structure of a frontal cyclone a diagnostic study of a mid latitude cyclone has been carried out using routinely available numerical weather prediction model products and imagery the cyclone was intense but not exceptionally so and the results are believed to have some generality the detailed description of the cyclone structure just before it began to deepen rapidly integrates concepts from a number of researchers into a common framework a dominant feature of the cyclone close to its centre was the cloud head a region of cloud with a sharp convex outer edge which formed poleward of the main polar front cloud band the cloud head was caused by two flows that entered it from the east ascending and fanning out within it one flow the cold conveyor belt brought low wet bulb potential temperature w air back into the cloud head from low levels ahead of the warm front the other flow was due to high w air that peeled off from the base of the main warm sector airflow i e part of the warm conveyor belt and travelled in the boundary layer back towards the cyclone centre first undercutting dry air that had earlier descended from the upper troposphere called a dry intrusion and then ascending at the upper boundary of the cloud head above the cold conveyor belt the transverse circulation that gave the ascent within the cloud head also led to the cold front fracturing along its length into two separate sharp surface cold fronts with a more diffuse frontal region in between frontal fracture the two sharp surface cold fronts were associated with narrow cold frontal rainbands line convection one of the line convection segments forming the southern edge of the cloud head the overrunning of the dry intrusion in the region of the frontal fracture led to a structure known as a split front in which an upper level humidity front began to run ahead of the position of the surface cold front a feature of the cyclone at this intermediate stage in its evolution was that a large proportion of the precipitation was being generated by ascent of relatively cold air the cold conveyor belt in the cloud head as part of the thermally indirect circulation at the left exit of a developing secondary upper level jet

formation of lava tubes and extensive flow field during the 1991 1993 eruption of mount etna detailed mapping during the 1991 1993 eruption of mount etna has shown that there is a relationship between tumuli ephemeral vents lava tubes and their parent lava flows during this eruption many tubes formed in stationary inflated a a lava flows ephemeral vents at the fronts of these stationary flows and above lava tubes fed secondary lava flows many of which subsequently developed new tubes the resulting complex network of tubes ephemeral vents and secondary flows was responsible for most of the widening thickening and lengthening of the 1991 1993 etna lava flow field the supply of relatively uncooled lava via tubes to distal parts of this flow field allowed lava to flow 3 km farther from the vent than the longest channel fed lava flow our observations suggest that lava tubes play a more important role in the formation of extensive a a flow fields on etna than has previously been recognized

a model for the formation of lava tubes by the growth of the crust from the levees 1 we propose a model to explain lava tube formation by the growth of crust slabs from the levees of a channel toward its center involving solid surface fragments the flow dynamics are described with the steady state solution of the navier stokes equation in a rectangular channel for a newtonian homogeneous isotropic and incompressible fluid the cooling of a lava flow is described by the mechanism of heat conduction into the atmosphere the presence of levees is taken into account both in the dynamical and in the thermal model as long as the flow cools a solid layer forms at the surface much thicker near the levees than at the center of the channel the crust that has formed breaks under the effects of the applied stresses solid blocks slow the fluid down the shear stress at the interface between crust and fluid lava increases and the flow thickens using the thin elastic plate approximation we determine conditions allowing a crust to resist both the action of the shear stress due to the drag of the underlying fluid and the tensile stress due to the weight of the crust itself detecting the required crust thickness and distances from the eruptive vent where the tube can form

the improve 1 storm of 1 2 february 2001 part i development of a forward tilted cold front and a warm occlusion abstract analysis of observations and the fifth generation pennsylvania state university national center for atmospheric research psu ncar mesoscale model mm5 are used to study the development of a forward tilted cold front off the coast of washington state the vertical velocity associated with the cold front produced a wide cold frontal rainband in the early stage of development the midtropospheric baroclinic zone or upper cold front moved forward with time over the warm sector to produce a structure similar to a split front the movement of the upper cold front was due to horizontal transport and frontogenetical propagation the frontogenetical propagation was produced by a combination of tilting and diabatic frontogenesis which resulted in a negative positive couplet of frontogenesis straddling the baroclinic zone the lower tropospheric cold front eventually caught up with the warm front to form a classical warm occlusion in the initial occluding process the converging frontal zones tilted i

geochemistry and volcanic features of harrat el fahda a young volcanic field in northwest arabia jordan abstract the wadi fill basalt of harrat el fahda was derived from the youngest volcanic activity in northeast jordan and forms one of the most recent harrats of the arabia plate it is characterized by the presence of abundant well preserved pressure ridges and pahoehoe lava structures it was developed due to intermittent eruption from an isolated volcanic center in a form of 3 5 successive basaltic pahoehoe flows the associated pressure ridges are elliptical in shape up to 50 m high and 200 m long the orientation with regard to flow direction is sub parallel along the margins and perpendicular along the center of the flow these ridges were formed by inflation and heaving pressure from below petrographical data show that the basalt is hollocrystalline fine grained and golmeroporphyritic modally three petro types are recognized olivine plagioclase basalt 20 olivine pyroxene basalt 25 and olivine basalt 55 geochemically the three petro types can be classified as alkaline to sub alkaline and termed as alkali olivine basalt they have similar compositional ranges of major and trace elements the magmas may have been derived from low degrees i e 5 9 of partial melting of an enriched garnet peridotite mantle source with limited fractionation and crustal contamination

toothpaste lava characteristics and origin of a lava structural type transitional between pahoehoe and aa toothpaste lava an important basalt structural type which illustrates the transition from pahoehoe to aa is particularly well displayed on the 1960 kapoho lava of kilauea volcano its transitional features stem from a viscosity higher than that of pahoehoe and a rate of flow slower than that of aa viscosity can be quantified by the limited settling of olivine phenocrysts and rate of flow by field observations related to the low angle slope on which the lava flowed much can be learned about the viscosity rheologic condition and flow velocity of lavas long after solidification by analyses of their structural characteristics and it is possible to make at least a semiquantitative assessment of the numerical values of these parameters

tracking of polar cap ionospheric patches using data assimilation 1 ionospheric f region patches are 2 10 larger than background electron densities in the polar ionosphere the eiscat svalbard incoherent radar esr observed a sequence of patches between 2000 2200 ut on 12 december 2001 in this paper the source of these structures is investigated using several other data sets together with a convection driven trajectory analysis the data are assimilated into ionospheric data assimilation three dimensional ida3d the background model used is the national center for atmospheric research thermosphere ionosphere mesosphere electrodynamics general circulation model ncar timegcm the trajectory analysis is based on maps of ionospheric convection obtained from the assimilative mapping of ionospheric electrodynamics amie in addition to patches a tongue of ionization toi is investigated it is shown that patches formed part of the toi it is tempting to conclude the toi and the patches originate at midlatitudes however the ida3d and trajectory analysis suggest that they were transported toward noon from the morning and afternoon sectors near 62 geographic latitude thus for this case the toi and patches did not originate at midlatitudes this work represents advances in the field of patch research a new capability to perform an analysis of patch origin and fate using three dimensional 3 d ionospheric assimilation and 2 d trajectory analysis codes is demonstrated for a sequence of patches observed 12 december 2001 the current resolution of the technique is not able to identify detailed patch formation mechanisms however by it can track the plasma back in time to locations and times where patch formation mechanisms operate

surface cooling advection and the development of different surface textures on active lavas on kilauea hawai i the validity of lava flow cooling models were investigated using data from a high resolution high frame rate thermal imaging camera on kilauea hawai i during august 2004 once the surface temperature data for small lava flow and lobes were corrected for emissivity viewing distance humidity and viewing angle it was clear that their upper surfaces were thermally stratified on eruption the interior of a stationary lava lobe was exposed by removing the crust and its cooling rate was measured at 30 hz for this flow the measured cooling trend was successfully modelled using a finite difference cooling model however modelled and measured cooling rates of a pahoehoe lobe and a small channelised lava flow were only in agreement until the crust began to deform the departure from the modelled trend at this point is attributed to two factors one is the complex cooling regime of a highly deformed ropy crust in which exposed lava at the crests of the ropes radiates in all directions compared with lava in the troughs where radiative cooling is less effective the second and more important reason for the difference is the reduced flow rate of the crust once it begins to be compressed the underlying visco elastic zone beneath the crust flows more rapidly than the crust and consequently advective heat flow significantly reduces cooling rates variations in heat loss from different flow textures and the incorporation of different advective heat components is clearly important in future flow models one of the critical parameters in such models is the temperature at which different surface textures develop temperature profiles along lobes and flows also revealed that rope textures developed on pahoehoe lavas when temperatures were in the range of 700 800 c brittle deformation of pahoehoe crust occurred when temperature dropped below 700 c and small pahoehoe lobes stopped advancing at temperatures of 600 650 c it is important to recognise that the flow front temperatures at which these flows stop advancing will be significantly greater than for larger flows on similar gradients the higher internal and basal shear stresses of large lava flows will allow the flow to advance until the visco elastic layer at the front of a front is significantly cooler than the temperatures recorded on these small flows on kilauea

tumulus development on lava flows insights from observations of active tumuli and analysis of formation models here we use observations of active flows along with detailed morphometric field measurements of more than 70 tumuli on flows at mount etna italy kilauea and hualalai us volcanoes to constrain a previously published model that estimates the pressure needed to form tumuli in an attempt to discover the nature and magnitude of pressure variations within active lava flow interiors we then consider how tumuli differ from idealized circular plates we incorporate observations of active tumuli and find that they may grow asymmetrically yet produce a symmetrical tumulus and can form where the flow path significantly changes direction bending models of clamped edges provide the most reasonable head estimates for the tumuli in our study tumulus formation requires the proper combination of cooling and effusion rate if cooling is too extensive and effusion rate too low the crust will provide too much resistance to bending if cooling is too limited and effusion rates too high crusts will not develop or have insufficient strength to resist fracture and subsequent breakouts we do not find it surprising that tumuli are rarely found over well established lava tubes that typically have rigid walls overlying crusts that exceed 2 m in thickness and provide too much resistance to bending silicic flows lack tumuli because the viscosity gradients within the flow are insufficient to concentrate stress in a localized area

re examination of the split cold front in the british isles cyclone of 17 july 1980 an analysis of an mm5 model simulation of a cyclone that passed over the british isles on 17 july 1980 indicates that the cyclone had some characteristics of both the split cold front model of browning and monk 1982 and of a schematic by browning and roberts 1996 most importantly the cyclone had the characteristic upper level baroclinic zone and its associated vertical velocity in advance of the surface front this is an integral part of both the split cold front model of browning and monk and browning and roberts s schematic and confirms the analysis of browning and monk simultaneously at different locations the cyclone also had the characteristics of a warm occlusion in the lower levels with the portion of the cold front that was above the warm front tipped forward with height the lower and upper portions of the cold front were not only fronts in equivalent potential temperature as proposed by browning and monk but true baroclinic zones with significant associated vertical velocity the complex structure of this cyclone in the british isles was similar to that of some storms in the pacific northwest of the united states locatelli et al 2005 copyright 2005 royal meteorological society

ionospheric response to the corotating interaction region driven geomagnetic storm of october 2002 unlike the geomagnetic storms produced by coronal mass ejections cmes the storms generated by corotating interaction regions cirs are not manifested by dramatic enhancements of the ring current the cir driven storms are however capable of producing other phenomena typical for the magnetic storms such as relativistic particle acceleration enhanced magnetospheric convection and ionospheric heating this paper examines ionospheric plasma anomalies produced by a cir driven storm in the middle and high latitude ionosphere with a specific focus on the polar cap region the moderate magnetic storm which took place on 14 17 october 2002 has been used as an example of the cir driven event four dimensional tomographic reconstructions of the ionospheric plasma density using measurements of the total electron content along ray paths of gps signals allow us to reveal the large scale structure of storm induced ionospheric anomalies the tomographic reconstructions are compared with the data obtained by digital ionosonde located at eureka station near the geomagnetic north pole the morphology and dynamics of the observed ionospheric anomalies is compared qualitatively to the ionospheric anomalies produced by major cme driven storms it is demonstrated that the cir driven storm of october 2002 was able to produce ionospheric anomalies comparable to those produced by cme driven storms of much greater dst magnitude this study represents an important step in linking the tomographic gps reconstructions with the data from ground based network of digital ionosondes

mechanisms of formation of lava tubes 1 we propose a model to describe lava tube formation considering lava as a newtonian fluid moving downslope in a rectangular channel we obtain flow velocity using an analytical steady state solution of the navier stokes equation shear stress is also calculated from velocity for a newtonian incompressible and isotropic fluid a 2 d model with heat flux assigned at the upper surface is introduced to describe lava cooling by radiation into the atmosphere and to obtain the flow temperature lava crust is considered as a plastic body and its rheology is described through the introduction of the yield strength as a function of temperature it describes the capacity of crustal structure to prevent shear deformation for lower shear stress values when lava temperature becomes lower than the solidus value ts a superficial thin solid layer develops in regions where shear stress xy is smaller than yield strength the model shows how the competition between these two functions xy and controls the development of crust width and the possible transition from a mobile crust to a stationary roof for typical parameter values of lava channels on mount etna crust develops in the central part of the flow laterally limited by two crust free regions we analyze the effects of some typical channel irregularities on surface shear stress and as a consequence on crust width growth we consider a variation of channel width and ground slope finding that crust widening is favored by channel widening or slope reduction in both cases the decrease in shear stress produces an increase in the fraction of channel width occupied by solid crust given a set of initial conditions defining eruptive parameters and channel features the model provides critical values of channel width and ground slope that allow tube formation the effect of different effusion rates on crust development is also studied with the result that tube formation is favored by low flow rates corresponding to lower values of xy

ionospheric storm simulations driven by magnetospheric mhd and by empirical models with data comparisons the results of two ionospheric simulations are compared with each other and with ionospheric observations of the southern hemisphere for the magnetic cloud passage event of january 14 1988 for most of the event one simulation agrees with observations while the other does not electric fields and electron precipitation patterns generated by a magnetospheric mhd model are used as inputs to a physical model of the ionosphere in the successful simulation while empirical electric fields and electron precipitation are used as the inputs for the second simulation in spite of ionospheric summer conditions a large and deep polar hole is developed this is seen in the in situ plasma observations made by the dmsp f8 satellite the hole is surprisingly present during both northward and southward imf conditions it is deepest for the storm phase of the southward imf period a well defined tongue of ionization is formed during this period these features have been reproduced by the tdim mhd simulation and to a lesser extent by the tdim empirical simulation however the model simulations have not been able to generate a storm enhanced density where one was observed by dmsp f8 during the initial phase of the storm the differences between the two f region ionospheric simulations are attributed to differences in the magnetospheric electric fields and precipitation patterns used as inputs this study provides a unique first simulation of the ionosphere s response to self consistent electric field and auroral precipitation patterns over a 24 hour period that leads into a major geomagnetic storm

a linkage between polar patches and plasmaspheric drainage plumes two distinct features are shown here to follow the same convection pattern polar ionization patches and plasmaspheric drainage plumes in this study the enhanced ionospheric electron concentration observed from millstone hill incoherent scatter radar is mapped to the equatorial plane the resulting trajectory there is found to coincide with the location of the draining plasmasphere as observed from a geosynchronous satellite the result indicates that both the f region electron concentration and the plasmaspheric drainage plume follow the newest separatrix the boundary between open and closed drift trajectories convecting sunward observations have shown that the polar patches are transported over the polar cap into the night side hence we conclude that the draining plasmasphere should follow a similar trajectory transporting plasmaspheric material over the polar cap into the tail plasma sheet

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

interaction of a warm season frontal system with the coastal mountains of the western united states part i prefrontal onshore push coastal ridging and alongshore southerlies abstract observational analyses and numerical simulations are used to investigate the interaction between a warm season frontal system trough and the complex terrain of the western united states prior to frontal landfall synoptically driven offshore flow was associated with the northward development of a thermal trough and a coastal pressure ridge and associated southerly winds moved northward along the coasts of northern california oregon washington and southwestern british columbia this coastal pressure ridge coupled with the subsequent weakening of the offshore flow resulted in the onshore push of cool marine air approximately 24 h before frontal passage the onshore surge of cool marine air into warm dry continental air associated with the thermal trough produced a mesofront that moved over the coastal and cascade mountains diagnosis of a realistic simulation of the event shows that both solar heating and adiabatic warming from downslope flow over the rockies and the cascade mountains are i

the volume and shape of the 1991 1993 lava flow field at mount etna sicily the 1991 1993 lava flow is the most voluminous flow erupted at mount etna sicily in over 300 years estimates of the volume obtained by various methods range from 205 106 m3 tanguy 1996 to over 500 106 m3 barberi et al 1993 this paper describes the results of an electronic distance measurement edm based field survey of the upper surface of the 1991 1993 flow field undertaken in 1995 the results were digitised interpolated and converted into a digital elevation model and then compared with a pre eruption digital elevation model constructed from a 1 25 000 contour map of the area based on 1989 aerial photographs our measurements are the most accurate to date and show that the 1991 1993 lava flow occupies a volume of 231 29 106 m3

in situ thermal characterization of cooling crystallizing lavas during rheology measurements and implications for lava flow emplacement abstract transport properties of natural silicate melts at super liquidus temperatures are reasonably well understood however migration and transport of silicate melts in the earth s crust and at its surface generally occur at sub liquidus temperatures and in settings where the melts undergo crystallization under various cooling and or decompression conditions in such dynamic situations the occurrence of processes such as the release of latent heat during phase changes viscous heating thermal advection and inertia and changing heat capacity all represent potential influences on the state and thereby on the physico chemical behavior of the system to date rheological data at sub liquidus temperatures are scarce and cooling rate dependent disequilibrium rheological data are virtually absent in fact no in situ thermal characterization of liquid or multiphase mixtures during rheological experiments under either static or dynamic thermal conditions has been presented to date here we describe a new experimental setup for in situ thermal characterization of cooling crystallizing lavas during viscosity measurement at temperatures up to 1600 c we use this device to recover in situ real time observations of the combined rheological and thermal evolution of natural re melted lava samples during the transient disequilibrium conditions characteristic of lava flows and shallow crustal magma migration and storage systems in nature we present the calibration procedure and the method employed to recover the thermal evolution of an experimental sample during flow in varying shear regimes assess the experimental uncertainty and show the ability of the apparatus to measure the release of latent heat of crystallization during transient rheological experiments we further report the results from a first experimental study on the rheological and thermal evolution of a basaltic lava undergoing continuous cooling at a series of different cooling rates and discuss the implications of the results for magma migration and lava flow emplacement

development of lava tubes in the light of observations at mauna ulu kilauea volcano hawaii during the 1969 1974 mauna ulu eruption on kilauea s upper east rift zone lava tubes were observed to develop by four principal processes 1 flat rooted crusts grew across streams within confined channels 2 overflows and spatter accreted to levees to build arched roofs across streams 3 plates of solidified crust floating downstream coalesced to form a roof and 4 pahoehoe lobes progressively extended fed by networks of distributaries beneath a solidified crust still another tube forming process operated when pahoehoe entered the ocean large waves would abruptly chill a crust across the entire surface of a molten stream crossing through the surf zone these littoral lava tubes formed abruptly in contrast to subaerial tubes which formed gradually all tube forming processes were favored by low to moderate volume rates of flow for sustained periods of time tubes thereby became ubiquitous within the pahoehoe flows and distributed a very large proportionof the lava that was produced during this prolonged eruption tubes transport lava efficiently once formed the roofs of tubes insulate the active streams within allowing the lava to retain its fluidity for a longer time than if exposed directly to ambient air temperature thus the flows can travel greater distances and spread over wider areas even though supply rates during most of 1970 1974 were moderate ranging from 1 to 5 m3 s large tube systems conducted lava as far as the coast 12 13 km distant where they fed extensive pahoehoe fields on the coastal flats some flows entered the sea to build lava deltas and add new land to the island the largest and most efficient tubes developed during periods of sustained extrusion when new lava was being supplied at nearly constant rates tubes can play a major role in building volcanic edifices with gentle slopes because they can deliver a substantial fraction of lava erupted at low to moderate rates to sites far down the flank of a volcano we conclude therefore that the tendency of active pahoehoe flows to form lava tubes is a significant factor in producing the common shield morphology of basaltic volcanoes

emplacement of the most recent lava flows on hualālai volcano hawai i a detailed field and petrologic study of the ca 1800 a d flows at hual lai volcano documents at least two eruptive episodes the hu ehu e flow field ending in 1801 and the ka p lehu flow several decades earlier the morphology and stratigraphy of the ka p lehu flow require an emplacement duration of several days to weeks based on a comparison with recent eruptive activity at mauna loa volcano the eruption cannot have occurred at the anomalously high rate 104 105 m3 s proposed by previous workers the hummocky flow surface of the later phase of the hu ehu e eruption suggests a duration of months based on a comparison with recent eruptive activity at k lauea volcano although none of the ca 1800 flows show evidence for extraordinarily fast emplacement or unusual fluid rheologies both flows show unusual features the abundant xenoliths for which the ka p lehu flow is famous were transported in numerous episodes of deposition and remobilization during which they eroded the channel systems through which they traveled lava transport in proximal and medial regions of both flow fields was probably through lava tubes as evidenced by preserved tubes and by the prevalence of p hoehoe lined channels that require thermally efficient transport of lava over great distances both flows also show abundant evidence for re occupation of older cones and lava tubes a characteristic that may typify infrequent eruptions of older volcanic systems although lava flows from hual lai volcano do not show anomalous eruptive behavior they pose a substantial hazard for coastal communities of kona

morphometric analysis of lava flow units case study over lidar derived topography at mount etna italy abstract high resolution lidar derived digital elevation models of volcanic areas can significantly improve knowledge of lava flow morphology and emplacement mechanisms here we focus on single flow units presenting a new semi automatic procedure which provides a quantitative analysis of their shape the method relies on the automatic processing of the elevation profiles obtained on transects orthogonal to the flow unit axis the initial phase of the mount etna flank eruption from september 2004 is taken as test case and the procedure is applied on an active lava flow which was emplaced on the eastern flank of the volcano the main topographic dataset used is a 2 m resolution digital elevation model obtained from a lidar survey starting from the axis of a lava flow unit our method yields morphometric data on the flow unit at a 2 m spacing calculating parameters including flow width channel width the heights of the levees inward and outward slope of levees and estimating pre emplacement slope along the axis the procedure is embedded in a customized gis which allows easy processing handling and displaying of data the procedure has also been applied to another flow unit emplaced during the october november 1999 overflow from the bocca nuova crater results show that the channel width seems to accommodate first order trends of the pre emplacement slope along the flow unit axis while it is little affected by high frequency changes in slope in contrast flow unit width and flow unit thickness are apparently influenced by small scale changes in slope the different emplacement conditions of the two flow units are reflected by the overall contrasting morphologies as shown by the different average thickness and by the different ratios between i flow width vs channel width and ii flow unit section area vs channel width the new method provides an enhanced systematic and thorough morphometric description of flow units which may improve the understanding of the emplacement mechanisms of lava flows on earth and other planets

multiradar observations of the polar tongue of ionization 1 we present a global view of large scale ionospheric disturbances during the main phase of a major geomagnetic storm we find that the low latitude auroral and polar latitude regions are coupled by processes that redistribute thermal plasma throughout the system for the large geomagnetic storm on 20 november 2003 we examine data from the high latitude incoherent scatter radars at millstone hill sondrestrom and eiscat tromso with superdarn hf radar observations of the high latitude convection pattern and dmsp observations of in situ plasma parameters in the topside ionosphere we combine these with north polar maps of stormtime plumes of enhanced total electron content tec derived from a network of gps receivers the polar tongue of ionization toi is seen to be a continuous stream of dense cold plasma entrained in the global convection pattern the dayside source of the toi is the plume of storm enhanced density sed transported from low latitudes in the postnoon sector by the subauroral disturbance electric field convection carries this material through the dayside cusp and across the polar cap to the nightside where the auroral f region is significantly enhanced by the sed material the three incoherent scatter radars provided full altitude profiles of plasma density temperatures and vertical velocity as the toi plume crossed their different positions under the cusp in the center of the polar cap and at the midnight oval polar cap boundary greatly elevated f peak density 1 5e12 m 3 and low electron and ion temperatures 2500 k at the f peak altitude characterize the sed toi plasma observed at all points along its high latitude trajectory for this event sed toi f region tec 150 1000 km was 50 tecu both in the cusp and in the center of the polar cap large upward directed fluxes of o 1 e14 m 2 s 1 were observed in the topside ionosphere

multispectral thermal infrared mapping of the 1 october 1988 kupaianaha flow field kilauea volcano hawaii multispectral thermal infrared radiance measurements of the kupaianaha flow field were acquired with the nasa airborne thermal infrared multispectral scanner tims on the morning of 1 october 1988 the tims data were used to map both the temperature and emissivity of the surface of the flow field the temperature map depicted the underground storage and transport of lava the presence of molten lava in a tube or tumulus resulted in surface temperatures that were at least 10 c above ambient the temperature map also clearly defined the boundaries of hydrothermal plumes which resulted from the entry of lava into the ocean the emissivity map revealed the boundaries between individual flow units within the kupaianaha field in general the emissivity of the flows varied systematically with age but the relationship between age and emissivity was not unique distinct spectral anomalies indicative of silica rich surface materials were mapped near fumaroles and ocean entry sites this apparent enrichment in silica may have resulted from an acid induced leaching of cations from the surfaces of glassy flows such incipient alteration may have been the cause for virtually all of the emissivity variations observed on the flow field the spectral anomalies representing areas where the acid attack was most intense

plateaus and sinuous ridges as the fingerprints of lava flow inflation in the eastern tharsis plains of mars abstract the tharsis montes rift aprons are composed of outpourings of lava from chaotic terrains to the northeast and southwest flank of each volcano sinuous and branching channel networks that are present on the rift aprons suggest the possibility of fluvial processes in their development or erosion by rapidly emplaced lavas but the style of lava flow emplacement throughout rift apron development is not clearly understood to better characterize the style of lava emplacement and role of fluvial processes in rift apron development we conducted morphological mapping of the pavonis mons southwest rift apron and the eastern tharsis plains using images from the high resolution imaging science experiment hirise mars orbiter camera moc context camera ctx thermal emission imaging system themis and high resolution stereo camera hrsc along with the mars orbiter laser altimeter mola precision experiment data records pedrs and gridded data our approach was to 1 search for depositional fans at the slope break between the rift apron and adjacent low slope plains 2 determine if there is evidence that previously formed deposits might have been buried by plains units 3 characterize the tharsis plains morphologies east of pavonis mons and 4 assess their relationship to the rift apron units we have not identified topographically significant depositional fans nor did we observe evidence to suggest that plains units have buried older rift apron units flow features associated with the rift apron are observed to continue across the slope break onto the plains in this area the plains are composed of a variety of small fissures and low shield vents around which broad channel fed and tube fed flows have been identified we also find broad flat topped plateaus and sinuous ridges mixed among the channels tubes and vents flat topped plateaus and sinuous ridges are morphologies that are analogous to those observed on the coastal plain of hawai i where lava flows have advanced from the volcano s several degree flank onto the nearly zero degree coastal plain when local volumetric flow rates are low flow fronts tend to spread laterally and often thicken via endogenous growth or inflation of the sheet like flow units if flow advance is restricted by existing topography into narrow pathways inflation can be focused into sinuous elongate ridges the presence of plateaus and ridges emplaced from the rift zones across the plains to the east of pavonis mons and a lack of fan like features or evidence for their burial are consistent with rift apron lavas crossing a slope break with low local volumetric flow rates that led to inflation of sheet like and tube fed lava flows

superposed epoch analysis of the dayside ionospheric response to four intense geomagnetic storms 1 prompt daytime ionospheric responses are presented for the following four intense geomagnetic storms 29 october 2003 30 october 2003 20 november 2003 and 7 november 2004 we perform a superposed epoch analysis of the storms by defining the start time of the epoch when the kan lee interplanetary electric field proportional to the reconnection electric field first reaches 10 mv m during a period of continuously southward bz measurements from the gps receiver onboard the champ satellite at 400 km altitude indicate significant low to middle latitude daytime total electron content tec increases above the satellite within 1 2 h of the defined start time for three of the storms 1400 local solar time the 20 november 2003 data follow a different pattern the largest tec increases appear several hours 5 7 following the interplanetary magnetic field bz event onset tec data obtained from ground based gps receivers for the november 2003 storm tend to confirm a late tec increase for this storm at 1400 lt estimates of vertical plasma uplift near the equator at jicamarca longitudes 281 e using the dual magnetometer technique suggest that variability of the timing of the tec response is associated with variability in the prompt penetration of electric fields to low latitudes it is also found that for the november 2003 magnetic storm the cross correlation function between the sym h index and the interplanetary electric field reached maximum correlation with a lag time of 4 h such a large lag time has never been noted before the long delays of both the ionosphere and magnetosphere responses need to be better understood

effusion rate trends at etna and krafla and their implications for eruptive mechanisms abstract using effusion rates obtained from ground and satellite based data we build a data set of 381 effusion rate measurements during effusive activity at etna and krafla between 1980 and 1999 this allows us to construct detailed effusion rate curves for six fissure fed eruptions at etna and krafla and four summit fed eruptions at etna these define two trends type i and ii type i trends have effusion rates that rise rapidly to an initial peak before declining more slowly resulting in an exponential decrease in eruption rate and declining growth in cumulative volume type ii trends are characterised by steady effusion and eruption rates and hence a linear increase in cumulative volume the former is typical of fissure eruptions and can be explained by tapping of an enclosed pressurised system the latter are typical of persistent etnean summit eruptions plus one persistent effusive eruption at stromboli 1985 1986 examined here and can be explained by overflow of the time averaged magma supply we use our effusion rate data to assess the magma balance at etna 1980 1995 and krafla 1975 1984 between 1980 and 1995 etna was supplied at a time averaged rate of 6 8 2 3 m 3 s 1 of which 13 was erupted at krafla 817 30 10 6 m 3 was erupted and intruded during 1975 1984 and the ratio of erupted to intruded volume was 0 3 at etna there is evidence for intrusion of the unerupted magma within and beneath the edifice as well as storage in the central magma column at krafla unerupted magma was intruded into a rift zone but an increasing proportion of the supply was erupted from 1980 onwards a result of the rift zone capacity being reached magma intruded prior to an eruptive event may also be entrained and or pushed out during eruption to contribute to the initial high effusion rate phases of type i events the detail in our effusion rate curves was only possible using a thermal approach which estimates effusion rates using satellite data we look forward to analysing satellite derived effusion rate trends in real time using data from current and soon to be launched sensors

lava effusion a slow fuse for paroxysms at stromboli volcano questo lavoro ha analizzato i risultati del monitoraggio termico delle eruzioni di stromboli del 2002 2003 e 2007 ed ha mostrato come prima di ogni parossisma il volume di lava eruttato nel corso dell attivita effusiva sia stato confrontabile questa osservazione ha fatto ipotizzare l esistenza di una decompressione critica nel sistema di alimentazione superficiale del vulcano raggiungibile anche lentamente che innesca la veloce risalita del magma ricco in gas responsabile dei parossismi durante l attivita effusiva a questa decompressione critica e associabile una soglia di volume di magma emesso che diventa la misura discriminante per valutare la fase critica del vulcano e predire il parossisma

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

unusual topside ionospheric density response to the november 2003 superstorm 1 we use observations from a variety of different ground and space based instruments including ionosonde ground and space based global positioning system gps receivers magnetometers and solar wind data from the advanced composition explorer ace to examine the response of the ionospheric f2 layer height during the november 2003 superstorm we found that the topside ionosphere responded unusually to the 20 november 2003 severe storm compared to behavior observed in a number of previous storms while ground based gps receivers observed a large enhancement in dayside tec the low earth orbiting 400 km champ satellite did not show any sign of dayside tec enhancement the real time vertical density profiles constructed from ground based gps tec using a tomographic reconstruction technique clearly revealed that the ionospheric f2 layer peak height had been depressed down to lower altitudes ionospheric f layer peak height hmf2 from the nearby ionosonde stations over europe also showed that the dayside f2 layer peak height was below 350 km which is below the orbiting height of champ the vertical e b drift estimated from ground based magnetometer equatorial electrojet delta h showed strong dayside downward drifts which may be due to the ionospheric disturbance dynamo electric field produced by the large amount of energy dissipation into high latitude regions this storm demonstrates that data from leo satellites varies widely among different superstorms

ionospheric storm time dynamics as seen by gps tomography and in situ spacecraft observations 1 during major geomagnetic storms anomalous enhancements of the ionospheric density are seen at high and middle latitudes a number of physical mechanisms have been invoked to explain these storm time density anomalies including an expansion of high latitude electric plasma convection to midlatitudes thermospheric neutral winds and changes in the ionospheric composition however it remains unclear which mechanism plays the dominant role in the formation of storm time density anomalies partly because of insufficient coverage of the measurements of global electric convection and thermospheric winds at midlatitudes this paper describes a novel technique for extracting the storm time e b convection boundary from in situ measurements of plasma bulk motion obtained by leo dmsp satellites the convection boundary estimated from the dmsp data during major magnetic storm of 20 november 2003 has been compared with the global distributions of the ionospheric plasma deduced from characteristics of gps signals acquired by a ground based network of gps receivers the tomographic inversion of gps data using a three dimensional time dependent inversion technique reveals the spatial and temporal evolution of the storm time density anomaly comparison between the tomographic reconstructions of the ionospheric plasma distributions and in situ dmsp measurements of plasma bulk motion suggests that the convective flow expanded low enough in latitude to encompass in part the formation of the midlatitude tec anomaly some features of the tec dynamics observed during the 20 november 2003 storm however suggest that mechanisms other than the expanded ionospheric convection such as thermospheric neutral winds are also involved in the formation of the midlatitude anomaly

a quantitative look at the demise of a basaltic vent the death of kupaianaha kilauea volcano hawai i the kupaianaha vent the source of the 48th episode of the 1983 to present pu u o o kupaianaha eruption erupted nearly continuously from july 1986 until february 1992 this investigation documents the geophysical and geologic monitoring of the final 10 months of activity at the kupaianaha vent detailed very low frequency vlf electromagnetic profiles across the single lava tube transporting lava from the vent were used to determine the cross sectional area of the molten lava within the tube combined with measurements of lava velocity these data provide an estimate of the lava output of kupaianaha in addition lava temperatures calculated from analysis of quenched glass and bulk rock chemistry were obtained for samples taken from the tube at the same site the combined data set shows the lava flux from kupaianaha vent declining linearly from 250 000 m3 day in april 1991 to 54 000 m3 day by november 1991 during that time surface breakouts of lava from weak points along the tube occurred progressively closer to the vent consistent with declining efficiency in lava transport there were no significant changes in lava temperature or in bulk mgo content during this period another eruptive episode the 49th began uprift of kupaianaha on 8 november 1991 and erupted lava concurrently with kupaianaha for 18 days lava flux from kupaianaha decreased in response to this new episode but the response was delayed by approximately 1 day after 14 november 1991 lava velocities were no longer measurable in the tube because the lava stream beneath the skylight had crusted over however the vlf derived electrical conductances documented the decreasing flux of molten lava through the tube kupaianaha remained active but output continued to decrease until early february 1992 when the last active surface flows were seen in november 1991 we used the linearly decreasing effusion rate to accurately predict the date for the death of the kupaianaha vent the linear nature of the decline in lava tube conductance and the delayed and slow response of the waha ula tube conductances to the 49th eruptive episode led us to speculate that a the kupaianaha vent shut down because of a decrease in driving pressure and not because of a freeze up of the vent and b that pu u o o episode 49 and kupaianaha were fed nearly vertically from a source deep within the rift zone

morphology of basaltic lava channels during the mt etna september 2004 eruption from airborne laser altimeter data 1 the morphological features of active lava channels acquired over mt etna by means of airborne laser altimeter data are presented the data were acquired on 16th september 2004 using an optech altm 3033 laser altimeter the flight height was about 2000 m above ground during the flight the lava erupted from the eastern part of the mt etna summit area flowed into the valle del bove the measured morphologic features are channel width wc flow width wf levee height hl flow thickness tf and channel depth dc the main lava flow shows a well developed channel with levees the average measured values for the morphologic features of this flow are wc 16 m wf 52 m hl 7 m tf 5 m and dc 2 m the wc parameter shows linear increase from about 7 m near the vent up to about 25 m close to the front 1600 m in length

structure of a frontal system over the northeast pacific ocean abstract a frontal system passed over the storm transfer and response experiment project area on 17 november 1980 as revealed by ship born rawinsonde surface and radar information this northeast pacific storm exhibited three components it linked surface and 500 mb troughs with marked surface windshift and associated confluence and horizontal wind shear but exhibiting no surface temperature change a midtropospheric cold katafront and an upper moisture front that was moving ahead more rapidly than the other components the upper moisture front was marked by a moisture gradient across the trailing edge of a large cloud region that moved with the winds at 500 mb or higher due to the horizontal thermal homogeneity of the marine boundary layer the confluence associated with the surface trough did not cause low level cold frontogenesis high w values of the upper portion of the frontal system indicate that air was advected from much farther south important characteristics of frontal system evolution

pāhoehoe a ā and block lava an illustrated history of the nomenclature lava flows occur worldwide and throughout history various cultures and geologists have described flows based on their surface textures as a result surface morphology based nomenclature schemes have been proposed in most languages to aid in the classification and distinction of lava surface types one of the first to be published was likely the nine class italian language description based classification proposed by mario gemmellaro in 1858 by far the most commonly used terms to describe lava surfaces today are not descriptive but instead are merely words specifically the hawaiian words a rough brecciated basalt lava and p hoehoe smooth glassy basalt lava plus block lava thick brecciated lavas that are typically more silicic than basalt a and p hoehoe were introduced into the western geological vocabulary by american geologists working in hawai i during the 1800s they and other nineteenth century geologists proposed formal lava type classification schemes for scientific use and most of them used the hawaiian words in 1933 ruy finch added the third lava type block lava to the classification scheme with the tripartite system being formalized in 1953 by gordon macdonald more recently particularly since the 1980s and based largely on studies of lava flow interiors a number of sub types and transitional forms of all three major lava types have been defined this paper reviews the early history of the development of the p hoehoe a and block lava naming system and presents a new descriptive classification so as to break out the three parental lava types into their many morphological sub types

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

lava channel roofing overflows breaches and switching insights from the 2008 2009 eruption of mt etna during long lived basaltic eruptions overflows from lava channels and breaching of channel levees are important processes in the development of extensive a lava flow fields short lived breaches result in inundation of areas adjacent to the main channel however if a breach remains open lava supply to the original flow front is significantly reduced and flow field widening is favoured over lengthening the development of channel breaches and overflows can therefore exert strong control over the overall flow field development but the processes that determine their location and frequency are currently poorly understood during the final month of the 2008 2009 eruption of mt etna sicily a remote time lapse camera was deployed to monitor events in a proximal region of a small ephemeral lava flow for over a period of 10 h the flow underwent changes in surface elevation and velocity repeated overflows of varying vigour and the construction of a channel roof a required prelude to lava tube formation quantitative interpretation of the image sequence was facilitated by a 3d model of the scene constructed using structure from motion computer vision techniques as surface activity waned during the roofing process overflow sites retreated up the flow towards the vent and eventually a new flow was initiated our observations and measurements indicate that flow surface stagnation and flow inflation propagated up flow at an effective rate of 6 m h 1 and that these processes rather than effusion rate variations were ultimately responsible for the most vigorous overflow events we discuss evidence for similar controls during levee breaching and channel switching events on much larger flows on etna such as during the 2001 eruption

altitudinal variation of the stable isotopes of snow in regions of high relief a major discontinuity in the variation of 18 o d with altitude in high mountains was first seen in data from mount logan yukon territory canada holdsworth and others 1991 the profile of vs altitude revealed three well defined regions 1 a lower monotonic fractionation sequence below 3 km 2 a middle layer typically 1 2 km thick within which values are nearly constant or stepped with altitude and 3 part of another fractionation sequence in the quasi geostrophic flow region above 5 3 km the middle region was inferred to be a mixed layer combining moisture from regions 1 and 3 this type of structure is now seen to occur on other high altitude mountains including cerro aconcagua argentina where observations reach almost 7 km the new observations confirm the general occurrence of a multi layered atmosphere during precipitation at high altitude glacier sites this structure is linked to synoptic scale polar cyclones where the middle layer is identified as being the signature of the warm front zone these results have implications for the common practice of using a specific spatially derived isotopic thermometer in the time domain for the paleoclimatic interpretation of high altitude ice core records

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

lava tubes terraces and megatumuli on the 1614 24 pahoehoe lava flow field mount etna sicily the 1614 1624 lava flow of mt etna was formed during a long duration flank eruption involving predominantly pahoehoe flows which produced unusual surface features including mega tumuli here defined and terraces detailed mapping of the flow units surface features and associated tubes reveals a complex sequence of emplacement for the field the stair stepped terraces appear to have been formed as a consequence of self damming of tube fed flows which developed perched ponds of lava surges of lava through tubes elevated sections of crusted lava at the distal ends of the flow to generate tumuli some as high as 130 m as a consequence of pressure via hydrostatic head conditions within the tube although pahoehoe lavas and the related features described here are atypical of mt etna they may reflect styles of eruption and lava emplacement found on volcanoes elsewhere

quantifying lava flow hazards in response to effusive eruption the integration of satellite data and modeling represents a step toward the next generation of quantitative hazard assessment in response to effusive volcano eruption onset satellite based thermal remote sensing of hotspots related to effusive activity can effectively provide a variety of products suited to timing locating and tracking the radiant character of lava flows hotspots show the location and occurrence of eruptive events vents discharge rate estimates may indicate the current intensity effusion rate and potential magnitude volume high spatial resolution multispectral satellite data can complement field observations for monitoring the front position length and extension of flows area physics based models driven or validated by satellite derived parameters are now capable of fast and accurate forecast of lava flow inundation scenarios hazard here we demonstrate the potential of the integrated application of satellite remote sensing techniques and lava flow models by using a retrospective analysis of the 2004 2005 effusive eruption at mount etna in italy the lava flow hazard was assessed by using the hotsat volcano hotspot detection system which works with satellite thermal infrared data and the magflow lava flow emplacement model which is able to relate the flow evolution to eruption conditions at the vent we used hotsat to analyze moderate resolution imaging spectroradiometer modis and spinning enhanced visible and infrared imager seviri data to output hotspot location lava thermal flux and effusion rate estimation this output was used to drive the magflow simulations of lava flow paths and to continuously update flow simulations we also show how landsat 7 enhanced thematic mapper etm and earth observing 1 eo 1 advanced land imager ali images complement the field observations to track the flow front position in time and add valuable data on lava flow advancement with which to validate the numerical simulations such integration at last makes timely forecasts of lava flow hazards during effusive crises possible at the great majority of volcanoes for which no monitoring exists

the control of lava flow during the 1991 1992 eruption of mt etna abstract all the actions carried out in 1992 to protect the village of zafferana etnea from being invaded by lava are described an earthen barrier 234 m long and 21 m high was firstly built in january 1992 by accumulating with mechanical escavators 370 000 m 3 of earth scoriae and stones this embankment contained the lava for about one month and was overflowed by april 9 1992 three additional smaller earthen barriers lenght 90 160 m height 6 12 m were built in april to gain time while the lava front was descending towards zafferana from the overflowed first embankment the major effort of the 1992 operation consisted of several attempts at stopping the lava front advance by diverting the flow out from the natural and extensively tunnelled channel through a skylight near the vent the main intervention point was located in valle del bove at an elevation of 2000 m at 8 km from zafferana in a zone almost unaccessible from land helicopters were hence extensively used during the whole operation initial interventions called for attempts at plugging a tunnel by dumping into it linked concrete blocks hedgehogs and blasted portions of the solid levee each intervention caused the partial obstruction of the tunnelled channel which determined major increases of lava overflow in valle del bove and the consequent halt of the most advanced fronts however benefits were of brief duration at the most two weeks of respite before new lava fronts approached again and again the outskirts of zafferana the final successful intervention was carried out on may 27 29 an artificial channel was dug departing from the natural one the solid separation levee was thinned to 3 m and blasted by 7000 kg of explosives after the explosion 2 3 of the lava flowed spontaneously in the artificial channel and then the total diversion was obtained the tunnel being plugged by dumping into the natural flow 230 m 3 of lava boulders as a consequence of the intervention the active natural lava front that on may 27 was only 850 m from zafferana came to an halt as did the entire flow downhill from the diversion point bringing back the situation as it was five months earlier a few days after the beginning of the eruption with the new front of the diverted flow at 6 7 km from zafferana in june 1992 the effusion rate halved from 30 to 15 m 3 s and with this reduced thrust the lava was no longer capable of covering long distances five months after the conclusive intervention the diverted lava continues to flow over its initial natural field but remaining confined in the upper valle del bove without any new threat to zafferana

mapping and downflow simulation of recent lava flow fields at mount etna in recent years progress in geographic information systems gis and remote sensing techniques have allowed the mapping and studying of lava flows in unprecedented detail a composite gis technique is introduced to obtain high resolution boundaries of lava flow fields this technique is mainly based on the processing of lidar derived maps and digital elevation models dems the probabilistic code downflow is then used to simulate eight large flow fields formed at mount etna in the last 25 years thanks to the collection of 6 dems representing mount etna at different times from 1986 to 2007 simulated outputs are obtained by running the downflow code over pre emplacement topographies simulation outputs are compared with the boundaries of the actual flow fields obtained here or derived from the existing literature although the selected fields formed in accordance with different emplacement mechanisms flowed on different zones of the volcano over different topographies and were fed by different lava supplies of different durations downflow yields results close to the actual flow fields in all the cases considered this outcome is noteworthy because downflow has been applied by adopting a default calibration without any specific tuning for the new cases considered here this extensive testing proves that if the pre emplacement topography is available downflow yields a realistic simulation of a future lava flow based solely on a knowledge of the vent position in comparison with deterministic codes which require accurate knowledge of a large number of input parameters downflow turns out to be simple fast and undemanding proving to be ideal for systematic hazard and risk analyses

how the variety of satellite remote sensing data over volcanoes can assist hazard monitoring efforts the 2011 eruption of nabro volcano abstract satellite remote sensing is becoming an increasingly essential component of volcano monitoring especially at little known and remote volcanoes where in situ measurements are unavailable and or impractical moreover the synoptic view captured by satellite imagery over volcanoes can benefit hazard monitoring efforts by monitoring we mean both following the changing styles and intensities of the eruption once it has started as well as nowcasting and eventually forecasting the areas potentially threatened by hazardous phenomena in an eruptive scenario here we demonstrate how the diversity of remote sensing data over volcanoes and the mutual interconnection between satellite observations and numerical simulations can improve lava flow hazard monitoring in response to effusive eruption time averaged discharge rates tadrs obtained from low spatial high temporal resolution satellite data e g modis seviri are complemented compared and fine tuned with detailed maps of volcanic deposits with the aim of constraining the conversion from satellite derived radiant heat flux to tadr maps of volcanic deposits include the time varying evolution of lava flow emplacement derived from multispectral satellite data e g eo ali landsat sentinel 2 aster as well as the flow thickness variations retrieved from the topographic monitoring by using stereo or tri stereo optical data e g pleiades planetscope aster finally satellite derived parameters are used as input and validation tags for the numerical modelling of lava flow scenarios our strategy is applied to the first historic eruption of nabro volcano eritrea occurred in june 2011 this eruptive event was characterized by the extraordinary quantity of so2 emitted into the atmosphere and the extent of the long lava flows which had a significant impact on the inhabitants of the eritrea ethiopia border region despite the low population density because of its remote position little was known about this eruption regarding the quantity of volcanic deposits and the timing and mechanisms of their emplacement we found that the total volume of deposits calculated from differences of digital elevation models dems is about 580 106 m3 of which about 336 106 m3 is the volume of the main lava flow that advanced eastward beyond the caldera multi spectral satellite observations indicate that the main lava flow had reached its maximum extent 16 km within about 4 days of the eruption onset on midnight 12 june lava flow simulations driven by satellite derived parameters allow building an understanding of the advance rate and maximum extent of the main lava flow showing that it is likely to have reached 10 5 km in one day with a maximum speed of 0 44 km h

solar and interplanetary sources of major geomagnetic storms dst 100 nt during 1996 2005 1 we present the results of an investigation of the sequence of events from the sun to the earth that ultimately led to the 88 major geomagnetic storms defined by minimum dst 100 nt that occurred during 1996 2005 the results are achieved through cooperative efforts that originated at the living with a star lws coordinated dataanalysis workshop cdaw held at george mason university in march 2005 on the basis of careful examination of the complete array of solar and in situ solar wind observations we have identified and characterized for each major geomagnetic storm the overall solar interplanetary solar ip source type the time velocity and angular width of the source coronal mass ejection cme the type and heliographic location of the solar source region the structure of the transient solar wind flow with the storm driving component specified the arrival time of shock disturbance and the start and ending times of the corresponding ip cme icme the storm driving component which possesses a prolonged and enhanced southward magnetic field bs may be an icme the sheath of shocked plasma sh upstream of an icme a corotating interaction region cir or a combination of these structures we classify the solar ip sources into three broad types 1 s type in which the storm is associated with a single icme and a single cme at the sun 2 m type in which the storm is associated with a complex solar wind flow produced by multiple interacting icmes arising from multiple halo cmes launched from the sun in a short period 3 c type in which the storm is associated with a cir formed at the leading edge of a high speed stream originating from a solar coronal hole ch for the 88 major storms the s type m type and c type events number 53 60 24 27 and 11 13 respectively for the 85 events for which the surface source regions could be investigated 54 63 of the storms originated in solar active regions 11 13 in quiet sun regions associated with quiescent filaments or filament channels and 11 13 were associated with coronal holes remarkably nine 11 cme driven events showed no sign of eruptive features on the surface or in the low corona e g no flare no coronal dimming and no loop arcade etc even though all the available solar observations in a suitable time period were carefully examined thus while it is generally true that a major geomagnetic storm is more likely to be driven by a frontside fast halo cme associated with a major flare our study indicates a broad distribution of source properties the implications of the results for space weather forecasting are briefly discussed

an experimental study of the surface thermal signature of hot subaerial isoviscous gravity currents implications for thermal monitoring of lava flows and domes received 22 july 2011 revised 23 november 2011 accepted 23 november 2011 published 7 february 2012 1 management of eruptions requires a knowledge of lava effusion rates for which a safe thermal proxy is often used however this thermal proxy does not take into account the flow dynamics and is basically time independent in order to establish a more robust framework that can link eruption rates and surface thermal signals of lavas measured remotely we investigate the spreading of a hot isoviscous axisymmetric subaerial gravity current injected at constant rate from a point source onto a horizontal substrate we performed laboratory experiments and found that the surface thermal structure became steady after an initial transient we develop a theoretical model for a spreading fluid cooled by radiation and convection at its surface that also predicts a steady thermal regime we show that despite the model s simplicity relative to lava flows it yields the correct order of magnitude for the effusion rate required to produce the radiant flux measured on natural lava flows for typical thermal lava properties and an effusion rate between 0 1 and 10 m 3 s 1 the model predicts a steady radiated heat flux ranging from 10 8 to 10 10 w the assessed effusion rate varies quasi linearly with the steady heat flux with much weaker dependence on the flow viscosity this relationship is valid only after a transient time which scales as the diffusive time ranging from a few days for small basaltic flows to several years for lava domes the thermal proxy appears thus less reliable to follow sharp variations of the effusion rate during an eruption

a comparison of the landsat image and laharz simulated lahar inundation hazard zone by the 2010 merapi eruption located above the java subduction zone merapi volcano is an active stratovolcano with a volcanic activity cycle of 1 5 years most merapi eruptions are relatively small with volcanic explosivity index vei of 1 3 however the most recent eruption which occurred in 2010 was quite violent with a vei of 4 and 386 people were killed in this study lahars and pyroclastic flow zones were detected using optical landsat images and the lahar and pyroclastic flow zone simulated using the laharz program to detect areal extents of lahar and pyroclastic flows using landsat images supervised classification was performed after atmospheric correction by using a cosine of the solar zenith correction cost model as a result the extracted dimensions of pyroclastic flows are nearly identical to the calatrava volcanic province cvp monthly reports then areas of potential lahar and pyroclastic flow inundation based on flow volume using the laharz program were simulated and mapped finally the detected lahars and pyroclastic flow zones were compared with the simulated potential zones using laharz program and verified results showed satisfactory similarity 55 63 between the detected and simulated zone the simulated zones using the laharz program can be used as an essential volcanic hazard map for preventing life and property damages for merapi volcano and other hazardous volcanic areas also the laharz program can be used to map volcano hazards in other hazardous volcanic areas

variation of the stable isotopes of water with altitude in the saint elias mountains of canada the stable isotopes of water measured in melt samples taken from snow pits and cores at locations between 1750 and 5930 m altitude on mount logan 5951 m and between 2900 and 4900 m on mount steele 5079 m in the saint elias mountains yukon show a distinctive altitudinal distribution several 18o and d versus altitude profiles indicate the general persistence of a nearly iso step or staircase structure separating a lower region of altitude dependent isotopic fractionation between 1750 and 3350 m from another apparent fractionation sequence appearing above about 5300 m both of these sequences but especially the lower one indicate orderly processes on the one hand postdepositional changes to isotope ratios in snow at different altitudes may cause distortions to an otherwise nearly monotonic isotope fractionation sequence but the main anomaly appears to be far too large to be explained in this way on the other hand an explanation linked to processes occurring in the lower and midtroposphere is based on established meteorological principles as well as on upper air data this hypothesis is proposed as the primary one to explain the gross features of the observed isotope profiles it is compatible with the concept of secondary source moisture arriving via the upper troposphere and it does not exclude the effects of postdepositional stratigraphic and stable isotope ratio changes over interannual time scales any vertical modulation of the observed isotope altitude structure from for example changes in wind regime would give rise to an additional signal in any ice core time series these findings identify a potential difficulty in the interpretation of stable isotope records obtained from high mountain ice core sites it is possible that the results may have application to atmospheric circulation modeling where the effects of extreme topography are being studied

magnetic field changes on lava flow to detect lava tubes abstract during the 1991 1993 etna eruption italy seven surveys of the total geomagnetic field intensity were carried out on two traverses ca 80 m long of the active flow where it displayed evidence for the presence of a lava tube underneath this experiment aimed at evaluating the efficiency of magnetic surveys in detecting the presence of tubes and at following their evolution in time the data showed the presence of an intense anomaly corresponding to the lava tube at the surface the use of a suitable thermomagnetic model allowed the calculation of the tube s magnetic effect at the surface an inverted dipolar anomaly of ca 4000 nt examination of the space time evolution of the magnetic field in other parts of the profile revealed the presence of several anomalous variations up to 1000 nt whose location was very persistent in time in particular the occurrence of relatively rapid magnetic field fluctuations in a well defined area in both profiles was attributed to the presence of another lava tube where magnetic effects by thermo mechanical erosion at the boundaries are likely to take place

emplacement and inflation of pahoehoe sheet flows observations and measurements of active lava flows on kilauea volcano hawaii inflated pahoehoe sheet flows have a distinctive horizontal upper surface which can be several hundred meters across and are bounded by steep monoclinal uplifts the inflated sheet flows we studied ranged from 1 to 5 m in thickness but initially propagated as thin sheets of fluid pahoehoe lava generally 20 30 cm thick individual lobes originated at outbreaks from the inflated front of a prior sheet flow lobe and initially moved rapidly away from their source velocities slowed greatly within hours due to radial spreading and to depletion of lava stored within the source flow as the outward flow velocity decreases cooling promotes rapid crustal growth at first the crust behaves plastically as pahoehoe toes form after the crust attains a thickness of 2 5 cm it behaves more rigidly and develops enough strength to retain incoming lava thus increasing the hydrostatic head at the flow front the increased hydrostatic pressure is distributed evenly through the liquid lava core of the flow resulting in uniform uplift of the entire sheet flow lobe initial uplift rates are rapid flows thicken to 1 m in 1 2 hours but rates decline sharply as crustal thickness increases and as outbreaks occur from the margins of the inflating lobe one flow reached a final thickness of nearly 4 m after 350 hr inflation data define power law curves whereas crustal cooling follows square root of time relationships the combination of data can be used to construct simple models of inflated sheet flows as the flow advances preferred pathways develop in the older portions of the liquid cored flow these pathways can evolve into lavatube systems within a few weeks formation of lava tubes results in highly efficient delivery of lava at velocities of several kilometers per hour to a flow front that may be moving 1 2 orders of magnitude slower if advance of the sheet flow is terminated the tube remains filled with lava that crystallizes in situ rather than draining to form the cave like lava tubes commonly associated with pahoehoe flows inflated sheet flows from kilauea and mauna loa are morphologically similar to some thick icelandic and submarine sheet flows suggesting a similar mechanism of emplacement the planar sheet like geometry of flood basalt flows may also result from inflation of sequentially emplaced flow lobes rather than nearly instantaneous emplacement as literal floods of lava

evaluation of seismic site response nearby underground cavities using earthquake and ambient noise recordings a case study in catania area italy abstract the influence of underground cavities in assessing local seismic response was studied in some test sites in the urban area of catania the investigations were performed both in a natural cavity and in artificial tunnels taking into account the near surface geological features earthquake and ambient noise records were processed through spectral ratio techniques investigating also on the possible directional effects a set of 70 local and regional earthquakes was recorded by seismic stations deployed nearby a grotto located in the northern part of the town as well as in a reference site on the bedrock as regards ambient noise measurements about 30 recording sites were selected locating the mobile stations inside the cavities as well as along short profiles crossing them spectral ratios coming out from performed measurements show that spectral peaks in the frequency range 3 0 7 0 hz appear stable nearby the cavity and show a tendency to be less pronounced at increasing distance from it moreover the natural period of buildings erected nearby and over the considered cavity was evaluated to investigate on possible soil structure interactions the results so far obtained point out that the height of the cavities plays an important role it appears evident that only cavities having height greater than about 4 m show significant h v amplification peaks moreover spectral ratios deriving from measurements performed inside the cavities show less pronounced spectral peaks than those obtained from measurements over and outside the cavities investigations about the interaction with nearby edifices show slight increments in the amplitude of spectral peaks representing the fundamental period of buildings located over the investigated grotto finally our observations set into evidence a tendency toward a pronounced polarization of the ground motion that is parallel to the main axis of the grotto

flow and instability of a viscous current down a slope if viscous fluid is released on a horizontal surface it rapidly takes up a circular plan form as it spreads this form is observed1 2 to be stable to any small disturbances which are initiated on the front due for example to irregularities in the horizontal surface or to chance perturbations alternatively if some fluid is released onto a sloping surface for example some liquid detergent on a slanted plate a quite different plan form occurs one two or more extended regions of fluid develop downslope as shown in fig 1a b a situation intermediate between these two is now discussed consider a broad band of viscous fluid uniform in depth across a slope released so as to flow down a constant slope by following the motion which is initially independent of the cross slope coordinate the speed of advance and the depth of the flow before it breaks up into a series of waves of ever increasing amplitude can be determined i present an expression for the wavelength of the front which is determined by surface tension and is independent of the coefficient of viscosity

structure and origin by injection of lava under surface crust of tumuli lava rises lava rise pits and lava inflation clefts in hawaii tumuli are positive topographic features that are common on hawaiian pahoehoe lava flow fields particularly on shallow slopes and 75 measured examples are presented here to document the size range tumuli form by up tilting of crustal plates without any crustal shortening and are thus distinguished from pressure ridges which are up buckled by laterally directed pressure the axial or star like systems of deep clefts that characterize tumuli are defined here as lava inflation clefts their tips advanced into red hot lava and they widened as uplift proceeded and while the lava crust was thickening flat surfaced uplifts formed like tumuli by injection of lava under a surface crust were previously called pressure plateaus but lava rise is proposed instead the pits that abound among lava rises previously attributed to collapse or subsidence are generally formed because the lava around them rose and the name lava rise pit is proposed unique examples of tumuli and lava rises from which lava drained out under a surface crust 1 5 to 2 5 m thick are described from kilauea caldera these examples show that in tumuli and lava rises the crust floats on considerable bodies of fluid lava and is able to do so because of its higher vesicle content the fluid lava loses many of its gas bubbles during residence beneath the crust the bulk densities of samples from tumuli show a general downward increase the form of the density profile is consistent with the relationship that for any given crustal thickness the density of fluid lava closely matched the average density of that crust suggesting that the lava was stably density stratified it is inferred that stable stratification was regulated by out flows of the more vesicular lava fractions loss of bubbles through the lava inflation clefts and entry of injected lava at its level of neutral buoyancy below the uppermost meter the downward decrease in vesicularity closely conforms with that expected by compression of a uniform mass of gas per unit mass of lava

karst geomorphology of carbonatic conglomerates in the folded molasse zone of the northern alps austria germany abstract the folded molasse zone of the northern alps consists of clastic sedimentary rocks that are usually not considered to be karstifiable however large areas within this zone are composed of carbonatic conglomerates numerous karst landforms have recently been discovered but are not recorded on official maps and in the literature therefore a research programme was initiated at the hochgrat site austria germany that included geomorphological mapping and characterisation of the karst phenomena both fracture controlled and hydrodynamically controlled karren were observed on conglomerate outcrops the predominant karst landforms dolines are typically circular funnel shaped most often 2 to 9 m in diameter 1 to 6 m deep and frequently act as swallow holes poljes that are atypically small 1 ha occur in either glacial cirques or syncline depressions are flat floored and lined with sediment and soil and drain underground via swallow holes short caves springs with marked discharge variations and estavelles are further evidence for karst development karstic landforms are widespread in carbonatic conglomerate terrains but their dimensions are smaller than in typical limestone karst the practical implications of these findings are also briefly mentioned in this paper

quantifying the effect of rheology on lava flow margins using fractal geometry this study aims at quantifying the effect of rheology on plan view shapes of lava flows using fractal geometry plan view shapes of lava flows are important because they reflect the processes governing flow emplacement and may provide insight into lava flow rheology and dynamics in our earlier investigation bruno et al 1992 we reported that flow margins of basalts are fractal having a characteristic shape regardless of scale we also found we could use fractal dimension d a parameter which quantifies flow margin convolution to distinguish between the two endmember types of basalts a a d 1 05 1 09 and pahoehoe d 1 13 1 23 in this work we confirm those earlier results for basalts based on a larger database and over a wider range of scale 0 125 m 2 4 km additionally we analyze ten silicic flows sio2 52 74 over a similar scale range 10 m 4 5 km we note that silicic flows tend to exhibit scale dependent or non fractal behavior we attribute this breakdown of fractal behavior at increased silica contents to the suppression of small scale features in the flow margin due to the higher viscosities and yield strengths of silicic flows these results suggest we can use the fractal properties of flow margins as a remote sensing tool to distinguish flow types our evaluation of the nonlinear aspects of flow dynamics indicates a tendency toward fractal behavior for basaltic lavas whose flow is controlled by internal fluid dynamic processes for silicic flows or basaltic flows whose flow is controlled by steep slopes our evaluation indicates non fractal behavior consistent with our observations

the structure water budget and radiational features of a high latitude warm front abstract on 30 september 1994 an arctic low pressure system passed over the southern beaufort sea area of northern canada and research aircraft observations were made within and around the warm front of the storm this study is unique in that the warm front contained subzero centigrade temperatures across the entire frontal region the overall structure of the warm front and surrounding region was similar to midlatitude storms however the precipitation rates liquid water content magnitudes horizontal and vertical winds vertical wind shear turbulence and thermal advection were very weak in addition a low level jet and cloud bands were aligned parallel to the warm front near neutral stability occurred within and around the front and conditional symmetric instability was likely occurring a steep frontal region resulted from strong coriolis influences that in turn limited the amount of cloud and precipitation ahead of the system the precipitation efficiency of the storm was high 60 but is beli

the initial phases of the 2008 2009 mount etna eruption a multidisciplinary approach for hazard assessment accepted for publication in journal of geophysical research copyright 2010 american geophysical union

lava rise plateaus and inflation pits in the mccartys lava flow field new mexico an analog for pāhoehoe like lava flows on planetary surfaces

development of the 1990 kalapana flow field kilauea volcano hawaii the 1990 kalapana flow field is a complex patchwork of tube fed pahoehoe flows erupted from the kupaianaha vent at a low effusion rate approximately 3 5 m3 s these flows accumulated over an 11 month period on the coastal plain of kilauea volcano where the pre eruption slope angle was less than 2 the composite field thickened by the addition of new flows to its surface as well as by inflation of these flows and flows emplaced earlier two major flow types were identified during the development of the flow field large primary flows and smaller breakouts that extruded from inflated primary flows primary flows advanced more quickly and covered new land at a much higher rate than breakouts the cumulative area covered by breakouts exceeded that of primary flows although breakouts frequently covered areas already buried by recent flows lava tubes established within primary flows were longer lived than those formed within breakouts and were often reoccupied by lava after a brief hiatus in supply tubes within breakouts were never reoccupied once the supply was interrupted during intervals of steady supply from the vent the daily areal coverage by lava in kalapana was constant whereas the forward advance of the flows was sporadic this implies that planimetric area rather than flow length provides the best indicator of effusion rate for pahoehoe flow fields that form on lowangle slopes

major geomagnetic storms dst 100 nt generated by corotating interaction regions 1 seventy nine major geomagnetic storms minimum dst 100 nt observed in 1996 to 2004 were the focus of a living with a star coordinated data analysis workshop cdaw in march 2005 in nine cases the storm driver appears to have been purely a corotating interaction region cir without any contribution from coronal mass ejection related material interplanetary coronal mass ejections icmes these storms were generated by structures within cirs located both before and or after the stream interface that included persistently southward magnetic fields for intervals of several hours we compare their geomagnetic effects with those of 159 cirs observed during 1996 2005 the major storms form the extreme tail of a continuous distribution of cir geoeffectiveness which peaks at dst 40 nt but is subject to a prominent seasonal variation of 40 nt which is ordered by the spring and fall equinoxes and the solar wind magnetic field direction toward or away from the sun the o brien and mcpherron 2000 equations which estimate dst by integrating the incident solar wind electric field and incorporating a ring current loss term largely account for the variation in storm size they tend to underestimate the size of the larger cir associated storms by dst 20 nt this suggests that injection into the ring current may be more efficient than expected in such storms four of the nine major storms in 1996 2004 occurred during a period of less than three solar rotations in september to november 2002 also the time of maximum mean imf and solar magnetic field intensity during the current solar cycle the maximum cir storm strength found in our sample of events plus additional 23 probable cir associated dst 100 nt storms in 1972 1995 is dst 161 nt this is consistent with the maximum storm strength dst 180 nt expected from the o brien and mcpherron equations for the typical range of solar wind electric fields associated with cirs this suggests that cirs alone are unlikely to generate geomagnetic storms that exceed these levels

a historical pyroclastic flow emplaced within a pre existing pleistocene lava tube silidong tianchi volcano changbaishan northeastern china pyroclastic flow deposits recently found within a pre existing lava tube at tianchi volcano represent to the best of our knowledge the only such reported occurrence worldwide in this case pyroclastic flow of tianchi s millennium eruption 1 ka traveled about 18 km from the summit eruptive source and poured successively into the 560 m long accessible segment of silidong lava tube mapping of tube morphology combined with detailed characterization of the features associated with the pumice flow deposits e g adhering of pyroclastic materials on tube walls fumarole pipes rootless vents and flow fronts of the deposit surface has enabled plausible inferences regarding the original within tube conditions and dynamic flow regime during emplacement we propose a model of an aggrading pyroclastic flow which locally varies its sedimentation rate the pyroclastic deposit is thicker in locations of reduced flow mobility and the resultant variations in deposit thickness appear to control the distribution of fumarole pipes and rootless vents

formation of polar ionospheric tongue of ionization during minor geomagnetic disturbed conditions previous investigations of ionospheric storm enhanced density sed and tongue of ionization toi focused mostly on the behavior of toi during intense geomagnetic storms little attention has been paid to the spatial and temporal variations of toi during weak to moderate geomagnetic disturbed conditions in this paper we investigate the source and development of toi during a moderate geomagnetic storm on 14 october 2012 multi instrumental observations including gps total electron content tec defense meteorological satellite program dmsp in situ measured total ion concentration and ion drift velocity superdarn measured polar ion convection patterns and electron density profiles from the poker flat incoherent scatter radar pfisr have been utilized in the current analysis gps tec maps show salient toi structures persisting for about 5 h over high latitudes of north america on 14 october 2012 in the later recovery phase of the storm when the magnitudes of imf by and bz were less than 5 nt the pfisr electron density profiles indicate that the extra ionization for tec enhancements mainly occurred in the topside ionosphere with no obvious changes in the bottomside ionosphere and vertical plasma drifts additionally there were no signatures of penetration electric fields in the equatorial electrojet data and upward ion drifts at high latitudes at the same time strong subauroral polarization streams with ion drift speeds exceeding 2 5 km s carried sunward fluxes and migrated toward lower latitudes for about 5 based on the dmsp cross track drift measurements based on those measurements we postulate that the combined effects of initial build up of ionization at midlatitudes through daytime production of ionization and equatorward or less poleward than normal daytime neutral wind reducing downward diffusion along the inclined filed lines and an expanded polar ion convection pattern and its associated horizontal plasma transport are important in the formation of the toi

thermal anomaly at the earth s surface associated with a lava tube abstract lava tubes are frequently encountered in volcanic areas the formation of lava tubes has strong implications on the volcanic hazard during effusive eruptions the thermal dissipation of lava flowing in a tube is reduced in respect to the lava flowing in an open channel so the lava may threaten areas that would not be reached by flows in open channels for this reason it is important to detect the presence of lava tubes in this work we propose a model to detect the presence and the characteristics of lava tubes by their thermal footprint at the surface we model numerically the temperature distribution and the heat flow both in the steady and the transient state and we take into account the principal thermal effects due to the presence of an active lava tube i e the conduction to the ground and the atmosphere the convection and the radiation in the atmosphere we assume that lava fluid is at high temperature in motion inside a sloping tube under the gravity force the thermal profile across the tube direction in particular the width of the temperature curve allows to evaluate the depth of the tube the values of maximum temperature and of tube depth allow to estimate the area of the tube section the shape of the temperature curve and its asymmetry can give information about the geometry of the tube if we observe volcanic areas at different times by thermal cameras we can detect anomalies and evaluate their causes during an eruption in particular we can evaluate whether they are due to active lava flows or not and what is their state for lava tubes we can connect thermal anomalies with lava tube position characteristics and state