice age have been recognised

vp and vs tomography of kyushu japan new insight into arc magmatism and forearc seismotectonics high resolution 3d tomographic images of the crust and upper mantle are determined under the entire arc region of kyushu by inverting a large number of arrival time data of p wave s wave and sp depth phases the hypocenters of the offshore earthquakes are accurately located by applying a combined method that makes use of sp depth phases and double difference of the p wave and s wave arrival times our tomographic results confirmed the major features delineated by previous studies and revealed some new features of structural heterogeneity related to arc magmatism beneath the kyushu arc high velocity anomalies correspond to the subducting philippine sea slab whilst low velocity zones in the mantle wedge are clearly imaged coinciding well with the velocity heterogeneities determined by previous studies strong low velocity anomalies are distributed extensively along the volcanic front and extend to the back arc side in the crust and upper mantle our present seismic images together with the previous results suggest that the fluids supplied by the dehydration processes of the descending philippine sea slab and the hot upwelling materials related to the opening of the okinawa trough might have contributed to the unzen volcanism under the forearc region of the kyushu subduction zone prominent low velocity anomalies are visible at depths of 10 40 km along the upper boundary of the subducting philippine sea slab and large interplate earthquakes are located around the low velocity zones which is similar to the features revealed in the northeast japan subduction zone the spatial distribution of large thrust earthquakes below the offshore region reflects the existence of weak coupled or decoupled portions on the interface of the subducting philippine sea slab

the transition from wave dominated estuary to wave dominated delta the late quaternary stratigraphic architecture of tiber river deltaic succession italy abstract this paper presents a detailed description of the stratigraphic architecture of the late pleistocene holocene tiber delta succession in order to document the passage from wave dominated estuary to wave dominated delta in the broader context of late quaternary sea level fluctuations this succession constitutes a sequence stratigraphic unit known as tiber depositional sequence tds which was deposited during the last glacial interglacial cycle last 120 ka our study is based on the examination of an enormous amount of data derived from the stratigraphy of about 300 wells petrographical and paleontological data foraminifera ostracoda pollen and plant macrofossils 14 c dating and from the integration of geomorphological and geoarcheological data recently a 100 m deep core pesce luna well was studied through a multidisciplinary approach and a detailed description of sedimentary facies foraminifer and ostracod assemblages pollen and 14 c dating is presented in this paper the new data allowed to produce three new correlation panels and to describe in more detail with respect to previous interpretations the stratigraphic depositional architecture of the tds which internally shows the preservation of sediment deposited during the early and late lowstand the transgressive and the highstand systems tracts alluvial and coastal depositional systems characterize the early lowstand phase of the tds which developed during the eustatic sea level fall between about 120 and 30 26 yr bp during the late lowstand phase which is characterized by stillstand and slow eustatic sea level rise a prograding delta and an aggrading incised valley fluvial fill developed the tiber incised valley was transformed into a wave dominated estuary during the transgressive phase tst whereas a coastal shelf sedimentation took place during the subsequent highstand phase hst this study confirms the lithofacies distribution resulting from transgression and infilling of the wave dominated estuaries but also shows how the transition to a wave dominated delta prograding at the time of sea level highstand occurred changes in sediment input climatic variations and more recently human activities played a major role in the development of the tiber delta during the last 20 000 yr bp in the last 3000 years a relationship between progradational phases of the delta and flood events of the tiber river has been highlighted suggesting also the formation and merging of barrier spits to the mainland

electrical conductivity anomalies beneath the western sea of kyushu japan geomagnetic depth soundings have been made in the area covering kyushu island and its neigh boring islands in the western sea of kyushu to investi gate the back arc conductivity structure the in phase induction arrows derived from geomagnetic variations are found to point roughly southwestwards at most sites on kyushu island for the period range 300 7200 sec this is quite different from some other areas of japan the non uniform thin sheet model calculation indicates that the induction arrows in this area are strongly influ enced by the surrounding seas however the observed arrows have much more intense westward components than indicated by the model calculations this strongly suggests existence of highly conducting layers hcls beneath the east china sea and the existence of hcls in the upper mantle are confirmed by a two dimensional finite element modeling these hcls may be consid ered to be a part of mantle upwelling extended to east

tomography of the source area of the 1995 kobe earthquake evidence for fluids at the hypocenter seismic tomography revealed a low seismic velocity 5 and high poisson s ratio 6 anomaly covering about 300 square kilometers at the hypocenter of the 17 january 1995 magnitude 7 2 kobe earthquake in japan this anomaly may be due to an overpressurized fluid filled fractured rock matrix that contributed to the initiation of the kobe earthquake

late quaternary depositional architecture of po and tevere river deltas italy and worldwide comparison with coeval deltaic successions abstract po and tevere rivers form two of the most important deltas of the whole mediterranean area detailed investigations have been carried out in the last decade beneath the present delta plains of these two river systems using borehole data correlation with the aid of radiocarbon dates and other dating methods pollens archaeology a detailed sequence stratigraphic framework has been constructed in both areas especially for the last glacial interglacial cycle regional subsidence combined with short term sea level fluctuations of relatively high amplitude played a fundamental role in creating subtracting accommodation during the long phase of falling sea level which followed the tyrrhenian substage 5e transgressive event a discontinuous record of this phase is present in the subsurface of the po plain whereas poor or no preservation has been detected in the tevere area progradational lowstand wedges accumulated during the last glacial maximum mostly in the central part of the basins far from the present deltas and are lacking in the study areas where a hiatal surface is invariably recorded below the transgressive deposits glacioeustasy exerted a major control on sedimentation in both areas during the latest pleistocene holocene sea level rise infilling of fluvial valleys and rapid landward migration of barrier lagoon systems in the context of wave dominated estuaries characterized the transgressive phase in both po and tevere systems in place drowning and transgressive submergence mechanisms of barrier migration were effective predominantly between 13 5 and 9 ka bp in contrast shoreface retreat was dominant in the late transgressive phase the maximum flooding surface mfs can be traced physically from continental to marine deposits and has similar characteristics in the po and tevere river systems being marked by peat layers or lagoonal deposits at landward locations and by distinctive lithological characteristics and micro and macrofossils assemblages basinwards above the mfs the early highstand systems tract records initially the filling of the lagoons followed by the rapid progradation of wave dominate delta systems and flanking strandplains autocyclic processes such as distributary channel avulsion delta lobe abandonment and local subsidence due to sediment compaction were the fundamental controlling factors on sedimentation during deposition of the hst the stratigraphic architecture of the post glacial po and tevere delta complexes closely resembles the basic facies successions documented from coeval deposits of wave dominated and wave influenced clastic coasts both locally within the mediterranean area and in other parts of the world our study emphasizes however some additional features and major differences with previously published depositional models including i the development of backstepping wave dominated estuaries during transgression ii consistent changes through time in the mechanism of barrier migration iii a later construction of the delta systems with respect to what traditionally considered

plant landscape and environmental changes recorded in marginal marine environments the ancient roman harbour of portus rome italy abstract the interpretation of past environment changes in coastal marshes river mouths and drainage channels connecting fresh to salt water bodies is a difficult task since several factors must be considered such as the variable influence of climate sea level changes coastline variations and changes in the river discharge it is even more difficult if this attempt is carried out in basins and channels of an ancient harbour used for centuries connected to the sea and to a river this is the case of the ancient harbour of rome located in the tiber delta area which had a prominent role during the imperial age in the mediterranean a town named portus arose in the vicinity and although sacked many times by barbarians was still very important during medieval times the romans managed the harbour the city and the surroundings and the impact on the environment must have been very strong a multi proxy approach was used to characterize and date environment and landscape changes in the ancient port of rome area from the 1st century to the 15th century ad plant macrofossil results have been integrated not only with pollen and microcharcoal but also with the tiber river bi millennial record available in literature this integration used to improve the chronological framing of the cores was carried out using ostracod analyses micro crustaceans commonly occurring in marginal marine environments and widely used for palaeoenvironmental reconstructions in particular the ability of some species to live within specific salinity ranges has been a precious tool to identify the hydrological setting of the depositional environment the cores recovered allowed recognition of two different sedimentary sequences the older shows the silting of the harbour during the first centuries and the younger records the sedimentation that occurred between the 4th and the 15th century ad this multi proxy approach applied to the study of plant remains indicates that 1 the human impact was lower during the first centuries ad than during late antiquity and middle ages or that 2 clues of human presence were easier to detect in a closed marshy area than in an open harbour the correlations between macroremains pollen percentage and concentration freshwater brackish water and salt water ostracods and the frequencies of tiber river floods during a 1500 year time span link some environmental changes and the silting of the harbour to the variations in hydrological regime of the tiber river

crustal heterogeneity and seismotectonics of the region around beijing china abstract a detailed three dimensional 3 d p wave velocity model of the crust and uppermost mantle under the chinese capital beijing region is determined with a spatial resolution of 25 km in the horizontal direction and 4 17 km in depth we used 48 750 precise p wave arrival times from 2973 events of local crustal earthquakes controlled seismic explosions and quarry blasts these events were recorded by a new digital seismic network consisting of 101 seismic stations equipped with high sensitivity seismometers the data are analyzed by using a 3 d seismic tomography method our tomographic model provides new insights into the geological structure and tectonics of the region such as the lithological variations and large fault zones across the major geological terranes like the north china basin the taihangshan and the yanshan mountainous areas the velocity images of the upper crust reflect well the surface geological and topographic features in the north china basin the depression and uplift areas are imaged as slow and fast velocities respectively the taihangshan and yanshan mountainous regions are generally imaged as broad high velocity zones while the quaternary intermountain basins show up as small low velocity anomalies velocity changes are visible across some of the large fault zones large crustal earthquakes such as the 1976 tangshan earthquake m 7 8 and the 1679 sanhe earthquake m 8 0 generally occurred in high velocity areas in the upper to middle crust in the lower crust to the uppermost mantle under the source zones of the large earthquakes however low velocity and high conductivity anomalies exist which are considered to be associated with fluids the fluids in the lower crust may cause the weakening of the seismogenic layer in the upper and middle crust and thus contribute to the initiation of the large crustal earthquakes

the holocene climatic evolution of mediterranean italy a review of the continental geological data we present a synthesis of geological stratigraphic geomorphological and stable isotope data collected from continental archives to highlight the environmental and climatic differences between the first and second half of the holocene of central and southern italy the beginning of the holocene is marked by rapid environmental change in mediterranean italy between c 9500 cal bp and c 6000 5500 cal bp average temperatures were probably higher and environmental conditions were generally stable between c 9000 and 7000 cal bp meteoric precipitation was at its highest the end of the wetter period seems to occur later at c 6000 5000 cal bp since c 6000 5000 cal bp rapid climatic excursions are apparent in different palaeoclimate proxies with both variability in meteoric precipitation and temperature evident of particular relevance is the event occurring at c 4200 cal bp this event heralds a period of significant environmental change in the apennines and more generally in central italy

multi parameter imaging in the 2016 mw 7 0 kumamoto earthquake kyushu japan and its implications for fluids in seismogenesis abstract fluids associated with structural heterogeneities in a seismogenic layer play a crucial role in triggering earthquakes and controlling their rupture processes but the mechanism of fluid intrusion and the relationship with earthquake initiation are unclear this study presents new seismic evidence of an earthquake mostly triggered by fluid intrusion associated with magmatism in kyushu sw japan seismic imaging revealed two zones with slow seismic velocities beneath the unzen and aso volcanoes with high poisson s ratio extending into the rupture belt of the 2016 mw 7 0 kumamoto earthquake the following features particularly the high poisson s ratio anomalies suggest the presence of fluids in the source area ascending from nearby magmatism anomalous crack density and saturation rate imply that the fractures pores are not fully saturated with fluids in the crust of the beppu shimabara graben possibly providing a path for fluids to penetrate into the source area either through highly fracture damaged faults or via incompletely saturated pores cracks fluid penetrating into the hypocenter areas from deep magma increases the pore pressure and decreases the coulomb failure function we therefore speculate that a system such as this with high pore pressure and fluids in the host faults might lower the threshold for fault failure thus increasing the likelihood of failure of the mainshock fault the results of this study suggest that the presence of fractures pores within extensional rift zones around the world might be critical for fluid migration and contribute to the initiation development and migration of seismic activity

structural control of rupturing of the mw7 9 2008 wenchuan earthquake china abstract analyses of global seismic waveform data for the 2008 devastating wenchuan earthquake have indicated where the rupture started and how it expanded here we reveal that the rupture process of this earthquake was strongly controlled by structural heterogeneities of the upper crust we made a tomographic inversion of 200 000 local travel time data according to which the rupture was confined in a presumably brittle layer of high p and s wave velocity anomalies within the upper 15 km depths the rupture propagated northeastward through the southwest sw segment of the fault and then jumped to the northeast ne segment with little slip at the intervening presumably ductile zone characterized by low p and s velocities with high poisson s ratio the rupture initiated near the southwestern end of the sw segment within a body of high poisson s ratio which extends down into the lower crust suggesting upward migration of deep seated aqueous fluid to trigger the earthquake by reducing the mechanical strength of the brittle layer

intracontinental seismicity strength of crustal units and the seismic signature of fault zones the distribution of intracontinental seismicity in the upper crust is compared with theoretically obtained strength depth curves based on recent laboratory data from cold and brittle frictional sliding as well as from high temperature creep data the lower crust is seen as a channel of enhanced ductility like jelly in a sandwich this rheological picture is compatible with the formation of mylonites in the lower crust and the appearance of cataclasites in the rigid upper crust sub horizontal zones of detachment prefer the upper part of the ductile lower crust in the continents resulting in the formation of crustal nappes during compressional phases the most active fault zones seem to exhibit reduced values of brittle elastic and inelastic parameters

insight into the origin of the tengchong intraplate volcano and seismotectonics in southwest china from local and teleseismic data received 18 june 2008 revised 22 february 2009 accepted 10 march 2009 published 13 may 2009 1 a high resolution tomographic image of the crust and upper mantle under yunnan province in southwest china was determined by using a large number of teleseismic data measured precisely from digital seismograms as well as local earthquake arrival times recorded by the dense yunnan seismic network the grid spacing of the tomographic model is 70 km 78 km in the horizontal directions and 4 70 km in depth our resulting model shows a clear low velocity low v 0 3 with respect to the average one dimensional velocity model column extending from the surface down to about 400 km depth under the active tengchong volcano and some high velocity high v anomalies existing in the mantle transition zone furthermore the low vanomaly extends horizontally toward the northeast at 250 to 400 km depth combining our tomographic results with geochemical and geological investigations we infer that the tengchong volcano is a rift related volcano caused by the subduction and dehydration of the indian plate as well as corner flow in the mantle wedge though the subducted slab is a continental plate our results show that the upwelling flow under tengchong originates at 400 km depth a prominent low v anomaly along the red river fault zone extends down to the upper mantle 100 km depth reflecting that the red river fault zone may have cut through the crust to the upper mantle the two dayao earthquakes m 6 1 and m 6 2 in 2003 occurred on the margin of high v anomalies and are underlain by a prominent low v anomaly in the lower crust and upper mantle suggesting that the dayao earthquakes may be associated with fluids released from the dehydration of the subducted indian slab these results are significantly improved compared with previous studies and provide new seismic constraints on the dynamic processes of the india asia collision

holocene sea level change in sicily and its implications for tectonic models new data from the taormina area northeast sicily the northeast coast of sicily shows emergent marine features that have been uplifting during the holocene along the footwalls of two major regional fault systems the malta escarpment and messina fault system previously uplift rates were interpreted as up to about 1 8 mm mm a 1 new dates on shelly remains collected close to sea level from the taormina area north of mount etna and amended sea level curves are used to show that uplift over the past 6000 years has been proceeding at a slower rate of about 1 4 mm a 1 however over a longer time period from the tyrrhenian oxygen isotope stage 5 5 about 125 ka to the present day the uplift rate has been yet slower at about 1 mm a 1 northeast sicily lies in a complex plate boundary region whereas in contrast the rest of sicily appears to have been stable throughout the later quaternary further comparisons show that the french mediterranean coast lambeck bard 2000 earth planet sci lett 175 202 222 is a region of crustal stability where movement is dominated by subsidence of the outer portion of the proglacial forebulge of the last glaciation there the coastline has been progressively submerged during the holocene and sea level has never been higher than at present northeastern sicily uplift is therefore more likely controlled by plate processes that mask most of the effects of glacio hydro isostatic adjustment

spatiotemporal distribution of low frequency earthquakes in southwest japan evidence for fluid migration and magmatic activity abstract low frequency earthquakes lfes in the lower crust and uppermost mantle are widely observed in southwest japan and they occur not only along the subducting philippine sea phs slab interface but also beneath active arc volcanoes the volcanic lfes are still not well understood because of their limited quantities and less reliable hypocenter locations in this work seismic tomography is used to determine detailed three dimensional 3 d p and s wave velocity vp and vs models of the crust and upper mantle beneath southwest japan and then the obtained 3 d vp and vs models are used to relocate the volcanic lfes precisely the results show that the volcanic lfes can be classified into two types pipe like and swarm like lfes and both of them are located in or around zones of low velocity and high poisson s ratio anomalies in the crust and uppermost mantle beneath the active volcanoes the pipe like lfes may be related to the fluid migration from the lower crust or the uppermost mantle whereas the swarm like lfes may be related to local magmatic activities or small magma chambers the number of lfes sometimes increases sharply before or after a nearby large crustal earthquake which may cause cracks and fluid migration the spatiotemporal distribution of the lfes may indicate the track of migrating fluids as compared with the tectonic lfes along the phs slab interface the volcanic lfes are more sensitive to fluid migration and local magmatic activities high pore pressures play an important role in triggering both types of lfes in southwest japan

seismic images of the source area of the 2004 mid niigata prefecture earthquake in northeast japan to better understand the generation mechanism of the 23 october 2004 mid niigata prefecture earthquake m 6 8 we used 120 352 p wave and 95 391 s wave high quality arrival times from 5013 earthquakes to determine the three dimensional seismic velocity vp vs and poisson s ratio structures in and around the source area the hypocenter locations of the aftershocks are relocated accurately by using absolute and relative travel time double difference data our results demonstrate that the seismic velocity and poisson s ratio vary markedly around the source area most active faults are located along the margins of low velocity and high velocity zones an obvious change in seismic velocity and poisson s ratio occurs between the northwest and southeast parts of the study area and this boundary zone reflects the spatial distribution of active faults being well consistent with the surface geological features most of the large historic crustal earthquakes are located in or around the low seismic velocity zones the mainshock hypocenter is located near the margin of low velocity high poisson s ratio and high velocity low poisson s ratio anomalies along the active fault zone a zone with pronounced low velocity and high poisson s ratio is clearly imaged in the lower crust under the source area reflecting the existence of fluids that are released due to the dehydration of the subducting pacific slab such fluids might have reduced the mechanical strength of the fault zone and thus initiated the mid niigata prefecture earthquake