thermal monitoring of north pacific volcanoes from space long term thermal modeling of volcanoes using satellite imagery provides an effective tool for monitoring remote yet dangerous volcanoes in the north pacific this region includes volcanoes in alaska the aleutian islands and the kamchatkan peninsula thermal infrared data collected multiple times per day from weather satellites show distinct signatures for three different types of volcanic activity at different volcanic centers near real time automated techniques are being developed to monitor relative changes in radiant temperature at volcanoes in this region radiant temperature values as a function of time are extracted and compared to background values for a series of active volcanoes by establishing a long term thermal record for these volcanoes significant deviations indicative of an impending eruption can be detected this tool is used to search for precursors to explosive eruptions in order to increase warning times and hazard mitigation for these potentially catastrophic events a six year archive of satellite imagery has been compiled for this active region and is available for study

impact cratering in sandstone the memin pilot study on the effect of pore water abstract planetary surfaces are subjected to meteorite bombardment and crater formation rocks forming these surfaces are often porous and contain fluids to understand the role of both parameters on impact cratering we conducted laboratory experiments with dry and wet sandstone blocks impacted by centimeter sized steel spheres we utilized a 40 m two stage light gas gun to achieve impact velocities of up to 5 4 km s 1 cratering efficiency ejection velocities and spall volume are enhanced if the pore space of the sandstone is filled with water in addition the crater morphologies differ substantially from wet to dry targets i e craters in wet targets are larger but shallower we report on the effects of pore water on the excavation flow field and the degree of target damage we suggest that vaporization of water upon pressure release significantly contributes to the impact process

low cost volcano surveillance from space case studies from etna krafla cerro negro fogo lascar and erebus satellite data offer a means of supplementing ground based monitoring during volcanic eruptions especially at times or locations where ground based monitoring is difficult being directly and freely available several times a day data from the advanced very high resolution radiometer avhrr offers great potential for near real time monitoring of all volcanoes across large 3000 3000 km areas herein we describe techniques to detect and locate activity estimate lava area thermal flux effusion rates and cumulative volume and distinguish types of activity application is demonstrated using data for active lavas at krafla etna fogo cerro negro and erebus a pyroclastic flow at lascar and open vent systems at etna and stromboli automated near real time analysis of avhrr data could be achieved at existing or cheap to install receiving stations offering a supplement to conventional monitoring methods

a strain based porosity model for use in hydrocode simulations of impacts and implications for transient crater growth in porous targets numerical modelling of impact cratering has reached a high degree of sophistication however the treatment of porous materials still poses a large problem in hydrocode calculations we present a novel approach for dealing with porous compaction in numerical modelling of impact crater formation in contrast to previous attempts e g p alpha model snowplow model our model accounts for the collapse of pore space by assuming that the compaction function depends upon volumetric strain rather than pressure our new e alpha model requires only four input parameters and each has a physical meaning the model is simple and intuitive and shows good agreement with a wide variety of experimental data ranging from static compaction tests to highly dynamic impact experiments our major objective in developing the model is to investigate the effect of porosity and internal friction on transient crater formation we present preliminary numerical model results that suggest that both porosity and internal friction play an important role in limiting crater growth over a large range in gravity scaled source size

study of volcanic activity at different time scales using hypertemporal land surface temperature data we apply a method for detecting subtle spatiotemporal signal fluctuations to monitor volcanic activity whereas midwave infrared data are commonly used for volcanic hot spot detection our approach utilizes hypertemporal longwave infrared based land surface temperature lst data using lst data of the second generation european meteorological satellites we study a a paroxysmal 1 day long eruption of mount etna italy b a prolonged 6 month period of effusive and lateral lava flows of the nyamuragira volcano democratic republic of congo and c intermittent activity in the permanent lava lake of nyiragongo democratic republic of congo over a period of 2 years 2011 2012 we compare our analysis with published ground based observations and satellite based alert systems results agree on the periods of increased volcanic activity and quiescence we further apply our analysis on mid infrared and long infrared brightness temperatures and compare the results we conclude that our study enables the use of lst data for monitoring volcanic dynamics at different time scales can complement existing methodologies and allows for use of long time series from older sensors that do not provide midwave infrared data

geochemical processes between steel projectiles and silica rich targets in hypervelocity impact experiments abstract the possibility of fractionation processes between projectile and target matter is critical with regard to the classification of the impactor type from geochemical analysis of impactites from natural craters here we present results of five hypervelocity memin impact experiments poelchau et al 2013 using the cr v co mo w rich steel d290 1 as projectile and two different silica rich lithologies seeberger sandstone and taunus quartzite as target materials our study is focused on geochemical target projectile interaction occurring in highly shocked and projectile rich ejecta fragments in all of the investigated impact experiments whether sandstone or quartzite targets the ejecta fragments show i shock metamorphic features e g planar deformation features pdf and the formation of silica glasses ii partially melting of projectile and target and iii significant mechanical and chemical mixing of the target rock with projectile material the silica rich target melts are strongly enriched in the projectile tracer elements cr v and fe but have just minor enrichments of co w and mo inter element ratios of these tracer elements within the contaminated target melts differ strongly from the original ratios in the steel the fractionation results from differences in the reactivity of the respective elements with oxygen during interaction of the metal melt with silicate melt our results indicate that the principles of projectile target interaction and associated fractionation do not depend on impact energies at least for the selected experimental conditions and water saturation of the target partitioning of projectile tracer elements into the silicate target melt is much more enhanced in experiments with a non porous quartzite target compared with the porous sandstone target this is mainly the result of higher impact pressures consequently higher temperatures and longer reaction times at high temperatures in the experiments with quartzite as target material

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

satellite detection long range transport and air quality impacts of volcanic sulfur dioxide from the 2014 2015 flood lava eruption at barðarbunga iceland the 2014 2015 bar arbunga vei ivotn fissure eruption at holuhraun produced about 1 5 km3 of lava making it the largest eruption in iceland in more than 200 years over the course of the eruption daily volcanic sulfur dioxide so2 emissions exceeded daily so2 emissions from all anthropogenic sources in europe in 2010 by at least a factor of 3 we present surface air quality observations from across northern europe together with satellite remote sensing data and model simulations of volcanic so2 for september 2014 we show that volcanic so2 was transported in the lowermost troposphere over long distances and detected by air quality monitoring stations up to 2750 km away from the source using retrievals from the ozone monitoring instrument omi and the infrared atmospheric sounding interferometer iasi we calculate an average daily so2 mass burden of 99 49 kilotons kt of so2 from omi and 61 18 kt of so2 from iasi for september 2014 this volcanic burden is at least a factor of 2 greater than the average so2 mass burden between 2007 and 2009 due to anthropogenic emissions from the whole of europe combining the observational data with model simulations using the united kingdom met office s numerical atmospheric dispersion modelling environment model we are able to constrain so2 emission rates to up to 120 kilotons per day kt d during early september 2014 followed by a decrease to 20 60 kt d between 6 and 22 september 2014 followed by a renewed increase to 60 120 kt d until the end of september 2014 based on these fluxes we estimate that the eruption emitted a total of 2 0 0 6 tg of so2 during september 2014 in good agreement with ground based remote sensing and petrological estimates although satellite derived and model simulated vertical column densities of so2 agree well the model simulations are biased low by up to a factor of 8 when compared to surface observations of volcanic so2 on 6 7 september 2014 in ireland these biases are mainly due to relatively small horizontal and vertical positional errors in the simulations of the volcanic plume occurring over transport distances of thousands of kilometers although the volcanic air pollution episodes were transient and lava dominated volcanic eruptions are sporadic events the observations suggest that i during an eruption volcanic so2 measurements should be assimilated for near real time air quality forecasting and ii existing air quality monitoring networks should be retained or extended to monitor so2 and other volcanic pollutants

thermal infrared satellite measurements of volcanic activity at stromboli and vulcano the use of landsat thermal infrared imagery gives a direct way of quantitatively monitoring the evolution of low amplitude thermal anomalies using nighttime landsat thematic mapper images of vulcano and stromboli volcanoes on october 23 1986 we have developed a simplified method for correcting atmospheric effects we were then able to identify thermal anomalies around the craters part of the stromboli lava flow formed 1 year earlier was also still warm enough to be detected we obtained fairly accurate estimates of relative surface anomaly radiative heat fluxes 29 5 w m 2 21 4 w m 2 and 37 5 w m 2 for the stromboli craters stromboli lava flow and vulcano crater respectively accounting for the convective heat loss significantly increases the estimates of the relative internal heat flux of geothermal origin we found values of 370 60 w m 2 for the stromboli crater region 220 50 w m 2 for the stromboli lava flow and 270 60 w m 2 for the vulcano crater despite the low precision these values are much higher than the 53 62 w m 2 limit defined by cassinis and lechi 1974 as the threshold where the geothermal flux can affect ground temperatures our study provides a unique systematic definition of thermal volcanic features found on stromboli and vulcano the spatial extents of the anomalies and their fluxes and associated errors

remote infrared detection of the cessation of volcanic eruptions when an effusive eruption ends lava surfaces initially cool rapidly so that within minutes temperatures across the hottest zones have dropped by 600 c this means that eruption cessation is simple to detect using satellite infrared data where a sudden irrecoverable decline in thermal radiance occurring over a period of hours is characteristic of termination avhrr data acquired during and after 5 eruptions at krafla iceland illustrate this in all cases the 3 9 m spectral radiance in the first image following the known time of eruption cessation is markedly reduced compared to that recorded during the eruption and subsequently remains at persistently low levels

experimental constraints on shock induced microstructures in naturally deformed silicates abstract planar deformation features pdfs in various minerals have long been accepted as evidence of impact induced deformation the uniqueness of this association was challenged in the context of the k t boundary extinction debate after mosaicism and microstructures similar to pdfs were reported from the products of explosive volcanism as a result of this debate a significant volume of new experimental and observational data on the development of shock induced microstructures has become available over the last ten years the results reveal that factors such as pre shock temperature pulse duration and crystallographic orientation of target minerals to the shock wave have a primary influence on how these microstructures develop data from diamond anvil cell and high pressure friction experiments reveal that the same solid state amorphization process that produces shock induced pdfs at low temperatures also occurs at much lower strain rates in static experiments the experimental data indicate that the amorphization process is thermally activated and that the character of the resulting pdfs is a function of the applied strain rate shock induced amorphization occurs along those crystallographic planes that are most readily transformed to the high pressure phase during very short pulse durations and produces pdfs that are visible at the optical scale lower strain rate deformation produces tem scale amorphization with orientations that are more homogeneously distributed throughout the target mineral and produces no optically visible pdfs the data confirm the uniqueness of multiple intersecting sets of optically visible pdfs as a diagnostic indicator of hypervelocity impact the data also support the hypothesis that the amorphization process can occur at a wide range of strain rates and that the limiting pressure for the process is controlled by the phase stability of the target mineral under the applied loading conditions not by the hel the data also suggest that the onset pressure the maximum pressure and the pressure range for producing optically visible pdfs decrease with increasing temperature and decreasing strain rate as the pressure range for optically visible pdf formation decreases it is replaced by homogeneous amorphization as observed in the anvil cell experiments thus the uniqueness of multiple intersecting sets of optically visible pdfs to hypervelocity impact is not due to a unique process but rather to a specific set of loading conditions that produce an optically visible microstructure likewise single sets of microdeformations observed in volcanic rocks are produced by the same process but at different loading conditions that preclude the development of multiple intersecting sets of pdfs the data also indicate that shock mosaicism which occurs above the hel represents a plastic response of the target mineral to loading rates that are too large to be accommodated by crystal plastic mechanisms observational data for some naturally deformed samples from the k t boundary the vredefort dome and volcanic rocks along with the experimental observations are used to constrain the range of conditions under which the natural microstructures form and to understand the differences between microstructures produced by impact volcanic and other natural processes finally some possible mechanisms for producing the microstructures observed in volcanic rocks are proposed

shock metamorphism of planetary silicate rocks and sediments proposal for an updated classification system we reevaluate the systematics and geologic setting of terrestrial lunar martian and asteroidal impactites resulting from single or multiple impacts for impactites derived from silicate rocks and sediments we propose a unified and updated system of progressive shock metamorphism shock metamorphosed rocks occur as lithic clasts or melt particles in proximal impactites at impact craters and rarely in distal impactites they represent a wide range of metamorphism typically ranging from unshocked to shock melted as the degree of shock metamorphism at a given shock pressure depends primarily on the mineralogical composition and the porosity of a rock or sediment sample different shock classification systems are required for different types of planetary rocks and sediments we define shock classification systems for eight rock and sediment classes which are assigned to three major groups of rocks and sediments 1 crystalline rocks with classes f m a and u 2 chondritic rocks class c and 3 sedimentary rocks and sediments with classes sr se and re the abbreviations stand for felsic f mafic m anorthositic a ultramafic u sedimentary rocks sr unconsolidated sediments se and regoliths re in each class the progressive stages of shock metamorphism are denominated s1 to sx these progressive shock stages are introduced as s1 s7 for f s1 s7 for m s1 s6 for a s1 s7 for u s1 s7 for c s1 s7 for sr s1 s5 for se and s1 s6 for re s1 stands for unshocked and sx variable between s5 and s7 stands for whole rock melting we propose a sequence of symbols characterizing the degree of shock metamorphism of a sample i e f s1 to f s7 with the option to add the tabulated pressure ranges in gpa in parentheses

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

near real time satellite monitoring during the 1997 2000 activity of volcan de colima mexico and its relationship with seismic monitoring abstract the 1997 2000 activity of volcan de colima provided a unique opportunity for the joint analysis of satellite and seismic monitoring techniques three stages of volcanic activity were observed pre lava stage stage of lava eruption stage of explosive eruptions advanced very high resolution radiometer satellite data provided observations of both summit thermal anomalies and ash emission daily monitoring of volcan de colima was performed using early morning or late night noaa 12 and 14 satellite passes gathered in real time at our satellite ground receiving station seismic observations were carried out by the red sismica del estado de colima good correlations are observed between seismic activity and parameters monitored by satellite during the three stages five seismic swarms were recorded during the reactivation period four of the seismic swarms coincided with periods of increase in summit temperature and strong ash emissions it is important to note that the ash emissions were observed a few days before the beginning of seismic swarms the thermal saturation at the summit was reached a few hours after the beginning of lava effusion on november 20 1998 and remained at this level until may 1999 even after the lava flow stopped in early february 1999 the lava front was also clearly identified as a source of thermal anomalies and ash plumes study of the summit temperature ash emission relationship allowed us to classify the strong explosions of 1999 2000 the strongest explosion on february 10 1999 produced the largest ash rich plumes that were detected over a wide area 150 km 2 and near saturation temperature anomalies 47 2 48 4 c the main limitation of volcano satellite monitoring occurs during overcast conditions clouds prevented us from monitoring the seismic swarm of july 1998 and the explosion of july 1999 this study shows that satellite monitoring on a near real time basis is a powerful tool not only for research in volcanology but also as an aid for scientific committees to define probable eruption scenarios during volcanic crisis and for civil protection authorities for risk mitigation due to ash emission and sudden heating of the crater without seismicity

modvolc near real time thermal monitoring of global volcanism modvolc is a non interactive algorithm developed at the hawaii institute of geophysics and planetology higp that uses low spatial resolution 1 km pixel size infrared satellite data acquired by the moderate resolution imaging spectroradiometer modis to map the global distribution of volcanic thermal anomalies in near real time modvolc scans the level 1b modis data stream on a pixel by pixel basis for evidence of pixel and sub pixel sized high temperature radiators once a hot spot has been identified its details location emitted spectral radiance time satellite observation geometry are written to ascii text files and transferred via ftp to higp from where the results are disseminated via the internet http modis higp hawaii edu in this paper we review the underlying principles upon which the algorithm is based before presenting some of the results and data that have been obtained since its inception we show how modvolc reliably detects thermal anomalies at a large number of persistently and sporadically active volcanoes that encompass the full range of common eruptive styles including erebus antarctica colima mexico karymsky kamchatka popocatepetl mexico etna italy and nyiragongo democratic republic of congo amongst others we also present a few cautionary notes regarding the limitations of the algorithm and interpretation of the data it provides

a comparison of observed and modeled surface waves in southern lake michigan and the implications for models of sediment resuspension 1 subsurface pressure sensors were used to make measurements of surface waves during 18 deployments in southern lake michigan between 1998 and 2000 most of the observations were made during the unstratified period november may in water depths between 10 and 55 m the observations as well as those obtained from the national data buoy center ndbc buoy 45007 which is located in the middle of the southern basin of the lake were compared to the results obtained from the great lakes environmental research laboratory glerl donelan wave model implemented on a 2 km grid the results show that the wave model does a good job of calculating the wave heights but consistently underestimates the wave periods in over 80 of the cases the bottom stresses calculated from both the observations and the wave model results agree as to whether or not resuspension occurs but over 70 of this agreement is for cases when resuspension does not occur both stresses predict resuspension about 6 of the time since the bottom stresses calculated from the model results are usually lower than those calculated from the observations resuspension estimates based on the wave model parameters are also lower than those calculated from the observed waves

lava effusion rates from hand held thermal infrared imagery an example from the june 2003 effusive activity at stromboli a safe easy and rapid method to calculate lava effusion rates using hand held thermal image data was developed during june 2003 at stromboli volcano italy we used a forward looking infrared radiometer flir to obtain images of the active lava flow field on a daily basis between may 31 and june 16 2003 during this time the flow field geometry and size where flows typically a few hundred meters long were emplaced on a steep slope meant that near vertical images of the whole flow field could be captured in a single image obtained from a helicopter hovering at an altitude of 750 m and 1 km off shore we used these images to adapt a thermally based effusion rate method previously applied to low and high spatial resolution satellite data to allow automated extraction of effusion rates from the hand held thermal infrared imagery a comparison between a thermally derived 0 23 0 87 m3 s 1 and dimensionally derived effusion rate 0 56 m3 s 1 showed that the thermally derived range was centered on the expected value over the measurement period the mean effusion rate was 0 38 0 25 m3 s 1 which is similar to that obtained during the 1985 86 effusive eruption and the time averaged supply rate calculated for normal non effusive strombolian activity a short effusive pulse reaching a peak of 1 2 m3 s 1 was recorded on june 3 2003 one explanation of such a peak would be an increase in driving pressure due to an increase in the height of the magma contained in the central column we estimate that this pulse would require the magma column to attain a height of 190 m above the effusive vent which is approximately the elevation difference between the vent and the floor of the ne crater our approach gives an easy to apply method that has the potential to provide effusion rate time series with a high temporal resolution

influence of stratification and shoreline erosion on reservoir sedimentation patterns sedimentation in the main pool of a deep maximum depth 50 m 227 km2 hydropower reservoir was modeled using a three dimensional numerical model of hydrodynamics and sedimentation for different wind inflow and outflow conditions short term velocity measurements made in the reservoir were used to validate some aspects of the hydrodynamic model the effects of thermal stratification on sedimentation patterns were investigated since the reservoir is periodically strongly stratified stratification alters velocity profiles and thus affects sedimentation in the reservoir sedimentation of reservoirs is often modeled considering only the deposition of sediments delivered by tributaries however the sediments eroding from the shorelines can contribute significantly to sedimentation if the shorelines of the reservoir erode at sufficiently high rates or if sediment delivery via tributary inflow is small thus shoreline erosion rates for a reservoir were quantified based on measured fetch parameterized be

risk evaluation detection and simulation during effusive eruption disasters lava ingress into a vulnerable population will be difficult to control so that evacuation will be necessary for communities in the path of the active lava followed by post event population infrastructural societal and community replacement and or relocation there is a pressing need to set up a response chain that bridges scientists and responders during an effusive crisis to allow near real time delivery of globally standard products for a timely and adequate humanitarian response in this chain the scientific research groups investigating lava remote sensing and modelling need to provide products that are both useful to and trusted by the crisis response community requirements for these products include a formats that can be immediately integrated into a crisis management procedure and b in an agreed and stable standard a review of current capability reveals that we are at a point where the community can provide such a response as is the aim of the red seed risk evaluation detection and simulation during effusive eruption disasters working group this book is the first production of this group and is intended not only as a directory of current capabilities and operational service providers but also as a statement of intent and need while providing a simulation designed to demonstrate how a truly pan disciplinary response to an effusive crisis could work

shock experiments with the h6 chondrite kernouve pressure calibration of microscopic shock effects shock recovery experiments were carried out on samples of the h6 chondrite kernouve at shock pressures of 10 15 20 25 30 35 45 and 60 gpa and preheating temperatures of 293 k low temperature experiments and 920 k high temperature experiments using a calculated equation of state of kernouve pressure pulse durations of 0 3 to 1 2 s were estimated the shocked samples were investigated by optical microscopy to calibrate the various shock effects in olivine orthopyroxene oligoclase and troilite the following pressure calibration is proposed for silicates 1 undulatory extinction of olivine gpa 2 weak mosaicism of olivine from 10 15 gpa to 20 25 gpa 3 onset of strong mosaicism of olivine at 20 25 gpa 4 transformation of oligoclase to diaplectic glass completed at 25 30 gpa low temperature experiments and at 20 25 gpa high temperature experiments 5 onset of weak mosaicism in orthopyroxene at 30 35 gpa low temperature experiments and at 25 30 gpa high temperature experiments and 6 recrystallization or melting of olivine starting at 45 60 gpa low temperature experiments and at 35 45 gpa high temperature experiments and completed above 45 60 gpa in the high temperature experiments troilite displays distinct differences between the samples shocked at low and high temperatures in the low temperature experiments the following effects can be observed in troilite 1 undulatory extinction up to 25 gpa 2 twinning up to 45 gpa 3 partial recrystallization from 30 to 60 gpa and 4 complete recrystallization 35 gpa whereas in the high temperature experiments troilite shows 1 complete recrystallization from 10 up to 45 gpa and 2 melting and crystallization above 45 gpa localized shock induced melting is observed in samples shocked to pressures 15 gpa in the high temperature experiments and 30 gpa for the low temperature experiments in the form of feni metal and troilite melt injections and intergrowths and as pockets and veins of whole rock melt obviously the onset and abundance of shock induced localized melting strongly depends on the initial temperature of the sample

first testing of a volcano doppler radar voldorad at mount etna italy a medium power 1 kw doppler radar of limited weight 110 kg and working in the uhf band has been developed for active remote sensing of volcanic eruptions named voldorad this radar is designed to monitor eruptive activities of variable magnitude at medium distance range 0 5 5 km in any weather condition and fills the gap between low and high power radar or sodar systems previously tested on volcanoes voldorad was operated for the first time during an eruption of mt etna on october 11 12 1998 doppler spectra recorded at 1 km distance from the vent reveal powerful echoes during the eruption paroxysm lava fountains which gradually decreased along with declining activity an average vertical velocity of 80 87 m s 1 is inferred for the eruptive jets

conditions of magma storage degassing and ascent at stromboli new insights into the volcano plumbing system with inferences on the eruptive dynamics stromboli is known for its persistent degassing and rhythmic strombolian activity occasionally punctuated by paroxysmal eruptions the basaltic pumice and scoria emitted during paroxysms and strombolian activity respectively differ in their textures crystal contents and glass matrix compositions which testify to distinct conditions of crystallization degassing and magma ascent we present here an extensive dataset on major elements and volatiles co2 h2o s and cl in olivine hosted melt inclusions and embayments from pyroclasts emplaced during explosive eruptions of variable magnitude magma saturation pressures were assessed from the dissolved amounts of h2 oa nd co2 taking into account the melt composition evolution both pressures and melt inclusion compositions indicate that 1 ca basaltic melts entrapped in high mg olivines fo89 90 generate stromboli basalts through crystal fractionation and 2 the stromboli plumbing system can be imaged as a succession of magma ponding zones connected by dikes the 7 10 km interval where magmas are stored and differentiate is periodically recharged by new magma batches possibly ranging from ca basalts to basalts with a co2 rich gas phase these deep recharges promote the formation of bubbly basalt blobs which are able to intrude the shallow plumbing system 2 4 km where co2 gas fluxing enhances h2o loss crystallization and generation of crystal rich dense degassed magma chlorine partitioning into the h2o co2 bearing gas phase accounts for its efficient degassing 69 under the open system conditions of strombolian activity paroxysms however are generated through predominantly closed system ascent of basaltic magma batches from the deep storage zone in this situation crystallization is negligible and sulfur exsolution starts at 170 mpa chlorine remains dissolved in the melt until lower pressures only 16 being lost upon eruption finally we propose a continuum in explosive eruption energy from strombolian activity to large paroxysmal events ultimately controlled by variable pressurization of the deep feeding system associated with magma and gas recharges

goes satellite and field observations of the 1998 eruption of volcan cerro azul galapagos islands the 1998 eruption of volcan cerro azul isla isabela galapagos islands was observed in near real time by the geostationary operational environmental satellite 8 goes 8 weather satellite due to the remote location of the eruption site 3 9 m radiance values derived from goes band 2 provide the best timing of the start and termination of the eruption which occurred on 15 sept and 21 oct respectively throughout the 36 day long eruption a total of 1335 thermal infrared images were collected of which 851 were cloud free and permitted the thermal anomaly to be detected a detailed chronology including 77 separate events was assembled from the goes data and field observations numerous attributes of the eruption were observed from the goes data including the sizes and dispersal of seven eruption plumes and the occurrence and timing of intra caldera effusive activity the growth of a lava flow on the se flank the formation of smoke and volcanic haze from the flank vent and burning of vegetation caused by lava flows entering vegetated areas were monitored both on the ground and with the satellite data in most cases goes images were processed as they were received every 30 min and were then distributed over the internet within minutes of reception these data provided timely high temporal information to field parties as well as enabled the documentation of the eruption the goes observations of cerro azul serve as a further example of the way in which the remote sensing community and field volcanologists can collaborate during future eruptions and permit the temporal and spatial resolution requirements for future satellites systems to be better defined

dynamic behavior of suspended sediment concentrations in a shallow lake perturbed by episodic wind events field experiments were conducted in lake balaton a large surface area 600 km2 but shallow mean depth 3 2 m lake in hungary to quantify the resuspension and deposition of bottom sediment due to episodic storm events measurements were made of windspeed and direction surface waves mean water velocity and suspended sediment concentration during significant wind events the computed bottom stress due to surface waves dominated that due to the mean current and therefore surface waves were assumed to be the major cause of sediment resuspension a simple model for the depth averaged suspended sediment concentration based on surface wave height was calibrated with about 10 h of data collected during one storm event and verified against 15 d of data collected at the same site the success of the suspended sediment model which assumes that the bottom sediment was noncohesive is surprising since the bottom material was composed predominantly of sediment in the clay and fine silt size ranges this fit may indicate the presence of a thin surface layer of loosely bound sediment that is continuously involved in resuspension the suspended sediment model could easily be integrated into a water quality model e g to predict light attenuation provided that lateral transport is negligible or it could be used to provide the bottom boundary condition for a more general suspended sediment transport model in which advective transport is included due to their small fall velocities finegrained particles i e those in the silt and clay size ranges are transported easily by flows an understanding of the dynamic behavior of these particles is particularly important in shallow lakes and estuaries since there they may repeatedly settle to the bot

etna 2004 2005 an archetype for geodynamically controlled effusive eruptions 1 the 2004 05 eruption of etna was characterised by outpouring of degassed lava from two vents within valle del bove after three months of eruption lava volumes were estimated to be between 18 5 and 32 106 m3 with eruption rate between 2 3 and 4 1 m3 s petrological analyses show that magma is resident in the shallow plumbing system emplaced during the last south east crater activity so2 flux data show no increase at the onset of the eruption and so2 hcl ratios in gas emitted from the eruptive fissure are consistent with a degassed magma no seismic activity was recorded prior to eruption unlike eruptions observed since the 1980 s the purely effusive nature of this eruption fed by a degassed resident magma and the fracture dynamics suggest that magmatic overpressure played a limited role in this eruption rather lateral spreading of etna s eastern flank combined with general inflation of the edifice triggered a geodynamically controlled eruption

the memin research unit scaling impact cratering experiments in porous sandstones the memin research unit multidisciplinary experimental and modeling impact research network is focused on analyzing experimental impact craters and experimental cratering processes in geological materials memin is interested in understanding how porosity and pore space saturation influence the cratering process here we present results of a series of impact experiments into porous wet and dry sandstone targets steel iron meteorite and aluminum projectiles ranging in size from 2 5 to 12 mm were accelerated to velocities of 2 5 7 8 km s 1 yielding craters with diameters between 3 9 and 40 cm results show that the target s porosity reduces crater volumes and cratering efficiency relative to nonporous rocks saturation of pore space with water to 50 and 90 increasingly counteracts the effects of porosity leading to larger but flatter craters spallation becomes more dominant in larger scale experiments and leads to an increase in cratering efficiency with increasing projectile size for constant impact velocities the volume of spalled material is estimated using parabolic fits to the crater morphology yielding approximations of the transient crater volume for impacts at the same velocity these transient craters show a constant cratering efficiency that is not affected by projectile size

igneous rocks formed by hypervelocity impact abstract igneous rocks are the primary building blocks of planetary crusts most igneous rocks originate via decompression melting and or wet melting of protolith lithologies within planetary interiors and their classification and compositional petrographic and textural characteristics are well studied as our exploration of the solar system continues so too does the inventory of intrusive and extrusive igneous rocks settings and processes the results of planetary exploration have also clearly demonstrated that impact cratering is a ubiquitous geological process that has affected and will continue to affect all planetary objects with a solid surface whether that be rock or ice it is now recognized that the production of igneous rocks is a fundamental outcome of hypervelocity impact the goal of this review is to provide an up to date synthesis of our knowledge and understanding of igneous rocks formed by hypervelocity impact following a brief overview of the basics of the impact process we describe how and why melts are generated during impact events and how impact melting differs from endogenic igneous processes while the process may differ we show that the products of hypervelocity impact can share close similarities with volcanic and shallow intrusive igneous rocks of endogenic origin such impact melt rocks as they are termed can display lobate margins and cooling cracks columnar joints and at the hand specimen and microscopic scale such rocks can display mineral textures that are typical of volcanic rocks such as quench crystallites ophitic porphyritic as well as features such as vesicles flow textures and so on historically these similarities led to the misidentification of some igneous rocks now known to be impact melt rocks as being of endogenic origin this raises the question as to how to distinguish between an impact versus an endogenic origin for igneous like rocks on other planetary bodies where fieldwork and sample analysis may not be possible and all that may be available is remote sensing data while the interpretation of some impact melt rocks may be relatively straightforward e g for clast rich varieties and those with clear projectile contamination we conclude that distinguishing between impact and endogenic igneous rocks is a non trivial task that ultimately may require sample investigation and analysis to be conducted caution is therefore urged in the interpretation of igneous rocks on planetary surfaces

a review of algorithms for detecting volcanic hot spots in satellite infrared data since the 1980s application of thermal infrared satellite data for volcano monitoring has rapidly evolved to become a proven operational tool due to the large quantities of data provided by sensors in polar and geostationary orbits as well as the sheer number of active volcanoes on earth processing and managing such data sets requires an enormous amount of workforce a number of algorithms have been developed to facilitate detection location and tracking of hot spots of active volcanoes a collation and review of hot spot detection algorithms developed and applied by the volcanological community reveals three main types which have been applied to date contextual fixed threshold and temporal the founding algorithms for these three classes are vast modvolc and rst respectively through comparison with manually based detections the performance of each algorithm was tested for sustained lava flows etna and stromboli strombolian activity stromboli lava dome growth and collapse augustine and fumarole fields vulcano it is shown that as the number of correctly identified anomalies increases so too does the number of false positives although each of the algorithms operates well within the limits and criteria of their design requirements and application under current data restraints no algorithm can be expected to perform perfectly

a year of lava fountaining at etna volumes from seviri 1 we present a new method that uses cooling curves apparent in high temporal resolution thermal data acquired by geostationary sensors to estimate erupted volumes and mean output rates during short lava fountaining events the 15 minute temporal resolution of the data allows phases of waxing and peak activity to be identified during short 150 to 810 minute long events cooling curves which decay over 8 to 21 hour periods following the fountaining event can also be identified application to 19 fountaining events recorded at etna by msg s seviri sensor between 10 january 2011 and 9 january 2012 yields a total erupted dense rock lava volume of 28 106 m3 with a maximum intensity of 227 m3 s 1being obtained for the 12 august 2011 event the time averaged output over the year was 0 9 m3 s 1 this being the same as the rate that has characterized etna s effusive activity for the last 40 years

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

shock metamorphism of quartz in nature and experiment ii significance in geoscience the occurrence of shock metamorphosed quartz is the most common petrographic criterion for the identification of terrestrial impact structures and lithologies its utility is due to its almost ubiquitous occurrence in terrestrial rocks its overall stability and the fact that a variety of shock metamorphic effects occurring over a range of shock pressures have been well documented these shock effects have been generally duplicated in shock recovery experiments and thus serve as shock pressure barometers after reviewing the general character of shock effects in quartz the differences between experimental and natural shock events and their potential effects on the shock metamorphism of quartz are explored the short pulse lengths in experiments may account for the difficulty in synthesizing the high pressure polymorphs coesite and stishovite compared to natural occurrences in addition post shock thermal effects are possible in natural events which can affect shock altered physical properties such as refractive index and cause annealing of shock damage and recrystallization the orientations of planar microstructures however are unaffected by post impact thermal events except if quartz is recrystallized and provide the best natural shock barometer in terms of utility and occurrence the nature of planar microstructures particularly planar deformation features pdfs is discussed in some detail and a scheme of variations in orientations with shock pressure is provided the effect of post impact events on pdfs is generally limited to annealing of the original glass lamellae to produce decorated pdfs resulting from the exsolution of dissolved water during recrystallization basal 0001 pdfs differ from other pdf orientations in that they are multiple mechanical brazil twins which are difficult to detect if not partially annealed and decorated the occurrence and significance of shock metamorphosed quartz and its other phases namely coesite stishovite diaplectic glass and lechatelierite are discussed for terrestrial impact structures in both crystalline non porous and sedimentary porous targets the bulk of past studies have dealt with crystalline targets where variations in recorded shock pressure in quartz have been used to constrain aspects of the cratering process and to estimate crater dimensions at eroded structures in sedimentary targets the effect of pore space results in an inhomogeneous distribution in recorded shock pressure and temperature which requires a different classification scheme for the variation of recorded shock compared to that in crystalline targets this is discussed along with examples of variations in the relative abundances of planar microstructures and their orientations which are attributed to textural variations in sedimentary target rocks examples of the shock metamorphism of quartz in distal ejecta such as at the k t boundary and from nuclear explosions are illustrated and are equivalent to that of known impact structures except with respect to characteristics that are due to long term post shock thermal effects finally the differences between the deformation and phase transformation of quartz by shock and by endogenic tectonic and volcanic processes are discussed we confirm previous conclusions that they are completely dissimilar in character due to the vastly different physical conditions and time scales typical for shock events compared to tectonic and volcanic events well characterized and documented shock effects in quartz are unequivocal indicators of impact in the natural environment

space based estimate of the volcanic heat flux into the atmosphere during 2001 and 2002 satellite remote sensing offers a convenient way to monitor changes in the thermal budgets of earth s subaerially active volcanoes by using data acquired by the national aeronautics and space administration s moderate resolution imaging spectro radiometer we have calculated the amount of heat released into the atmosphere by 45 volcanoes active during 2001 and 2002 in order to quantify the contribution active volcanism makes to earth s energy budget we report that the amount of heat radiated into the troposphere by these volcanoes as detected from space was 5 34 3 10 16 and 5 30 3 10 16 j yr during 2001 and 2002 respectively this energy flux is three orders of magnitude less than the amount of energy consumed by the united states of america for residential manufacturing and transportation purposes during 1999

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

active spreading and regional extension at mount etna imaged by sar interferometry abstract large flank instability has been proposed by most recent authors as a major process in the dynamics of mount etna however several aspects of the models are still disputed such as the boundaries of the moving area and the driving force for the instability in this paper we present synthetic aperture radar interferometric data which allow us to identify two main sectors of active instability where the deformational process differs an eastern sector is bounded to the north by the pernicana provenzana fault to the west by the north rift zone and the south rift zone and to the south by the mascalucia tremestieri trecastagni fault system interferograms provide new data on the activity and extent of the southern boundary which was previously underestimated in this sector the structural features indicate an eastward sliding driven by e w regional extension which can be interpreted as a result of the retreating slab of the ionian subduction a second collapsing sector exists along the southern flank of mount etna where the interferograms show the presence of an active anticlinal ridge this ridge is interpreted as the result of southward gravity spreading over a basal decollement between etna and its plio quaternary basement and the hyblean platform the two sectors first became active in summer 1996 after the beginning of a new cycle of eruptive activity at the summit the activity was ongoing until january 1998 with the deformation rate ranging from 4 6 mm yr for the mascalucia tremestieri trecastagni faults to 12 mm yr for the anticlinal ridge

lava discharge during etna s january 2011 fire fountain tracked using msg seviri etna s january 2011 eruption provided an excellent opportunity to test the ability of meteosat second generation satellite s spinning enhanced visible and infrared imager seviri sensor to track a short lived effusive event the presence of lava fountaining the rapid expansion of lava flows and the complexity of the resulting flow field make such events difficult to track from the ground during the etna s january 2011 eruption we were able to use thermal data collected by seviri every 15 min to generate a time series of the syn eruptive heat flux lava discharge waxed over a 1 h period to reach a peak that was first masked from the satellite view by a cold tephra plume and then was of sufficient intensity to saturate the 3 9 m channel both problems made it impossible to estimate time averaged lava discharge rates using the syn eruptive heat flux curve therefore through integration of data obtained by ground based doppler radar and thermal cameras as well as ancillary satellite data from moderate resolution imaging spectrometer and advanced very high resolution radiometer we developed a method that allowed us to identify the point at which effusion stagnated to allow definition of a lava cooling curve this allowed retrieval of a lava volume of 1 2 106 m3 which if emitted for 5 h was erupted at a mean output rate of 70 m3 s 1 the lava volume estimated using the cooling curve method is found to be similar to the values inferred from field measurements

elevated gas flux and trace metal degassing from the 2014 2015 fissure eruption at the barðarbunga volcanic system iceland the 2014 bar arbunga rifting event in iceland resulted in a 6 month long eruption at holuhraun this eruption was characterized by high lava discharge rate and significant gas emission the so2 flux for the first 3 months was measured with satellite sensors and the petrologic method high resolution time series of the satellite data give 1200 kg s that concurs with 1050 kg s obtained from melt inclusion minus degassed lava sulfur contents scaled to the mass of magma produced a high purity gas sample with elevated s cl due to limited chlorine degassing reveals a similar degassing pattern of trace metals as observed at k lauea hawai i and erta ale ethiopia this suggests a common degassing mechanism at mantle plume related volcanoes the trace metal fluxes calculated from trace element to sulfur ratios in the gas sample and scaled to the sulfur dioxide flux are 1 2 orders of magnitude stronger at holuhraun than k lauea and erta ale in contrast volcanoes at convergent margins etna and stromboli italy have 1 2 orders of magnitude higher trace element fluxes most likely caused by abundant chlorine degassing this emphasizes the importance of metal degassing as chlorine species short lived disequilibria between radon daughters 210pb 210bi 210po measured in the gas suggest degassing of a continuously replenished magma batch beneath the eruption site earlier and deep degassing phase of carbon dioxide and polonium is inferred from low 210po 210pb in the gas consistent with magma transfer rate of 0 75 m s

radiative heat power at stromboli volcano during 2000 2011 twelve years of modis observations abstract twelve years of night time modis moderate resolution imaging spectroradiometer observations has been analysed to detect and quantify the radiative heat power emitted by stromboli volcano from march 2000 to september 2011 using an accurate background subtraction of the modis signal at 4 m we were able to discriminate two main regimes of thermal radiation related to different levels of volcanic activity effusive eruptions occurred on december 28 2002 and february 27 2007 radiated at an average of 186 mw with a frequency of alert detection of 50 95 conversely during the typical strombolian activity an average of 9 mw is radiated with a frequency of alert detection of 0 45 although during the effusive eruptions the radiative power is basically controlled by the lava discharge rate our results suggest that during non effusive periods strombolian regime both the intensity and the frequency of modis alerts are controlled by the height of the magmatic column feeding the activity at the surface in particular we found that a radiative power of 50 mw corresponds to a high magma column which is exposed in the vent area at the same rate in which the deeper gas rich magma is typically supplied within the feeding system of stromboli 0 3 m3 s 1 in this condition the magmatic system approaches steady state regimes above this threshold a transition from strombolian to effusive regimes may occur as shown by the detection of 50 mw 8 10 days before the onset of both the last two major flank eruptions these values were reached after 1 2 months of gradual increase of the radiative power which was likely associated the rising of the magma column within the shallowest portion of the conduit in addition our data suggest that over the years 2000 2011 several cycles of rise and fall of the magma column have occurred which however did not culminate into an effusive eruption but only into recurrent episodes of sustained spattering or fountaining and summit overflows these fluctuations has substantially increased in frequency and intensity after the 2007 eruption thus suggesting that this event has perturbed in some way the shallow plumbing system of stromboli we stress that the detection of a radiative power higher than 50 mw is a clear evidence of a very high magma column which may prelude the onset of an effusive eruption and or periods of sustained vent activity in conclusion we suggest that systematic analysis of modis data can be used to detect variations in the intensity of strombolian activity and may considerably improve volcano surveillance at stromboli as well as at other open system volcanoes

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

sulphur release from flood lava eruptions in the veidivotn grimsvotn and katla volcanic systems iceland book description humans have long marvelled at and feared the odorous and colourful manifestations of volcanic emissions and in some cases have harnessed them for their economic value the degassing process responsible for these phenomena is now understood to be one of the key factors influencing the timing and nature of volcanic eruptions moreover the surface emissions of these volatiles can have profound effects on the atmospheric and terrestrial environment and climate even more fundamental are the relationships between the history of planetary outgassing differentiation of the earth s interior chemistry of the atmosphere and hydrosphere and the origin and evolution of life this book provides a compilation of 23 papers that investigate the behaviour of volatiles in magma the feedbacks between degassing and magma dynamics and the composition flux and environmental atmospheric and climatic impacts of volcanic gas emissions

volcano monitoring using short wavelength infrared data from satellites data from remote sensing satellites operating in the short wavelength infrared can be used to measure temperatures of about 150 c and above the gain settings of the landsat thematic mapper tm sensors are such that to record pixel integrated temperatures from 150 c to over 1000 c requires the use of several spectral bands if the radiant source occupies less than a whole pixel as is the case for fumaroles or a crusted lava surface with incandescent cracks then the pixel integrated temperature is less than the actual surface temperature of the hot areas and appears to be different at each wavelength by determining pixel integrated temperature in two spectral bands we can estimate both the temperature and size of hot areas which occupy less than a complete pixel in some cases our observations provide the only available data on the state of activity of a particular volcano in others they support and refine field observations our landsat tm data reveal otherwise unobserved precursor and subsequent activity related to the september 1986 eruption of lascar volcano chile and supplement other data on the march 1986 eruption of augustine volcano alaska they also indicate the continued presence of lava lakes at erta ale ethiopia in the absence of any ground based observations and document minor eruptive activity at mount erebus antarctica landsat multispectral scanner data have been used to measure the variation in temperature along a lava flow on sierra negra galapagos islands which occurred in 1979

pāhoehoe flow cooling discharge and coverage rates from thermal image chronometry 1 theoretically and empirically derived cooling rates for active p hoehoe lava flows show that surface cooling is controlled by conductive heat loss through a crust that is thickening with the square root of time the model is based on a linear relationship that links log time with surface cooling this predictable cooling behavior can be used assess the age of recently emplaced sheet flows from their surface temperatures using a single thermal image or image mosaic this allows quantification of the variation in areal coverage rates and lava discharge rates over 48 hour periods prior to image capture for p hoehoe sheet flow at k lauea hawai i this gives coverage rates of 1 5 m2 min at discharge rates of 0 01 0 05 m3 s increasing to 40 m2 min at 0 4 0 5 m3 s our thermal chronometry approach represents a quick and easy method of tracking flow advance over a three day period using a single thermal snap shot

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

the first day of the cenozoic highly expanded cretaceous paleogene k pg boundary section from the chicxulub peak ring recovered by international ocean discovery program iodp international continental scientific drilling program icdp expedition 364 provides an unprecedented window into the immediate aftermath of the impact site m0077 includes 130 m of impact melt rock and suevite deposited the first day of the cenozoic covered by

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

chronology of the episode 54 eruption at kilauea volcano hawaii from goes 9 satellite data the free availability of goes satellite data every 15 minutes makes these data an attractive tool for studying short term changes on cloud free volcanoes in the pacific basin we use cloud free goes 9 data to investigate the chronology of the january 1997 episode 54 eruption of kilauea volcano hawaii seventy six images for this effusive eruption were collected over a 60 hour period and show the opening and shutdown of active fissures the draining and refilling of the pu u o o lava lake and the cessation of activity at the ocean entry

modeling eruption source parameters by integrating field ground based and satellite based measurements the case of the 23 february 2013 etna paroxysm

using the landsat thematic mapper to detect and monitor active volcanoes an example from lascar volcano northern chile the landsat thematic mapper tm offers a means of detecting and monitoring thermal features of active volcanoes using the tm we have discovered a prominent thermal anomaly on lascar volcano northern chile data from two short wavelength infrared channels of the tm show that material within a 300 m diameter pit crater was at a temperature of at least 380 c on two dates in 1985 the thermal anomaly closely resembles in size and radiant temperature the anomaly over the active lava lake at erta ale in ethiopia an eruption took place at lascar on september 16 1986 tm data acquired on october 27 1986 revealed significant changes within the crater area we find that lascar is in a much more active state than any other volcano in the central andes and for this reason it merits further careful monitoring our studies show that the tm is capable of confidently identifying thermal anomalies less than 100 m in size at temperatures of above 150 c and thus it offers a valuable means of monitoring the conditions of active or potentially active volcanoes particularly those in remote regions

observation and simulation of surface waves in two water supply reservoirs observations and model predictions of progressive surface waves were made for cannonsville and schoharie reservoirs located in southeastern new york state these reservoirs are deep with steep bottom slopes and relatively small fetch the donelan great lakes environmental research lab model a parametric second generation wave model was applied to these reservoirs assuming deep water throughout the domain this assumption was based on the relatively small waves and steep bottom slopes resulting in a very narrow region of wave interaction with the bottom along a lee shore previous applications of this model have been for water bodies with larger fetch observations of wave characteristics were made near the shoreline at two sites in cannonsville and one site in schoharie using submerged pressure sensors from which the height of larger waves was determined model hindcasts were made for the observation periods with model inputs being wind speed and direction and water surface elevation the model performed well in simulating significant wave height determined from observations some implications of the use of wave model simulations to predict sediment resuspension in these and other deep lakes and reservoirs are discussed

an unloading foam model to constrain etna s 11 13 january 2011 lava fountaining episode 1 the 11 13 january 2011 eruptive episode at etna volcano occurred after several months of increasing ash emissions from the summit craters and was heralded by increasing so2 output which peaked at 5000 megagrams day several hours before the start of the eruptive activity the eruptive episode began with a phase of strombolian activity from a pit crater on the eastern flank of the se crater explosions became more intense with time and eventually became transitional between strombolian and fountaining before moving into a lava fountaining phase fountaining was accompanied by lava output from the lower rim of the pit crater emplacement of the resulting lava flow field as well as associated lava fountain and strombolian phases was tracked using a remote sensing network comprising both thermal and visible cameras thermal surveys completed once the eruptive episode had ended also allowed us to reconstruct the emplacement of the lava flow field using a high temporal resolution geostationary satellite data we were also able to construct a detailed record of the heat flux during the fountain fed flow phase and its subsequent cooling the dense rock volume of erupted lava obtained from the satellite data was 1 2 106 m3 this was emplaced over a period of about 6 h to give a mean output rate of 55 m3 s 1 by comparison geologic data allowed us to estimate dense rock volumes of 0 85 106 m3 for the pyroclastics erupted during the lava fountain phase and 0 84 1 7 106 m3 for lavas erupted during the effusive phase resulting in a total erupted dense rock volume of 1 7 2 5 106 m3 and a mean output rate of 78 117 m3 s 1 the sequence of events and quantitative results presented here shed light on the shallow feeding system of the volcano

a simple explanation for the space based calculation of lava eruption rates abstract knowing how lava effusion rates vary during basaltic eruptions can be of great significance when trying to provide preliminary forecasts regarding how far lava will flow however problems exist in accurately determining effusion rates using conventional field based techniques to ameliorate this problem harris et al j geophys res 102 1997 7985 8003 bull volcanol 59 1997 49 64 j volcanol geotherm res 102 2000 237 269 developed a method for determining effusion rates using infrared satellite data and showed how the method could be used to provide realistic estimates of effusion rates repeatedly during several eruptions at kilauea hawai i krafla iceland etna and stromboli italy harris et al j geophys res 102 1997 7985 8003 bull volcanol 59 1997 49 64 indicate that their method allows instantaneous lava effusion rates to be determined thermodynamically by equating the amount of heat lost by an active lava flow derived from the satellite data to the amount of heat liberated by the cooling mass of lava the purpose of this paper is to provide a simpler alternative explanation we find that rather than being used to calculate heat loss harris et al j geophys res 102 1997 7985 8003 bull volcanol 59 1997 49 64 j volcanol geotherm res 102 2000 237 269 actually use the satellite data to estimate the area of active lava present within the satellite s field of view at the movement of data acquisition thus changes in the effusion rates they present can only be proportional to changes in this area the active flow areas were then multiplied by a constant the value of which is obtained from a crude approximation of the lava flows heat balance crucially the absolute value of this term falls within the range of an empirically derived parameter that was found by pieri and baloga j volcanol geotherm res 30 1986 29 45 to explain strong linear correlations between eruption rate i e the time averaged effusion rate and lava flow area for 34 historic hawaiian flows as a result we find that the method of harris et al j geophys res 102 1997 7985 8003 does not yield instantaneous effusion rates but instead provides a valid and useful way to estimate average effusion rates i e the eruption rate from measurements of flow area

revision and recalibration of existing shock classifications for quartzose rocks using low shock pressure 2 5 20 gpa recovery experiments and mesoscale numerical modeling a combination of shock recovery experiments and numerical modeling of shock deformation in the low shock pressure range from 2 5 to 20 gpa for two dry sandstone types of different porosity a completely water saturated sandstone and a well indurated quartzite provides new insights into strongly heterogeneous distribution of different shock features 1 for nonporous quartzo feldspathic rocks the traditional classification scheme stoffler 1984 is suitable with slight changes in pressure calibration 2 for water saturated quartzose rocks a cataclastic texture microbreccia seems to be typical for the shock pressure range up to 20 gpa this microbreccia does not show formation of pdfs but diaplectic quartz glass sio2 melt is formed at 20 gpa 1 vol 3 for porous quartzose rocks the following sequence of shock features is observed with progressive increase in shock pressure 1 crushing of pores 2 intense fracturing of quartz grains and 3 increasing formation of diaplectic quartz glass sio2 melt replacing fracturing the formation of diaplectic quartz glass sio2 melt together with sio2 high pressure phases is a continuous process that strongly depends on porosity this experimental observation is confirmed by our concomitant numerical modeling recalibration of the shock classification scheme results in a porosity versus shock pressure diagram illustrating distinct boundaries for the different shock stages

automated volcanic eruption detection using modis abstract the moderate resolution imaging spectroradiometer modis flown on board nasa s first earth observing system eos platform terra offers complete global data coverage every 1 2 days at spatial resolutions of 250 500 and 1000 m its ability to detect emitted radiation in the short 4 m and long 12 m wave infrared regions of the electromagnetic spectrum combined with the excellent geolocation of the image pixels 200 m makes it an ideal source of data for automatically detecting and monitoring high temperature volcanic thermal anomalies this paper describes the underlying principles of and results obtained from just such a system our algorithm interrogates the modis level 1b data stream for evidence of high temperature volcanic features once a hotspot has been identified its details location emitted spectral radiance satellite observational parameters are written to an ascii text file and transferred via file transfer protocol ftp to the hawaii institute of geophysics and planetology higp where the results are posted on the internet http modis higp hawaii edu the global distribution of volcanic hotspots can be examined visually at a variety of scales using this website which also allows easy access to the quantitative data contained in the ascii files themselves we outline how the algorithm has proven robust as a hotspot detection tool for a wide range of eruptive styles at both permanently and sporadically active volcanoes including soufriere hills montserrat popocatepetl mexico bezymianny russia and merapi java amongst others we also present case studies of how the system has allowed the onset development and cessation of discrete eruptive events to be monitored at nyamuragira congo piton de la fournaise reunion island and shiveluch russia

volcanology 2020 how will thermal remote sensing of volcanic surface activity evolve over the next decade abstract volcanological remote sensing spans numerous techniques wavelength regions data collection strategies targets and applications attempting to foresee and predict the growth vectors in this broad and rapidly developing field is therefore exceedingly difficult however we attempted to make such predictions at both the american geophysical union agu meeting session entitled volcanology 2010 how will the science and practice of volcanology change in the coming decade held in december 2000 and the follow up session 10 years later looking backward and forward volcanology in 2010 and 2020 in this summary paper we assess how well we did with our predictions for specific facets of volcano remote sensing in 2000 the advances made over the most recent decade and attempt a new look ahead to the next decade in completing this review we only consider the subset of the field focused on thermal infrared remote sensing of surface activity using ground based and space based technology and the subsequent research results this review keeps to the original scope of both agu presentations and therefore does not address the entire field of volcanological remote sensing which uses technologies in other wavelength regions e g ultraviolet radar etc or the study of volcanic processes other than the those associated with surface mostly effusive activity therefore we do not consider remote sensing of ash gas plumes for example in 2000 we had looked forward to a golden age in volcanological remote sensing with a variety of new orbital missions both planned and recently launched in addition exciting field based sensors such as hand held thermal cameras were also becoming available and being quickly adopted by volcanologists for both monitoring and research applications all of our predictions in 2000 came true but at a pace far quicker than we predicted relative to the 2000 2010 timeframe the coming decade will see far fewer new orbital instruments with direct applications to volcanology however ground based technologies and applications will continue to proliferate and unforeseen technology promises many exciting possibilities that will advance volcano thermal monitoring and science far beyond what we can currently envision

thermal monitoring of lascar volcano chile using infrared data from the along track scanning radiometer a 1992 1995 time series lascar volcano 22 22 s 67 44 w is the most active volcano of the central andes of northern chile activity since 1984 has been characterised by periods of lava dome growth and decay within the active crater punctuated by explosive eruptions we present herein a technique for monitoring the high temperature activity within the active crater using frequent measurements of emitted shortwave infrared swir radiation made by the spaceborne along track scanning radiometer atsr the atsr is an instrument of low spatial resolution pixels 1 km across that shares certain characteristics with the modis instrument planned for use as a volcano monitoring tool in the nasa eos volcanology project we present a comprehensive time series of over 60 cloud and plume free nighttime atsr observations for 1992 1995 a period during which lascar experienced its largest historical eruption variations in short wavelength infrared flux relate directly to changes in high temperature surfaces within the active crater from these data interpretations can be made that supplement published field reports and that can document the presence and status of the lava dome during periods where direct ground based observations are lacking our data agree with less frequent information collected from sensors with high spatial resolution such as the landsat thematic mapper oppenheimer et al 1993 and are consistent with field observations and models that relate subsidence of the dome to subsequent explosive eruptions matthews et al 1997 most obviously lascar s major april 1993 eruption follows a period in which the magnitude of emitted shortwave infrared radiation fell by 90 at this time subsidence of the 1991 1992 lava dome was reported by field observers and this subsidence is believed to have impeded the escape of hot volatiles and ultimately triggered the eruption smithsonian institution 1993a extrapolating beyond the period for which field observations of the summit are available our data show that the vulcanian eruption of 20 july 1995 occurred after a period of gradual increase in short wavelength infrared flux throughout 1994 and a more rapid flux decline during 1995 we attribute this additional otherwise undocumented cycle of increasing and decreasing swir radiance as most likely representing variations in degassing through fumaroles contained within the summit crater alternatively it may reflect a cycle of dome growth and decay the explosive eruption of 17 december 1993 appears to have followed a similar but shorter variation in swir flux and we conclude that large explosive eruptions are more likely when the 1 6 m signal has fallen from a high to a low level the atsr instrument offers low cost data at high temporal resolution despite the low spatial detail of the measurements atsr type instruments can provide data that relate directly to the status of lascar s lava dome and other high temperature surfaces we suggest that such data can therefore assist with predictions of eruptive behaviour deduced from application of physical models of lava dome development at this and similar volcanoes

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

the first memin shock recovery experiments at low shock pressure 5 12 5 gpa with dry porous sandstone as part of the memin research program this project is focused on shock deformation experimentally generated in dry porous seeberger sandstone in the low shock pressure range from 5 to 12 5 gpa special attention is paid to the influence of porosity on progressive shock metamorphism shock recovery experiments were carried out with a high explosive set up that generates a planar shock wave and using the shock impedance method cylinders of sandstone of average grain size of 0 17 mm and porosity of about 19 vol and containing some 96 wt sio2 were shock deformed shock effects induced with increasing shock pressure include 1 already at 5 gpa the entire pore space is closed quartz grains show undulatory extinction on average 134 fractures per mm are observed dark vesicular melt glass of the composition of the montmorillonitic phyllosilicate component of this sandstone occurs at an average amount of 1 6 vol 2 at 7 5 gpa quartz grains show weak but prominent mosaicism and the number of fractures increases to 171 per millimeter two additional kinds of melt both based on phyllosilicate precursor could be observed a light colored vesicular melt and a melt containing large iron particles the total amount of melt all types increased in this experiment to 2 4 vol raman spectroscopy confirmed the presence of shock deformed quartz grains near the surface 3 at 10 and 12 5 gpa quartz grains also show weak but prominent mosaicism the number of fractures per mm has reached a plateau value of approximately 200 and the total amount of the different melt types has increased to 4 8 vol diaplectic quartz glass could be observed locally near the impacted surface in addition local shock effects most likely caused by multiple shock wave reflections at sandstone container interfaces occur throughout the sample cylinders and include locally enhanced formation of pdf as well as shear zones associated with cataclastic microbreccia diaplectic quartz glass and sio2 melt overall findings from these first experiments have demonstrated that characteristic shock effects diagnostic for the confirmation of impact structures and suitable for shock pressure calibration are rare so far they are restricted to the limited formation of pdf and diaplectic quartz glass at shock pressures of 10 gpa and above

a chronology of the 1991 to 1993 mount etna eruption using advanced very high resolution radiometer data implications for real time thermal volcano monitoring between december 1991 and march 1993 a continuous effusive eruption at mount etna built a 7 6 km2 lava flow field flows extended to within 1 km of the town of zafferana before a successful artificial diversion was carried out higher up the volcano during this eruption the spaceborne advanced very high resolution radiometer avhrr acquired 308 images on which the activity could be detected since these data can be freely and directly available such coverage potentially allows regular real time monitoring ground observations and a flow map that we produced using a spot image and electronic distance measurement allowed us to develop and test data extraction techniques avhrr radiance maps were consistent with known locations of surface activity these documented the transition from channel to tube fed phases the changing threat to zafferana and flow diversion quantitative analysis of the avhrr data enabled estimation of active lava area thermal flux effusion rates and total flow field volume our estimates for eruption rate and total flow field volume 5 6 to 7 6 m3 s and 220 106 to 300 106 m3 respectively are in agreement with published ground based estimates of 5 8 m3 s and 235 106 m3 these correlations demonstrate the high degree of confidence that can now be placed in interpretations of avhrr time series for eruptions where ground based data are scanty

liquefaction of sedimentary rocks during impact crater development abstract impact crater development on every planetary body requires catastrophic movement of large volumes of crustal rocks the process produces well known features such as brecciation and frictional melting but a mechanism that explains how rocks accommodate the strain during the cratering flow remains unclear here we investigate target rocks from the araguainha impact crater central brazil that typify what happens to a consolidated fluid saturated sedimentary rock at 2 km below the surface prior to the impact event sandstone units record a pattern of chaotic large scale folds and pervasive microscopic grain to grain brecciation that result from rock strength degradation triggered by the impact field mapping and extensive textural observations indicate that these sandstones experienced initial microstructural damage from the shock wave and that this process may have weakened grain to grain bonds and started the process of pervasive microbrecciation accompanying heating and decompression lead to vaporization and expansion of fluids in the sandstone pores magnifying the process of brecciation by effectively liquefying the rock mass and allowing for chaotic folding at a range of scales up to blocks 100 m in length in the central uplift this is a vaporization assisted microbrecciation and it may have inhibited the formation of pseudotachylites because energy was dissipated by pervasive microcracking vaporization of pore fluids and large scale chaotic folding rather than localized displacement on brittle faults and frictional heating we suggest that impact liquefaction of sedimentary rocks depends on whether the presence of pore fluids and related micro brecciation are sufficient to dissipate most of the impact energy

diaplectic quartz glass and sio2 melt experimentally generated at only 5 gpa shock pressure in porous sandstone laboratory observations and meso scale numerical modeling abstract a combination of shock recovery experiments and numerical modeling of shock deformation in the low pressure range from 2 5 to 17 5 gpa in dry porous seeberger sandstone provides new significant insights with respect to the heterogeneous nature of shock distribution in such important upper crustal material for which to date no pressure calibrated scheme for shock metamorphism exists we found that pores are already completely closed at 2 5 gpa shock pressure whole quartz grains or parts of them are transformed to diaplectic quartz glass and or sio 2 melt starting already at 5 gpa whereas these effects are not observed below shock pressures of 30 35 and 45 gpa respectively in shock experiments with quartz single crystals the appearance of diaplectic glass or melt is not restricted to the zone directly below the impacted surface but is related to the occurrence of pores in a much broader zone the combined amount of these phases increases distinctly with increasing shock pressure from 0 03 vol at 5 gpa to 80 vol at 17 5 gpa in accordance with a previous shock classification for silica phases in naturally shocked coconino sandstone from meteor crater that was based on varied slopes of the coconino sandstone hugoniot curve our observations allow us to construct a shock pressure classification for porous sandstone consistent with shock stages 1b 4 of the progressive shock metamorphism classification of kieffer 1971 numerical modeling at the meso scale provides the explanation for the discrepancy of shock deformation in porous material and single crystal quartz in keeping with our experimental results it confirms that pore space is completely collapsed at low nominal pressure and demonstrates that pore space collapse results in localized pressure amplification that can exceed 4 times the initial pressure this provides an explanation for the formation of diaplectic quartz glass and lechatelierite as observed in the low shock pressure experiments the numerical models predict an amount of sio 2 melt similar to that observed in the shock experiments this also shows that numerical models are essential to provide information beyond experimental capabilities

effusive to explosive transition during the 2003 eruption of stromboli volcano the persistent explosive activity of stromboli volcano italy ceased in december 2002 and correlated with the onset of a seven month long effusive eruption on the volcano flank from new vents that opened just below the summit craters we intensively monitored this effusive event collecting and interpreting in real time an extensive multiparametric geophysical data set the resulting data synergy allowed detailed insights into the conduit dynamics that drove the eruption and the transition back to the typical strombolian activity we present a direct link between gas flux magma volume flux and seismicity supporting a gas driven model whereby the balance between gas flux and gas overpressure determines whether the system will support effusive or explosive activity this insight enabled us to monitor the migration of the magma column up the conduit and to explain the onset of explosive activity

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