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

ionospheric current source modeling and global geomagnetic induction using ground geomagnetic observatory data long period global scale electromagnetic induction studies of deep earth conductivity are based almost exclusively on magnetovariational methods and require accurate models of external source spatial structure we describe approaches to inverting for both the external sources and three dimensional 3 d conductivity variations and apply these methods to long period t 1 2 days geomagnetic observatory data our scheme involves three steps 1 observatory data from 60 years only partly overlapping and with many large gaps are reduced and merged into dominant spatial modes using a scheme based on frequency domain principal components 2 resulting modes are inverted for corresponding external source spatial structure using a simplified conductivity model with radial variations overlain by a two dimensional thin sheet the source inversion is regularized using a physically based source covariance generated through superposition of correlated tilted zonal quasi dipole current loops representing ionospheric source complexity smoothed by earth rotation free parameters in the source covariance model are tuned by a leave one out cross validation scheme 3 the estimated data modes are inverted for 3 d earth conductivity assuming the source excitation estimated in step 2 together these developments constitute key components in a practical scheme for simultaneous inversion of the catalogue of historical and modern observatory data for external source spatial structure and 3 d earth conductivity

pleistocene glacial relief of the central part of mt prokletije albanian alps abstract the central and highest area of mt prokletije albanian alps is situated in northern albania and eastern montenegro at 42 30 n the highest peak is maja e jezerces 2694 m detailed geomorphological mapping was used to reconstruct the positions of former glaciers the longest ropojana glacier had a length of 12 5 km and surface of 20 km 2 others include valbona glacier 9 5 km 10 5 km 2 grbaja glacier 5 km 6 7 km 2 and bogicevica glacier 6 km 6 9 km 2 three series of moraines can be distinguished the lowest at an average altitude of 990 m average ela 1750 m the middle series at 1350 m ela 1942 m and the highest at 1900 m ela 2123 m as no advanced dating methods have yet been used to provide a numerical chronological framework for these features hypotheses are made based on the comparison with the advanced studies of other similar mountains in the mediterranean region the moraines of the first stage lowest series correspond to one of pre lgm glaciations middle or even early wurmian the second stage moraines probably correspond to lgm and the third stage could be attributed to younger dryas the mapping included a number of inactive and active rock glaciers as well as three small active glaciers surface 5 ha and less at 1980 2100 m altitude in the area close to maja e jezerces

on the heterogeneous electrical conductivity structure of the earth s mantle with implications for transition zone water content 1 we have investigated the lateral variations in mantle electrical conductivity structure using electromagnetic sounding data for this purpose we used very long time series up to 51 years of geomagnetic observatory data at six locations encompassing different geological settings to compute response functions that cover the broadest possible frequency range 3 9 to 95 2 days furstenfeldbruck fur europe hermanus her south africa langzhou lzh china alice springs asp australia tucson tuc united states north america and honolulu hon united states north pacific we inverted the response functions beneath each observatory for a local radial conductivity profile using a stochastic sampling algorithm specifically we found significant lateral variations in conductivity throughout the mantle with resolution limited to the depth range 500 1200 km at 600 km depth conductivity varies between 0 1 and 0 4 s m and increases to 1 3 2 0 s m at 800 km depth beneath all stations except her 0 5 s m at 900 km depth conductivity increases further to 1 4 2 4 s m with her hon and asp being most conductive this trend persists to a depth of 1200 km comparison with conductivity profiles constructed from laboratory measurements of mantle mineral conductivities and models of earth s mantle composition and thermal state reveal that significant thermochemical variations are at the origin of the observed heterogeneities in mantle conductivity found here because of the somewhat large error bounds on sampled conductivity profiles and the reduced sensitivity of the electromagnetic sounding data above 500 km depth constraints on transition zone water content are less conclusive although h2o contents 0 5 wt in the midtransition zone appear less likely

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

three dimensional imaging of electrical conductivity in the mantle transition zone beneath the north pacific ocean by a semi global induction study abstract the three dimensional 3 d electrical conductivity distribution in and around the mantle transition zone mtz beneath the north pacific is imaged by inverting revised geomagnetic responses at 13 geomagnetic observatories and cable responses of 8 long baseline submarine cables in the area two one dimensional 1 d models representing the average structure beneath the north pacific were employed as the reference and initial models for the 3 d conductivity inversions the features in the revised semi global conductivity model in the mtz are 1 a high conductivity anomaly beneath the philippine sea 2 a high conductivity anomaly beneath the hawaiian islands and 3 a low conductivity anomaly beneath and in the vicinity of northern japan arrhenius plots of the conductivity and temperature estimated from global seismic tomography models indicate that the anomalies in the mtz beneath northern japan and most areas under hawaii can be explained mainly by the temperature effect but that the conductivity beneath the philippine sea requires an additional cause to explain the higher conductivity if the cause is the effect of water then the present result suggests high water content of 1 wt or more throughout the mtz beneath the philippine sea

the distal segment of etna s 2001 basaltic lava flow etna s 2001 basaltic lava flow provided a good example of the distal flow segment between the flow front and stable channel across which the flow evolves from channel contained to dispersed this zone was mapped with meter precision using lidar data collected during 2004 and 2005 these data supported by field mapping show that the flow front comprised eight lobes each 10 to 20 m high the flow front appears to have advanced not as a single unit but as a series of lobes moving forward one lobe at a time primary lobes were centered on the channel axis and marginal lobes were off axis the lobes advanced as breakouts of low yield strength lava from the flow core of the stalled flow front marginal lobes were abandoned and contributed to marginal levees flanking the transitional channel for etna s 2001 flow the transitional channel is 140 m wide 700 m long and fed a 240 m long zone of dispersed flow the change from stable to transitional channel occurred at a major reduction in slope above this the stable channel is 5 2 km long 55 to 105 m wide and bounded by 15 to 25 m high levees and the stable channel is located over a previous channel in a final stage of activity lava ponding at the break in slope that marks the terminus of the stable channel put pressure on the eastern levee causing it to fail liberated lava then fed a final break out to the east similar flow front features occur at other volcanoes indicating that similar processes are characteristic of dispersed flow zones

redox state microstructure and viscosity of a partially crystallized basalt melt abstract as measured in air above the glass transition range the viscosity of an alkali basalt increases markedly with time by about two orders of magnitude in 12 h this effect is essentially physical and due to the presence of microcrystals although partial crystallization of the melt into spinel and an sio2 poor pyroxene leads to a considerable enrichment in silica of the residual liquid partial crystallization depends strongly on the initial redox state of samples in that the presence of ferrous iron is required for spinel crystals to form and for pyroxene to nucleate and grow around them other measurements show that the viscosity of the crystal free liquid decreases slightly with increasing ratios r fe2 fe because the differences between samples with r 0 16 and 0 83 amount to about 1 5 and 0 3 log units at 950 and 1400 k respectively comparisons of the viscosities of the residual liquid matrix and of the initially crystal free basalt show that physical effects caused by the presence of microcrystals begin to be observed at a low crystal fraction of 5 vol finally a model of viscosity calculation is developed for the melts which reproduces all data obtained in this work to better than 10

on the vertical gradient and associated heterogeneity in mantle electrical conductivity abstract equivalent scalar magnetotelluric response functions obtained from the robust analysis of geomagnetic field daily mean values at 16 magnetic observatories have been systematically inverted data from these sites were found to contain sufficient one dimensional 1 d data consistent with required source field assumptions for meaningful interpretation and were also found to have acceptably well bounded response function confidence limits previous work is reviewed which indicates that significant lateral heterogeneity in mantle conductivity structure is required by the data and that most of these data are adequately modeled by a series of simple two layered earth models with a conductivity jump at depths of 500 1000 km regional variations in upper mantle conductivity have previously been suggested by systematic inversion using the h algorithm these features are examined in the restricted model space of conductance delta functions the statistical significance of these variations is also investigated new evidence is found here for the coast effect at very long periods as well as related evidence for the presence of electrically conductive zones in the upper mantle beneath the pacific ocean semi norm minimization inversion techniques are applied to directly place strong constraints on the sharpness of the vertical conductivity gradient in the mid mantle the mid mantle conductivity jump is required to be abrupt with values beneath this mid mantle transition zone of o 1 s m 1 at all sites

geomagnetic induction in a heterogeneous sphere fully three dimensional test computations and the response of a realistic distribution of oceans and continents summary long period geomagnetic data can resolve large scale 3 d mantle electrical conductivity heterogeneities which are indicators of physiochemical variations found in the earth s dynamic mantle a prerequisite for mapping such heterogeneity is the ability to model accurately electromagnetic induction in a heterogeneous sphere a previously developed finite element method solution to the geomagnetic induction problem is validated against an analytic solution for a fully 3 d geometry an ov axis spherical inclusion embedded in a uniform sphere geomagnetic induction is then modelled in a uniform spherical mantle overlain by a realistic distribution of oceanic and continental conductances our results indicate that the contrast in electrical conductivity between oceans and continents is not primarily responsible for the observed geographic variability of long period geomagnetic data in the absence of persistent high wavenumber magnetospheric disturbances this argues strongly for the existence of large scale high contrast electrical conductivity heterogeneities in the mid mantle lastly for several periods the geomagnetic anomaly associated with a mid mantle spherical inclusion is calculated a high contrast inclusion can be readily detected beneath the outer shell of oceans and continents a comparison between observed and computed c responses suggests that the mid mantle contains more than one order of magnitude of lateral variability in electrical conductivity while the upper mantle contains at least two orders of magnitude of lateral variability in electrical conductivity

temperature of an active lava channel from spectral measurements kilauea volcano hawaii a narrow band spectroradiometer was used to determine the characteristic temperatures of a very active channeled lava flow for the phase 50 eruption of pu u o o on the east rift zone of kilauea volcano hawaii during the twilight of 19 february 1992 14 spectra of this activity were acquired over a 51 minute interval 18 29 to 19 20 hawaiian standard time hst from which the thermal distribution of energy of two 18 m2 areas one near the center and one near the margin of the flow may be investigated a twocomponent thermal mixing model applied to the data taken of the center of the channel gave in the most powerful instance 1 8x105 w m2 a crust temperature of 940 c a hot component temperature of 1120 c and a hot radiating area of 60 of the total area a simultaneous spectrum acquired near the channeled flow margin yielded a crust temperature of 586 c and a hot area of only 1 2 of the total area radiating at 1130 c average radiant flux densities recorded for the center of the lava channel 1 3x105 w m2 average are much greater than previous measurements of lava lakes 4 9x103 w m2 or recently emplaced lava flows maximum of 7 2x104 w m2 the energetic nature of this eruption is shown by satellite measurements made at 02 33 hst on 22 february 1992 by the advanced very high resolution radiometer in band 2 0 72 1 10 m these show the utility of using existing satellites with moderate resolution 1 km x 1 km pixels and high temporal coverage eight overpasses each day for hawaii as potential thermal alarms for rapidly assessing the hazard potential of large volcanic eruptions

simulating the thermorheological evolution of channel contained lava flowgo and its implementation in excel flowgo is a one dimensional model that tracks the thermorheological evolution of lava flowing down a channel the model does not spread the lava but instead follows a control volume as it descends a line of steepest descent centred on the channel axis the model basis is the jeffreys equation for newtonian flow modified for a bingham fluid and a series of heat loss equations adjustable relationships are used to calculate cooling crystallization and down channel increases in viscosity and yield strength as well as the resultant decrease in velocity here we provide a guide that allows flowgo to be set up in excel in doing so we show how the model can be executed using a slope profile derived from google tm earth model simplicity and ease of source term input from google tm earth means that this exercise allows i easy access to the model ii quick global application and iii use in a teaching role output is tested using measurements made for the 2010 eruption of piton de la fournaise la reunion island the model is also set up for rapid syneruptive hazard assessment at piton de la fournaise as we show using the example of the response to the june 2014 eruption

comparison of the response of the landsat 7 enhanced thematic mapper plus and the earth observing 1 advanced land imager over active lava flows using near simultaneously acquired landsat 7 enhanced thematic mapper plus etm and earth observing 1 advanced land imager ali data we assess the relative radiant responses over active lava flows from the mt etna july august 2001 flank eruption by assessing the extent of saturation between the two instruments and using the dual band method of extracting sub pixel thermal information we show that the ali represents an improvement over the etm in the present ability to assess temperatures of hot active lava flows for a number of reasons 1 the extra spectral channels provided by ali compliment the current swir channels on etm by providing a greater number of paired channel combinations for input into the dual band method thus dual band temperature solutions can be determined for a greater range of lava flow types than previously possible using the two paired channel combinations available with the etm 2 the ali instrument is less susceptible than etm to saturation within the swir especially when using channels 5 5p and 4p at wavelengths of 1 65 1 25 and 0 87 m respectively 3 the greater radiometric sensitivity of the ali 12 bit electronics coupled with a significantly higher signal to noise ratio aid in obtaining successful dual band solutions

cooling rate of an active hawaiian lava flow from nighttime spectroradiometer measurements a narrow band spectroradiometer has been used to make nighttime measurements of the phase 50 eruption of pu u o o on the east rift zone of kilauea volcano hawaii on february 19 1992 a ger spectroradiometer was used to determine the cooling rate of an active lava flow this instrument collects 12 bit data between 0 35 to 3 0 m at a spectral resolution of 1 5 nm thirteen spectra of a single area on a pahoehoe flow field were collected over a 59 minute period 21 27 22 26 hst from which the cooling of the lava surface has been investigated a two component thermal mixing model flynn 1992 applied to data for the flow immediately on emplacement gave a best fit crustal temperature of 768 c a hot component at 1150 c and a hot radiating area of 3 6 of the total area over a 52 minute period within the time interval between flow resurfacings the lava flow crust cooled by 358 c to 410 c at a rate that was as high as 15 c min 1 our observations have significance both for satellite observations of active volcanoes and for numerical models of the cooling of lava flows during their emplacement

on the combination of the magnetotelluric and the geomagnetic depthsounding method for resolving an electrical conductivity increase at 400 km depth the simultaneous use of two different passive electromagnetic em sounding techniques for resolving the upper mantle electrical conductivity structure is emphasized the geomagnetic gm method uses magnetic field variations at periods between 3 hours and 600 hours yielding penetration depths between 300 km and 1000 km the magnetotelluric mt method is applied to field variations at periods between a few seconds and 16 hours and yields penetration depths between a few km and 600 km this is an extension of both methods using additional d sub st data for mt and additional s sub q data for gm in application to field data from western europe the resulting overlap of the target depths includes an electrical conductivity increase from 10 sup minus 2 s m at 300 km to 1 s m at 700 km depth while a single conductivity jump at either 400 500 or 700 km cannot explain the broadband data although the olivine to spinel transition is a possible explanation of the conductivity enhancement at 400 km depth another mineralogy could also occur this conductivity increase has not been resolved in other sub continental profiles and lateral heterogeneity is probable in this depth range 27 refs 3 figs 2 tabs

variations in the electrical conductivity of the upper mantle beneath north america and the pacific ocean variations in the electrical conductivity of the mantle beneath carty lake in the canadian shield tucson in the southwest united states and honolulu and midway in the north central pacific were determined through the inversion of long period magnetotelluric and geomagnetic depth sounding data inversion of computed response functions is carried out using a minimum structure regularized approach the upper mantle beneath carty lake is approximately an order of magnitude more resistive than the upper mantle beneath tucson and nearly 1 5 orders of magnitude more resistive than honolulu and midway island inversions were also carried out where the minimum structure constraint was removed at known upper mantle discontinuities these models show a jump in conductivity of 1 5 orders of magnitude across the 660 km discontinuity a result that is consistent with laboratory experiments on realistic mantle assemblages mantle conductivity profiles at carty lake are significantly more resistive than those at tucson honolulu and midway to depths of 300 400 km these observations likely reflect differing thermal states the presence or absence of partial melt and volatiles and may also be related to chemical differences between depleted and undepleted upper mantle the observed conductivity variations may be interpreted as lateral variations in temperature partial melt and or dissolved hydrogen in olivine

model of the geoelectrical structure of the mid and lower mantle in the europe asia region summary the conductivity structure of the earth s mantle was estimated using the induction method down to 2100 km depth for the europe asia region for this purpose the responses obtained at seven geomagnetic observatories irt kiv mos nvs hlp wit and ngk were analysed together with reliable published results for 11 yr variations 1 d spherical modelling has shown that beneath the mid mantle conductive layer 600 800 km the conductivity increases slowly from about 1 s m 1 at 1000 km depth to 10 s m 1 at 1900 km while further down 1900 2100 km this increase is faster published models of the lower mantle conductivity obtained using the secular 30 60 yr variations were also considered in order to estimate the conductivity at depths down to the core the new regional model of the lower mantle conductivity does not contradict most modern geoelectrical sounding results this model supports the idea that the mantle base situated below 2100 km depth has a very high conductivity

the treatment of flat areas and depressions in automated drainage analysis of raster digital elevation models methods developed to process raster digital elevation models dem automatically in order to delineate and measure the properties of drainage networks and drainage basins are being recognized as potentially valuable tools for the topographic parameterization of hydrological models all of these methods ultimately rely on some form of overland flow simulation to define drainage courses and catchment areas and therefore have difficulty dealing with closed depressions and flat areas on digital land surface models some fundamental assumptions about the nature of these problem topographic features in dem are implicit in the various techniques developed to deal with them in automated drainage analysis the principal assumptions are 1 that closed depressions and flat areas are spurious features that arise from data errors and limitations of dem resolution 2 that flow directions across flat areas are determined solely by adjacent cells of lower elevation and 3 that closed depressions are caused exclusively by the underestimation of dem elevations it is argued that while the first of these assumptions is reasonable given the quality of dems generally available for hydrological analysis the others are not rather it seems more likely that depressions are caused by both under and overestimation errors and that flow directions across flat areas are determined by the distribution of both higher and lower elevations surrounding flat areas two new algorithms are introduced that are based on more reasonable assumptions about the nature of flat areas and depressions and produce more realistic results in application these algorithms allow breaching of depression outlets and consider the distribution of both higher and lower elevations in assigning flow directions on flat areas the results of applying these algorithms to some real and hypothetical landscapes are presented 1998 john wiley sons ltd

numerical modeling of lava flow cooling applied to the 1997 okmok eruption comparison with advanced very high resolution radiometer thermal imagery 1 throughout february and march 1997 okmok volcano in the eastern aleutian islands of alaska erupted a 6 km long lava flow of basaltic a a within its caldera in the first part of the study a numerical model for lava flow cooling was developed by patrick et al and applied to the flow to better understand the nature of its cooling in this second part of the study the model predictions for lava surface temperature over a 200 day cooling period were compared to advanced very high resolution radiometer avhrr thermal imagery various methods were used to extract the subpixel lava temperature from the avhrr pixel integrated values including the dual band method and pixel merging inherent to these approaches is the multicomponent modeling of the lava surface temperature whereas active flows have been shown to have several thermal components so too do flows undergoing extended cooling because of the dependence of the methods on the avhrr instantaneous field of view ifov the scan dependent ifov dimensions and overlap values were considered results from patrick et al indicate that convective heat loss from the surface largely controls surface temperature during extended cooling but the functions governing this heat loss mechanism are poorly understood avhrr derived temperatures from this part of the study suggest that values for the convective heat transfer coefficient for this flow were most commonly between 50 and 100 w m 2 k 1 and generally above 25 w m 2 k 1 these results are in agreement with previously measured values from the field but are significantly higher than those assumed in other remote sensing studies of cooling lava also the avhrr data corroborate the modeled prediction of seasonal warming of the lava surface

an application of thin sheet electromagnetic modelling to the tasman sea abstract the method of thin sheet approximation is invoked for the ocean layer to model and interpret magnetotelluric mt data observed on the floor of the tasman sea between australia and new zealand a technique to remove 3d distortion from the observed seafloor mt data is developed from the thin sheet model mt responses the de distorted data then appear isotropic and are reinverted using 1d procedures this approach thus assists interpretation through a combination of 3d forward modelling procedures and 1d inversion a seafloor sediment layer is shown to have a strong effect on observed seafloor mt data also an exercise is carried out to compare the results given by the vertical gradient sounding vgs method with seafloor mt data the electrical conductivity structure beneath the tasman sea is analysed in terms of an upper mantle lithosphere and asthenosphere and a highly conducting lower mantle the observed anisotropy in seafloor mt data is diagnostic of a lithospheric conductivity of less than 10 4 s m 1 conductivity rises by two orders of magnitude below 80 km to greater than 10 2 s m 1 and is probably related to an asthenospheric layer in the upper mantle seismic interpretations similarly place a low velocity zone below a depth of 70 km at a depth of approximately 400 km the conductivity is approximately 1 s m 1 consistent with global estimates for the lower mantle there is little evidence for major change with age in the structure across the tasman sea

on the electrical conductivity of the mid mantle i calculation of equivalent scalar magnetotelluric response functions summary the problem of global conductivity sounding has been re posed in order to investigate the possible existence of large scale lateral heterogeneities in mid mantle conductivity a response function z h is robustly estimated and scaled into an equivalent scalar magnetotelluric impedance by assuming the geomagnetic field spatial variations are adequately described by a p10 spherical harmonic data found to be inconsistent with this representation in either the time frequency or spatial domain are excluded from the analysis making use of this relationship robust statistical techniques and careful data handling procedures have been applied to a new global magnetic database containing well in excess of 106 daily mean values 1358 observatory years spanning the period 1883 1980 a set of spatially distributed scalar frequency domain impedance functions for a variety of tectonic provinces result from this analysis response functions consistent with both the p10 assumption and local 1 d earth structure were found for 22 of the 79 observatories examined the set of acceptable response functions is presented along with a summary of data quality for the observatories represented in the database

recent behaviour of the debeli namet glacier durmitor montenegro a small cirque glacier is present in a north east facing cirque on the mountain of sljeme 2455 m a s l in the durmitor massif montenegro sediment ridges in front of this glacier are interpreted as moraines and can be attributed to recent glacier activity over the past 130 years lichenometry was applied to determine the relative ages of different moraines using aspicilia calcarea agg one set of moraines dates from about 1878 ad whilst another set of inner moraines dates from about 1904 ad the most recent moraines appear to have formed within the last 11 years in front of an active glacier margin copyright 2007 john wiley sons ltd

measurements of wind friction speeds over lava surfaces and assessment of sediment transport wind velocity profiles were obtained over alluvial plains lava flows and a cinder cone in the mojave desert to determine the wind shear and the potential for particle transport it was found that aerodynamic roughness zo for winds increases nearly a factor of 5 as flow crosses from the alluvium to the lava surface resulting in wind shear that is 21 greater thus wind erosion and sand flux may be substantially enhanced over the lava field moreover wind flow turbulence is enhanced in the wake of the cinder cone which also increases erosion and sediment transportation by the wind

spatial variations in lava flow field thermal structure and effusion rate derived from very high spatial resolution hyperspectral mivis data 1 high spatial resolution hyperspectral measurements of volcanic thermal anomalies allow for an unconstrained solution of a two component thermal model this can be used for identification of lava flow emplacement style and the calculation of lava flow heat and volume flux the multispectral infrared and visible imaging spectrometer mivis is an airborne sensor equipped with 72 bands in the short infrared range and 10 bands in the thermal infrared region of the spectrum we used mivis acquired for mount etna italy during the july august 2001 eruption to solve the dual band equations in an unconstrained fashion using three bands of unsaturated data our results suggest a complex thermal structure for etnean lava flows this is characterized by a downflow transition from a lightly crusted active channel to a more heavily crusted distal section both surrounded by zones of stagnant cooling flow where exposed molten material is absent and maximum temperatures are thus lower the total flow field effusion rate obtained for 29 july 2001 0700 local time of 8 16 m3 s is in excellent agreement with that obtained from ground based measurements and advanced very high resolution radiometer data flow by flow effusion rates obtained from the mivis data vary depending on whether the vent is linked to the central conduit or the dyke that was injected from greater depth as well as vent elevation with lower elevation vents experiencing higher effusion rates

genesis stability and preservation potential of large lateral moraines of alpine valley glaciers towards a unifying theory based on findelengletscher switzerland abstract lateral moraines are prominent features of glaciated landscapes in high mountain environments and key landforms in glacier and palaeoclimatic reconstructions yet compared to smaller moraines they have been little studied and several aspects are not well understood we here present detailed sedimentological results from the lateral moraines of findelengletscher in sw switzerland to gain new insights into the formation of these landforms the lateral moraines studied here stand up to 140 m above the valley floor are over 3 km long and strongly asymmetrical in cross profile with distal slopes between 29 and 36 and proximal slopes that are commonly 41 64 but locally reach angles of up to 80 recorded lithofacies comprise loose clast and matrix supported stratified diamicts and intercalated sorted sediments in the distal slopes and near the crestline overconsolidated matrix supported massive and weakly stratified diamicts and streaked out sorted sediment lenses in the core and proximal slopes and partly intercalated dark brown layers overlain by loose and consolidated diamicts exposed in near vertical walls in the proximal flank these are interpreted as supraglacial debris flow units with intercalated fluvial wash horizons glaciotectonised and subglacial traction till with boudinaged and streaked out sediment lenses and palaeosoils overlain by sediment produced by overtopping of the former moraine surface during a subsequent advance of the glacier clast shape analysis and process observations reveal that the dominant mode of transport is subglacial and glaciofluvial and that the main mode of sediment delivery to the moraines is by debris flows after the material has been transferred from the bed via englacial debris bands and meltout at the surface this differs from previous studies that found that a supraglacial source was dominant sedimentary structures clast fabric and process observations during the 1979 1980 readvance of findelengletscher strongly suggest that proximal layers of reworked pre existing sediments and or basal traction zone till have been plastered onto the moraine core in several locations causing a high degree of overconsolidation and strongly clustered fabric eigenvalues s 1 0 94 with clustering parallel to the moraine crestline this suggests that a combination of basal lateral drag and lateral plastering produces the observed proximal stability and ensures a high preservation potential we develop a conceptual model that describes alpine lateral moraines as structurally complex landforms that do not just record a single event as often surmised and we discuss implications for palaeo glacier reconstruction and the application of numerical dating methods

the changing morphology of an open lava channel on mt etna an open channel lava flow on mt etna sicily was observed during may 30 31 2001 data collected using a forward looking infrared flir thermal camera and a minolta land cyclops 300 thermal infrared thermometer showed that the bulk volume flux of lava flowing in the channel varied greatly over time cyclic changes in the channel s volumetric flow rate occurred over several hours with cycle durations of 113 190 min and discharges peaking at 0 7 m3 s 1 and waning to 0 1 m3 s 1 each cycle was characterized by a relatively short high volume flux phase during which a pulse of lava with a well defined flow front would propagate down channel followed by a period of waning flow during which volume flux lowered pulses involved lava moving at relatively high velocities up to 0 29 m s 1 and were related to some change in the flow conditions occurring up channel possibly at the vent they implied either a change in the dense rock effusion rate at the source vent and or cyclic variation in the vesicle content of the lava changing its bulk volume flux pulses would generally overspill the channel to emplace p hoehoe overflows during periods of waning flow velocities fell to 0 05 m s 1 blockages forming during such phases caused lava to back up occasionally backup resulted in overflows of slow moving a that would advance a few tens of meters down the levee flank compound levees were thus a symptom of unsteady flow where overflow levees were emplaced as relatively fast moving p hoehoe sheets during pulses and as slow moving a units during backup small localized fluctuations in channel volume flux also occurred on timescales of minutes volumes of lava backed up behind blockages that formed at constrictions in the channel blockage collapse and or enhanced flow under around the blockage would then feed short lived wave like down channel surges real fluctuations in channel volume flux due to pulses and surges can lead to significant errors in effusion rate calculations

forecasting lava flow paths by a stochastic approach 1 a stochastic model named downflow is presented to forecast possible lava flow paths with the aim of hazard assessment and mitigation the model relies on the fact that lava flow emplacement is in many cases controlled by topography the potential inundation area of the flow is determined by considering a number of steepest paths over stochastic perturbations of the original topography since the code requires very short computational time and few input data the model proved to be a very useful tool to obtain real time predictions during the initial phase of an eruption the necessary topographic information can be obtained by photogrammetry radar altimetry or laser scanning techniques downflow has been successfully applied to a number of flows including the september 2004 lava flow where updated topographies were available

one two and three phase viscosity treatments for basaltic lava flows 1 lava flows comprise three phase mixtures of melt crystals and bubbles while existing one phase treatments allow melt phase viscosity to be assessed on the basis of composition water content and or temperature two phase treatments constrain the effects of crystallinity or vesicularity on mixture viscosity however three phase treatments allowing for the effects of coexisting crystallinity and vesicularity are not well understood we investigate existing one and two phase treatments using lava flow case studies from mauna loa hawaii and mount etna italy and compare these with a three phase treatment that has not been applied previously to basaltic mixtures at etna melt viscosities of 425 30 pa s are expected for well degassed 0 1 w h2o and 135 10 pa s for less well degassed 0 4 wt h2o melt at 1080 c application of a three phase model yields mixture viscosities 45 crystals 25 35 vesicles in the range 5600 12 500 pa s this compares with a measured value for etnean lava of 9400 1500 pa s at mauna loa the three phase treatment provides a fit with the full range of field measured viscosities giving three phase mixture viscosities upon eruption of 110 140 pa s 5 crystals no bubble effect due to sheared vesicles to 850 1400 pa s 25 30 crystals 40 60 spherical vesicles the ability of the three phase treatment to characterize the full range of melt crystal bubble mixture viscosities in both settings indicates the potential of this method in characterizing basaltic lava mixture viscosity

effects of martian conditions on numerically modeled cooling limited channelized lava flows 1 we used the flowgo thermorheological model to examine the effects of martian gravitational and environmental conditions on the cooling limited behavior of lava flowing in a channel the largest effect is due to the lower gravity on mars as compared to earth which causes lava to flow more slowly the lower velocity means that heat loss per distance down a mars channel is greater even though the lower velocity also produces a higher percentage cover of insulating crust gravity alone causes the mars flow to be 65 km shorter than an earth flow with an equivalent volumetric flow rate the cooler ambient mars atmosphere causes a slight increase in heat loss by forced convection this slows the flow a bit more resulting in a very slight increase in heat loss per distance by all mechanisms and decreases the modeled flow length by 1 km a difference well below our model uncertainty replacing terrestrial values of atmospheric density viscosity thermal conductivity heat capacity and cubic expansivity makes convection less efficient and increases flow length by 15 km nevertheless at the same volumetric flow rate lava flows 50 km less far under martian conditions than under terrestrial conditions our specific model flow has a volumetric flow rate of 5000 m3 s 1 and traveled 190 km down a channel on a constant 7 slope this volumetric flow rate is slightly less than the maximum rates during the 1783 1785 laki eruption and is 5 10 times greater than those of typical mauna loa eruptions

the long period electromagnetic response of the earth summary the techniques of complex demodulation and spherical harmonic analysis have been used to examine the time frequency and location dependent properties of the long period electromagnetic response of the earth fourteen years of daily three component magnetic field data recorded by 18 permanent geomagnetic observatories were used to estimate the response in the period range 2 200 day it is found that lateral conductivity inhomogeneities within the earth notably the oceans have a considerable effect on the observed response even at these long periods

the initial cooling of pahoehoe flow lobes in this paper we describe a new thermal model for the initial cooling of pahoehoe lava flows the accurate modeling of this initial cooling is important for understanding the formation of the distinctive surface textures on pahoehoe lava flows as well as being the first step in modeling such key pahoehoe emplacement processes as lava flow inflation and lava tube formation this model is constructed from the physical phenomena observed to control the initial cooling of pahoehoe flows and is not an empirical fit to field data we find that the only significant processes are a heat loss by thermal radiation b heat loss by atmospheric convection c heat transport within the flow by conduction with temperature and porosity dependent thermal properties and d the release of latent heat during crystallization the numerical model is better able to reproduce field measurements made in hawai i between 1989 and 1993 than other published thermal models by adjusting one parameter at a time the effect of each of the input parameters on the cooling rate was determined we show that a the surfaces of porous flows cool more quickly than the surfaces of dense flows b the surface cooling is very sensitive to the efficiency of atmospheric convective cooling and c changes in the glass forming tendency of the lava may have observable petrographic and thermal signatures these model results provide a quantitative explanation for the recently observed relationship between the surface cooling rate of pahoehoe lobes and the porosity of those lobes jones 1992 1993 the predicted sensitivity of cooling to atmospheric convection suggests a simple field experiment for verification and the model provides a tool to begin studies of the dynamic crystallization of real lavas future versions of the model can also be made applicable to extraterrestrial submarine silicic and pyroclastic flows

electrical conductivity of a natural mg fe sio3 majorite garnet the electrical conductivity of meteoritic majorite measured at 10 hz under a nitrogen atmosphere at ambient pressure is 3 8 1 8 10 7 s m at room temperature and displays an arrhenius behavior with an activation energy of 0 55 0 1 ev over the temperature range 290 370 k extrapolating these values to conditions of the earth s mantle suggests that majorite and spinel can account for the increase in electrical conductivity observed from the upper mantle to the transition zone where these phases are stable

the glacial history of the pindus mountains greece abstract geomorphological evidence for pleistocene glaciation has been mapped in the pindus mountains of northwest greece and the chronology of glaciation in this area has been established through soil profile analysis and u series dating of secondary carbonates calcite formed within glacial deposits three glacial stages are evident in the sedimentological and geomorphological records the earliest and most extensive recorded glaciation predates 350 000 yr b p and was characterized by extensive valley glaciers and ice fields a more recent glaciation occurred before the last interglacial and was characterized by glaciers that reached midvalley positions the last phase of glaciation in greece is recorded by small cirque glacier moraines and relict periglacial rock glaciers the glacial and periglacial sequence on mount tymphi has been used in conjunction with a reference parastratotype the long lacustrine sequence at ioannina to provide a chronostratigraphical framework for cold stage deposits in g

alluvial sediment sources in a glaciated catchment the voidomatis basin northwest greece x ray diffraction xrd of the fine matrix component of four alluvial units and modern channel sediments in the voidomatis river basin of northwest greece shows that fine sediment sources have changed considerably during the late quaternary the matrix fraction of the modern channel sediments is derived predominantly from erosion of local flysch rocks and soils during the last glaciation however the fine sediment load of the voidomatis river was dominated by glacially ground finely comminuted limestone materials limestone derived fine sediment is not produced in significant amounts under modern climatic conditions by combining this xrd work with a detailed programme of clast lithologic 1 analysis we have reconstructed former bedload and fine sediment load composition the lithological properties of both the coarse 8 256 mm and fine 63 m elements of the sediment load have varied markedly during the late quaternary a simple semiquantitative assessment of fine sediment mineralogy using diffractogram peak height data has provided a valuable complement to the information gathered from more traditional clast lithological techniques together in favourable geological settings fine fraction mineralogy and clast lithological analysis can provide a valuable tool for the reconstruction of late quaternary alluvial environments

on the electrical conductivity of the mid mantle ii delineation of heterogeneity by application of extremal inverse solutions summary long period equivalent scalar magnetotelluric impedance functions from 22 magnetic observatories distributed over the earth s surface are inverted to test the hypothesis that there exists significant lateral heterogeneity in the electrical conductivity structure of the mid mantle limited spaces of extremal models are examined and strict bounds are placed on the range of permissible models joint d inversion of combined response functions from observatory pairs proves the requirement for global heterogeneity while exploration of h layered earth model space suggests systematic regional heterogeneity indicating that enhanced upper mantle conductivity is found within the pacific basin and baikal rift zone and is absent elsewhere the results of these extremal inverse solutions are compared with the backus gilbert like schmucker inversion and a heuristic inversion

northeastern pacific mantle conductivity profile from long period magnetotelluric sounding using hawaii to california submarine cable data we present results of a long period magnetotelluric mt investigation of the electrical structure beneath the eastern north pacific the electric field data consist of 2 years of continuously recorded voltages across an unpowered 4000 km long submarine telephone cable haw 1 extending from point arena california to oahu hawaii the electric field measurements are coherent to some degree with magnetic field measurements from honolulu observatory at periods of 0 1 to 45 days this coherence is enhanced at long periods over that observed with point electric field sensors due to horizontal averaging of the motional electric fields of spatial scale smaller than the cable length significantly diminishing their effect robust controlled leverage mt response estimates and their jacknife confidence limits are computed for the haw 1 to honolulu data an equivalent scalar mt response obtained from honolulu magnetic variations data is used to correct the haw 1 mt response for static shift and to extend the mt response estimate to periods of 100 days the composite response function satisfies necessary and sufficient conditions for consistency with a one dimensional conductivity structure and is most sensitive to structure between 150 and 1000 km inversion of the mt response reveals a conductive zone 0 05 0 1 s m between 150 and 400 km depth and a positive gradient below 500 km these observations are consistent with previous mt studies in the north pacific this upper mantle conductivity is too high to be explained by solid state conduction in dry olivine using reasonable mantle geotherms calculations based on measurements of hydrogen solubility and diffusivity in olivine indicate that h dissolved in olivine possibly combined with a lattice preferred orientation consistent with measured seismic anisotropy provide sufficient conductivity enhancement to explain the inversion results the high conductivity may also be explained by the presence of gravitationally stable partial melt comparison of the haw 1 results with long period mt studies conducted on land reveals differences in upper mantle conductivity between different tectonic regimes in particular the upper mantle beneath the pacific ocean is considerably more conductive than that beneath the canadian shield and similar in conductivity to that beneath the basin and range

reconstructing the transport history of glacigenic sediments a new approach based on the co variance of clast form indices abstract two indices are used to describe the aggregate shape and roundness characteristics of glacially transported clasts the c40 index the percentage of clasts with c a ratios 0 4 and the ra index the percentage of very angular and angular clasts in a sample analysis of the between and within sample co variance of these indices provides a powerful tool for discriminating actively and passively transported clasts in glacigenic deposits use of these indices is illustrated in an analysis of the form characteristics of clasts from lateral and frontal moraines at storbreen jotunheimen these fall between those of actively transported clasts in basal till low c40 and ra values and those of unmodified frost weathered clasts high c40 and ra values both indices decline down moraine within sample analyses of clast shape demonstrates that these aggregate clast form gradients reflect changes in the relative proportions of actively and passively transported debris on the moraines rather than progressive modification of actively transported clasts these analyses also indicate that actively transported clasts form the dominant component of the moraines particularly near the former glacier terminus further applications of the approach developed here are suggested

the glacial history of the dinaric alps montenegro abstract large areas of montenegro were glaciated during the pleistocene this paper presents evidence from the massifs of central montenegro including durmitor and sinjajevina moracke planine maganik prekornica and vojnik glacial deposits have been subdivided on the basis of morphostratigraphy and soil weathering and 31 u series ages from cemented tills provided a geochronological framework the largest glaciation occurred before 350 ka when a series of conjoined ice caps over the massifs of central montenegro covered a total area of nearly 1500 km 2 these formed during mis 12 and correspond with the largest skamnellian stage glaciations in greece to the south later middle pleistocene glaciations occurred during the penultimate glacial cycle correlating with the vlasian stage in greece mis 6 when ice caps covered an area of 720 km 2 over central montenegro there is also geochronological evidence of glacial deposits dating from the interval between mis 12 and mis 6 before the interglacial complex of mis 7 this glaciation appears to have been very similar in extent to that which occurred during mis 6 the last glacial cycle in central montenegro was characterised by valley and cirque glaciers covering a total area of 49 km 2 it is very likely that glaciers have been present in the mountains of central montenegro during every glacial cycle since a small glacier still survives today the smaller glaciers of the last glacial cycle are likely to have been associated with summer temperatures that were warmer than those of earlier cold stages the striking contrast in the extent and thickness of ice cover during the cold stages of the pleistocene has an important bearing on the geomorphological and biological evolution of the balkans

pleistocene ice caps on the coastal mountains of the adriatic sea ice caps once covered large areas of mount orjen 1894 m on the adriatic coast of montenegro bosnia herzegovina croatia the largest ice cap covered an area of c 165 km2 and reached a maximum ice thickness of c 450 m in some areas reaching down to 500 m above modern sea level u series dating of secondary carbonates within moraines indicates that the most extensive glaciation occurred during the middle pleistocene correlating with a major phase of glaciation in greece to the south during mis 12 c 480 430 ka later less extensive glaciations are also recorded in the cirques and valleys and correlate with glaciations during mis 6 190 130 ka and mis 5d 2 110 11 7 ka each phase of glaciation would have required large amounts of snow accumulation under modern precipitation values which at c 5000 mm are some of the highest in europe mean annual temperatures would need to be only c 5 6 c lower in order to form similar sized glaciers today a mean annual temperature depression of 12 13 c would still require 1000 mm of snow accumulation water equivalent to balance ablation suggesting sustained moisture supply during pleistocene cold stages such sustained precipitation supply during pleistocene cold stages is likely to have been facilitated by major temperature contrasts between the european landmass and the mediterranean sea which are likely to have sustained lee side vortices to the south of the alps in the gulf of genoa and adriatic sea forming weak moisture bearing depressions which tracked across the eastern adriatic coastal mountains large ice caps on the dinaric alps would have blocked the inland penetration of these depressions resulting in much drier conditions in the balkan interior creating favourable conditions for the deposition of thick accumulations of loess the last glaciers on orjen formed during the younger dryas 12 9 11 7 ka and confirm the influence of north atlantic ocean circulation on pleistocene climate change in this part of the mediterranean

pleistocene hydrology of north america the role of ice sheets in reorganizing groundwater flow systems 1 while the geomorphic consequences of pleistocene megafloods have been known for some time it has been only in the past 2 decades that hydrogeologists and glaciologists alike have begun to appreciate the important impact that ice sheet aquifer interactions have had in controlling subsurface flow patterns recharge rates and the distribution of fresh water in confined aquifer systems across north america in this paper we document the numerous lines of geochemical isotopic and geomechanical evidence of ice sheet hydrogeology across north america we also review the mechanical thermal and hydrologic processes that control subsurface fluid migration beneath ice sheets finite element models of subsurface fluid flow permafrost formation and ice sheet loading are presented to investigate the coupled nature of transport processes during glaciation deglaciation these indicate that recharge rates as high as 10 times modern values occurred as the laurentide ice sheet overran the margins of sedimentary basins the effects of ice sheet loading and permafrost formation result in complex transient flow patterns within aquifers and confining units alike using geochemical and environmental isotopic data we estimate that the volume of glacial meltwater emplaced at the margins of sedimentary basins overrun by the laurentide ice sheet totals about 3 7 104 km3 which is about 0 2 of the volume of the laurentide ice sheet subglacial infiltration estimates based on continental scale hydrologic models are even higher 5 10 of meltwater generated these studies in sum call into question the widely held notion that groundwater flow patterns within confined aquifer systems are controlled primarily by the water table configuration during the pleistocene rather groundwater flow patterns were likely much more complex and transient in nature than has previously been thought because pleistocene recharge rates are believed to be highly variable these studies have profound implications for water resource managers charged with determining sustainable pumping rates from confined aquifers that host ice sheet meltwater

observations of the effect of wind on the cooling of active lava flows 1 we present the first direct observations of the cooling of active lava flows by the wind we confirm that atmospheric convective cooling processes i e the wind dominate heat loss over the lifetime of a typical pahoehoe lava flow in fact the heat extracted by convection is greater than predicted especially at wind speeds less than 5 m s and surface temperatures less than 400 c we currently estimate that the atmospheric heat transfer coefficient is about 45 50 w m 2 k 1 for a 10 m s wind and a surface temperature 500 c further field experiments and theoretical studies should expand these results to a broader range of surface temperatures and wind speeds