discussion geological investigation and optical dating of quaternary siliciclastic sediments near apalachicola north west florida usa by burdette et al 2012 sedimentology 59 1836 1849

flowgo a kinematic thermo rheological model for lava flowing in a channel we present a kinematic self adaptive numerical model to describe the down flow thermal and rheological evolution of channel contained lava as our control volume of lava advances down a channel it cools and crystallizes an increasingly thick and extensive surface crust grows and its heat budget and rheology evolve by estimating down flow heat and velocity loss our model calculates the point at which the control volume becomes stationary giving the maximum distance lava flowing in the channel can extend modeled effusion rates velocities widths surface crust parameters heat budget cooling temperature crystallinity viscosity and yield strength all compare well with field data collected during eruptions at mauna loa k lauea and etna modeled lengths of 25 27 2 5 5 7 and 0 59 0 83 km compare with measured lengths of 25 27 4 and 0 75 km for the three flows respectively over proximal flow portions we calculate cooling crystallization viscosity and yield strength of 1 10 c km 1 0 001 0 01 volume fraction km 1 103 104 pa s and 10 3 102 pa respectively at the flow front cooling crystallization viscosity and yield strength increase to 100 c km 1 0 1 volume fraction km 1 106 107 pa s and 103 104 pa respectively all of which combine to cause the lava to stop flowing our model presents a means of a analyzing lava flow thermo rheological relationships b identifying important factors in determining how far a channel fed flow can extend c assessing lava flow hazard and d reconstructing flow regimes at prehistoric unobserved or remote flows

rapid magma ascent recorded by water diffusion profiles in mantle olivine mechanisms and rates of magma ascent play a critical role in eruption dynamics but remain poorly constrained phenomena water dissolved in mantle minerals as hydrogen and partitioned into the magma during ascent may provide clues to quantifying magma ascent rates prior to eruption we determined the dehydration profiles in olivine crystals from peridotite mantle xenoliths within the pali aike alkali basalt from patagonia chile the results demonstrate that the amount of water stored in the uppermost mantle has likely been underestimated due to water loss during transport using experimental diffusion data for hydrogen we estimate that the xenoliths reached the surface from 60 70 km depth in several hours a surprisingly rapid rise comparable to ascent rates for kimberlite magmas

coastal barriers nomenclature processes and classification issues abstract the designation coastal barrier related terms and their varied interpretations and critical concepts in coastal plain and nearshore geology underwent numerous reincarnations over the years this designation was first applied to shore parallel sand and gravel built ocean front islands and spits that separate open marine environments from paralic inshore environments that they shelter a more recently recognized third category includes mainland strandplain chenier and dunefield barriers either as original components of mainland coasts or subsequently welded to the coastal plain a parallel but closely related terminology developed mostly in australia and brazil identifies several specific process categories recognizable in the three basic barrier groups in the absence of lagoons and tidal wetlands shore ridges that front and are contiguous with the mainland coastal plain have been mistakenly assigned to the barrier island category greatly diminished wave energy and consequently minor littoral drift volumes account for the relative rarity and much smaller dimensions of prograded landforms in estuarine islands and bay shore beaches in paralic inshore basins due to wave and related littoral drift processes however diminished in comparison with open marine shores morphological similarities between aggraded landforms of open marine through estuarine settings are to be expected however the multitude of proposed fetch limited diminished wave energy estuarine islands characterized by diminutive narrow beaches sand spits even occasional small dunes and miniature strandplains lack the essential functional attributes intrinsic to true barrier islands while barrier islands may form even on relatively low wave energy and or sediment deficient marine shores the term is inappropriate for islands located in low energy paralic basins including estuaries or in coastal plains where frontal shore ridges are not backed by lagoons landforms erroneously ascribed in a variety of facies settings as barrier islands or islands frequently are mainland attached beach ridge plains or beach fringed marshlands instead narrow marshland beaches and mainland strandplain barriers are segmented into short islands by intervening narrow tidal creeks fluvial distributary channels or storm cuts that separate them improved fundamental and functional definitions of barrier islands their comparison with the many genetic categories of islands and mainland shore beaches found in estuarine basins and wetlands should lead to a better understanding of paralic island evolution processes on the global scale

simulations of the 2004 lava flow at etna volcano using the magflow cellular automata model since the mechanical properties of lava change over time lava flows represent a challenge for physically based modeling this change is ruled by a temperature field which needs to be modeled magflow cellular automata ca model was developed for physically based simulations of lava flows in near real time we introduced an algorithm based on the monte carlo approach to solve the anisotropic problem as transition rule of ca a steady state solution of navier stokes equations was adopted in the case of isothermal laminar pressure driven bingham fluid for the cooling mechanism we consider only the radiative heat loss from the surface of the flow and the change of the temperature due to mixture of lavas between cells with different temperatures the model was applied to reproduce a real lava flow that occurred during the 2004 2005 etna eruption the simulations were computed using three different empirical relationships between viscosity and temperature

continuous gps and broad scale deformation across the rhine graben and the alps in order to study the ongoing tectonic deformation in the rhine graben area we reconstruct the local crustal velocity and the strain rate field from gps array solutions following the aim of this work we compile the velocities of permanent gps stations belonging to various networks euref agnes regal and rgp in central western europe moreover the strain rate field is displayed in terms of principal axes and values while the normal and the shear components of the strain tensor are calculated perpendicular and parallel to the strike of major faults the results are compared with the fault plane solutions of earthquakes which have occurred in this area a broad scale kinematic deformation model across the rhine graben is provided on the basis of tectonics and velocity results of the gps permanent stations the area of study is divided into four rigid blocks between which there might be relative motions the velocity and the strain rate fields are reconstructed along their borders by estimating a uniform rotation for each block the tectonic behaviour is well represented by the four block model in the rhine graben area while a more detailed model will be needed for a better reconstruction of the strain field in the alpine region

viscosity of hydrous etna basalt implications for plinian style basaltic eruptions water dissolved in a silicate melt can strongly influence its physical properties and thus magma behavior during crystallization degassing foaming and fragmentation etna is a basaltic volcano whose activity is dominated by effusive eruptions which have long represented a threat to the densely populated surrounding area recently recognition of the products of a plinian eruption 122 b c has raised further issues for hazard assessment at etna and other basaltic volcanoes constraining the behavior of etna magma under conditions relevant to both effusive and explosive hazards requires viscosity data under conditions near the glass transition here we have investigated the viscosity of hydrous etna lava in order to better understand eruptive processes which characterize this volcano the experimental methods which have been used include piston cylinder synthesis of the hydrated melts micropenetration viscometry for low temperature viscosity measurements and near infrared spectroscopy for the evaluation of sample homogeneity and measurements of water content additionally scanning calorimetric determinations were performed to check whether incipient crystallization had occurred sample compositions were determined using electron microprobe analysis and 57fe mossbauer spectroscopy results from this study are compared with previous reports of trachytic phonolitic and model calc alkaline rhyolite hpg8 compositions the viscosity of the basaltic melt dry and wet has been parameterized in terms of temperature and water content via the non arrhenian equation log10 4 643 5 812 44 427 04 h2o t k 499 31 28 74 ln h2o where is the viscosity in pa s h2o is the water content in wt and t is the temperature in kelvin we observe that the viscosity of alkali basalt at more than 0 5 wt h2o is similar to that of an alkaline trachyte agnano monte spina eruption phlegrean fields and much higher than that of a peralkaline phonolite teide tenerife at similar silica contents and nbo t for water contents above 1 5 wt the viscosity of the basalt is similar to that of rhyolitic melts with similar water contents at temperatures ranging from 1 050 to 1 150 c and with water contents between 0 5 and 2 3 wt eruptive conditions the viscosities calculated using the equation defined in this study are 1 in reasonable agreement with those calculated using shaw s model and 2 much lower than those experimentally determined in a previous study however outside these temperature and water content ranges the agreement with shaw s model 1972 breaks down

spatial probability distribution of future volcanic eruptions at el hierro island canary islands spain abstract the 2011 submarine eruption that took place in the proximity of el hierro island canary islands spain has raised the need to identify the most likely future emission zones even on volcanoes characterized by low frequency activity here we propose a probabilistic method to build the susceptibility map of el hierro i e the spatial distribution of vent opening for future eruptions based on the probabilistic analysis of volcano structural data of the island collected through new fieldwork measurements bathymetric information as well as analysis of geological maps orthophotos and aerial photographs these data have been divided into different datasets and converted into separate and weighted probability density functions which were included in a non homogeneous poisson process to produce the volcanic susceptibility map the most likely area to host new eruptions in el hierro is in the south western part of the west rift high probability locations are also found in the northeast and south rifts and along the submarine parts of the rifts this map represents the first effort to deal with the volcanic hazard at el hierro and can be a support tool for decision makers in land planning emergency measures and civil defense actions

radiocarbon ages of holocene pelado guespalapa and chichinautzin scoria cones south of mexico city implications for archaeology and future hazards pelado guespalapa and chichinautzin monogenetic scoria cones located within the sierra del chichinautzin volcanic field scvf at the southern margin of mexico city were dated by the radiocarbon method at 10 000 2 800 4 700 and 1 835 years b p respectively most previous research in this area was concentrated on xitle scoria cone whose lavas destroyed and buried the pre hispanic town of cuicuilco around 1 665 35 years b p the new dates indicate that the recurrence interval for monogenetic eruptions in the central part of the scvf and close to the vicinity of mexico city is 2 500 years if the entire scvf is considered the recurrence interval is 1 700 years based on fieldwork and landsat imagery interpretation a geologic map was produced morphometric parameters characterizing the cones and lava flows determined and the areal extent and volumes of erupted products estimated the longest lava flow was produced by guespalapa and reached 24 km from its source total areas covered by lava flows from each eruption range between 54 chichinautzin and 80 km2 pelado and total erupted volumes range between 1 and 2 km3 cone an average eruption rate for the entire scvf was estimated at 0 6 km3 1 000 years these findings are of importance for archaeological as well as volcanic hazards studies in this heavily populated region

a quantitative approach for evaluating lava flow simulation reliability lavasim code applied to the 2001 etna eruption an edited version of this paper was published by agu copyright 2009 american geophysical union

geometric difference between non feeder and feeder dikes feeder dikes bring magma to the surface non feeder dikes become arrested and never reach the surface the differences if any between these dike types remain largely unexplored because in the field it is normally unknown if a particular dike is a feeder or non feeder here we present measurements of feeder and non feeder dikes exposed from depths of 200 m to the surface in the walls of the a d 2000 caldera collapse of the miyakejima volcano japan a typical feeder thickness reaches a maximum of 2 4 m at the surface decreases rapidly to 1 m at a depth of 20 40 m and then remains constant to the bottom of the exposure by contrast a typical non feeder thickness reaches a maximum of 1 5 2 m at 15 45 m below the tip and then decreases slowly with depth to 0 5 1 m at the bottom of the exposure we propose that free surface effects and magmatic overpressure driving pressure changes during the eruption cause the overall shape of a feeder to differ from that of a non feeder

proximal tephra hazards recent eruption studies applied to volcanic risk in the auckland volcanic field new zealand abstract auckland new zealand is unique in being a metropolitan area built on an active volcanic field despite the small size and intensity of auckland eruptions the risk from tephra fall is high because of the high density of buildings and lifelines the nature of this threat can be evaluated by comparisons with historical strombolian and hawaiian eruptions which have occurred in non populated areas cone building phases of such eruptions are typically protracted i e weeks to months in duration prolonging the period during which emergency managers will have to fine tune mitigation for numerous parameters such as fluctuations in intensity and wind shifts rapid cone growth during future eruptions will define a region of some 30 to 100 ha where complete destruction will occur on a time scale of hours the cost of this destruction is likely to range between nz 200m and nz 1 4b ca us 130m to us 900m beyond this we have modeled the cumulative long term effect of the build up of a downwind blanket of lapilli and ash by estimating accumulation rates for three phases of the 1959 k lauea iki eruption in hawai i the effect of changing wind direction was evaluated using low level wind data from auckland these results show that intervals between 4 and 100 h will lapse before onset of significant damage to buildings

influences on the variability of eruption sequences and style transitions in the auckland volcanic field new zealand abstract monogenetic basaltic volcanism is characterised by a complex array of eruptive behaviours reflecting spatial and temporal variability of the magmatic properties e g composition eruptive volume magma flux as well as environmental factors at the vent site e g availability of water country rock geology faulting these combine to produce changes in eruption style over brief periods minutes to days in many eruption episodes monogenetic eruptions in some volcanic fields often start with a phreatomagmatic vent opening phase that later transforms into dry magmatic explosive or effusive activity with a strong variation in the duration and importance of this first phase such an eruption sequence pattern occurred in 83 of the known eruption in the 0 25 my old auckland volcanic field avf new zealand in this investigation the eruptive volumes were compared with the sequences of eruption styles preserved in the pyroclastic record at each volcano of the avf as well as environmental influencing factors such as distribution and thickness of water saturated semi to unconsolidated sediments topographic position distances from known fault lines the avf showed that there is no correlation between ejecta ring volumes and environmental influencing factors that is valid for the entire avf in contrary using a set of comparisons of single volcanoes with well known and documented sequences resultant eruption sequences could be explained by predominant patterns of the environment in which these volcanoes were erupted based on the spatial variability of these environmental factors a first order susceptibility hazard map was constructed for the avf that forecasts areas of largest likelihood for phreatomagmatic eruptions by overlaying topographical and shallow geological information combining detailed phase by phase breakdowns of eruptive volumes and the event sequences of the avf along with the new susceptibility map more realistic eruption scenarios can be developed for different parts of the volcanic field this approach can be applied to tailoring field and sub field specific hazard forecasting at similar volcanic fields worldwide

numerical simulation of basaltic lava flows in the auckland volcanic field new zealand implication for volcanic hazard assessment monogenetic volcanic fields such as the auckland volcanic field avf new zealand are common on the earth s surface and are typically dominated by basaltic lava flows up to 10 s of km long in monogenetic volcanic fields located in close proximity to human population and infrastructure lava flows are a significant threat in this study lava flow emplacement conditions for some basaltic eruptions of the avf were reconstructed using the thermo rheological magflow model eight existing lava flows in the avf were simulated using magflow and eruptive volumes measured from light detection and ranging lidar derived digital terrain models dtms fitting the simulations to the dimensions of actual lava flows provides insight into their emplacement mechanisms and conditions such as effusion rate and probable eruption durations by looking at emplacement in different settings the likely magma ascent rate for studied avf eruptions is calculated to have been on the order of 0 1 m s in the avf the typical estimated duration of past lava flows was from a minimum of 2 days for small volume flows such as little rangitoto 0 0015 km3 up to 83 days for large volume flows such as three kings 0 078 km3 the three best fitting simulations were used to establish eruption scenarios for future volcanic hazard mapping for the avf inferences of eruption duration that will be useful for developing realistic emergency management plans and recovery scenarios for this densely populated volcanic field are also provided

luminescence dating of interglacial coastal depositional systems recent developments and future avenues of research abstract luminescence dating offers new opportunities to explore the evolution of quaternary marine coastal facies and landforms this review highlights the main advances in luminescence geochronology of interglacial coastal sediments through the analysis of 547 luminescence ages most of which were published during the last decade the majority of these reported luminescence investigations have been carried out along passive margin coasts since the turn of the century the discovery of a normalization procedure known as single aliquot regeneration sar has drastically reduced data scatter and improved precision with the consequence that quartz sar optically stimulated luminescence osl has become the dating protocol of choice for the last interglacial lig period a more complex technique known as thermally transferred osl tt osl is presumably proposed for dating older interglacials of the mid pleistocene and beyond feldspar luminescence is increasingly being applied to dating pleistocene sea level high stands due to a much higher dose saturation level than quartz osl the use of feldspar irsl infrared stimulated luminescence is limited by the occurrence of variable but ubiquitous anomalous fading af following the advent of af correction methods several middle pleistocene sites have been amenable to dating albeit with significant related uncertainties recently new protocols involving the measurement of post ir irsl at elevated temperatures have yielded relatively coherent ages for interglacial sediments up to ca 300 ka quartz osl tt osl af corrected irsl and post ir irsl ages are generally correlated with periods of sea level high stands a few ages are reported from the early and middle part of the middle pleistocene as mis11 9 and more commonly mis7 high stands are documented in strongly uplifting active margin coasts however by far the most obvious age peak corresponds to the end of the lig the mis5e shoreline is probably the most studied and luminescence dated coastal feature of all as the chronology of the sea level markers is crucial to assess global eustatic sea level variations through the course of the last interglacial nevertheless the observed abundance of young 100 120 ka luminescence ages for presumed mis5e sediments may underline methodological issues and or reflect the higher preservation potential of late regressive sequences on the other hand the occurrence of geographically distant reports of mis5a high stand might reflect a true eustatic origin for this event age analysis supports the impression of general reliability of luminescence for the timing of former sea level high stands there is a clear need to address issues in dose rate variability in the phenomenology of fading in feldspar and in the behaviour of luminescence growth with dose both in laboratory and natural conditions these could be addressed and properly evaluated by dating different minerals as multiple or single grains with consequent variable internal dose rates more robust practices in the application of luminescence dating techniques could eventually constrain the age uncertainties to no better than 2 3 therefore the strength of luminescence as a dating tool is more in terms of its extended age range and the ubiquity of datable material

using infrared satellite data to drive a thermo rheological stochastic lava flow emplacement model a method for near real time volcanic hazard assessment 1 we combine two flow simulation models to provide a computationally efficient means of predicting the final dimensions of active lava flows by using a stochastic approach to predict all the downhill paths that a lava flow could possibly follow and a thermo rheological model to terminate these paths once the predicted cooling limited length for the flow has been attained this approach allows for rapid assessment of the area likely to be inundated by lava the 1991 1993 eruption of mount etna is used as a case study lava effusion rate exerts a strong control on the maximum length a lava flow can attain and we demonstrate how the model can be driven by time varying effusion rates obtained from infrared satellite data as such data are obtained in near real time this approach allows flow simulations to be updated in a timely manner in response to changing eruption conditions

vtfs project development of the lava flow simulation code lavasim with a model for three dimensional convection spreading and solidification 1 the lava flow simulation code lavasim has been developed to give accurate predictions of volcanic disasters and to support evacuation plans the code uses three dimensional analysis with free surface evaluation including boundary transport between the melt and the crust it is therefore applicable to various types of lava flows and flow behaviors such as flood basalts subaqueous lava flows and levee formation heat transfer between the lava and the ground air and water and between the melt and crust of the flow is calculated by using appropriate relations the code has been verified by applying it to actual lava flows and the simulation results have been compared with observations of the izu osima flows of 1986 the lava flow rate temperature and properties were assigned values based on data from existing literature the comparisons demonstrated the code s capability for prediction of inundated areas and maximum flow lengths the present code is expected to be useful for real time prediction during eruptions in addition to assessing volcanic hazards and designing protection structures for existing installations against possible future lava flows

near real time forecasting of lava flow hazards during the 12 13 january 2011 etna eruption we are grateful to eumetsat for seviri data to nasa for modis data and tonoaafor avhrr data the authors thank one anonymous reviewer and v acocella for their helpful and constructive comments this study was performed with the financial support from the v3 lava project ingv dpc 2007 2009 contract

geological investigation and optical dating of quaternary siliciclastic sediments near apalachicola north west florida usa ground penetrating radar and single aliquot regenerative dose optically stimulated luminescence were used to determine the depositional environments and age of unconsolidated siliciclastic sediments near apalachicola florida five direct push cores five vibracores and 28 optically stimulated luminescence samples were collected as well as 7 km of ground penetrating radar data a new model of cosmic dose rate calculation which removes the effect of a much younger aeolian cap was utilized to calculate more representative optically stimulated luminescence ages five radar facies were identified based on reflector amplitude and orientation the resulting data indicate that the tertiary quaternary shelly sediments were deposited before marine isotope stage 6 the quaternary alluvium was deposited during marine isotope stage 6 and the quaternary beach ridge and dune was deposited during the marine isotope stage 5e sea level highstand which peaked at approximately 2 5 m above present sea level in this area

amplified hazard of small volume monogenetic eruptions due to environmental controls orakei basin auckland volcanic field new zealand orakei maar and tuff ring in the auckland volcanic field is an example of a basaltic volcano in which the style and impacts of the eruption of a small volume of magma were modulated by a fine balance between magma flux and groundwater availability these conditions were optimised by the pre 85 ka eruption being hosted in a zone of fractured and variably permeable plio pleistocene mudstones and sandstones orakei maar represents an end member in the spectrum of short lived basaltic volcanoes where substrate conditions rather than the magmatic volatile content was the dominant factor controlling explosivity and eruption styles the eruption excavated a crater 80 m deep that was subsequently filled by slumped crater wall material followed by lacustrine and marine sediments the explosion crater may have been less than 800 m in diameter but wall collapse and wave erosion has left a 1 000 m diameter roughly circular basin a tuff ring around part of the maar comprises dominantly base surge deposits along with subordinate fall units grain size texture and shape characteristics indicate a strong influence of magma water and magma mud interactions that controlled explosivity throughout the eruption but also an ongoing secondary role of magmatic gas driven expansion and fragmentation the tuff contains 70 of material recycled from the underlying plio pliestocene sediments which is strongly predominant in the 2 fraction the magmatic clasts are evolved alkali basalt consistent with the eruption of a very small batch of magma the environmental impact of this eruption was disproportionally large when considering the low volume of magma involved dre 0 003 km3 hence this eruption exemplifies one of the worst case scenarios for an eruption within the densely populated auckland city destroying an area of 3 km2 by crater formation and base surge impact an equivalent scenario for the same magma conditions without groundwater interaction would yield a scoria spatter cone with a diameter of 400 550 m destroying less than a tenth of the area affected by the orakei event

late holocene slackwater deposits on the nakagawa river tochigi prefecture japan a continuous succession of slackwater deposits was investigated on the nakagawa river karasuyama town in tochigi prefecture japan forty one and 32 flood events were estimated from two sedimentary cores minimum sedimentation rate is estimated at 4 6 mm year and the calculated maximum flood recurrence interval is 14 years the sedimentation rates are high compared to other published data and are thought to be the key reason as to why these deposits were preserved in japan previously considered too humid high sediment accumulation rates are thought to compensate for any bioturbation activity that would disturb and homogenise the slackwater deposits this study is important because it presents a new arena for palaeoflood analysis suggesting that there is potential for slackwater preservation in similar humid settings

penultimate deglacial sea level timing from uranium thorium dating of tahitian corals the timing of sea level change provides important constraints on the mechanisms driving earth s climate between glacial and interglacial states fossil corals constrain the timing of past sea level by their suitability for dating and their growth position close to sea level the coral derived age for the last deglaciation is consistent with climate change forced by northern hemisphere summer insolation nhi but the timing of the penultimate deglaciation is more controversial we found by means of uranium thorium dating of fossil corals that sea level during the penultimate deglaciation had risen to 85 meters below the present sea level by 137 000 years ago and that it fluctuated on a millennial time scale during deglaciation this indicates that the penultimate deglaciation occurred earlier with respect to nhi than the last deglacial beginning when nhi was at a minimum

three long lava flows in north queensland the kinrara toomba and undara basaltic lava flows are from 55 to 160 km long and range in age from 13 to 190 ka the lavas were emplaced down low gradients 0 2 to 0 4 with volumes ranging up to 30 km3 they were not unusually hot at eruption 1130 1160 nor unusually fluid gentle topography controlled the flows and shallow drainage lines captured them lava tubes operated in places and some drained to form caves injection under surface crust was widespread producing inflation features ranging from tumuli and low plateaus to extensive ridges sustained eruption was essential for the development of the long flows but each is composite with pauses between successive pulses that partially covered the earlier longer flows the lava structures are mainly pahoehoe but some a a lavas are present of the three volcanoes involved undara is a simple low angle lava cone with a 200 m wide crater toomba is a low angled cone with several eruption centers and kinrara has a deep crater with evidence of strong fountaining effusion rates are not known but may have been relatively low similar to those observed in hawaiian volcanoes lava tubes most of which remained undrained are believed to have been of major importance in flow emplacement given the evidence of successive flows and the time needed to develop widespread inflation it is suggested that the two long flows over 100 km involved many decades of eruption

the influence of magma plumbing complexity on monogenetic eruptions jeju island korea terra nova 23 70 75 2011 abstract continuous pyroclastic successions from monogenetic volcanoes in the jeju island volcanic field korea were targeted for detailed geochemical investigations of juvenile ejecta to show that multiple distinct magma pulses may be erupted during a single monogenetic eruption deeply derived and possibly multiply sourced evolving magma pulses may erupt sequentially from the same vent and form generally uninterrupted depositional sequences with continuous chemical trends alternatively pulses can rise independently resulting in breccia horizons and truncation surfaces in depositional sequences and in stepped and mixed chemical trends we infer that uninterrupted eruptions result from clear plumbing systems in which a single large dyke system feeds an eruption and where differently sourced magmas are erupted independently congested plumbing systems consisting of dyke complexes give rise to vent shifts asymmetrical eruptive centres and composite depositional sequences integration of chemical variation and eruptive dynamics provides a powerful means of understanding monogenetic volcanoes

rapid and widespread response of the lower mississippi river to eustatic forcing during the last glacial interglacial cycle the lower mississippi valley provides an exceptional fi eld example for studying the response of a continental scale alluvial system to upstream and downstream forcing associated with the large orbitally controlled glacialinter glacial cycles of the late quaternary however the lack of a numerical chronology for the widespread pleistocene strata assemblage known as the prairie complex which borders the holocene fl oodplain of the lower mississippi river has so far precluded such an analysis here we apply optically stimulated luminescence osl dating mainly on silt sized quartz from prairie complex strata in total 27 osl ages indicate that the prairie complex consists of multiple allostratigraphic units that formed mainly during marine isotope stages 7 5e and 5a thus the aggradation of the prairie complex is strongly correlated with the sea level highstands of the last two glacialinterglacial cycles fluvial incision during the sea level fall associated with the mis 5a mis 4 transition extended as far inland as 600 km from the present day shoreline testifying to the dominant downstream control of fl stratigraphic architecture in the lower mississippi valley in addition the short reaction time of the lower mississippi river suggests that large fl uvial systems can respond much more rapidly to allogenic forcing than is commonly believed

prospects for interregional correlations using wisconsin and holocene aridity episodes northern gulf of mexico coastal plain abstract luminescence dating of extensive dune fields and associated eolian sandsheets provided a chronology of recently recognized pleistocene and early holocene dry climate episodes in the currently humid warm temperate northern northeastern gulf of mexico region scattered parabolic dunes and clusters of intersecting parabolic dunes along with elongated shore transverse and shore parallel dunes developed these landforms occur in a 390 km long and 2 to 3 km wide semicontinuous belt in southeast alabama and northwestern florida dune elevations reach 22 m sangamon coastal barrier sectors were the primary source of the eolian sand deflation was coeval with early wisconsin to mid holocene marine low sea levels and associated distant shorelines early holocene dune dates were synchronous with indications of a hypsithermal dry interval in southeast louisiana the yucatan and the south atlantic seaboard overlapping with dry episodes in yucatan and the high plains texas dunes and louisiana and texas prairie mounds especially in the southwest texas coast still dominated by dry climate suggests intervals of early to late holocene drought the dates provide the basis for identifying and correlating wisconsin early and late holocene climate phases between currently semiarid and humid coastal and interior areas they contribute to future studies including interregional paleoclimate modeling although pleistocene coastal eolian deposition coincided with glaciation in the northern interior and with cooler temperatures of a reduced gulf of mexico holocene aridity phases may have been related to major variations in the position of high pressure cells storm tracks and branches of the jet stream and even to prolonged la nina conditions

phreatomagmatic eruptions through unconsolidated coastal plain sequences maungataketake auckland volcanic field new zealand abstract maungataketake is a monogenetic basaltic volcano formed at 85 89 ka in the southern part of the auckland volcanic field avf new zealand it comprises a basal 1100 m diameter tuff ring with a central scoria spatter cone and lava flows the tuff ring was formed under hydrogeological and geographic conditions very similar to the present the tuff records numerous density stratified wet base surges that radiated outward up to 1 km decelerating rapidly and becoming less turbulent with distance the pyroclastic units dominantly comprise fine grained expelled grains from various sedimentary deposits beneath the volcano mixed with a minor component of juvenile pyroclasts 35 vol subtle lateral changes relate to deceleration with distance and vertical transformations are minor pointing to stable explosion depths and conditions with gradual transitions between units and no evidence for eruptive pauses this volcano formed within and on 60 m thick plio pleistocene poorly consolidated highly permeable shelly sands and silts kaawa formation capped by near impermeable water saturated muds tauranga group these sediments rest on moderately consolidated miocene aged permeable turbiditic sandstones and siltstones waitemata group magma water fuelled thermohydraulic explosions remained in the shallow sedimentary layers excavating fine grained sediments without brittle fragmentation required on the whole the resulting cool wet pyroclastic density currents were of low energy the unconsolidated shallow sediments deformed to accommodate rapidly rising magma leading to development of complex sill like bodies and a range of magma water contact conditions at any time the weak saturated sediments were also readily liquefied to provide an enduring supply of water and fine sediment to the explosion loci changes in magma flux and or subsequent stabilisation of the conduit area by a lava ring barrier led to ensuing strombolian and fire fountaining eruption phases future eruptions in littoral environments around auckland are likely to be of this type producing base surges that rapidly decrease in energy over short runout distances 1 km

mitigation of lava flow invasion hazard through optimized barrier configuration aided by numerical simulation the case of the 2001 etna eruption abstract lava flow spreading along the flanks of etna volcano often produces damages to the land and proprieties the impact of these eruptions could be mitigated by building artificial barriers for controlling and slowing down the lava as recently experienced in 1983 1991 1993 2001 and 2002 this study investigates how numerical simulations can be adopted for evaluating the effectiveness of barrier construction and for optimizing their geometry considering as test case the lava flows emplaced on etna s south flank during 2001 the flow temporal evolutions were reconstructed deriving the effusion rate trends together with the pre eruption topography were adopted as input data of the magflow simulation code three simulations were then conducted to simulate lava flow with and without barriers the first aimed at verifying the reconstruction of the effusion rate trends while the others at assessing the performance of the barrier system realized during the eruption in comparison with an alternative solution here proposed a quantitative analysis carried out on the first simulation confirms the suitability of the selected test case the comparison of the three simulated thickness distributions showed both the effectiveness of the barriers in slowing down the lava flow and the sensitivity of the magflow code to the topographical variations represented by the barriers finally for reducing both the time necessary to erect the barrier and the barrier environmental impact the gabion s barrier construction was analyzed the implemented and tested procedure enforces the capability of using numerical simulations for designing optimized lava flow barriers aimed at making swifter mitigatory actions upon lava flows and improving the effectiveness of civil protection interventions during emergencies

a new approach to risk assessment of lava flow at mount etna destruction of human property by lava flow invasion is a significant volcanic hazard at mount etna italy where reliable risk maps are important for risk mitigation we present new high resolution quantitative risk maps of mount etna that are based on lava flow simulations starting from more than 70 000 different potential vents a probability distribution of vent location an empirical relationship for the maximum length of lava flows and a database of buildings in addition to standard risk maps which classify areas according to the expected damage at each point we classify each point of the volcano with respect to the damage that would occur if a vent opened at that point the resulting maps should help local authorities in making the necessary decisions to deal with ongoing eruptions and to plan long term land use

an emergent strategy for volcano hazard assessment from thermal satellite monitoring to lava flow modeling abstract spaceborne remote sensing techniques and numerical simulations have been combined in a web gis framework lav hazard to evaluate lava flow hazard in real time by using the hotsat satellite thermal monitoring system to estimate time varying tadr time averaged discharge rate and the magflow physics based model to simulate lava flow paths the lav hazard platform allows timely definition of parameters and maps essential for hazard assessment including the propagation time of lava flows and the maximum run out distance we used lav hazard during the 2008 2009 lava flow forming eruption at mt etna sicily italy we measured the temporal variation in thermal emission up to four times per hour during the entire duration of the eruption using seviri and modis data the time series of radiative power allowed us to identify six diverse thermal phases each related to different dynamic volcanic processes and associated with different tadrs and lava flow emplacement conditions satellite derived estimates of lava discharge rates were computed and integrated for the whole period of the eruption almost 14 months showing that a lava volume of between 32 and 61 million cubic meters was erupted of which about 2 3 was emplaced during the first 4 months these time varying discharge rates were then used to drive magflow simulations to chart the spread of lava as a function of time tadrs were sufficiently low 3 s that no lava flows were capable of flowing any great distance so that they did not pose a hazard to vulnerable agricultural and urban areas on the flanks of etna

volcanic risk ranking for auckland new zealand ii hazard consequences and risk calculation in a companion paper a methodology for ranking volcanic hazards and events in terms of risk was presented and the likelihood and extent of potential hazards in the auckland region new zealand investigated in this paper the effects of each hazard are considered and the risk ranking completed values for effect are proportions of total loss and as with likelihood and extent are based on order of magnitude

shallow seated controls on styles of explosive basaltic volcanism a case study from new zealand abstract the pyroclastic deposits of many basaltic volcanic centres show abrupt transitions between contrasting eruptive styles e g hawaiian versus strombolian or dry magmatic versus wet phreatomagmatic these transitions are controlled dominantly by variations in degassing patterns magma ascent rates and degrees of interaction with external water we use crater hill a 29 ka explosive effusive monogenetic centre in the auckland volcanic field new zealand as a case study of the transitions between these end member eruptive styles the crater hill eruption took place from at least 4 vents spaced along a nne trending 600 m long fissure that is contained entirely within a tuff ring generated during the earliest eruption phases early explosive phases at crater hill were characterised by eruption from multiple unstable and short lived vents later dominantly extrusive volcanism took place from a more stable point source most of the crater hill pyroclastic deposits were formed in 3 phreatomagmatic p and 4 dry magmatic m episodes forming in turn the outer tuff ring and maar crater p1 m1 p2 and scoria cone 1 m2 m4 this activity was followed by formation of a lava shield and scoria cone 2 purely wet activity is represented by the bulk of p1 and p2 and purely dry activity by much of m2 m4 however m1 and parts of m2 and m4 show evidence for simultaneous eruptions of differing style from adjacent vents and rapid variations in the extent and timing of magma water interaction at each vent the nature of the wall rock lithics and these rapid variations in inferred water magma ratios imply interaction was occurring mostly at depths of 80 m and the vesicularity patterns in juvenile clasts from these and the p beds imply that rapid degassing occurred at these shallow levels we suggest that abrupt transitions between eruptive styles in time and space at crater hill were linked to changes in the local magma supply rate and patterns and vigour of degassing during the final metres of ascent