novel retrieval of volcanic so2 abundance from ultraviolet spectra projects i firb miur simulazione dei flussi lavici con gli automi cellulari n rbau01rmz4 002 ii sviluppo di sistemi di monitoraggio funded by dipartimento di protezione civile della regione sicilia ingv istituto nazionale di geofisica e vulcanologia sezione di catania italy iii eu funded sixth framework programme project 18354 novac iv leverhulme trust fellowship

the 2010 ash emissions at the summit craters of mt etna relationship with seismo acoustic signals 1 mt etna volcano italy typically generates lava fountains and strombolian eruptions from the summit craters producing significant emissions of tephra which may cause moderate to high impact both in the atmosphere and on the ground however we have also witnessed a number of minor ash emissions that although far less powerful may pose considerable volcanic hazards in this paper we deal with three ash emissions occurring in 2010 8 april at southeast crater 25 august at bocca nuova and 14 15 november at northeast crater correlating their volcanological features with the associated seismo acoustic signals we provide details regarding the chronology eruption column dispersal of the deposit and texture grain size componentry and morphology of the emitted ash each eruptive episode has also been characterized by means of seismo acoustic analyses evaluating the volcanic acoustic seismic ratio vasr furthermore the source of volcanic tremor recorded from march to december 2010 was localized the joint volcanological and seismo acoustic analyses allowed distinguishing two main kinds of ash emissions types a 8 april and 25 august and b 14 15 november regarding the former the accumulation of gas below a dense cap rock obstructing the conduit vent giving rise with the uncorking to impulsive explosivity was hypothesized the latter type instead is characterized by a longer lasting and less explosivity likely due to the existence of open conduit conditions therefore type b ash emissions are less hazardous than type a this simple model regarding minor explosive activity may constitute a starting point to assess the volcanic risk from unexpected explosions

eruptive processes leading to the most explosive lava fountain at etna volcano the 23 november 2013 episode the 23 november 2013 lava fountain at etna volcano was the most explosive of the last 44 episodes that have occurred at etna in 2011 2013 we infer the total magma volume erupted by thermal images analysis and show that it was characterized by a very high time averaged discharge rate tadr of 360 m3 s 1 having erupted 1 6 106 m3 of dense rock equivalent magma volume in just 45 min which is more than 3 times the tadr observed during previous episodes two borehole dilatometers confirmed the eruption dynamics inferred from the thermal images when compared to the other lava fountains this episode can be considered as the explosive end member however the erupted volume was still comparable to the other lava fountain events we interpret that the 23 november explosive end member event was caused by more primitive and gas rich magma entering the system as demonstrated by the exceptional height reached by the lava fountain

infrared image analysis of volcanic thermal features lascar volcano chile 1984 1992 fifteen landsat thematic mapper tm images of lascar volcano chile recorded between december 1984 and april 1992 document the evolution of a lava dome within the summit crater four of the scenes were acquired at night in every image the two short wavelength infrared bands 5 and 7 have detected thermal radiation from the volcano as a consequence of the planck distribution function the relative response of these two channels depends on the proportions of very hot 600 c surfaces occupying tiny pixel areas and broader regions at moderate temperatures 280 c intercomparison of bands 5 and 7 thereby provides a means for interpreting tm thermal anomalies even in the absence of ground observations pronounced changes in the configuration and intensity of the lascar anomaly suggest that the volcano has experienced at least two cycles of lava dome activity since 1984 the first of these progressed through a cooling period possibly reflecting a reduced flux of magmatic volatiles at the surface and culminated in an explosive eruption on september 16 1986 which appears to have completely destroyed the inferred lava dome the tm data indicate that a new dome had been emplaced by november 1987 more than 15 months before it was first discovered by local observers lascar s style of cyclical effusive and explosive activity is typical of many volcanoes and the remote sensing techniques presented herein could be applied elsewhere

dynamics of a lava fountain revealed by geophysical geochemical and thermal satellite measurements the case of the 10 april 2011 mt etna eruption 1 geophysical tilt seismic tremor and gravity signals geochemical crater so2flux and infrared satellite measurements are presented and discussed to track the temporal evolution of the lava fountain episode occurring at mt etna volcano on 10 april 2011 the multi disciplinary approach provides insight into a gas rich magma source trapped in a shallow storage zone inside the volcano edifice this generated the fast ascending gas magma dispersed flow feeding the lava fountain and causing the depressurization of a deeper magma storage satellite thermal data allowed estimation of the amount of erupted lava which summed to the tephra volume yielded a total volume of erupted products of about 1 106 m3 thanks to the daylight occurrence of this eruptive episode the so2 emission rate was also estimated showing a degassing cycle reaching a peak of 15 000 mg d 1 with a mean daily value of 5 700 mg d 1 the so2 data from the previous fountain episode on 17 18 february to 10 april 2011 yielded a cumulative degassed magma volume of about 10 5 106 m3 indicating a ratio of roughly 10 1 between degassed and erupted volumes this volumetric balance differently from those previously estimated during different styles of volcanic activities with long term years recharging periods and middle term weeks to months effusive eruptions points toward the predominant role played by the gas phase in generating and driving this lava fountain episode

imaging the multi level magma reservoir at mt etna volcano italy 1 the continuous gps network operating on mt etna with its 36 stations is currently one of the largest worldwide the aim of this network is the evaluation of volcanic hazard and the modelling of the active sources in this paper we propose an in depth analysis and modelling of continuous gps data collected at mt etna from may 2008 to december 2010 the analyzed period has been divided into four different coherent phases 1 14 may 2008 02 august 2008 deflation of the entire gps network 2 02 august 2008 14 june 2009 deflation of the summit area and inflation at lower heights 3 14 june 2009 21 may 2010 inflation of the entire gps network 4 21 may 2010 31 december 2010 inflation at medium and low heights and end of the inflation in the summit area analytical models indicate a non uniform deformation style revealing spaced sources acting at different time on different segments of a multi level magma reservoir the etnean plumbing system imaged here is depicted as an elongated magma reservoir that extends from the volcano body downwards to about 6 5 km below sea level b s l sloping slightly towards the north west with storage volumes located at about 6 5 2 0 and 0 0 km b s l the changes in position of the modelled pressure sources during the analyzed time intervals indicate that throughout the 2008 eruptive period the deformation field was mostly driven by the upward migration of magma on the other hand the pattern of deformation recorded after the end of the eruption strongly suggests a significant contribution of the magma overpressure generated by the gas boiling thus outlining the importance of volatiles content in magma

a mineralogical model for density and elasticity of the earth s mantle 1 we present a thermodynamic model of high pressure mineralogy that allows the evaluation of phase stability and physical properties for the earth s mantle the thermodynamic model is built from previous assessments and experiments in the five component cfmas system cao feo mgo al2o3 sio2 including mineral phases that occur close to typical chemical models of the mantle and reasonable mantle temperatures in this system we have performed a system gibbs free energy minimization including pure end member phases and a nonideal formulation for solid solutions solid solutions were subdivided into discrete pseudocompounds and treated as stoichiometric phases during computation of chemical equilibrium by the simplex method we have complemented the thermodynamic model with a model of shear wave properties to obtain a full description of aggregate elastic properties density bulk and shear moduli that provide a useful basis for the consideration of seismic and geodynamic models of the earth s mantle the thermodynamic model described here is made available for research and training purposes through a web interface http www earthmodel org we examine its validity in light of experiments from mineral physics and briefly discuss inferences for mantle structure

multiparametric study of the february april 2013 paroxysmal phase of mt etna new south east crater european fp7 med suv mediterranean supersite volcanoes grant number 308665 european research council european fp7 fp 2007 2013 erc grant number 279802 sigma sistema integrato di sensori in ambiente cloud per la gestione multirischio avanzata

radiative temperature measurements at kupaianaha lava lake kilauea volcano hawaii field spectroradiometer data in the wavelength range of 0 4 2 5 m and spectral resolution of 1 5 nm have been used to compute the radiative temperature of the surface of kupaianaha lava lake kilauea volcano hawaii two sets of observations a total of 120 spectra were made on october 12 1987 and january 23 1988 when the lava lake was in a period of active overturning the area of the surface for which temperatures were measured was 0 23 0 55 m2 two numerical models of two and three components have been used to match the measured radiant flux ratios and to describe the surface of the lava pond in terms of radiant area and temperature three stages of activity on the lake surface are identified stage 1 characterized by magma fountaining and overturning events exhibited the hottest crustal temperatures 180 572 c and the largest fractional hot areas 10 3 stage 1 average flux densities were 2 2 104 w m2 the highest recorded for the three stages of activity on either day the largest radiative area of fresh magma was 29 at 1100 c while cooling from magmatic temperatures to newly formed crust at 790 c took place in a matter of seconds stage 2 marked by rifting events between plates of crust exhibited crustal temperatures between 100 and 340 c with fractional hot areas at least an order of magnitude lower than those found for stage 1 average flux densities calculated for three examples of stage 2 activity were 5 3 103 w m2 stage 3 which was quiescent periods when the lake was covered by a thick crust dominated the activity of the lake both temporally and spatially over 90 of the time the characteristic crustal temperature of stage 3 was 80 345 c with most solutions near 200 300 c and fractional hot areas of 10 5 of the viewing area average flux densities for stage 3 were 4 9 103 w m2 for many stage 3 examples a two component model was sufficient to describe the spectral data however for almost all of the stage 1 and 2 examples and the remainder of the stage 3 examples a three component model was required these determinations of lava temperature and radiant area have relevance for satellite and airborne measurements of the thermal characteristics of active volcanoes and indicate that temporal variability of the thermal output of lava lakes occurs on the time scale of seconds to minutes

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

ducks low cost thermal monitoring units for near vent deployment abstract during 1999 we designed and tested a thermal monitoring system to provide a cheap robust modular real time system capable of surviving the hostile conditions encountered proximal to active volcanic vents in november 2000 the first system was deployed at pu u o o kilauea hawai i to target persistently active vents aside from some minor problems such as sensor damage due to tampering this system remained operational until january 2004 the success of the prototype system led us to use the blueprint for a second installation at stromboli aeolian islands italy this was deployed dug into a bomb proof bunker during may 2002 and survived the april 2003 paroxysmal eruption despite being located just 250 m from the vent in both cases careful waterproofing of connectors and selection of suitable protection has prevented water damage and corrosion in the harsh atmosphere encountered at the crater rim the pu u o o system cost us 10 000 and comprises four modules sensors transmission and power hub repeater station and reception site the sensor component consists of three thermal infrared thermometers housed in pelican cases fitted with germanium arsenide selenium windows two 1 field of view fov sensors allow specific vents to be targeted and a 60 fov sensor provides a crater floor overview a hard wire connection links to a pelican case housed microprocessor modem and power module from here data are transmitted via a repeater site to a dedicated pc at the hawaiian volcano observatory here data are displayed with a delay of 3 s between acquisition and display the modular design allows for great flexibility at stromboli 1 and 15 fov sensor modules can be switched depending changes in activity style and crater geometry in addition a direct line of site to the stromboli reception center negates the repeater site requirement reducing the cost to us 5500 for a single sensor system we have also constructed self contained units with internal data loggers for us 1500 unit these have been tested at kilauea stromboli etna masaya santiaguito fuego pacaya poas soufriere hills villarrica and erta ale these instruments have proved capable of detecting thermal signals associated with 1 gas emission 2 gas jetting events 3 crater floor collapse 4 lava effusion 5 lava flow in tubes 6 lava lake activity 7 lava dome activity and 8 crater lake skin temperature

effects of undrained strength anisotropy on surface subsidences induced by the construction of shallow tunnels the implementation of an anisotropic soil model that allows consideration of the variation of undrained strength due to anisotropy is described this analysis is then used to identify the significance of strength anisotropy on the prediction of deformation behaviour of a shallow tunnel it is found that for the case of an unlined tunnel attention should be given to the effect of strength anisotropy particularly for a soil possessing type k anisotropy i e where the smallest undrained strength occurs at an angle other than the vertical or the horizontal and the smallest value usually occurs at an angle of 45 deg on the other hand for a lined tunnel the effect of strength anisotyopy upon the surface settlement profile will depend upon the size of a so called gap parameter the gap represents the net effect of loss of ground and some workmanship factors in a plane strain finite element analysis increasing the gap eases the restrictions imposed by the tunnel lining upon possible soil deformations thereby increasing the effect of strength anisotropy however it is shown that for a lined tunnel with a moderate value of gap detailed consideration of strength anisotropy may not be necessary

seismoacoustic investigations of paroxysmal activity at mt etna volcano new insights into the 16 november 2006 eruption 1 on 16 november 2006 a 1 day long paroxysmal eruption occurred at the summit craters of mt etna volcano a multiparametric approach consisting of analyzing infrasonic seismic and video camera recordings was carried out to follow its evolution volcanological and geophysical observations identified three eruptive phases in the first phase infrasonic and seismic characteristics reflected the highly explosive nature of the activity waveform characterization of infrasound events confirmed the activity of the several explosive vents at the summit of southeast crater sec during the second phase results highlighted the decoupling between seismic and infrasonic sources which was due to the decrease in explosive activity and the reactivation of effusive vents located south of bocca nuova and on the saddle between bocca nuova and sec the third phase was the most intense and was characterized by various volcanic phenomena pyroclastic flows jets of dark ash and white steam the very high radiated infrasonic energy together with infrasound event features led us to infer a gas enrichment of the shallow magma column preceding by a few minutes and likely related to the pyroclastic flows in the sec area after the eruption at sec variations in infrasound events related to the activity of northeast crater nec were found the observed spectral changes and the source mechanism modeling of the nec infrasound events suggest the existence of a link in the plumbing system feeding the two craters

infrasound from tungurahua volcano 2006 2008 strombolian to plinian eruptive activity abstract strombolian to plinian activity from tungurahua volcano ecuador has been recorded by the autonomous infrasound arrays of the acoustic surveillance for hazardous eruptions ashe project since early 2006 our studies suggest that acoustic energy release during large eruptions does appear to broadly scale with eruption intensity this manuscript provides a detailed chronology and characterization of tungurahua s eruptive activity between 2006 and 2008 and demonstrates the ability to constrain source parameters of significant eruptions such as onset duration and escalation at regional distances by combining infrasound and remote sensing techniques the ashe system in ecuador automatically detected over 20 000 volcanic explosions at an array 37 km from tungurahua and was successful at notifying the onset escalation and cessation of a hazardous february 2008 eruption with a latency of 5 min elevated infrasonic energy from sustained and intense tungurahua eruptions correlates well with ash column heights and their lateral extent during the study period the spectra of these sustained explosive eruptions appear to be recurrent readily recognizable and indicative of volcanic jetting and significant atmospheric ash injection the paroxysmal plinian phase of the august 2006 eruption produced an ash cloud that extended well into the stratosphere 24 km coinciding with a shift of the dominant jetting frequency from 0 25 hz to below 0 1 hz and radiation of over 5 107 w of acoustic power transient explosions were often marked by minor or no ash release and are presumed to be more gas rich a change in the acoustic spectrum of volcanic jetting was also detected in the transition from a sustained to collapsed eruption column at the end of the july 14 2006 eruption the jetting spectrum at tungurahua during a period of sustained pyroclastic density current production changes from a typical double peaked to a single peaked spectrum suggesting remote acoustic monitoring can help ascertain the stability and dynamics of an eruptive column

shallow magma pathway geometry at mt etna volcano 1 a fundamental goal of volcano seismology is to understand the dynamics of active magmatic systems in order to assess eruptive behavior and the associated hazard imaging of magma conduits quantification of magma transport and investigation of long period seismic sources together with their temporal variations are crucial for the comprehension of eruption triggering mechanisms at mt etna volcano several intense episodes of tremor activity were recorded during 2007 in association with strombolian activity and or intense fire fountaining episodes occurring from the south east crater sec the locations of the tremor sources and of the long period seismic events are used here to constrain both the area and the depth range of magma degassing highlighting the geometry of the shallow conduits feeding sec the imaged conduits consist of two connected resonating dike like bodies nnw sse and nw se oriented extending from sea level to the surface in addition we show how tremor long period lp and very long period vlp event locations and signatures reflect pressure fluctuations in the plumbing system associated with the ascent discharge of gas rich magma linked to the lava fountains the evidence here reported also corroborated by ground deformation variations can help develop a better prediction and early warning system for those eruptions effusive or explosive that apparently manifest no clear precursors

lava fountains during the episodic eruption of south east crater mt etna 2000 insights into magma gas dynamics within the shallow volcano plumbing system mt etna in sicily italy is well known for frequent effusive and explosive eruptions from both its summit and flanks south east crater se crater one of the four summit craters has been the most active in the last 20 years and often produces episodic lava fountains over periods lasting from a few weeks to months the most striking of such eruptive phases was in 2000 sixty four lava fountains separated by quiescent intervals and sometimes associated with lava overflows occurred that year between january and june a time period during which we consider the volcano to have been in episodic eruption this paper presents mainly results of petrochemical investigations carried out on both tephra and lavas collected during a number of the lava fountain episodes in 2000 the new data have been integrated with volcanological and seismic information in order to correlate the features of the eruptive activity with magma gas dynamics in the plumbing system of se crater the main findings allow us to characterise the 2000 episodic eruption in the framework of the recent se crater activity in particular we infer that the onset of the 2000 eruption was triggered by the ascent of new more primitive and volatile rich magma that progressively intruded into the se crater reservoir where it mixed with the resident more evolved magma furthermore we argue that the 2000 se crater lava fountains largely resulted from the instability of a foam layer accumulated at the top of the underlying reservoir and rebuilt prior to each episode in agreement with the collapsing foam model for lava fountains

measuring volcanic degassing of so2 in the lower troposphere with aster band ratios we present a new method for measuring so2 with the data from the aster advanced spaceborne thermal emission and reflectance radiometer orbital sensor the method consists of adjusting the so2 column amount until the ratios of radiance simulated on several aster bands match the observations we present a sensitivity analysis for this method and two case studies the sensitivity analysis shows that the selected band ratios depend much less on atmospheric humidity sulfate aerosols surface altitude and emissivity than the raw radiances measurements with 25 relative precision are achieved but only when the thermal contrast between the plume and the underlying surface is higher than 10 k for the case studies we focused on miyakejima and etna two volcanoes where so2 is measured regularly by cospec or scanning doas the so2 fluxes computed from a series of ten images of miyakejima over the period 2000 2002 is in agreement with the long term trend of measurement for this volcano on etna we compared so2 column amounts measured by aster with those acquired simultaneously by ground based automated scanning doas the column amounts compare quite well providing a more rigorous validation of the method the so2 maps retrieved with aster can provide quantitative insights into the 2d structure of non eruptive volcanic plumes their dispersion and their progressive depletion in so2

open path ftir spectroscopy of magma degassing processes during eight lava fountains on mount etna in june july 2001 a series of 16 discrete lava fountain paroxysms occurred at the southeast summit crater sec of mount etna preceding a 28 day long violent flank eruption each paroxysm was preceded by lava effusion growing seismic tremor and a crescendo of strombolian explosive activity culminating into powerful lava fountaining up to 500 m in height during 8 of these 16 events we could measure the chemical composition of the magmatic gas phase h2o co2 so2 hcl hf and co using open path fourier transform infrared op ftir spectrometry at 1 2 km distance from sec and absorption spectra of the radiation emitted by hot lava fragments we show that each fountaining episode was characterized by increasingly co2 rich gas release with co2 so2 and co2 hcl ratios peaking in coincidence with maxima in seismic tremor and fountain height whilst the so2 hcl ratio showed a weak inverse relationship with respect to eruption intensity moreover peak values in both co2 so2 ratio and seismic tremor amplitude for each paroxysm were found to increase linearly in proportion with the repose interval 2 6 days between lava fountains these observations together with a model of volatile degassing at etna support the following driving process prior to and during the june july 2001 lava fountain sequence the shallow 2 km magma reservoir feeding sec received an increasing influx of deeply derived carbon dioxide likely promoted by the deep ascent of volatile rich primitive basalt that produced the subsequent flank eruption this co2 rich gas supply led to gas accumulation and overpressure in sec reservoir generating a bubble foam layer whose periodical collapse powered the successive fountaining events the anti correlation between so2 hcl and eruption intensity is best explained by enhanced syn eruptive degassing of chlorine from finer particles produced during more intense magma fragmentation

insights into magma and fluid transfer at mount etna by a multiparametric approach a model of the events leading to the 2011 eruptive cycle 1 since the second half of the 1990s the eruptive activity of mount etna has provided evidence that both explosive and effusive eruptions display periodic variations in discharge and eruption style in this work a multiparametric approach consisting of comparing volcanological geophysical and geochemical data was applied to explore the volcano s dynamics during 2009 2011 in particular temporal and or spatial variations of seismicity volcano tectonic earthquakes volcanic tremor and long period and very long period events ground deformation gps and tiltmeter data and geochemistry so2 flux co2 flux co2 so2 ratio were studied to understand the volcanic activity as well as to investigate magma movement in both deep and shallow portions of the plumbing system feeding the 2011 eruptive period after the volcano deflation accompanying the onset of the 2008 2009 eruption a new recharging phase began in august 2008 this new volcanic cycle evolved from an initial recharge phase of the intermediate shallower plumbing system and inflation followed by i accelerated displacement in the volcano s eastern flank since april 2009 and ii renewal of summit volcanic activity during the second half of 2010 culminating in 2011 in a cyclic eruptive behavior with 18 lava fountains from new southeast crater nsec furthermore supported by the geochemical data the inversion of ground deformation gps data and the locations of the tremor sources are used here to constrain both the area and the depth range of magma degassing allowing reconstructing the intermediate and shallow storage zones feeding the 2011 cyclic fountaining nsec activity

three years of so2 flux measurements of mt etna using an automated uv scanner array comparison with conventional traverses and uncertainties in flux retrieval 1 sviluppo di sistemi di monitoraggio dipartimento di protezione civile della regione sicilia 2 ingv istituto nazionale di geofisica e vulcanologia sezione di catania italy 3 novac network for observation of volcanic and atmospheric change eu funded sixth framework programme project 18354 4 uk nerc national centre for earth observation via the dynamic earth and geo hazards

a global study of volcanic infrasound characteristics and the potential for long range monitoring abstract volcanic infrasound from explosive eruptions is detectable at distances up to 1000 s of km and is often recorded on the international monitoring system ims infrasound network though infrasound produced by individual volcanoes has previously been studied more general relationships between infrasound characteristics and eruption parameters remain unclear therefore using a dataset comprising 110 events at 39 globally distributed volcanoes we assess the ability of the ims to monitor remote volcanoes and investigate whether volcanic infrasound exhibits consistent trends across a range of eruption styles and intensities acoustic pressure amplitude and frequency content of the volcanic infrasound were measured and acoustic energy was also calculated these were compared along with the maximum distance of detection for each event to the maximum plume height reported for the event which was used as a proxy for event intensity of the events investigated 62 were detected by at least one infrasound station the maximum distance at which an event was detected generally increased with the plume height and infrasound produced during the eruption of manam png in january 2005 which produced a plume which rose over 20 km above the summit was detected at a distance of 10 671 km total acoustic energy and acoustic pressure amplitude corrected for geometrical spreading increased with plume height whilst the lowest frequency present in the volcanic infrasound decreased additionally relationships seen between infrasound characteristics and eruption plume height indicate that analyses of this data alone could constrain vital estimates of plume heights for otherwise un observed eruptions taken together these findings indicate that if made available for this purpose in the future the ims infrasound network could complement existing monitoring techniques by detecting and characterising eruptions at remote volcanoes which often have no local monitoring networks