the cryptotephra record of the marine isotope stage 12 to 10 interval 460 335 ka at tenaghi philippon greece exploring chronological markers for the middle pleistocene of the mediterranean region abstract precise chronologies that allow direct correlation of paleoclimate archives are a prerequisite for deciphering the spatiotemporal characteristics of short term climate variability such chronologies can be established through the analysis of tephra layers that are preserved in the respective sedimentary archives here we explore the yet untapped tephrochronological potential of the eastern mediterranean region for the middle pleistocene specifically for the interval spanning marine isotope stages mis 12 10 460 335 ka high resolution cryptotephra analysis was carried out on peat cores spanning the mis 12 10 interval that have been recovered from the iconic climate archive of tenaghi philippon ne greece eighteen primary cryptotephras were identified and major and trace element analyses of single glass shards from all cryptotephras were performed in order to correlate them with their eruptive sources the results suggest origins from both italian and aegean arc volcanoes specifically one cryptotephra layer could be firmly correlated with the cape therma 1 eruption from santorini which makes it the first distal tephra finding for this eruptive event while eight further cryptotephras could be tentatively correlated with their volcanic or even eruptive sources the provenance of another nine cryptotephras as yet remains unknown the relatively large number of cryptotephras that could not be assigned to specific volcanic sources and eruptive events reflects the still considerable knowledge gap regarding the geochronology and geochemistry of proximal tephra deposits from the middle pleistocene of the central and eastern mediterranean regions due to the lack of well dated middle pleistocene eruptions we provide age estimates for all cryptotephra layers identified in the mis 12 10 interval at tenaghi philippon based on high resolution pollen data from the same cores while eight of the identified cryptotephras were deposited within mis 12 438 427 ka one cryptotephra was deposited at the onset of mis 11 419 ka five cryptotephras during the younger part of mis 11 391 367 ka and four cryptotephras during mis 10 359 336 ka the high number of cryptotephras from multiple sources as recorded in the mis 12 10 interval at tenaghi philippon highlights the key role of this archive for linking tephrostratigraphic lattices for the middle pleistocene of the central and eastern mediterranean regions

transient changes in well water level in bore wells in western india due to the 2004 mw 9 3 sumatra earthquake large water level changes were observed in six bore wells in the koyna region in western india following the great sumatra earthquake of m w 9 3 on 2004 december 26 this earthquake occurred at 00 58 50 coordinated universal time utc off the coast of sumatra located about 3000 km from the koyna region the arrival time of the p wave recorded at the koyna seismic station was 01 04 24 45 utc the anomalous water level changes were observed at 01 15 utc at all of these wells where the sampling rate was 15 min no abnormal changes were noticed in the preceding sampling time at 01 00 utc clearly indicating that these changes occurred due to the passage of seismic waves generated by the sumatra earthquake however due to the large sampling interval it is difficult to correlate the water level changes either to shear or surface waves no local earthquake was recorded by the network during this period the anomalous water level changes were of the order of 2 65 cm and show either a spikelike or a steplike change these types of changes are attributed to the dynamic strain induced by the passage of seismic waves most probably long period surface waves

volatile emission during the eruption of baitoushan volcano china north korea ca 969 ad magma volume dre 24 5 km3 the main phase ca 95 vol is represented by comenditic tephra deposited dominantly as widespread fallout blankets and proximal ignimbrites the eruption column is estimated to have reached ca 25 km and thus entered the stratosphere a late phase 5 vol is represented by trachyte emplaced chiefly as moderately welded ignimbrites the comendites contain 3 and the trachytes 10 20 vol phenocrysts mainly anorthoclase hedenbergite and fayalite primary glassy melt inclusions with no signs of leakage were found only in phenocrysts in the comenditic tephra whereas those in phenocrysts in the trachytes are devitrified the comendite magma is interpreted to have been generated by fractional crystallization from a trachyte magma represented by melt inclusions in the phenocrysts in the comendite tephra the mass of volatiles emitted to the atmosphere during the eruption was estimated using the petrologic method the average h2o concentration of the comenditic matrix glass is 1 5 wt probably largely secondary and of the corresponding melt inclusions 5 2 wt melt inclusions in feldspar and quartz present the highest halogen concentrations with a calculated average for chlorine of 4762 ppm and for fluorine of 4294 ppm the comenditic matrix glasses are represented by a fluorine rich 3992 ppm f and fluorine poor group 2431 ppm f averaging 3853 ppm for chlorine only 20 of all sulfur analyses of the comenditic matrix glasses and melt inclusions are above the detection limit of 250 ppm s the difference between pre and post eruptive concentration of h2o is at least 3 7 0 6 wt h2o taking into consideration re hydration of the matrix glass and possible leakage of melt inclusions the difference between pre and post eruptive concentrations of the halogens amounts to 909 90 ppm cl and 1863 280 ppm and 302 40 ppm f the difference for s was estimated based on the average of the maximum s concentrations in the melt inclusions 455 ppm s and the detection limit resulting in 205 40 ppm s the calculated mass of volatiles injected into the atmosphere based on the erupted magma volume and volatile data is 1796 453 megatons for h2o 45 10 megatons for chlorine 42 11 megatons for fluorine and 2 0 6 megatons for sulfur the 969 20 ad eruption of baitoushan volcano one of the largest eruptions of the past 2000 years is thought to have had a substantial but possibly short lived effect on climate

quaternary fluvial volcanic stratigraphy and geochronology of the capitoline hill in rome in and around rome coastal and fluvial sediments influenced by quaternary sea level changes interfinger with accurately datable highly potassic pyroclastic volcanic units we describe the complex internal geology of the capitoline hill for centuries a place of leading importance in ancient rome and more recently a focus of archaeological research outcrops and many new drill cores reveal at least four cycles of valley cutting and filling probably recording the history of the tiber river in response to changes in sea level single crystal 40 ar 39 ar dates on sanidine give ages of 518 6 413 5 and 353 2 ka for three prominent volcanic units filling separate paleovalleys the roman region offers the potential for direct age calibration of the quaternary sea level record

structure and evolution of the sacrofano baccano caldera sabatini volcanic complex rome abstract sacrofano eruptive center in the eastern part of the sabatini volcanic complex was active between 0 5 and 0 09 m y ago the baccano geothermal area lies at the western edge of sacrofano caldera sedimentary substrata that form the reservoir for this geothermal system were exposed at the surface at the beginning of volcanic activity the volcanic history of the sacrofano center can be divided into three stages 1 1 construction of the sacrofano pyroclastic edifice by predominantly strombolian activity 2 2 collapse of sacrofano caldera following eruption of pyroclastic flows 3 3 development of the baccano explosive center at the western edge of sacrofano caldera and collapse of baccano caldera hydrovolcanic activity that began at the end of the first stage of sacrofano can be explained by a drop in the magma level in the conduit that relieved hydrostatic pressure in the aquifer as intense fracturing associated with caldera collapse penetrated the carbonate reservoir the entrapped water flowed towards the conduit to balance the pressure change the close link between tectonism and volcanism in the sacrofano center suggests that eruptions there may have been triggered by gravity faults related to regional tectonics

the 2002 denali fault earthquake alaska a large magnitude slip partitioned event the mw moment magnitude 7 9 denali fault earthquake on 3 november 2002 was associated with 340 kilometers of surface rupture and was the largest strike slip earthquake in north america in almost 150 years it illuminates earthquake mechanics and hazards of large strike slip faults it began with thrusting on the previously unrecognized susitna glacier fault continued with right slip on the denali fault then took a right step and continued with right slip on the totschunda fault there is good correlation between geologically observed and geophysically inferred moment release the earthquake produced unusually strong distal effects in the rupture propagation direction including triggered seismicity

revisiting kokkinopilos middle pleistocene radiometric dates for stratified archaeological remains in greece the red bed site of kokkinopilos is an emblematic and yet also most enigmatic open air palaeolithic site in greece stimulating controversy ever since its discovery in 1962 while early research raised claims for stratigraphically in situ artifacts later scholars considered the material reworked and of low archaeological value a theory that was soon to be challenged again by the discovery of in situ lithics including handaxes here we present results of a latest and long term research that includes geoarchaeological assessments geomorphological mapping and luminescence dating we show that the site preserves an overall undisturbed sedimentary sequence related to an ephemeral lake marked by palaeosols and stratigraphic units with palaeolithic material that is geologically in situ and hence datable our study resolves the issues that have been the source of controversy the depositional environment stratigraphic integrity chronological placement and archaeological potential of the site moreover the minimum ages obtained through luminescence dating demonstrate that the lithic component with bifacial specimens considerably pre dates the last interglacial and therefore comprises the earliest stratigraphically defined and radiometrically assessed archaeological material in greece kokkinopilos has served as a reference site for the interpretation of all other red bed sites in north west greece therefore our results have significantly wider implications by analogy to kokkinopilos the open air sites of epirus should not anymore be considered by default as inscrutable palimpsests with limited archaeological potential rather these sites can be excavated and chronologically constrained this realization opens up new prospects for future research in epirus an area that is the most prolific in palaeolithic remains in greece

mantle dynamics and the heat flow into the earth s continents reducedcontinental heat flow defined as the measured heat flow minus that due to radiogenic sources in the upper crust initially decreases with time after the last thermotectonic event in a region1 but then tends to stabilize at a roughly constant value which is higher than would be predicted by a conductive cooling model fig 1 here we argue that this behaviour results from the influence that continents have on mantle heat loss the finite thermal conductivity of continental crust and the fact that it is not recycled into the mantle on a large scale as is oceanic crust allows stable continental blocks to limit the local heat flux out of the mantle numerical models that allow blocks of crust to form over a mantle layer demonstrate how thermal perturbations associated with mantle convection penetrate into continents causing lateral temperature variations at their base that parallel those in the mantle just below this tends to establish a constant flux of heat from the mantle into the continents which accounts for the trend in reduced heat flow

seismicity in the vicinity of the snorcle corridors of the northern canadian cordillera the slave northern cordillera lithospheric evolution snorcle corridors of the northern cordillera sample some of the most and least seismically active regions of canada the earthquake history of this region is short precise determination of earthquake locations and depths is not possible even today nonetheless significant gains in our knowledge of the seismicity of this region have been made in recent years from studies of historic earth quakes microseismicity studies and advances in waveform modelling techniques combined with broadband data that allow for determination of focal mechanisms and depths for moderate earthquakes this article summarizes our current knowledge of the seismicity and seismic hazards across the region these detailed analyses have shown that i the largest historical earthquakes have occurred in regions of ongoing microseismicity ii the largest earthquakes have occurred in pairs or in swarms suggesting that stress triggering is important in this region iii the active faults are concentrated in the offshore region iv there is a concentration of seismicity in the fold and thrust belt several hun dred kilometres from the active plate margin and v there is no seismicity associated with the quaternary volcanic zone in northern british columbia potentially damaging magnitude m 5 earthquakes can be expected every few years in the vicinity of the northern cordillera the mw 7 9 denali alaska earthquake where mw is the moment magnitude was a good reminder that the effects of a large earthquake can be substantial even hundreds of kilometres from the epicentre detailed studies of seismicity earth structure and tectonics with the latter made possible in large part by the snorcle transect will allow for informed decision making for resource development and the design of safe structures and infrastructure in the northern canadian cordillera resume les corridors du projet snorcle de la cordillere septentrionale permettent d echantillonner quelques unes des regions sismiques les plus et les moins actives du canada l histoire des seismes de cette region est breve meme

an extremely large magnitude eruption close to the plio pleistocene boundary reconstruction of eruptive style and history of the ebisutoge fukuda tephra central japan abstract an extremely large magnitude eruption of the ebisutoge fukuda tephra close to the plio pleistocene boundary central japan spread volcanic materials widely more than 290 000 km2 reaching more than 300 km from the probable source characteristics of the distal air fall ash 150 km away from the vent and proximal pyroclastic deposits are clarified to constrain the eruptive style history and magnitude of the ebisutoge fukuda eruption eruptive history had five phases phase 1 is phreatoplinian eruption producing 105 km3 of volcanic materials phases 2 and 3 are plinian eruption and transition to pyroclastic flow plinian activity also occurred in phase 4 which ejected conspicuous obsidian fragments to the distal locations in phase 5 collapse of eruption column triggered by phase 4 generated large pyroclastic flow in all directions and resulted in more than 250 350 km3 of deposits thus the total volume of this tephra amounts over 380 490 km3 this indicates that the volcanic explosivity index vei of the ebisutoge fukuda tephra is greater than 7 the huge thickness of reworked volcaniclastic deposits overlying the fall units also attests to the tremendous volume of eruptive materials of this tephra numerous ancient tephra layers with large volume have been reported worldwide but sources and eruptive history are often unknown and difficult to determine comparison of distal air fall ashes with proximal pyroclastic deposits revealed eruption style history and magnitude of the ebisutoge fukuda tephra hence recognition of the ebisutoge fukuda tephra is useful for understanding the volcanic activity during the pliocene to pleistocene is important as a boundary marker bed and can be used to interpret the global environmental and climatic impact of large magnitude eruptions in the past

impacts of the october 2012 magnitude 7 8 earthquake near haida gwaii canada on 27 october 2012 a magnitude m w 7 8 earthquake occurred in the sparsely populated region of haida gwaii british columbia canada formerly called the queen charlotte islands this was the second largest recorded earthquake in canadian history it was felt throughout british columbia and as far away as the yukon alberta and montana roughly 1600 km from the epicenter in some locations notably on haida gwaii the perceivable shaking lasted 1 5 2 min with very strong shaking for about 30 s strong ground motions recorded at three locations in the region reached a maximum horizontal acceleration of 0 2 g fortunately this earthquake resulted in very limited damage partly because of the relatively large distance more than 60 km between population centers and the fault rupture and partly because of seismic resistance of the generally low wood frame construction found on the islands we examine the various physical effects from the shaking e g tsunami landslides building damage loss of hot springs cataloged by field crews and reported by the inhabitants of haida gwaii and the surrounding regions these will serve as a guide toward the potential impact from future large earthquakes on the various haida gwaii communities through a community decimal intensity evaluation of people s accounts it was revealed that although intensities were close to expected near the source zone regional intensities were lower than predicted by the conventional western north america theoretical relation finally the october 2012 earthquake may be used as a scenario event for moderate subduction earthquakes in other more populated areas of british columbia canada and the world online material abridged did you feel it reports

statistical analysis of the 2002 mw 7 9 denali earthquake aftershock sequence we study the scaling properties of the aftershock sequence of the 2002 m w 7 9 denali earthquake the sequence exhibits nontrivial scaling behavior in magnitude aftershock decay rates and aftershock inter occurrence times in particular we observe a marked variability in the gutenberg richter gr exponent the b value in space between early and late times after the mainshock and over different magnitude ranges we find strong indications that certain aspects of this variability might be ascribed to the occurrence of some of the aftershocks on and around a supershear rupture associated with this event particularly we observe a statistically higher b value for the aftershocks that occurred in the zone surrounding the supershear rupture we further outline a method to obtain an average b value consistent with the theory and statistical properties of the data we find a significant difference between the magnitude of the largest aftershock and the mainshock this is analyzed and discussed using the modified bath s law it is observed that the aftershock decay rate can be approximated by the modified omori law the distribution of inter occurrence times is studied and we show that it can be explained in terms of a nonhomogeneous poisson process through time we further observe that the rescaled inter occurrence time distributions for various magnitude thresholds collapse into a universal functional form which indicates that the aftershock sequence exhibits self similarity in both magnitude and time in particular the statistical features of the aftershock sequence show that the rupture process or the preconditions that lead to it may influence aftershock statistics

late pliocene volcaniclastic products from southern apennines distal witness of early explosive volcanism in the central tyrrhenian sea two volcaniclastic successions intercalated in pliocene basinal clays from the southern apennines have been analysed to determine their provenance and their relationship with the geodynamic evolution of the western mediterranean the studied deposits are exclusively made up of ashy pyroclasts dominated by fresh acidic to intermediate glass mostly in the form of shards pumice fragments and groundmass fragments with vitrophyric texture crystals include pl opx cpx hbl and rare bt sedimentological features suggest that the volcanic material accumulated near the basin margin by primary fallout processes and was later remobilized by density currents 40 ar 39 ar geochronology allowed dating of one succession at 2 24 0 06 ma corresponding to the late pliocene composition of the volcaniclastic material is typical of a transitional high k calc alkaline series the age and chemical composition constrain the provenance of the volcaniclastic rocks from the southern tyrrhenian domain here volcanic centres were active during pliocene time approximately at the northern end of a volcanic arc formed before the opening of the southernmost part of the sea this paper shows that a detailed study of volcaniclastic products from the southern apennines and calabria can be very useful in collecting new pieces of information on the eruption history of the southern tyrrhenian domain since they record additional data not available from the study of exposed volcanic edifices

gps seismology application to the 2002 mw 7 9 denali fault earthquake abstract the 2002 denali fault alaska earthquake m w 7 9 caused one or more components of most broadband seismometers in western canada to clip yet did not trigger strong motion instruments thus leaving a substantial gap in the seismic record of this event however the large amplitude surface waves generated by this event were well recorded by the global positioning system gps in the same region out to epicentral distances of more than 3000 km in this article we explore the capabilities of gps seismology specifically how the relative strengths of gps and seismic data sets can be exploited in order to more effectively study earthquake source characteristics and wave propagation effects high rate 1 hz gps data from 23 stations throughout western north america have been analyzed to derive displacement waveforms for this event and the impact of instrumentation gps receiver model and error reduction strategy modified sidereal and spatial filtering on the noise characteristics of displacement time series at each gps site was assessed after applying error reduction methods to gps displacements the final average noise floors of 0 5 cm in the horizontal and 1 5 cm in the vertical indicate that large dynamic displacements are observable by gps we validate the gps displacements by comparing broadband seismic recordings integrated to displacement with gps recordings for four effectively colocated sets of instruments we show excellent agreement between the unclipped seismic and gps recordings of the surface waves from the denali earthquake over the period range of 10 50 sec and for ground displacements exceeding about 1 0 cm thus a large gps displacement data set is now available for western north america an area where records of this event were previously missing or incomplete the final gps seismograms are archived at incorporated research institutions for seismology iris for public use in future studies of the 2002 denali earthquake

computer simulation of transport and deposition of the campanian y 5 ash analyses of grain size and modal composition of the campanian tuff ash layer y 5 from 11 deep sea cores have been carried out this layer represents ash fall that has been correlated with the 38 000 y b p campanian ignimbrite thunell et al 1979 a deposit formed by the largest eruption documented in the mediterranean region during the late pleistocene barberi et al 1978 the bulk deposit is bimodal in grain size and dominated by glass shards the calculated mean grain size of the coarse mode of the individual size distributions decreases with distance from the source and progressively approaches a near constant fine mode of approximately 13 microns distal samples are unimodal in grain size these data combined with a set of vertical profiles of wind 10 year average have been used as input to a computer model that simulates fallout of tephra modelling indicates that the downwind variation of grain size of the coarse mode can be accurately reproduced with transport of ash between 5 and 35 km the observed fine mode of the deposit cannot however be generated by transport of ash as individual particles at these elevations such transport would result in deposition of virtually all of the fine ash beyond the studied area deposition of fine ash within the studied distance of 1600 km from source can only occur by fallout as particle aggregates from a high eruption plume or as individual particles from co ignimbrite ash clouds with a maximum elevation of 3 km the large volume of ash in the fine mode 70 wt and the irregularity in azimuth of low level winds argue against major low level transport of co ignimbrite ash rather the ash may have been derived from both a plinian eruption column and high altitude clouds of co ignimbrite ash with settling of fine ash as particle aggregates

glass chemistry in volcaniclastic sediments of odp leg 107 site 650 sedimentary sequence provenance and chronological implications abstract a detailed chemical investigation of volcanic glass fragments from volcaniclastic strata 6 tephras 1 volcanic debris flow 12 volcanic turbidites of odp leg 107 site 650 sedimentary sequence leads to a varied pattern in terms of both provenance and age constraints the six analyzed tephra strata indicate a provenance from at least three different volcanic provinces aeolian campanian and sicilian channel pantelleria island the older tephra strata 021 018 012 have a large amount of orogenic rhyodacite rhyolite deposits that may be attributed to the aeolian province although no subaerial coeval volcanic activity of similar composition has so far been documented in the aeolian arc tephra 007 is related to the pantelleria island activity and particularly to an ignimbrite episode dated circa 130 ka tephra strata 005 and 003 have a clear campanian provenance and are correlated with analogous tephra layers observed in the tyrrhenian and ionian seas dated circa 107 and 60 ka respectively in the oldest portion of the sequence from 1 3 to 0 13 ma the volcaniclastic sediments were only derived from the aeolian domain whereas in the latest 130 ka the campanian influx becomes much more predominant therefore a general k enrichment trend is observed in the temporal sequence of all the analyzed samples almost 700 point analyses which may be related both to a variation in the source area and to the specific pleistocene magmatic evolution of the peri tyrrhenian volcanic provinces

symmetries of volcanic distributions on mars and earth and their mantle plume dynamics the symmetries in the distribution of major volcanic centers on mars have been analyzed by employing a technique involving the angular self similarity of point fields the distribution of all central vent volcanoes exhibits an axisymmetry along with a reflecting symmetry about a plane whose normal is the axis of axisymmetry the latter axis is skewed by about 30 from the rotational axis and is suggested to represent the early axis of symmetry of the interior dynamics the high level of symmetry of mars volcanic distribution may be the result of a focusing of seismic energy from a major impact in the hellas area that formed the hellas basin and may have triggered the onset of volcanic activity in the greater tharsis area if the highland paterae near the hellas region are not taken into account in the analysis an asymmetry with respect to the reflecting plane appears this is probably representative of the late hesperian and amazonian when the once global volcanic activity had retreated to the tharsis province these angular symmetries suggest a simple pattern of long wavelength axisymmetric martian mantle convection involving a large stationary plume as shown by our three dimensional 3 d spherical shell simulations on the basis of these calculations we venture to propose that the volcanic history of mars reflects the transformation of a bipolar mantle plume structure into a single megaplume by the process of plume plume collision acting in concert with the deep martian phase transitions this transformation might have overcome the original pattern induced by a major impact forming the hellas basin we have repeated the procedure for the earth s hotspot distribution which revealed both axisymmetry and a certain level of reflecting symmetry this similarity between the two planets is striking the symmetries of the earth s hotspot distribution are probably due to the interaction of the lower mantle megaplumes with the endothermic perovskite to spinel phase transition

norwegian seiches from the giant 2011 tohoku earthquake 1 seismic waves of the giant 2011 tohoku earthquake triggered seiches in western norwegian fjords the seiching began a half hour after the earthquake origin time the oscillations were noted by eyewitnesses and recorded by surveillance and cell phone cameras the observations show maximum trough to peak amplitudes of 1 0 1 5 m and periods of 67 100 s the water waves were not triggered from the arrival of the surface waves the timing inferred for other seiches instead the seiching began during the passage of horizontal s waves we reproduced the s wave trigger by means of a shallow water wave model calibrated previously to norwegian tides and storm surges the simulations which used the observed earthquake motion as forcing show water waves with periods and amplitudes similar to those in the film clips however the strongest horizontal ground oscillations with shorter periods 20 30 s did not contribute much to the formation of the seiches

convection in spherical fluid shells with an outer crust of variable thickness abstract we investigate linear and nonlinear convection in a thick spherical fluid shell on which a thin spherical layer of a lighter but much more viscous fluid of variable thickness with lower thermal conductivity is superimposed this crust moves horizontally in response to the convective motion in the inner spherical fluid shell through its varying thickness the thin outer spherical layer acts as a thermal blanket of varying impedance and thus provides a strong feedback on convective motions in the lower mantle shell solutions for the thin outer spherical layer are obtained analytically and matched to the numerical solutions for motions in the mantle shell we first perform a linear stability analysis for the onset of time dependent convection the analysis is then extended to nonlinear axisymmetric solutions with or without equatorial symmetry finally fully three dimensional solutions are computed demonstrating that there exists a rich variety of time dependent spherical convection patterns the time dependence originates from the crustal thickness instability which corresponds to a hopf bifurcation even in the absence of convective overturning busse 1978 the results of the analysis show that even a small volume of crustal material may cause a significant temporal and spatial complexity of the convection flow

40 ar 39 ar ages and stratigraphy of the latera caldera italy the latera caldera is a well exposed volcano where more than 8 km3 of mafic silica undersaturated potassic lavas scoria and felsic ignimbrites were emplaced between 380 and 150 ka isotopic ages obtained by 40ar 39ar analysis of single sanidine crystals indicate at least four periods of explosive eruptions from the caldera the initial period of caldera eruptions began at 232 ka with emplacement of trachytic pumice fallout and ignimbrite they were closely followed by eruption of evolved phonolitic magma after roughly 25 ky several phonolitic ignimbrites were deposited and they were followed by phreatomagmatic eruptions that produced trachytic ignimbrites and several smaller ash flow units at 191 ka compositionally zoned magma then erupted from the northern caldera rim to produce widespread phonolitic tuffs tephriphonolitic spatter and scoria bearing ignimbrites after 40 ky of mafic surge deposit and scoria cone development around the caldera rim a compositionally zoned pumice sequence was emplaced around a vent immediately northwest of the latera caldera this activity marks the end of large scale explosive eruptions from the latera volcano at 156 ka

the mw 7 9 denali fault earthquake of 3 november 2002 felt reports and unusual effects across western canada the 3 november 2002 m w 7 9 denali fault earthquake was one of the largest north american earthquakes of the past 100 years this earthquake located 330 km to the west of the yukon alaska border generated 260 reports of shaking and other unusual effects to distances of 3500 km across western canada felt intensity for this earthquake ranged from v at communities in the yukon closest to the epicenter about 350 km distance iv across much of the yukon territory distances of 350 to 750 km iii across much of northern british columbia to ii in southern british columbia and alberta about 2400 km distance in many instances people reported feeling nauseous or seasick and having trouble standing the long period ground motions generated by this earthquake displacements greater than 10 cm were recorded in the yukon caused water to spill from swimming pools generated seiches in lakes and rivers and affected wells instances of dirty well water to distances of 3500 km across western canada

tephra from the minoan eruption of santorini in sediments of the black sea the explosive eruption of santorini volcano in the aegean sea about 3 300 years ago is of considerable archaeological and volcanological significance1 5 here we report the discovery of tephra from this minoan event in laminated sediments of the black sea this finding provides constraints on the distribution of debris from the eruption we estimate a minimum fallout area of 2 l06 km2 extending from the black sea in the north to the southeastern mediterranean sea the main dispersal axis trends through southern turkey in agreement with other studies of minoan tephra6 7 the tephra deposits should provide a useful reference horizon for assessing the chronology of black sea sediments which has been much debated8 15

long period effects of the denali earthquake on water bodies in the puget lowland observations and modeling analysis of strong motion instrument recordings in seattle washington resulting from the 2002 m w 7 9 denali alaska earthquake reveals that amplification in the 0 2 to 1 0 hz frequency band is largely governed by the shallow sediments both inside and outside the sedimentary basins beneath the puget lowland sites above the deep sedimentary strata show additional seismic wave amplification in the 0 04 to 0 2 hz frequency range surface waves generated by the m w 7 9 denali alaska earthquake of 3 november 2002 produced pronounced water waves across washington state the largest water waves coincided with the area of largest seismic wave amplification underlain by the seattle basin in the current work we present reports that show lakes union and washington both located on the seattle basin are susceptible to large water waves generated by large local earthquakes and teleseisms a simple model of a water body is adopted to explain the generation of waves in water basins this model provides reasonable estimates for the water wave amplitudes in swimming pools during the denali earthquake but appears to underestimate the waves observed in lake union

correlation of a tephra layer in western greece with a late pleistocene eruption in the campanian province of italy abstract the kalodiki fen is a 2 km 2 mire in a small basin within a tectonic depression in epirus western greece since the last glaciation the basin has been occupied by a freshwater lake and has accumulated as much as 9 m of peat which continues to form today a 10 cm thick light brown to olive fine sandy layer appears in cores at depths ranging from 2 9 to 5 7 m the sand fraction of this layer consists mostly of pumice fragments and brown and colorless glass shards with similar major element compositions and it also contains crystal fragments of feldspars mainly sanidine ferromagnesian minerals and probably sphene and apatite the colorless glass has an index of refraction 1 519 0 002 a sample of the overlying peat layer gave a minimum radiocarbon age of about 31 800 1200 yr b p for the deposition of the tephra the likely age of the tephra its index of refraction and its mineralogical and chemical characteristics display strong similarities to tephra from the campanian province of italy mineralogically similar tephra layers have also been reported from a peat deposit at philippi in northeastern greece

the phlegraean fields structural evolution volcanic history and eruptive mechanisms abstract the main event within the volcanic history of the phlegraean fields was the eruption about 35 000 years ago of a huge alkali trachytic ignimbrite 80 km 3 dre followed by caldera collapse the pre caldera activity evidence from geothermal wells and surface outcrops changed from submarine to subaerial shortly before the ignimbrite eruption the caldera was subsequently invaded by the sea and became progressively filled with tuffites and subordinate submarine flows in its northern half the last submarine explosive activity dates back to 12000 10500 yr with the eruption of mostly hydroplinian yellow tuffs recent mostly subaerial activity consists of a series of explosive eruptions whose volume decreases with time until the last eruption of mt nuovo in 1538 a d two peaks in recent activity occur at 10000 8000 and 4700 3000 years ago during post caldera activity eruptive vents migrated from the caldera rim toward the center where there are two distinct zones of recent vents minor collapses occurred within the caldera after the main eruptions often they are eccentric to the vent and displaced toward the caldera center phlegraean explosive activity is characterized by water magma interaction eruptive events without a hydromagmatic component are extremely rare in most cases the evolved trachytic magmas interacted with surface water either the sea or intracaldera lakes however there is evidence of interaction of magma with deep seated aquifers for some plinian events explosivity i e the efficiency of the transformation of thermal into kinetic energy during magma water interaction is largely controlled by the primary fragmentation of the magmatic melt

convection underneath a crust inhomogeneously enriched in heat sources application to martian mantle dynamics abstract two and three dimensional spherical convection models are presented which investigate the convection structure beneath a crust inhomogeneously enriched in radioactive elements the resulting convection patterns show a focusing of upwellings under the enriched part of the crust and downwellings under the not enriched part that maintain large scale horizontal motion from the warmer to the cooler region beneath the lithosphere and vice versa above the core mantle boundary this flow pattern is observed in all examined models independent of the mantle heating mode it is however more pronounced for models with a considerable amount of internal heating than for models with almost total bottom heating thermal blanketing of the mantle beneath the enriched part of the crust plays only a minor role in the lateral heat flux distribution within the lithospheric mantle and is almost insignificant for the surface heat flux distribution which is dominated by crustal heat generation implications of the results for mars are discussed

aeolian dust transport and deposition over crete and adjacent parts of the mediterranean sea monitoring of dust deposition at several stations on crete over a three year period has shown that the present day depositional flux is of the order of 10 100 gm 2 yr 1 most of the dust deposition takes place during a few annual dust events which typically last for 1 3 days dust haze episodes are usually associated with southerly or southwesterly winds which transport fine sediment from north africa dust is raised by a wide variety of meteorological conditions which generate strong near surface winds in the source areas but major long range transport events are often associated with cold fronts linked to the passage of deep mid latitude depressions during winter and spring dust haze frequency and deposition rates are highest in western crete and decrease towards the east suggesting that transport from tunisia and neighbouring parts of north africa is particularly important the measured rate of dust deposition is well below the minimum level required for loess formation deposits which have previously been identified as loess are shown to be uncemented marine marls of tertiary age laboratory analysis of red soils surface sediments and bedrock samples has confirmed that many of the soils contain an important aeolian dust component but it is concluded that a more important source of soil parent material is provided by weathering of local rocks many of the soils contain significant amounts of quartz sand which cannot have been transported across the sea from north africa reworking of weathered material and deposited dust is extensive and is accomplished by both aeolian and fluvial processes tectonically controlled depressions in the mountains and parts of the coastal lowlands have acted as long term sinks in which a thickness of several metres of sediment and soil has accumulated during the quaternary

surface waves of the 2011 tohoku earthquake observations of taiwan s dense high rate gps network 1 surface waves generated by the 2011 mw 9 0 tohoku japan earthquake were recorded by both the high rate gps and broadband seismic stations in taiwan in this study we investigate the precision of high rate gps displacements and estimate the feasibility of using gps for seismology study in taiwan one hertz observations of 210 continuous gps stations in taiwan and neighboring islands were processed using a precise point positioning technique to estimate the absolute epoch by epoch positions generated by the tohoku earthquake modified sidereal filtering was used to correct for near daily periodical variations of high rate position time series that may be influenced by multipath effects and a band pass filter was used to remove noises from marginal frequencies for all the 210 stations the gps precision after modified sidereal filtering improved from 8 2 to 7 4 mm in the horizontal and from 19 5 to 12 7 mm in the vertical components except for about 20 of the data with large position errors after applying the band pass filter in the teleseismic frequency band 0 008 0 08 hz excluding 54 stations with noisy data 156 continuous gps stations were selected surface wave displacements derived from both high rate gps and broadband seismometers are highly consistent and the correlation coefficients are enhanced by a band pass filter 0 008 0 08 hz from 0 85 to 0 95 in the horizontal and from 0 58 to 0 85 in the vertical components we consider continuous gps can be used as an alternative approach to study characteristics of surface wave propagation in taiwan

dimensions and dynamics of co ignimbrite eruption columns very powerful volcanic eruptions cannot always form classical plinian eruption columns1 4 instead collapsing fountains may develop above the vent and shed pyroclastic flows which spread laterally along the ground5 the upper part of these hot dense pyroclastic flows may become buoyant through the entrainment heating and expansion of ambient air coupled with the sedimentation of larger clasts suspended in the flow the buoyant material may rise in a co ignimbrite eruption column carrying massive quantities of fine dust and volatiles into the stratosphere6 7 here we present a model of this process and show that the co ignimbrite columns associated with the eruptions of toba8 9 75 000 years ago and tambora10 in 1815 may have ascended only about 32 and 23 km the latter is comparable with the less powerful 1982 plinian eruption column of el chichon11 this corroborates arguments that the mass of sulphuric acid aerosols injected into the stratosphere and not the eruptive power determines the climatic impact of an eruption12 13

petrogenesis and tectonic setting of the roman volcanic province italy abstract the volcanism in the roman province of italy can be modelled by the partial melting of heterogeneously enriched mantle sources the heterogeneity was created by materials derived from a subducted slab which can still be traced geophysically beneath the central apennines new petrographical and chemical data are presented for the high k calc alkaline and the shoshonitic volcanics of the campania region primary magmas are present only locally the existence of spatial zonation in the volcanism of campania is documented for the first time the shoshonitic leucite basanitic and leucititic volcanics of the phlegraean fields procida ischia and the somma vesuvius areas are at similar degrees of evolution about two times richer in nb and ba than those of northwestern campania and the latium part of the roman province accordingly distinct north western and south eastern subprovinces can be defined the evaluation of enrichment factors that is the abundance ratio between the average contents of each element in the relatively primitive lavas of the low k and the high k suites shows that the mantle sources prior to k metasomatism were different in the two sub provinces of the roman province in the north western one they resembled the sources of ocean island tholeiites and moderately enriched mor basalts in the south east they were similar to those of ocean island alkaline lavas and enriched morb s modelling based on k p ce sr rb ba th sm eu gd y nb and 87 sr 86 sr was carried out it indicates that the range of mantle sources of the volcanics in northwestern campania and latium can be modelled by the addition of 3 to 20 of materials derived by partial melting of carbonaceous pelites to a sr enriched mantle wedge comparable to the honolulu mantle source least enriched in nb the production of sr enriched mantle wedge requires either the action of fluids produced by dehydration of subducted oceanic crust or a small amount of metasomatism caused by the presence of carbonatite melts the near absence of ti ta nb yb and the highly fractionated ree in the metasomatizing component requires the presence of residual garnet and accessory ti rich minerals during the partial melting of the subducted sediments the writers propose that the mantle wedge overlying the subducted slab was hybridized by melts produced by partial fusion of subducted material derived from the continental crust probably sediments this process played a dominant role in the generation of the mantle sources from which the high k calc alkaline shoshonitic leucite basanitic and leucititic magmas of the roman province were derived

effects of vertical boundaries on infinite prandtl number thermal convection summary the physics of thermomechanical coupling of the continental lithosphere and its surrounding mantle is studied using a simple hydrodynamic model in which a fluid is heated from below and is bounded by rigid side walls rayleigh numbers up to 106 are considered a series of finite element stability analyses is employed to characterize systematically the nature of convective instability in such a system the marginal stability of a bounded fluid is increased not only by the rigid boundary condition on side walls but also by heat conduction across side walls the planform of convection at the marginal state is 3 d having convective rolls aligned perpendicular to side walls the characteristics of non linear convection at supercritical rayleigh numbers are investigated by first calculating 2 d steady state solutions and then applying 2 d and 3 d stability analyses the 2 d stability analysis shows that the presence of side walls significantly reduces the transition rayleigh number for time dependent convection and the 3 d stability analysis shows that heat conduction through side walls strongly prefers 3 d convective motion finally the characteristics of 3 d convection are analysed through the 3 d single mode approximation both 2 d and 3 d single mode solutions demonstrate that conducting side walls reduce the strength of convection at low rayleigh numbers but have a negligible influence at higher rayleigh numbers we therefore propose that the basal topography of the continental lithosphere can modulate the convective planform efficiently in the upper mantle

the pianico tephra an early middle pleistocene record of intraplate volcanism in the mediterranean distal tephra are a valuable record of the volcano tectonic evolution of an area under study here we document the case of the early middle pleistocene rhyolitic tephra of pianico discovered in the southern italian alps the geochemical characteristics of pianico are unique among the distal tephra outcropping in italy and indicate an intraplate volcanism at the source the alkali composition and trace elements show a striking resemblance with the rhyolitic complex of the euganean hills located 170 km from pianico however these rhyolites are much older oligocene alternatively the source of this intraplate volcanic episode could be located in the southern tyrrhenian sea

revised tuning of ocean drilling program site 964 and kc01b mediterranean and implications for the δ18o tephra calcareous nannofossil and geomagnetic reversal chronologies of the past 1 1 myr 1 high resolution color reflectance records of kc01 and kc01b calabrian ridge ionian sea are presented and compared with a modified spliced high resolution color reflectance record of ocean drilling program odp site 964 this comparison revealed that kc01b is characterized by intensive deformation between 27 and 28 5 m piston depth and that some sapropels are tectonically reduced in thickness moreover the piston coring has caused considerable stretching in the top of kc01 and kc01b using a new splice of odp site 964 as guide previous astronomical tuned timescales of kc01b and odp site 964 were evaluated this evaluation resulted in a new sapropel based astronomical timescale for the last 1 1 myr the new timescale implies a much more uniform change in sedimentation rate for the ionian sea cores two prominent excursions to lighter values in the 18o record of the planktonic foraminiferal species globigerinoides ruber occur during marine isotopic stages 12 and 16 applying the new timescale these shifts correspond with maxima in obliquity and are punctuated by minima in the precession cycle they are absent in global ice volume records and are interpreted as reflecting a summer low salinity surface water lens that floats on top of extremely saline intermediate and deep waters at times of the very low sea levels during these glacial periods all biostratigraphic and magnetostratigraphic events found in kc01b and odp site 964 were re dated according to the new timescale and the ages of 33 tephra layers were reviewed the new ages for the calabrian ridge 2 and 3 magnetic events in the brunhes are concordant with minima in the global sint800 composite record derived from worldwide deep sea records of relative paleointensity and have been attributed to the big lost and la palma excursions respectively

plinian fall deposits from vulsini volcanic district central italy stratigraphic investigations of the vulsini volcanic district indicate the existence of five prominent plinian fall deposits deposited over a period of about 0 34 ma the oldest deposit basal pumices crops out mainly in the peripheral areas and is one of the largest plinian events in the vulsini district with a volume of about 9 km3 and a calculated column height exceeding 30 km subcircular patterns of isopachs and isopleths around the bolsena lake indicate emplacement in wind free conditions and suggest a source vent location in the northernmost sector of the present bolsena lake where it is possible that an older central volcanic structure existed the four younger plinian fall deposits are related to bolsena activity the oldest of these named the ponticello and orvieto bagnoregio pumices are mainly distributed on the north eastern sector of the vulsini district their volumes are an order of magnitude lower than that of the basal unit and the estimated column heights do not exceed 20 km the younger ospedaletto pumice deposit has a ne sw dispersal axis whereas the youngest casetta pumice deposit is found only in the north eastern sector of the district their estimated volumes are respectively 1 2 and 0 1 km3 whereas the inferred vent areas appear to be located slightly to the east of the ponticello and orvieto bagnoregio pumice deposit source areas the chronology of the ospedaletto and casetta pumices indicates that the final plinian activity from the bolsena complex is contemporaneous with the latera activity the decreasing volumes from the oldest to the youngest units together with the progressive shifting northeastwards of the source vents may be related to the volcano tectonic subsidence of the bolsena area the source vents for the post basal pumices events are mainly clustered just north of bolsena village where the greatest displacement during subsidence occurred accordingly source vent shifting appears to be related to the progressive opening of normal faults from the inner to the outer margin of the bolsena depression

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

an exceptionally thick middle pleistocene tephra layer from epirus greece abstract a newly recognized 2 m thick trachytic volcanic ash deposit from northwestern greece is dated at 374 000 7000 yr and correlated with the middle pleistocene volcanic activity of central italy the deposit represents ash fallout from one of the largest volcanic eruptions in europe of the past 400 000 yr and should provide an important stratigraphic marker within the poorly dated middle pleistocene deposits of italy and greece