geomorphometric analysis of the 2014 2015 barðarbunga volcanic eruption iceland abstract topographical information is of fundamental interest for a wide range of disciplines including glaciology agriculture communication network planning or hazard management in volcanology elevation data are of particular importance when assessing material flows throughout a volcanic system to obtain accurate estimates of time varying topography in volcanic active regions high resolution digital elevation models dems are required to monitor and evaluate topographical changes and especially volumetric gains and losses during the 2014 2015 bar arbunga eruption iceland multi temporal tandem x dem sequences were evaluated the 2014 2015 volcanic eruption was associated with the rare event of a caldera collapse visible on the surface of the vatnajokull glacier as well as major lava effusion in the holuhraun plain before investigating topographical change at the two study areas the tandem x dems were analysed for absolute and relative height errors resulting from the radar system parameters the sar processing or the local environment the uncertainty investigation determined that acquisitions over the snow covered bar arbunga caldera were primarily affected by microwave penetration into snow and dems over the holuhraun lava field exhibited increased height errors due to active lava flows and dynamic outwash plain the topographical analysis of the 2014 2015 bar arbunga eruption revealed a maximum vertical displacement of approximately 65 m and 43 m at the study area of the bar arbunga caldera and holuhraun lava field respectively with a total subsidence volume of 1 40 0 13 km3 and a dense rock equivalent dre lava volume of 1 36 0 07 km3 known uncertainties in volume were decreased by approximately 35 and 77 accordingly taking into account the calculation of rates the temporal development of caldera collapse and lava effusion was found to exhibit a near exponential decrease the ratio between subsidence and dre lava volume moreover indicated the coupling between piston collapse and magma drainage

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

deep magma body beneath the summit and rift zones of kilauea volcano hawaii a magnitude 7 2 earthquake in 1975 caused the south flank of kilauea volcano hawaii to move seaward in response to slippage along a deep fault since then a large part of the volcano s edifice has been adjusting to this perturbation the summit of kilauea extended at a rate of 0 26 meter per year until 1983 the south flank uplifted more than 0 5 meter and the axes of both the volcano s rift zones extended and subsided the summit continues to subside these ground surface motions have been remarkably steady and much more widespread than those caused by either recurrent inflation and deflation of the summit magma chamber or the episodic propagation of dikes into the rift zones kilauea s magmatic system is therefore probably deeper and more extensive than previously thought the summit and both rift zones may be underlain by a thick near vertical dike like magma system at a depth of 3 to 9 kilometers

spatiotemporal variability of active lava surface radiative properties using ground based multispectral thermal infrared data abstract active lava surfaces emplaced during effusive eruptions are typically observed in the form of lava flows lakes or domes there are numerous volcanoes on earth that regularly produce active lava including k lauea volcano in hawai i which had a continually active lava flow field from the 1980s until the end of the last eruptive phase in 2018 during the last decade of that period it also had a persistent lava lake at the summit this study used a new ground based miniature multispectral thermal camera mmt cam imaging system to acquire high spatiotemporal data of active lava surfaces at k lauea volcano in 2018 the goal was to quantify the short term variability of the radiative properties e g emissivity kinetic temperature and heat flux of molten lava during cooling and propagation using concurrent in situ multispectral thermal infrared tir measurements as expected there was a strong positive correlation between kinetic temperature fraction of exposed melt and heat flux importantly there is also a negative or inverse correlation found for the emissivity of lava surfaces with temperature during cooling immediately following emplacement the temporal results reveal low and high frequency 10s of minutes to seconds changes in radiative properties up to 25 and 5 variability respectively the spatial analysis provided insights into emplacement dynamics and activity potential through the interpretation of the improved heat flux measurements for example these data highlighted lava lake over turning subsurface supply pathways and lava flow breakout zones additionally the first calibrated in situ emissivity measurements of actively emplaced lava indicated a lower efficiency of radiant heat flux from molten lava surfaces prior to a viscoelastic crust forming which results in lower calculated heat fluxes than previous estimates this implies that prior heat budget calculations and lava flow propagation models may have overestimated heat flux by at least 20 from the molten lava prior to cooling and crust formation therefore the results of this study allow for more accurate calibration of prior calculations and models resulting in more accurate values and a reduction in the uncertainty of hazard models reliant on these values

deucalionis regio mars evidence for a new type of immobile weathered soil unit abstract a small equatorial region south of sinus meridiani deucalionis regio has been found spectrally distinct from other regions as seen in a high spectral resolution telescopic image of mars interpretations from a variety of other observations including infrared radiometric data historical occurrences of localized dust storms and general circulation wind modeling also suggest that the surface of deucalionis regio has properties that are different than those of nearby regions arabia acidalia sinus meridiani and oxia in terms of expression of color crystalline hematite content and perhaps pyroxene abundance and mineralogy the thermophysical and aeolian observations indicate that the soils in deucalionis regio are relatively immobile despite the likely occurrence of winds strong enough to move unconsolidated materials we propose that the soils in this region are indurated or crusted we predict that a mars observer class thermal emission spectrometer and gamma ray spectrometer will show the presence of crust forming minerals and elements in the soils of this region the spatial correlation between areas that have been previously proposed to be regional exposures of crust and areas that are spectrally similar to deucalionis regio may suggest a possible genetic relationship between the composition and the physical properties

video monitoring reveals pulsating vents and propagation path of fissure eruption during the march 2011 pu u ō ō eruption kilauea volcano abstract lava fountains are a common eruptive feature of basaltic volcanoes many lava fountains result from fissure eruptions and are associated with the alignment of active vents and rising gas bubbles in the conduit visual reports suggest that lava fountain pulses may occur in chorus at adjacent vents the mechanisms behind such a chorus of lava fountains and the underlying processes are however not fully understood the march 2011 eruption at pu u kilauea volcano was an exceptional fissure eruption that was well monitored and could be closely approached by field geologists the fissure eruption occurred along groups of individual vents aligned above the feeding dyke we investigate video data acquired during the early stages of the eruption to measure the height width and velocity of the ejecta leaving eight vents using a sobel edge detection algorithm the activity level of the lava fountains at the vents was determined revealing a similarity in the eruption height and frequency based on this lava fountain time series we estimate the direction and degree of correlation between the different vents we find that the height and velocity of the eruptions display a small but systematic shift in time along the vents indicating a lateral migration of lava fountaining at a rate of 11 m s from w to e this finding is in agreement with a propagation model of a pressure wave originating at the kilauea volcano and propagating through the dyke at 10 m s from w to e based on this approach from videos only 30 s long we are able to obtain indirect constraints on the physical dyke parameters with important implications for lateral magma flow processes at depth this work shows that the recording and analysis of video data provide important constraints on the mechanisms of lava fountain pulses even though the video sequence is short it allows for the confirmation of the magma propagation direction and a first order estimation of the dyke dimensions

surface unit characterization of the mauna ulu flow field kilauea volcano hawai i using integrated field and remote sensing analyses abstract investigation of surface units in the mauna ulu flow field kilauea volcano hawai i was conducted through field and remote sensing analyses recently acquired advanced spaceborne thermal emission and reflection radiometer aster and master modis aster airborne simulator datasets which cover the visible through thermal wavelength region have been analyzed and correlated with a field based characterization of mauna ulu flow unit surfaces field observations were made of unit morphologies decimeter to decameter scale as well as small scale millimeter to centimeter scale surface textures estimates were made of the extent of surface crust spallation as well as the abundance of vesicles and phenocrysts on the surface crust and spallation surfaces the field based characteristics were compared with remote sensing data including visible and near infrared reflectance spectra thermal infrared emissivity spectra and emissivity derived small scale roughness visible wavelength characteristics are controlled primarily by color luster and decimeter to meter scale surface irregularities whereas thermal wavelength characteristics are primarily controlled by the abundance of small scale roughness elements such as vesicles although individual data pixels are not of sufficient resolution to identify typical individual lava flow units using point spectra mean spectra allow characterization of unit surface crusts flow unit morphologies and surface textures are related to differences in emplacement and post emplacement modification of a a and pahoehoe lobes pahoehoe surface properties reflect the flow regime during emplacement and the history of cooling degassing and crystal formation settling the nature of pahoehoe surface crusts indicates that within the wide range of emplacement conditions expressed within the flow field two sets of conditions are dominant producing a bronzy smooth crust or a dark rough crust the former makes up the majority of the pahoehoe surfaces and reflects minimal cooling and degassing prior to emplacement whereas the latter reflects cooling and crystallization during storage within the flow field this study provides a detailed characterization of mauna ulu surface units and presents an integrated field and remote sensing approach to mapping and interpreting the emplacement of lava flow fields

transient deformation following the 30 january 1997 dike intrusion at kīlauea volcano hawai i on 30 january 1997 an intrusion on k lauea volcano opened a new fissure within the east rift zone erz at n pau crater 3 km uprift from the ongoing eruptions at pu u the fissure eruption lasted 22 h and opened a 5 1 km long nearly vertical dike 1 9 m extending from the surface to a depth of 2 4 km owen et al 2000b during the eruption the lava pond at pu u drained and eruptions ceased there pu u eventually refilled in late february and eruptions resumed there on 28 march 1997 continuous gps data show a large transient following the 30 january 1997 dike intrusion after lengthening 40 cm during the initial eruption the baseline between two stations spanning the erz lengthened an additional 10 cm over the following 6 months a coastal station kaep also exhibited transient deformation as it continued to move southward 5 cm over the same 6 month period the baseline between two stations spanning k lauea s summit caldera contracted sharply during the eruption but gradually recovered to slightly longer than its previous length 2 months after the intrusion we use the extended network inversion filter mcguire and segall 2003 to invert continuous gps data for volume change of a spherical pressure source under k lauea s summit opening distribution on a nearly vertical dike in the erz and potential slip on a decollement 9 km beneath the south flank following the 30 january intrusion rift extension continued below the initial dike intrusion for the duration of the transient decollement slip regardless of its assumed depth is not required to fit the data the modeled transient summit reinflation and rift opening patterns under n pau crater coincide with changes in observed behavior of pu u s lava pond rift opening accelerated while pu u eruptions paused and began to decelerate after the lava pond reappeared nearly a month after the n pau eruption the transient deformation is interpreted as resulting from shallow accommodation of the new dike volume

growth of the lava dome and extrusion rates at soufriere hills volcano montserrat west indies 2005 2008 the third episode of lava dome growth at soufriere hills volcano began 1 august 2005 and ended 20 april 2007 volumes of the dome and talus produced were measured using a photo based method with a calibrated camera for increased accuracy the total dense rock equivalent dre volume of extruded andesite magma 306 51 mm3 was similar within error to that produced in the earlier episodes but the average extrusion rate was 5 6 0 9 m3s 1 dre higher than the previous episodes extrusion rates varied in a pulsatory manner from 0 5 m3s 1 to 20 m3s 1 on 18 may 2006 the lava dome had reached a volume of 85 mm3 dre and it was removed in its entirety during a massive dome collapse on 20 may 2006 extrusion began again almost immediately and built a dome of 170 mm3 dre with a summit height 1047 m above sea level by 4 april 2007 there were few moderate sized dome collapses 1 10 mm3 during this extrusive episode in contrast to the first episode of dome growth in 1995 8 when they were numerous the first and third episodes of dome growth showed a similar pattern of low 0 5 m3s 1 but increasing magma flux during the early stages with steady high flux after extrusion of 25 mm3

spatiotemporal model of kīlauea s summit magmatic system inferred from insar time series and geometry free time dependent source inversion k lauea volcano hawai i island has a complex magmatic system including summit reservoirs and rift zones kinematic models of the summit reservoir have so far been limited to first order analytical solutions with pre determined geometry to explore the complex geometry and kinematics of the summit reservoir we apply a multitrack wavelet based insar interferometric synthetic aperture radar algorithm and a novel geometry free time dependent modeling scheme to map spatiotemporally distributed surface deformation signals over k lauea s summit we process sar data sets from two overlapping tracks of the envisat satellite including 100 images during the period 2003 2010 following validation against global positioning system gps data we invert the surface deformation time series to constrain the spatiotemporal evolution of the magmatic system without any prior knowledge of the source geometry the optimum model is characterized by a spheroidal and a tube like zone of volume change beneath the summit and the southwest rift zone at 2 3 km depth respectively to reduce the model dimension we apply a principal component analysis pca scheme which allows for the identification of independent reservoirs the first 3 pcs explaining 99 63 8 28 5 and 6 6 respectively of the model include six independent reservoirs with a complex interaction suggested by temporal analysis the data and model presented here in agreement with earlier studies improve the understanding of k lauea s plumbing system through enhancing the knowledge of temporally variable magma supply storage and transport beneath the summit and verify the link between summit magmatic activity seismicity and rift intrusions

identification of structural controls in an active lava dome with high resolution dems volcan de colima mexico monitoring the topography of active lava domes is critical for detecting changes that may trigger or influence collapse or explosive activity internal dome structure and conditions are more difficult to elucidate but also play vital roles here we describe the exposure following an explosion of significant scarps in the active dome at volcan de colima mexico that are interpreted as evidence of brittle failure planes and a complex internal dome morphology in the first use of automated 3d computer vision reconstruction techniques structure from motion and multi view stereo sfm mvs on an active volcanic dome we derive high resolution surface models from oblique and archive photographs taken with a consumer camera the resulting 3d models were geo referenced using features identified in a web sourced orthoimage no ground based measurements were required in december 2010 the dome 2 14 106 m3 had a flat upper surface reflecting an overall ductile emplacement regime between then and may 2011 a period of low explosivity was accompanied by a small volume loss 0 4 105 m3 and arcuate steps appeared in the dome surface suggesting the presence of localized planes of weakness the complex array of summit scarps was exposed following a significant explosion in june 2011 and is interpreted to be the surface expression of fault planes in the dome the 1 m resolution dems indicated that the region of greatest volume loss was not coincident with the assumed location of the conduit and that heterogeneity within the dome may have been important during the june explosion

time averaged discharge rate of subaerial lava at kīlauea volcano hawai i measured from tandem x interferometry implications for magma supply and storage during 2011 2013 differencing digital elevation models dems derived from terrasar add on for digital elevation measurements tandem x synthetic aperture radar imagery provides a measurement of elevation change over time on the east rift zone ezr of k lauea volcano hawai i the effusion of lava causes changes in topography when these elevation changes are summed over the area of an active lava flow it is possible to quantify the volume of lava emplaced at the surface during the time spanned by the tandem x data a parameter that can be difficult to measure across the entirety of an 100 km2 lava flow field using ground based techniques or optical remote sensing data based on the differences between multiple tandem x derived dems collected days to weeks apart the mean dense rock equivalent time averaged discharge rate of lava at k lauea between mid 2011 and mid 2013 was approximately 2 m3 s which is about half the long term average rate over the course of k lauea s 1983 present erz eruption this result implies that there was an increase in the proportion of lava stored versus erupted a decrease in the rate of magma supply to the volcano or some combination of both during this time period in addition to constraining the time averaged discharge rate of lava and the rates of magma supply and storage topographic change maps derived from space based tandem x data provide insights into the four dimensional evolution of k lauea s erz lava flow field tandem x data are a valuable complement to other space air and ground based observations of eruptive activity at k lauea and offer great promise at locations around the world for aiding with monitoring not just volcanic eruptions but any hazardous activity that results in surface change including landslides floods earthquakes and other natural and anthropogenic processes

physicochemical models of effusive rhyolitic eruptions constrained with insar and dem data a case study of the 2011 2012 cordon caulle eruption abstract the 9 month long 2011 2012 eruption of cordon caulle southern andes chile is the best instrumentally recorded rhyolitic eruption to date and the first time that the effusion of a rhyolitic flow has been observed in detail we use interferometric synthetic aperture radar insar with time lapse digital elevation models dems and numerical models to study the dynamics of coupled magma reservoir deflation and lava effusion insar recorded 2 2 2 5 m of subsidence after the first three days of the eruption which can be modeled using a spheroidal magma reservoir at a depth of 5 km 20 km long and with a pressure drop of 20 30 mpa the source is elongated in the nw se direction and its large dimensions imply a large plumbing system active throughout the eruption and spanning neighboring volcanoes with a slight change in the geometry halfway through the effusive phase tandem x and pleiades dems record the extrusion of both the rhyolitic lava flow and the intrusion of a shallow laccolith around the eruptive vent after the third day of the eruption with a total volume of 1 45 km3 dre the laccolith was emplaced during the first month of the eruption during both the explosive and effusive stages of the eruption both the reservoir pressure drop and the extruded volume time series follow quasi exponential trends and can be explained by a model that couples the reservoir pressure decrease time and pressure dependent variations in the magma properties inside of the reservoir and conduit flow this model predicts both the temporal evolution and amplitude of both time series during the effusive phase and a magma compressibility of 10 10 pa 1 half the reported compressibility of the magma of the sub plinian explosive phase further we estimate that the reservoir contained 1 3 wt dissolved h2o at the onset of lava effusion with no exsolved co2 and h2o in the reservoir throughout the effusive phase this implies that the magma was significantly degassed after the explosive phase the remaining volatiles in the magma after the explosive stage might have caused magma fragmentation consistent with the hybrid explosive effusive style observed during the waning of the eruption

ecmwf analyses and forecasts of stratospheric winter polar vortex breakup september 2002 in the southern hemisphere and related events abstract breakup of the polar stratospheric vortex in the northern hemisphere is an event that is known to be predictable for up to a week or so ahead this is illustrated using data from the 45 yr ecmwf re analysis era 40 for the sudden warmings of january 1958 and february 1979 and operational ecmwf data for february 2003 it is then shown that a similar level of skill was achieved in operational forecasts for the split of the southern stratospheric vortex in late september 2002 the highly unusual flow conditions nevertheless exposed a computational instability of the forecast model analyses and forecasts from reruns using improved versions of the forecasting system are presented isentropic maps of potential vorticity and specific humidity provide striking pictures of the advective processes at work forecasts as well as analyses are shown to be in good agreement with radiosonde measurements of the temperature changes associated with vortex movement distortion and breakup during august and septem

the multi scale influence of topography on lava flow morphology predicting lava flow pathways is important for understanding effusive eruptions and for volcanic hazard assessment one particular challenge is understanding the interplay between flow pathways and substrate topography that is often rough on a variety of scales 1 m to 10 s km to study this problem we develop a lava flow modeling framework that combines spectral analysis of substrate roughness with a new lava flow model multiflow the mutliflow model includes a multiple flow direction routing algorithm in conjunction with a thresholding function that limits the extent of the flow comparison of multiflow results with recent flows on mt etna mauna loa and kilauea suggests that multiflow accurately predicts the influence of topography on lava flow paths and morphology spectral filtering of pre flow digital elevation models allow us to quantify which topographic wavelengths are most important for influencing lava flow pathways filtering constrains the height of pre existing objects that flow overtop as a measure of flow thickness and aids in identifying divergence of flow pathways from pre eruptive topography that would result from modification of the substrate by the flow low pass filter cutoffs in the range of 10 100 m significantly improve the fit between modeled flow and real flow paths suggesting a sensitivity of lava flow paths to such mesoscale topographic wavelengths the three case studies are generalized with a parameter investigation of lava flow branching on synthetic red noise topography we demonstrate that the tendency of a flow to branch or not can be predicted on the basis of spectral characteristics of the underlying surface we end by examining spectral signatures associated with volcanic and erosional processes on the island of hawai i that may aid in forecasting lava flow pathways and deconvolving competing topographic construction and erosion in volcanic landscapes on longer timescales

edifice strength and magma transfer modulation at piton de la fournaise volcano 1 from 2003 to 2007 eruptive activity at piton de la fournaise was shown to follow cycles comprising many summit proximal eruptions and finishing by a distal eruption gps measurements evidenced striking asymmetric deformation between its western and eastern flanks horizontal displacements recorded during interdistal periods showed a characteristic amplitude at the top of the eastern flank displacements recorded at the base of the summit cone showed a bimodal distribution with low amplitudes during interdistal periods and large ones during distal eruptions to account for displacement asymmetry characteristic amplitude and large flank displacement we modeled the volcanic edifice using a drucker prager elastoplastic rheology friction angles of 15 and 30 were needed to model the displacements respectively during distal eruptions and interdistal periods this change shows that strain weakening occurred during distal events large plastic displacement that occurred in the eastern flank during distal eruptions relaxed the horizontal elastic stress accumulated during interdistal periods it triggered summit deflation horizontal magma transfer and distal flank eruption and reset the eruptive cycle our elastoplastic models also show that simple source geometries may induce large eastern flank displacements that would be explained by a complex geometry in a linear elastic edifice magma supply is often thought to control volcano s eruptive activity with surface deformation reflecting changes in magma supply rate the volcano s response being linear our results bring some evidences that on piton de la fournaise time space discretization of magma transfer may be the result of the edifice s nonlinear response rather than changes in magma supply

combined morphological and thermal analysis of lava flows a way to boost understanding of emplacement dynamics during emplacement lavas modify the pre existing topography and release a large amount of heat in spite of the relevance of both heat and mass release combined morphological and thermal analyses have been seldom carried out at a flow field scale here we consider a channelised lava flow unit formed at mt etna during the 2001 flank eruption and we show that by combining a morphological analysis of the pre and post emplacement topography with the analysis of the syn eruptive thermal signature critical insights about the processes driving mass and heat dissipation can be derived our results suggest that in the considered lava flow the pre emplacement slope controls heat dissipation and can influence the thickness of the final lava deposit with possible implications for hazard assessment the width of the lava channel instead appears less sensitive to the pre emplacement slope and tends to regularly increase with increasing distance from the vent

measuring large topographic change with insar lava thicknesses extrusion rate and subsidence rate at santiaguito volcano guatemala lava flows can produce changes in topography of the order of 10s 100s of metres a knowledge of the resulting volume change provides evidence about the dynamics of an eruption using differential insar phase delays it is possible to estimate height differences between the current topography and a digital elevation model dem this does not require a pre event sar image so it does not rely on interferometric phase remaining coherent during eruption and emplacement synthetic tests predict that we can estimate lava thicknesses of as little as 9 m given a minimum of five interferograms with suitably large orbital baseline separations in the case of continuous motion such as lava flow subsidence we invert interferometric phase simultaneously for topographic change and displacement we apply this to santiaguito volcano guatemala and measure increases in lava thickness of up to 140 m between 2000 and 2009 largely associated with activity between 2000 and 2005 we find a mean extrusion rate of 0 437 0 06 m

lava flow volume and morphology from digitised contour maps a case study at mount etna sicily abstract the volume and morphology of a lava flow field can be measured by mapping and comparing the topography before and after lava emplacement contour maps are a widely available source of topographic data containing a record of the geomorphological changes at volcanoes due to lava emplacement this paper explores the use of 1 25 000 scale digitised contour maps for mapping two lava flows of diverse eruption history and morphology at mount etna sicily we find that subtracting dems created from these maps gives a good representation of volume and shape for thicker lava flows 10 m mean thickness in the case of the 1983 lava flow however thinner

using tandem x to measure pyroclastic flow source location thickness and volume application to the 3rd june 2018 eruption of fuego volcano guatemala abstract the estimation of the volume of volcanic flows during an ongoing eruption is challenging but this information is crucial for improving risk assessment and for forecasting future events although previous studies have shown the ability of tandem x satellite data to derive the thickness and the volume of lava flow fields during effusive eruptions the method has not been explored yet for pyroclastic flows using bi static interferometry we produce tandem x dem on fuego volcano guatemala to measure the significant topographic changes caused by the 3rd june 2018 eruption which destroyed the town of san miguel los lotes we estimate the volume of the pyroclastic density currents pdcs to be 15 1 4 2 106 m3 the deposits are likely to be the source of lahars during future rainy seasons we identify the main channel of deposition positive elevation changes and the source region of pyroclastic material areas of significant substrate erosion and vegetation destruction negative elevation changes our results show that the june 3rd 2018 pyroclastic flow was predominantly composed of material which had gravitationally collapsed from a location close to the vent the eroded material increased the volume of the flow bulking and likely caused the run out distance of the 2018 pdc to be larger than previous eruptions 1999 2017 this study highlights the potential of remote sensing techniques for actively monitoring topography changes in inaccessible locations and to rapidly derive deposit volumes

evolution of dike opening during the march 2011 kamoamoa fissure eruption kīlauea volcano hawai i 1 the 5 9 march 2011 kamoamoa fissure eruption along the east rift zone of k lauea volcano hawai i followed months of pronounced inflation at k lauea summit we examine dike opening during and after the eruption using a comprehensive interferometric synthetic aperture radar insar data set in combination with continuous gps data we solve for distributed dike displacements using a whole k lauea model with dilating rift zones and possibly a deep decollement modeled surface dike opening increased from nearly 1 5 m to over 2 8 m from the first day to the end of the eruption in agreement with field observations of surface fracturing surface dike opening ceased following the eruption but subsurface opening in the dike continued into may 2011 dike volumes increased from 15 to 16 to 21 million cubic meters mcm after the first day eruption end and 2 months following respectively dike shape is distinctive with a main limb plunging from the surface to 2 3 km depth in the up rift direction toward k lauea s summit and a lesser projection extending in the down rift direction toward pu u at 2 km depth volume losses beneath k lauea summit 1 7 mcm and pu u 5 6 mcm crater relative to dike plus erupted volume 18 3 mcm yield a dike to source volume ratio of 2 5 that is in the range expected for compressible magma without requiring additional sources inflation of k lauea s summit in the months before the march 2011 eruption suggests that the kamoamoa eruption resulted from overpressure of the volcano s magmatic system

dome growth at mount cleveland aleutian arc quantified by time series terrasar x imagery synthetic aperture radar imagery is widely used to study surface deformation induced by volcanic activity however it is rarely applied to quantify the evolution of lava domes which is important for understanding hazards and magmatic system characteristics we studied dome formation associated with eruptive activity at mount cleveland aleutian volcanic arc in 2011 2012 using terrasar x imagery interferometry and offset tracking show no consistent deformation and only motion of the crater rim suggesting that ascending magma may pass through a preexisting conduit system without causing appreciable surface deformation amplitude imagery has proven useful for quantifying rates of vertical and areal growth of the lava dome within the crater from formation to removal by explosive activity to rebirth we expect that this approach can be applied at other volcanoes that host growing lava domes and where hazards are highly dependent on dome geometry and growth rates

calculation of lava effusion rates from landsat tm data we present a thermal model to calculate the total thermal flux for lava flowing in tubes on the surface or under shallow water once defined we use the total thermal flux to estimate effusion rates for active flows at kilauea hawaii on two dates input parameters were derived from landsat thematic mapper tm field and laboratory measurements using these parameters we obtain effusion rates of 1 76 0 57 and 0 78 0 27 m3 s 1 on 23 july and 11 october 1991 respectively these rates are corroborated by field measurements of 1 36 0 14 and 0 89 0 09 m3 s 1 for the same dates kauahikaua et al 1996 using weather satellite avhrr data of lower spatial resolution we obtain similar effusion rates for an additional 26 dates between the two tm derived measurements we assume that although total effusion rates at the source declined over the period the shut down of the ocean entry meant that effusion rates for the surface flows alone remained stable such synergetic use of remotely sensed data provides measurements that can a contribute to monitoring flow field evolution and b provide reliable numerical data for input into rheological and thermal models we look forward to being able to produce estimates for effusion rates using data from high spatial resolution sensors in the earth observing system eos era such as landsat 7 the hyperspectral imager the advanced spaceborne thermal emission spectrometer and the advanced land imager

photogrammetric monitoring of lava dome growth during the 2009 eruption of redoubt volcano abstract the 2009 eruption of redoubt volcano alaska began with a phreatic explosion on 15 march followed by a series of at least 19 explosive events and growth and destruction of at least two and likely three lava domes between 22 march and 4 april on 4 april explosive activity gave way to continuous lava effusion within the summit crater we present an analysis of post 4 april lava dome growth using an oblique photogrammetry approach that provides a safe rapid and accurate means of measuring dome growth photogrammetric analyses of oblique digital images acquired during helicopter observation flights and fixed wing volcanic gas surveys produced a series of digital elevation models dems of the lava dome from 16 april to 23 september the dems were used to calculate estimates of volume and time averaged extrusion rates and to quantify morphological changes during dome growth effusion rates ranged from a maximum of 35 m 3 s 1 during the initial two weeks to a low of 2 2 m 3 s 1 in early summer 2009 the average effusion rate from april to july was 9 5 m 3 s 1 early rapid dome growth was characterized by extrusion of blocky lava that spread laterally within the summit crater in mid to late april the volume of the dome had reached 36 10 6 m 3 roughly half of the total volume and dome growth within the summit crater began to be limited by confining crater walls to the south east and west once the dome reached the steep north sloping gorge that breaches the crater growth decreased to the south but the dome continued to inflate and extend northward down the gorge effusion slowed during 16 april 1 may but in early may the rate increased again this rate increase was accompanied by a transition to exogenous dome growth from mid may to july the effusion rate consistently declined the decrease is consistent with observations of reduced seismicity gas emission and thermal anomalies as well as declining rates of geodetic deflation or inflation these trends suggest dome growth ceased by july 2009 the volume of the dome at the end of the 2009 eruption was about 72 10 6 m 3 more than twice the estimated volume of the largest dome extruded during the 1989 1990 eruption in total the 2009 dome extends over 400 m down the glacial gorge on the north end of the crater with a total length of 1 km width of 500 m and an average thickness of 200 m

the roughness of natural terrain a planetary and remote sensing perspective we examine the various methods and parameters in common use for quantifying and reporting surface topographic roughness it is shown that scale dependent roughness parameters are almost always required though not widely used we suggest a method of standardizing the parameters that are computed and reported so that topographic data gathered by different workers using different field techniques can be directly and easily intercompared we illustrate the proposed method by analyzing topographic data from 60 different surfaces gathered by five different groups and examine the information for common features we briefly discuss the implications of our analysis for studies of planetary surface roughness lander safety and radar remote sensing modeling and analysis

magma supply and storage at kilauea volcano hawaii 1956 1983 abstract shallow crustal magma reservoirs beneath the summit of kilauea volcano and within its rift zones are linked in such a way that the magma supply to each can be estimated from the rate of ground deformation at the volcano s summit our model builds on the well documented pattern of summit inflation as magma accumulates in a shallow summit reservoir followed by deflation as magma is discharged to the surface or into the rift zones magma supply to the summit reservoir is thus proportional to summit uplift and supply to the rift zones is proportional to summit subsidence the average proportionality constant is 0 33 10 6 m 3 rad this model yields minimum supply estimates because it does not account for magma which escapes detection by moving passively through the summit reservoir or directly into the rift zones calculations suggest that magma was supplied to kilauea during july 1956 april 1983 at a minimum average rate of 7 2 10 6 m3 month roughly 35 of the net supply was extruded the rest remains stored within the volcano s east rift zone 55 and southwest rift zone 10 periods of relatively rapid supply were associated with the large kapoho eruption in 1960 and the sustained mauna ulu eruptions in 1969 1971 and 1972 1974 bursts of harmonic tremor from the mantle beneath kilauea were also unusually energetic during 1968 1975 suggesting a close link between kilauea s deep magma supply region and shallow storage reservoirs it remains unclear whether pulses in magma supply from depth give rise to corresponding increases in shallow supply or if instead unloading of a delicately balanced magma transport system during large eruptions or intrusions triggers more rapid ascent from a relatively constant mantle source

lava flow mapping and volume calculations for the 2012 2013 tolbachik kamchatka fissure eruption using bistatic tandem x insar the bistatic acquisition mode of the german tandem x radar satellite mission provides a reliable source for measuring morphological changes associated with volcanic activity we present the use of this system to measure key lava flow parameters including thickness volume runout and flow extent by using two tandem x data pairs to generate digital elevation models dems prior to and immediately following the 2012 2013 eruption of tolbachik volcano kamchatka morphometric parameters and areal distribution of the new lava flow field are determined using a cell by cell elevation difference between the two dems a total flow volume of 0 53 0 07 km3 a mean flow thickness of 14 5 m and a modal thickness of 7 8 m are calculated we use these calculated flow parameters as input to a volume limited lava flow emplacement model model simulations are able to reproduce the sw portion of the 2012 2013 tolbachik lava flow using a 75 m shuttle radar topography mission srtm dem and the 15 m tandem x derived dem with goodness of fit measures of 56 3 and 59 6 respectively based on the jaccard similarity coefficient the flow simulation done using srtm data underestimates the observed 14 4 km flow runout by over 3 km while the simulation with tandem x data overestimates flow runout by about 1 5 km performance of the lava flow modeling algorithm is highly dependent on the modal lava thickness highlighting the importance of using tandem x dems to provide precise lava flow measurements in order to constrain input parameters for numerical modeling of lava flows

analysis of active lava flows on kilauea volcano hawaii using sir c radar correlation measurements precise eruption rates of active pahoehoe lava flows on kilauea volcano hawaii have been determined using spaceborne radar data acquired by the space shuttle imaging radar c sir c a coastal site downslope from the pu9u o9o vent was imaged once per day on each of the four days of october 7 10 1994 day to day decorrelation due to resurfacing was determined by interferometric combination of the data at 15 m resolution over a wide area on successive days new lava resurfaced 335700 m 2 368775 m 2 and 356625 m 2 assuming an average pahoehoe flow thickness of 50 cm a mean effusion rate for this period is approximately 2 m 3 s the radar observations show persistent surface activity at each site rather than downslope migration of coherent lava flows

relationships between pahoehoe surface units topography and lava tubes at mauna ulu kilauea volcano hawaii lava flow field development at mauna ulu was analyzed by characterizing pahoehoe surface units and their distribution relative to pre mauna ulu topography and the main lava tube system four pahoehoe surface units were identified in the field and described on the basis of color surface texture and morphology broad flat sheets unit i networks of interconnected glassy surfaced toes unit ii late stage breakout lobes of viscous toes unit iii and irregular surfaces exhibiting meter scale roughness which typically occur as channels unit iv the distribution of these units was mapped on high resolution aerial photographs using an automated supervised classification technique geographical information systems gis analyses utilized digitized 6 m 20 foot contour interval topography of the pre mauna ulu surface and the mapped lava tube network to assess the influence of topography and lava tubes on the emplacement of surface flows the four pahoehoe units represent variations in emplacement conditions on the basis of the various flow regimes sheet toe and channel and surface textures smooth glassy and rough displayed these surface units show a limited correlation to pre mauna ulu topography based on their mean underlying slopes the higher flow rates indicated by the channelized surfaces of unit iv are spatially correlated with higher 22 2 mean underlying slopes relative to those of the sheets of unit i 14 2 and the toe networks representing units ii 15 2 and iii 15 9 the distribution of the four units does not appear to be directly related to their proximity to the largest scale of lava tubes suggesting two possible scenarios the main lava tubes do not significantly affect surface unit emplacement within the study area and or these tubes do not preferentially emplace any of the four units identified in this study

tandem x time series analysis reveals lava flow volume and effusion rates of the 2012 2013 tolbachik kamchatka fissure eruption assessing eruption volumes is one of the major challenges in volcano research but provides valuable insights into the dynamics of an eruption and the associated hazard one way to estimate this important parameter is the generation and differencing of digital elevation models dems acquired before during and after an eruption the satellite mission tandem x enables generation of time series of dems using synthetic aperture radar satellite imagery we use these data to study the 2012 2013 eruption of tolbachik in kamchatka we developed a processing scheme for generation of 18 dems from tandem x imagery that relies on the generation of a preeruption dem which is used to process the syneruption and posteruption data pairs differencing each dem with the preeruption dem enables mapping the lava flows and measuring lava flow volume over time and to estimate lava extrusion rates we find a final lava flow volume of 0 53 km3 covering an area of 36 km2 by the end of the eruption an uncertainty analysis is performed while analyzing the dem differences in areas where no topographic change is expected leading to an error of 0 01 km3 for the final lava flow volume the lava effusion was with 247 92 m3 s very high in the first days of the eruption and rapidly decayed toward its end while many basaltic eruptions follow an exponentially decaying flow model the extrusion rates at tolbachik are more compatible with a 1 t model this special characteristic might be useful to gain further insight into the eruption process at tolbachik

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

analysis of the 2001 lava flow eruption of mt etna from three dimensional mapping 1 the 2001 etna eruption was characterized by a complex temporal evolution with the opening of seven eruptive fissures each feeding different lava flows this work describes a method adopted to obtain the three dimensional geometry of the whole lava flow field and for the reconstruction based on topographic data of the temporal evolution of the largest lava flow emitted from a vent located at 2100 m a s l preeruption and posteruption digital elevation models dem were extracted from vector contour maps comparison of the two dems and analysis of posteruption orthophotos allowed us to estimate flow area thickness and bulk volume additionally the two dimensional temporal evolution of the 2100 flow was precisely reconstructed by means of maps compiled during the eruption these data together with estimates of flow thickness allowed us to evaluate emitted lava volumes and in turn the average volumetric flow rates the analysis performed in this paper provided a total lava bulk volume of 40 1 106 m3 for the whole lava flow field most of which emitted from the 2100 vent 21 4 106 m3 the derived effusion rate trend shows an initial period of waxing flow followed by a longer period of waning flow this is in agreement not only with the few available effusion rate measurements performed during the eruption but also with the theoretical model of wadge 1981 for the temporal variation in discharge during the tapping of a pressurized source

synthetic aperture radar interferometry to measure earth s surface topography and its deformation synthetic aperture radar interferometry insar from earth orbiting spacecraft provides a new tool to map global topography and deformation of the earth s surface radar images taken from slightly different viewing directions allow the construction of digital elevation models of meter scale accuracy these data sets aid in the analysis and interpretation of tectonic and volcanic landscapes if the earth s surface deformed between two radar image acquisitions a map of the surface dis placement with tens of meters resolution and subcentimeter accuracy can be con structed this review gives a basic overview of insar for earth scientists and presents a selection of geologic applications that demonstrate the unique capabilities of insar for mapping the topography and deformation of the earth

tracking lava flow emplacement on the east rift zone of kīlauea hawai i with synthetic aperture radar coherence 1 lava flow mapping is both an essential component of volcano monitoring and a valuable tool for investigating lava flow behavior although maps are traditionally created through field surveys remote sensing allows an extraordinary view of active lava flows while avoiding the difficulties of mapping on location synthetic aperture radar sar imagery in particular can detect changes in a flow field by comparing two images collected at different times with sar coherence new lava flows radically alter the scattering properties of the surface making the radar signal decorrelated in sar coherence images we describe a new technique sar coherence mapping scm to map lava flows automatically from coherence images independent of look angle or satellite path we use this approach to map lava flow emplacement during the pu u kupaianaha eruption at k lauea hawai i the resulting flow maps correspond well with field mapping and better resolve the internal structure of surface flows as well as the locations of active flow paths however the scm technique is only moderately successful at mapping flows that enter vegetation which is also often decorrelated between successive sar images along with measurements of planform morphology we are able to show that the length of time a flow stays decorrelated after initial emplacement is linearly related to the flow thickness finally we use interferograms obtained after flow surfaces become correlated to show that persistent decorrelation is caused by post emplacement flow subsidence

volcano deformation and eruption forecasting recent advances in global positioning system gps tilt and interferometric synthetic aperture radar insar have greatly increased the availability of volcano deformation data these measurements combined with appropriate source models can be used to estimate magma chamber depth and to provide information on chamber shape and volume change however kinematic models cannot constrain magma chamber volume and provide no predictive

high resolution dem generation from spaceborne and terrestrial remote sensing data for improved volcano hazard assessment a case study at nevado del ruiz colombia abstract volcanoes with rugged terrain remain a challenging target for generating high resolution digital elevation models dems especially in tropical areas with frequent cloud cover using nevado del ruiz volcano as an example we combined dems from the tandem x tdx satellite mission terrestrial radar interferometry tri and structure from motion sfm to generate a new dem with 10 m spatial resolution this is the first study combining satellite radar ground based radar photography and freely available global dems to generate a high resolution dem without data gaps tdx data from ascending and descending orbits were combined to generate the base dem instead of using a raster format to fuse dems generated from different data sets with different resolutions we developed a methodology based on 3 d point clouds 1 re georeference the 5 m tri and 1 m sfm dems to the 10 m tdx dem using the iterative closest point icp algorithm to minimize the horizontal and vertical discrepancy between dems then 2 merge the multiple point clouds to generate a final dem without data gaps using an adaptive algorithm that uses two search distances to smooth the transition at the edges of different data sets we assess the new 10 m dem by comparing simulated inundation zones obtained with two volcano flow models laharz for lahars and volcflow for pyroclastic flows and find significant differences with respect to the 30 m srtm dem our laharz simulation over the new dem shows a longer lahar run out distance for pyroclastic flows the volcflow simulation over the new dem produces highly channelized flows over the steep portions of a river channel and gives a larger extent of thicker deposits compared to those obtained with the 30 m srtm dem quantitative and qualitative geomorphic analysis suggests that up to date dems with high spatial resolution 10 m or even better need to be generated to improve volcano hazard assessment for active volcanoes

shallow magma accumulation at kīlauea volcano hawai i revealed by microgravity surveys for vertical displacement at the summit of about 1 3 m and 160 gal respectively the volume of magma lost based on grav ity data and assuming a reasonable magma density exceeded the volume of summit col lapse suggesting the creation of 40 90 10 6 abstract using microgravity data collected at k lauea volcano hawai i united states between november 1975 and january 2008 we document signifi cant mass increase beneath the east margin of halema uma u crater within k lauea s summit caldera surprisingly there was no sustained uplift accompanying the mass accumulation we propose that the positive grav ity residual in the absence of signifi cant uplift is indicative of magma accumulation in void space probably a network of interconnected cracks which may have been created when magma withdrew from the summit in response to the 29 november 1975 m 7 2 south fl ank earthquake subsequent refi lling documented by gravity represents a gradual recovery from that earthquake a new eruptive vent opened at the summit of k lauea in 2008 within a few hundred meters of the positive gravity residual maximum probably tapping the reservoir that had been accumulating magma since the 1975 earthquake

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

pulsed inflation of pahoehoe lava flows implications for flood basalt emplacement abstract dilated fractures in hawaiian pahoehoe lava flows contain three zones that show the kinematics of inflation the upper columnar zone forms through thermal contraction prior to inflation the middle planar zone reflects inflation induced tension and the lower banded zone contains evidence of brittle and ductile deformation the formation of the lower banded zone requires varying strain rates during fracture propagation and is best explained by a model where small pulses of lava inject beneath the cooled flow crust through a network of preferred pathways we demonstrate via simple models of pipe flow that this inflation mechanism is incapable of producing areally extensive continental flood basalts on earth although it may explain related features on large martian volcanoes

topographic and stochastic influences on pahoehoe lava lobe emplacement a detailed understanding of p hoehoe emplacement is necessary for developing accurate models of flow field development assessing hazards and interpreting the significance of lava morphology on earth and other planetary surfaces active p hoehoe lobes on k lauea volcano hawai i were examined on 21 26 february 2006 using oblique time series stereo photogrammetry and differential global positioning system measurements during this time the local discharge rate for peripheral lava lobes was generally constant at 0 0061 0 0019 m3 s but the areal coverage rate of the lobes exhibited a periodic increase every 4 13 0 64 min this periodicity is attributed to the time required for the pressure within the liquid lava core to exceed the cooling induced strength of its margins the p hoehoe flow advanced through a series of down slope and cross slope breakouts which began as 0 2 m thick units i e toes that coalesced and inflated to become approximately meter thick lobes the lobes were thickest above the lowest points of the initial topography and above shallow to reverse facing slopes defined relative to the local flow direction the flow path was typically controlled by high standing topography with the zone directly adjacent to the final lobe margin having an average relief that was a few centimeters higher than the lava inundated region this suggests that toe scale topography can at least temporarily exert strong controls on p hoehoe flow paths by impeding the lateral spreading of the lobe observed cycles of enhanced areal spreading and inflated lobe morphology are also explored using a model that considers the statistical likelihood of sequential breakouts from active flow margins and the effects of topographic barriers

image based measurement of flux variation in distal regions of active lava flows 1 understanding the processes involved with the advance of lava flows is critical for improving hazard assessments at many volcanoes here we describe the application of computer vision and oblique photogrammetric techniques to visible and thermal images of active a flows in order to investigate distal flow processes at mount etna sicily photogrammetric surveys were carried out to produce repeated topographic data sets for calculation of volumetric lava flux at the flow fronts velocity profiles from a distal channel were obtained by rectification of a thermal image sequence and are used to investigate the rheological properties of the lava significant variations of the magma flux were observed and pulses of increased flux arrived within the flow front region on timescales of several hours the pulses are believed to be the distal result of more frequent flux changes observed in the vent region hence they reflect the importance of flow processes which are believed to cause the coalescence of flux pulses along the channel system as well as short period variations in effusion rate in considering advance processes for the individual flow fronts it must be assumed that they were fed by a highly unsteady flux which was volumetrically at least an order of magnitude lower than that observed near the vent

rapid low cost photogrammetry to monitor volcanic eruptions an example from mount st helens washington usa we describe a low cost application of digital photogrammetry using commercially available photogrammetric software and oblique photographs taken with an off the shelf digital camera to create sequential digital elevation models dems of a lava dome that grew during the 2004 2008 eruption of mount st helens msh volcano renewed activity at msh provided an opportunity to devise and test this method because it could be validated against other observations of this well monitored volcano the datasets consist of oblique aerial photographs snapshots taken from a helicopter using a digital single lens reflex camera twelve sets of overlapping digital images of the dome taken during 2004 2007 were used to produce dems and to calculate lava dome volumes and extrusion rates analyses of the digital images were carried out using photogrammetric software to produce three dimensional coordinates of points identified in multiple photos the evolving morphology of the dome was modeled by comparing successive dems results were validated by comparison to volume measurements derived from traditional vertical photogrammetric surveys by the us geological survey cascades volcano observatory our technique was significantly less expensive and required less time than traditional vertical photogrammetric techniques yet it consistently yielded volume estimates within 5 of the traditional method this technique provides an inexpensive rapid assessment tool for tracking lava dome growth or other topographic changes at restless volcanoes

thermal mapping of a pāhoehoe lava flow kīlauea volcano abstract p hoehoe lava flows are a major component of hawaiian eruptive activity and an important part of basaltic volcanism worldwide in recent years p hoehoe lava has destroyed homes and threatened parts of hawai i with inundation and disruption in this study we use oblique helicopter borne thermal images to create high spatial resolution 1 m georeferenced thermal maps of the active p hoehoe flow on k lauea volcano s east rift zone thermal maps were created on 27 days during 2014 2016 in the course of operational monitoring encompassing a phase of activity that threatened the town of p hoa our results illustrate and reinforce how p hoehoe flows are multicomponent systems consisting of the vent master tube distributary tubes and surface breakouts the thermal maps accurately depict the distribution and character of p hoehoe breakouts through time and also delineate the subsurface lava tube surface breakouts were distributed widely across the p hoehoe flow with significant portions concurrently active well upslope of the flow front often concentrated in clusters of activity that evolved through time gradual changes to surface breakout distribution and migration relate to intrinsic processes in the flow including the slow evolution of the distributary tube system abrupt disruptions to this system and the creation of new breakouts and associated hazards were triggered by extrinsic forcing namely fluctuations in lava supply rate at the vent which disrupted the master lava tube although the total area of a p hoehoe flow has been suggested to relate to effusion rate our results show that changes in the proportion of expansion vs overplating can complicate this relationship by modifying existing techniques we estimate time averaged discharge rates for the flow during 2014 2016 generally in the range of 1 2 m 3 s 1 mean 1 3 0 4 m 3 s 1 less than half of k lauea s typical eruption rate on the east rift zone and suggestive of a weak eruptive regime during 2014 2016 we caution however that this discharge rate approach requires further independent corroboration the thermal maps provide the first synoptic characterization of p hoehoe flow activity at high spatial resolution essential both for operational hazard assessment and fundamental understanding of p hoehoe behavior

variations in magma supply rate at kilauea volcano hawaii when an eruption of kilauea lasts more than 4 months so that a well defined conduit has time to develop magma moves freely through the volcano from a deep source to the eruptive site at a constant rate of 0 09 km3 yr at other times the magma supply rate to kilauea estimated from geodetic measurements of surface displacements may be different for example after a large withdrawal of magma from the summit reservoir such as during a rift zone eruption the magma supply rate is high initially but then lessens and exponentially decays as the reservoir refills different episodes of refilling may have different average rates of magma supply during four year long episodes in the 1960s the annual rate of refilling varied from 0 02 to 0 18 km3 yr bracketing the sustained eruptive rate of 0 09 km3 yr for decade long or longer periods our estimate of magma supply rate is based on long term changes in eruptive rate we use eruptive rate because after a few dozen eruptions the volume of magma that passes through the summit reservoir is much larger than the net change of volume of magma stored within kilauea the low eruptive rate of 0 009 km3 yr between 1840 and 1950 compared to an average eruptive rate of 0 05 km3 yr since 1950 suggests that the magma supply rate was lower between 1840 and 1950 than it has been since 1950 an obvious difference in activity before and since 1950 was the frequency of rift zone eruptions eight rift zone eruptions occurred between 1840 and 1950 but more than 20 rift zone eruptions have occurred since 1950 the frequency of rift zone eruptions influences magma supply rate by suddenly lowering pressure of the summit magma reservoir which feeds magma to rift zone eruptions a temporary drop of reservoir pressure means a larger than normal pressure difference between the reservoir and a deeper source so magma is forced to move upward into kilauea at a faster rate

volumetric characteristics of lava flows from interferometric radar and multispectral satellite data the 1995 fernandina and 1998 cerro azul eruptions in the western galapagos we have used a suite of remotely sensed data numerical lava flow modeling and field observations to determine quantitative characteristics of the 1995 fernandina and 1998 cerro azul eruptions in the western galapagos islands flank lava flow areas volumes instantaneous effusion rates and average effusion rates were all determined for these two eruptions for which only limited syn eruptive field observations are available using data from spot topsar ers 1 and ers 2 we determined that the 1995 fernandina flow covers a subaerial area of 6 5 106 m2 and has a subaerial dense rock equivalent dre volume of 42 106 m3 field observations atsr satellite data and the flowgo numerical model allow us to determine that the effusion rate declined exponentially from a high of 60 200 m3 s 1 during the first few hours to 5 m3 s 1 prior to ceasing after 73 days with a mean effusion rate of 4 16 m3 s 1 integrating the atsr derived exponentially declining effusion rate over the eruption duration produces a total subaerial submarine dre volume of between 27 and 100 106 m3 the range in values being due to differing assumptions about heat loss characteristics only values in the higher part of this range are consistent with the independently derived subaerial volume using spot topsar ers 1 and ers 2 data we determine that the 1998 cerro azul flow is 16 km long covers 16 km2 and has a dre volume of 54 106 m3 flowgo produces at vent velocity and effusion rate values of 11 m s 1 and 600 m3 s 1 respectively the velocity value agrees well with the 12 m s 1 estimated in the field the mean effusion rate total dre volume duration was 7 47 m3 s 1 dike dimensions fissure lengths and pressure gradients along the conduit based on magma chamber depth estimates of 3 5 km produce mean effusion rates for the two eruptions that range over nearly four orders of magnitude the range being due to uncertainty in the magma viscosity dike dimensions and pressure gradient between magma chamber and vent although somewhat consistent with mean effusion rates from other techniques their wide range makes them less useful the exponentially declining effusion rates during both eruptions are consistent with release of elastic strain being the driving mechanism of the eruptions our results provide independent input parameters for previously published theoretical relationships between magma chamber pressurization and eruption rates that constrain chamber volumes and increases in volume prior to eruption as well as time constants of exponential decay during the eruption the results and theoretical relationships combine to indicate that at both volcanoes probably 25 30 of the volumetric increase in the magma chamber erupted as lava onto the surface in both eruptions the lava flow volumes are less than 1 of the magma chamber volume

estimating lava volume by precision combination of multiple baseline spaceborne and airborne interferometric synthetic aperture radar the 1997 eruption of okmok volcano alaska interferometric synthetic aperture radar insar techniques are used to calculate the volume of extrusion at okmok volcano alaska by constructing precise digital elevation models dems that represent volcano topography before and after the 1997 eruption the posteruption dem is generated using airborne topographic synthetic aperture radar topsar data where a three dimensional affine transformation is used to account for the misalignments between different dem patches the preeruption dem is produced using repeat pass european remote sensing satellite data multiple interferograms are combined to reduce errors due to atmospheric variations and deformation rates are estimated independently and removed from the interferograms used for dem generation the extrusive flow volume associated with the 1997 eruption of okmok volcano is 0 154 spl plusmn 0 025 km sup 3 the thickest portion is approximately 50 m although field measurements of the flow margin s height do not exceed 20 m the in situ measurements at lava edges are not representative of the total thickness and precise dem data are absolutely essential to calculate eruption volume based on lava thickness estimations this study is an example that demonstrates how insar will play a significant role in studying volcanoes in remote areas

constraints on the partitioning of kīlauea s lavas between surface and tube flows estimated from infrared satellite data sulfur dioxide emission rates and field observations this paper describes how observations of sulfur dioxide so2 degassing rates obtained in situ thermal emission rates obtained from infrared satellite data and semiquantitative flow field observations can be used to elucidate the partitioning of lava between the surface and tube systems at k lauea volcano hawai i over a decadal timescale for most of our study period 2000 to 2009 we found that the infrared spectral radiance measured by moderate resolution imaging spectroradiometer from the flow field under clear sky conditions is controlled by the lava effusion rate and the amount of flow accommodated by the subsurface tube system at k lauea the degree of tubing is estimated qualitatively using field observations and we show that the satellite data and in situ gas data can be used to estimate the percentage of lava on the surface relative to the total amount erupted this empirical relationship works to describe many cases in the past decade at k lauea but breaks down when there is a lack of concurrent clear sky radiance and so2 data or when magma is being stored and degassed prior to eruption our observations provide a simple way to estimate the partitioning of k lauea s total lava supply between surface and tube fed flows using a long term dataset this is important because the transition between periods when lava is distributed primarily by surface flows to periods where tubes dominate has been suggested to indicate significant changes in the character of decadal scale eruptions at k lauea heliker et al bull volcanol 59 381 393 1998 in addition it is during those times when surface flows predominate that the flow field does most of its lateral expansion and the hazards associated with the lava effusion become more pronounced

the 2007 8 volcanic eruption on jebel at tair island red sea observed by satellite radar and optical images we use high resolution optical images and interferometric synthetic aperture radar insar data to study the september 2007 january 2008 jebel at tair eruption comparison of pre and post eruption optical images reveals several fresh ground fissures a new scoria cone near the summit and that 5 9 0 1 km2 of new lava covered about half of the island decorrelation in the insar images indicates that lava flowed both to the western and to the northeastern part of the island after the start of the eruption while later lavas were mainly deposited near the summit and onto the north flank of the volcano from the insar data we also estimate that the average thickness of the lava flows is 3 8 m resulting in a bulk volume of around 2 2 107 m3 we observe no volcano wide pre or post eruption uplift which suggests that the magma source may be deep the co eruption interferograms on the other hand reveal local and rather complex deformation we use these observations to constrain a tensile dislocation model that represents the dike intrusion that fed the eruption the model results show that the orientation of the dike is perpendicular to the red sea rift implying that the local stresses within the volcanic edifice are decoupled from the regional stress field

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

lava effusion rate definition and measurement a review measurement of effusion rate is a primary objective for studies that model lava flow and magma system dynamics as well as for monitoring efforts during on going eruptions however its exact definition remains a source of confusion and problems occur when comparing volume flux values that are averaged over different time periods or spatial scales or measured using different approaches thus our aims are to 1 define effusion rate terminology and 2 assess the various measurement methods and their results we first distinguish between instantaneous effusion rate and time averaged discharge rate eruption rate is next defined as the total volume of lava emplaced since the beginning of the eruption divided by the time since the eruption began the ultimate extension of this is mean output rate this being the final volume of erupted lava divided by total eruption duration whether these values are total values i e the flux feeding all flow units across the entire flow field or local i e the flux feeding a single active unit within a flow field across which many units are active also needs to be specified no approach is without its problems and all can have large error up to 50 however good agreement between diverse approaches shows that reliable estimates can be made if each approach is applied carefully and takes into account the caveats we detail here there are three important factors to consider and state when measuring giving or using an effusion rate first the time period over which the value was averaged second whether the measurement applies to the entire active flow field or a single lava flow within that field and third the measurement technique and its accompanying assumptions

topographic mapping from interferometric synthetic aperture radar observations interferometric synthetic aperture radar observations provide a means for obtaining high resolution topographic terrain maps from data acquired simultaneously at two slightly displaced antennas calculation of the three dimensional coordinates of all the points in a radar image can be made from the combination of along track slant range and interferometer fringe measurements thus the result compensates for the layover exhibited by conventional radar maps and removes the false targets generated by multiple signal paths to a given object in the scene we have derived a topographic map of a portion of the san francisco bay area utilizing data that were recorded by a radar system mounted on a nasa cv990 aircraft and processed by a general purpose digital computer this map displays the height above sea level of a region approximately 11 km by 10 km in size sampled on an 11 m pixel grid uncertainties in the estimated height result from imprecise knowledge of the observational geometry radar bandwidth limitations and finite signal to noise ratios for our system each factor contributed approximately 3 4 m to a relative rms error of about 6 m additional global errors of the order of 10 m can result from inaccurate monitoring of aircraft attitude the statistical variation of the height measurements from the ocean portion of the map which we can presume to be quite flat is 2 10 m rms which is consistent with the theoretical estimate comparison of our results with u s geological survey contour maps indicates a high degree of correlation between the two sets of altitude data

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

observations on basaltic lava streams in tubes from kilauea volcano island of hawai i from 1986 to 1997 the pu u o o kupaianaha eruption of kilauea produced a vast pahoehoe flow field fed by lava tubes that extended 10 12 km from vents on the volcano s east rift zone to the ocean within a kilometer of the vent tubes were as much as 20 m high and 10 25 m wide on steep slopes 4 10 a little farther away from the vent some tubes formed by roofing over of lava channels lava streams were typically 1 2 m deep flowing within a tube that here was typically 5 m high and 3 m wide on the coastal plain 1 tubes within inflated sheet flows were completely filled typically 1 2 m high and several tens of meters wide tubes develop as a flow s crust grows on the top bottom and sides of the tubes restricting the size of the fluid core the tubes start out with nearly elliptical cross sectional shapes many times wider than high broad flat sheet flows evolve into elongate tumuli with an axial crack as the flanks of the original flow were progressively buried by breakouts temperature measurements and the presence of stalactites in active tubes confirmed that the tube walls were above the solidus and subject to melting sometimes the tubes began downcutting progressive downcutting was frequently observed through skylights a rate of 10 cm d was measured at one skylight for nearly 2 months

radar interferogram filtering for geophysical applications the use of sar interferometry is often impeded by decorrelation from thermal noise temporal change and baseline geometry power spectra of interferograms are typically the sum of a narrow band component combined with broad band noise we describe a new adaptive filtering algorithm that dramatically lowers phase noise improving both measurement accuracy and phase unwrapping while demonstrating graceful degradation in regions of pure noise the performance of the filter is demonstrated with sar data from the ers satellites over the jakobshavns glacier of greenland

temporal monitoring of subglacial volcanoes with tandem x application to the 2014 2015 eruption within the barðarbunga volcanic system iceland on august 29 2014 a lava eruption commenced in the holuhraun plain north east of the bar arbunga caldera in iceland the eruption ended on february 27 2015 thus lasting for a period of about 6 months during these months the magma chamber below the caldera gradually deflated feeding the eruption and causing the rare event of a slow caldera collapse in this scenario tandem x remote sensing data are of particular interest by producing medium high resolution and accurate elevation models of the caldera it is possible to evaluate volume losses and topographical changes to increase the knowledge about the ongoing activity in particular five tandem x bistatic acquisitions have been commanded between august 01 2014 and november 08 2014 two of them before the volcanic eruption and three of them during the event additionally to fully cover the volcanic activity the lava field 48 km north east of the caldera has also been monitored in the first part of the paper the expected elevation accuracy is studied on two levels absolute and relative height accuracies are analyzed by inspecting the x band signal propagation into snow and by investigating the impact of the main geometrical system parameters and the local geomorphology in the second part of the paper the analysis is applied to the bar arbunga volcanic system including a validation performed using complementary altimeter data the main geophysical outcome is the accurate temporal height tracking of the entire caldera and the glacial volcanic system the measured volume loss at the caldera location is about 1 billion cubic meters in two months with an average rate of subsidence of nearly 50 cm day these numbers confirm other independent sources and can be compared to lava volume measurements finally the last segment of the dyke that propagated from the bar arbunga caldera to the holuhraun lava field is mapped and a graben structure with a width of up to 1 km and a sinking of a few meters is reported

a relation between lava discharge rate thermal insulation and flow area set using lidar data 1 a simple linear relation can be used to link time averaged discharge rate tadr and lava flow area a the relation applies to given insulation conditions as described by the characteristic flow surface temperature te and will vary from case to case depending on rheological and topographic influences on flow spreading most flows have insulation conditions that change through time modifying the relationship between tadr and area as insulation conditions evolve using lidar data we can define tadr the flow area that the discharge feeds and te allowing generation of a case specific relation to convert satellite data derived flow areas to tadr for etna s 2006 lava flow field we obtain a relation whereby tadr 5 6 10 6 a for well insulated conditions te 100 c and tadr 1 5 10 4 a for poorly insulated conditions te 600 c

magma compressibility and the missing source for some dike intrusions 1 dike intrusions are often accompanied by localized deflation interpreted as depressurizing magma chambers feeding the dike in some cases the inferred volume decrease is a factor of 4 or 5 less than the volume increase of the dike here we explore whether this discrepancy can be explained by compressibility of the magma combined with the fact that cracks are much more compliant than equidimensional magma chambers if pressure changes are small the magma compressibility m is constant and the dike ends up in hydrostatic equilibrium with an ellipsoidal magma chamber at the same depth the ratio rv of the volume of the crack to the volume lost by the chamber is rv 1 4 m 3 1 where is the host rock rigidity for gas poor magmas m 0 6 2 10 10 pa 1 and 3 25 gpa we find 1 2 rv 7 7 large changes in magma compressibility due to gas exsolution increase rv

topographic analyses of k lauea volcano hawai i from interferometric airborne radar we analyze digital topographic data collected in september 1993 over a 500 km2 portion of k lauea volcano hawai i by the c band 5 6 cm wavelength topographic synthetic aperture radar topsar airborne interferometric radar field surveys covering an 1 km2 area of the summit caldera and the distal end of an 8 m thick a flow indicate that the 10 m spatial resolution topsar data have a vertical accuracy of 1 2 m over a variety of volcanic surfaces after conversion to a common datum topsar data agree favorably with a digital elevation model dem produced by the u s geological survey usgs with the important exception of the region of the ongoing eruption which postdates the usgs dem this dem comparison gives us confidence that subtracting the usgs data from topsar data will produce a reasonable estimate of the erupted volume as of september 1993 this subtraction produces dense rock equivalent dre volumes of 392 439 and 90 106 m3 for the pu u k pa ianah and episode 50 53 stages of the eruption respectively these are 124 89 and 94 of the volumes calculated by staff of the hawaiian volcano observatory hvo but do not include lava of k pa ianah and episodes 50 53 that flowed into the ocean and are thus invisible to topsar accounting for this lava increases the topsar volumes to 124 159 and 129 of the hvo volumes including the 2 m uncertainty derived from the field surveys produces topsar derived volumes for the eruption as a whole that range between 81 and 125 of the usgs derived values the vesicularity and ocean corrected topsar volumes yield volumetric eruption rates of 4 5 4 5 and 2 7 m3 s for the three stages of the eruption which compare with hvo derived values of 3 6 2 8 and 2 1 m3 s respectively our analysis shows that care must be taken when vertically registering the topsar and usgs dems to a common datum because c band topsar penetrates only partially into thick forest and therefore produces a dem within the tree canopy whereas the usgs dem is adjusted for vegetation

monitoring an effusive eruption at piton de la fournaise using radar and thermal infrared remote sensing data insights into the october 2010 eruption and its lava flows

lava lake level as a gauge of magma reservoir pressure and eruptive hazard forecasting volcanic activity relies fundamentally on tracking magma pressure through the use of proxies such as ground surface deformation and earthquake rates lava lakes at open vent basaltic volcanoes provide a window into the uppermost magma system for gauging reservoir pressure changes more directly at k lauea volcano hawai i usa the surface height of the summit lava lake in halema uma u crater fluctuates with surface deformation over short hours to days and long weeks to months time scales this correlation implies that the lake behaves as a simple piezometer of the subsurface magma reservoir changes in lava level and summit deformation scale with and shortly precede changes in eruption rate from k lauea s east rift zone indicating that summit lava level can be used for short term forecasting of rift zone activity and associated hazards at k lauea