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Sample records for active volcano mt

  1. Explosive activity at Mt. Yasur volcano: characterization of acoustic signals

    NASA Astrophysics Data System (ADS)

    Spina, L.; Taddeucci, J.; Scarlato, P.; Freda, C.; Gresta, S.

    2012-04-01

    Mt. Yasur (Vanuatu Islands) is an active volcano characterized by persistent Strombolian to mild Vulcanian explosive activity, well known to generate a broad variety of air pressure waves. Between 9 and 12 July 2011, we recorded explosive activity from the three active vents of Mt. Yasur by means of a multiparametric station, comprising thermal and visual high-speed cameras and two ECM microphones recording both infrasonic and sonic signals at 10 kHz sampling frequency. A total of 106 major acoustic events, lasting on average 5 seconds (up to 20 in some ash-rich explosion), correspond to visually recorded explosions at the vents and exhibit a surprisingly broad waveform variability. Major events intervene between minor transients with strongly repetitive waveforms typical of puffing activity. Spectral analyses have been computed on both major events and whole traces. Analysis of major events, carried out using a 5.12 s long window, reveals peak frequencies mostly beneath 5 Hz, only a few events displaying a notable energy content in the sonic band (up to 100 Hz ca). Peak-to-peak amplitude as well as RMS values (evaluated from event start to end) were computed on both raw and filtered (above and below 20 Hz) signals. Spectrograms of the whole traces, carried out using 1.28, 2.56, and 5.12 seconds long windows with 50% overlap, outline clearly the frequency content of major events and the occurrence of puffing ones. We also evaluated the peak frequency of each spectrum of the spectrogram, in order to detect spectral variation of the puffing signal. Considering their great variability, we classified the major events on the base of their spectral content rather than on waveform, grouping together all events having similar spectra by cross-correlating them. Three spectral families cover most of the dataset, as follows: 1) variable and irregular shaped spectra, with energy mainly below 4 Hz; 2) monochromatic events, with simple spectra corresponding in the time domain to

  2. Thermal surveillance of active volcanoes. [infrared scanner recordings of thermal anomalies of Mt. Baker volcano

    NASA Technical Reports Server (NTRS)

    Friedman, J. D. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. By the end of 1973, aerial infrared scanner traverses for thermal anomaly recordings of all Cascade Range volcanoes were essentially completed. Amplitude level slices of the Mount Baker anomalies were completed and compiled at a scale of 1:24,000, thus producing, for the first time, an accurate map of the distribution and intensity of thermal activity on Mount Baker. The major thermal activity is concentrated within the crater south of the main summit and although it is characterized by intensive solfataric activity and warm ground, it is largely subglacial, causing the development of sizable glacier perforation features. The outgoing radiative flux from the east breach anomalies is sufficient to account for the volume of ice melted to form the glacier perforations. DCP station 6251 has been monitoring a thermally anomalous area on the north slope of Mount Baker. The present thermal activity of Mount Baker accounts for continuing hydrothermal alteration in the crater south of the main summit and recurrent debris avalanches from Sherman Peak on its south rim. The infrared anomalies mapped as part of the experiment SR 251 are considered the basic evidence of the subglacial heating which was the probable triggering mechanism of an avalanche down Boulder Glacier on August 20-21, 1973.

  3. ASTER Images Mt. Usu Volcano

    NASA Technical Reports Server (NTRS)

    2000-01-01

    On April 3, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra Satellite captured this image of the erupting Mt. Usu volcano in Hokkaido, Japan. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image the Earth for the next 6 years to map and monitor the changing surface of our planet.

    This false color infrared image of Mt Usu volcano is dominated by Lake Toya, an ancient volcanic caldera. On the south shore is the active Usu volcano. On Friday, March 31, more than 11,000 people were evacuated by helicopter, truck and boat from the foot of Usu, that began erupting from the northwest flank, shooting debris and plumes of smoke streaked with blue lightning thousands of feet in the air. Although no lava gushed from the mountain, rocks and ash continued to fall after the eruption. The region was shaken by thousands of tremors before the eruption. People said they could taste grit from the ash that was spewed as high as 2,700 meters (8,850 ft) into the sky and fell to coat surrounding towns with ash. 'Mount Usu has had seven significant eruptions that we know of, and at no time has it ended quickly with only a small scale eruption,' said Yoshio Katsui, a professor at Hokkaido University. This was the seventh major eruption of Mount Usu in the past 300 years. Fifty people died when the volcano erupted in 1822, its worst known eruption.

    In the image, most of the land is covered by snow. Vegetation, appearing red in the false color composite, can be seen in the agricultural fields, and forests in the mountains. Mt. Usu is crossed by three dark streaks. These are the paths of ash deposits that rained out from eruption plumes two days earlier. The prevailing wind was from the northwest, carrying the ash away from the main city of Date. Ash deposited can be traced on the image as far away as 10 kilometers (16

  4. Volcanogenic fluorine in rainwater around active degassing volcanoes: Mt. Etna and Stromboli Island, Italy.

    PubMed

    Bellomo, S; D'Alessandro, W; Longo, M

    2003-01-01

    Many studies have assessed the strong influence of volcanic activity on the surrounding environment. This is particularly true for strong gas emitters such as Mt. Etna and Stromboli volcanoes. Among volcanic gases, fluorine compounds are potentially very harmful. Fluorine cycling through rainwater in the above volcanic areas was studied analysing more than 400 monthly bulk samples. Data indicate that only approximately 1% of fluorine emission through the plume is deposited on the two volcanic areas by meteoric precipitations. Although measured bulk rainwater fluorine fluxes are comparable to and sometimes higher than in heavily polluted areas, their influence on the surrounding vegetation is limited. Only annual crops, in fact, show some damage that could be an effect of fluorine deposition, indicating that long-living endemic plant species or varieties have developed some kind of resistance.

  5. Detailed analysis of amplitude and recurrence times of LP activity at Mt. Etna Volcano, Italy.

    NASA Astrophysics Data System (ADS)

    Cauchie, L.; Saccorotti, G.; Bean, C.; de Barros, L.

    2012-04-01

    Long-Period (LP) events recorded on many volcanoes worldwide are thought to be associated with conduit resonance triggered by fluid flow instabilities throughout the volcano plumbing system. The rate of Long-Period activity, however, varies greatly depending on the particular volcano taken into account. At Piton de la Fournaise, for instance, LP event rate is on the order of 10 events /year, while at Mt. Etna it is not unusual to observe several thousands of events per month. This work is aimed at improving our understanding of the LP source mechanism through a statistical analysis of detailed LP catalogues. The behaviour of LP activity is compared with the empirical laws governing earthquakes recurrence (e.g., Gutenberg-Richter [GR] and Omori's laws), in order to understand what relationships, if any, exist between these two apparently different earthquake classes. In particular, we investigated the amplitude and the recurrence time of LP activity on Mt. Etna, Italy, using data from a temporary network (inter-station distance ~5km ) and a small-aperture array (inter-station distance ~50m) deployed in 2005. Some 13,000 LP events were detected in August 2005 through a short-term average/long-term average (STA/LTA) method. Directional properties of these events were obtained by applying a Plane Wave Fitting (PWF) method to data from the small array. The different directions of propagation measured for such events suggest that at least two different sources are active. From PWF alone we were not able to isolate the contribution of individual sources without ambiguity. LP signals, however, exhibit a high degree of waveform similarity, thus providing a criterion for classification / source separation. Using correlation analysis, we then grouped the events into families containing comparable waveforms. By waveforms stacking, we obtained a representative, template event for each family. These template signals were then used for a Matched-Filtering of the continuous data

  6. Mercury distribution in seawater of Kagoshima Bay near the active Volcano, Mt. Sakurajima in Japan.

    PubMed

    Ando, Tetsuo; Yamamoto, Megumi; Tomiyasu, Takashi; Tsuji, Mayumi; Akiba, Suminori

    2010-04-01

    Kagoshima bay has a highly active volcano in its center. In the filtered seawater and suspended matter collected from 200-m deep fumaroles at the bottom of the inner bay, the geometric mean concentrations of total mercury were 7.6 and 65.0 ng/L, respectively. The surface seawater collected at the inner bay had a higher concentration of mercury when compared to that in the bay entrance (average: 1.0 vs. 0.5 ng/L). In July, however, no such difference was observed. The fumaroles seem to contribute to relatively high concentrations of mercury in the inner bay except in summer, when thermal cline is formed.

  7. Seismic Activity Related to the 2002-2003 Mt. Etna Volcano Eruption (Italy): Fault Plane Solutions and Stress Tensor Computation

    NASA Astrophysics Data System (ADS)

    Barberi, G.; Cammarata, L.; Cocina, O.; Maiolino, V.; Musumeci, C.; Privitera, E.

    2003-04-01

    Late on the night of October 26, 2002, a bi-lateral eruption started on both the eastern and the southeastern flanks of Mt. Etna. The opening of the eruptive fracture system on the NE sector and the reactivation of the 2001 fracture system, on the S sector, were accompanied by a strong seismic swarm recorded between October 26 and 28 and by sharp increase of volcanic tremor amplitude. After this initial phase, on October 29 another seismogenetic zone became active in the SE sector of the volcano. At present (January 2003) the eruption is still in evolution. During the whole period a total of 862 earthquakes (Md≫1) was recorded by the local permanent seismic network run by INGV - Sezione di Catania. The maximum magnitude observed was Md=4.4. We focus our attention on 55 earthquakes with magnitude Md≫ 3.0. The dataset consists of accurate digital pickings of P- and S-phases including first-motion polarities. Firstly earthquakes were located using a 1D velocity model (Hirn et alii, 1991), then events were relocated by using two different 3D velocity models (Aloisi et alii, 2002; Patane et alii, 2002). Results indicate that most of earthquakes are located to the east of the Summit Craters and to northeast of them. Fault plane solutions (FPS) obtained show prevalent strike-slip rupture mechanisms. The suitable FPSs were considered for the application of Gephart and Forsyth`s algorithm in order to evaluate seismic stress field characteristics. Taking into account the preliminary results we propose a kinematic model of the eastern flank eastward movement in response of the intrusion processes in the central part of the volcano. References Aloisi M., Cocina O., Neri G., Orecchio B., Privitera E. (2002). Seismic tomography of the crust underneath the Etna volcano, Sicily. Physics of the Earth and Planetary Interiors 4154, pp. 1-17 Hirn A., Nercessian A., Sapin M., Ferrucci F., Wittlinger G. (1991). Seismic heterogeneity of Mt. Etna: structure and activity. Geophys. J

  8. Mercury distribution in seawater of Kagoshima Bay near the active Volcano, Mt. Sakurajima in Japan.

    PubMed

    Ando, Tetsuo; Yamamoto, Megumi; Tomiyasu, Takashi; Tsuji, Mayumi; Akiba, Suminori

    2010-04-01

    Kagoshima bay has a highly active volcano in its center. In the filtered seawater and suspended matter collected from 200-m deep fumaroles at the bottom of the inner bay, the geometric mean concentrations of total mercury were 7.6 and 65.0 ng/L, respectively. The surface seawater collected at the inner bay had a higher concentration of mercury when compared to that in the bay entrance (average: 1.0 vs. 0.5 ng/L). In July, however, no such difference was observed. The fumaroles seem to contribute to relatively high concentrations of mercury in the inner bay except in summer, when thermal cline is formed. PMID:20182698

  9. Stereo Image of Mt. Usu Volcano

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On April 3, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra Satellite captured this image of the erupting Mt. Usu volcano in Hokkaido, Japan. This anaglyph stereo image is of Mt Usu volcano. On Friday, March 31, more than 15,000 people were evacuated by helicopter, truck and boat from the foot of Usu, that began erupting from the northwest flank, shooting debris and plumes of smoke streaked with blue lightning thousands of feet in the air. Although no lava gushed from the mountain, rocks and ash continued to fall after the eruption. The region was shaken by thousands of tremors before the eruption. People said they could taste grit from the ash that was spewed as high as 2,700 meters (8,850 ft) into the sky and fell to coat surrounding towns with ash. A 3-D view can be obtained by looking through stereo glasses, with the blue film through your left eye and red film with your right eye at the same time. North is on your right hand side. For more information, see When Rivers of Rock Flow ASTER web page Image courtesy of MITI, ERSDAC, JAROS, and the U.S./Japan ASTER Science Team

  10. TOMO-ETNA MED-SUV.ISES an active seismic and passive seismic experiment at Mt. Etna volcano. An integrated marine and onland geophysical survey.

    NASA Astrophysics Data System (ADS)

    Ibáñez, Jesus. M.; Patane, Domenico; Puglisi, Guisseppe; Zuccarello, Lucciano; Bianco, Francesca; Luehr, Birger; Diaz-Moreno, Alejandro; Prudencio, Janire; Koulakov, Ivan; Del Pezzo, Edoardo; Cocina, Ornella; Coltelli, Mauro; Scarfi, Lucciano; De Gori, Pascuale; Carrion, Francisco

    2014-05-01

    An active seismic experiment to study the internal structure of Etna Volcano is going to carried out on Sicily and Aeolian islands. The main objective of the TOMO-ETNA MED-SUV.ISES experiment, beginning in summer 2014, is to perform a high resolution seismic tomography, in velocity and attenuation, in Southern Italy, by using active and passive seismic data, in an area encompassing outstanding volcanoes as Mt. Etna, and Aeolian volcanoes. The achievement of this objective is based on the integration and sharing of the in-situ marine and land experiments and observations and on the implementation of new instruments and monitoring systems. For the purpose, onshore and offshore seismic stations and passive and active seismic data generated both in marine and terrestrial environment will be used. Additionally, other geophysical data, mainly magnetic and gravimetric data will be considered to obtain a joint Upper Mantle-Crust structure that could permit to make progress in the understanding of the dynamic of the region. This multinational experiment which involves institutions from Spain, Italy, Germany, United Kingdom, Ireland, France, Malta, Portugal, Russia, USA and Mexico. During the experiment more than 6.600 air gun shots performed by the Spanish Oceanographic vessel "Sarmiento de Gamboa" will be recorder on a dense local seismic network consisting of 100 on land non-permanent stations, 70 on land permanent stations and 20-25 OBSs. Contemporaneously other marine geophysical measures will be performed using a marine Gravimeter LaCoste&Romberg Air-Sea Gravity System II and a Marine Magnetometer SeaSPY. The experiments will provide a unique data set in terms of data quantity and quality, and it will provide a detailed velocity and attenuation structural image of volcano edifice. The results will be essential in the development and interpretation of future volcanic models. It is noteworthy that this project is fully transversal, multidisciplinary and crosses several

  11. Vulnerability of settlements around Mt. Cameroon volcano, Cameroon

    NASA Astrophysics Data System (ADS)

    Zogning, Appolinaire; Spinetti, Claudia; Ngouanet, Chretien; Tchoudam, David; Kouokam, Emmanuel; Thierry, Pierre; Bignami, Christian; Fabrizia Buongiorno, Maria; Ilaria Pannaccione Apa, Maria

    2010-05-01

    Located at the bottom of the Gulf of Guinea, Cameroon is exposed to a large variety of natural hazards, including volcanism. Most of the hazard are concentrated around the active volcano Mt. Cameroon which combines effusive and explosive types of activity. The threatened stakes are numerous and different exposed: people, settlements, industrial plantations, petrol refinery and many other factories and infrastructures. Until 2005, no risk management plans has been available. In 2006, the French Embassy in Cameroon, within the framework of a financial convention between Cameroon and France, put in place the GRINP (Management of Natural Risks and Civil Protection) project whose objective was to reinforce the capacity of Cameroon's civil protection department and thus, contribute to the improvement of the security of the population faced with catastrophes. The objective was to realize a Risk Prevention Plan at a local council scale, and taking into consideration the specific natural risks of each zone. The general objective of the RPP was to clearly draw land use maps for risks zones, showing the overlay of stakes with risk of different intensities. In 2008 European Commission funded the Mia-Vita project (Mitigating and Assessing Volcanic Impacts on Terrain and human Activities). The aim of the project is to improve the crisis management capabilities based on monitoring and early warning systems and secure communications; reduction of people's vulnerability and development of recovering capabilities after an event occurs for both local communities and ecological systems. Keyword: natural hazards, Mt. Cameroon, vulnerability, risk prevention plan

  12. Mt. Pinatubo Volcano - Post Eruption, Luzon, Philippines

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Mt. Pinatubo on the island of Luzon (15.0N, 120.5E) erupted catastrophically in June 1991 after over 600 years of inactivity. Even in this cloudy view, the full extent of the eruption is obvious. Thick layers of ash completely surrounds the crater and the effect of mudflows in this previously heavily forested and agricultural region can be traced as ribbons flowing downhill. Clark AFB, once the crossroads of the SW Pacific can only partially be seen.

  13. Mt. Pinatubo Volcano - Post Eruption, Luzon, Philippines

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Mt. Pinatubo on the island of Luzon (15.0N, 120.0E) erupted catastrophically in June 1991 after over 600 years of inactivity. In this vertical view, the full extent of the eruption is obvious. Thick layers of ash completely surrounds the crater and the effect of mudflows in this previously heavily forested and agricultural region can be traced as ribbons flowing downhill. Clark AFB, once the crossroads of the SW Pacific can only partially be seen.

  14. Mt. Pinatubo Volcano - Post Eruption, Luzon, Philippines

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Mt. Pinatubo, on the island of Luzon (15.0N, 120.5E) erupted catastrophically in June 1991, probably the largest of the twentieth century. Great rivers of gray ash (mud flows) radiate in all directions from the newly formed caldera. Within the caldera, a small lake can be seen. Since the eruption, the local environment has been impacted by mud flows and on a global scale, some of the ash is expected to remain in the atmosphere for several more years.

  15. Magma Supply Path Beneath Mt. Asama Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Takeo, M.; Yamamoto, M.; Ohminato, T.; Aoki, Y.

    2005-12-01

    On September 1, 2004, a moderate eruption occurred at Mt. Asama, in central Japan, for the first time in the last 21 years. An earthquake swarm started on August 31, 2004, lasting just before the eruption. After this first eruption, 4 moderate eruptions had occurred by the end of November, 2004. Hypocenters of more than three hundreds volcanic earthquakes occurring from January 1, 2004 to January 31, 2005, were relocated using the double-difference earthquake location algorithm [Waldhauser, F. and Ellsworth, W. L., 2000] to get an accurate hypocenter distribution. The relocated hypocenter distribution reveals a sharp image of seismicity composed of two groups. The one group forms an WNW-SSE striking zone at a depth of 1 km to 1.5 km deep below the sea level. The eastern end of this seismic zone lies about 3 km deep beneath the summit crater and extends westward over 2 km in length. The other group forms a narrow vertical seismic zone extending from the eastern edge of the first group to just under the summit crater. Aoki et al. [2005] reveals that dike intrusions occurred several times before and after the summit eruption based on the GPS data. The east parts of intrusive dikes are overlapped with the first seismic group. Moreover, the top depths of these dikes coincide with the depth of the first group. The hypocenters of the swarm, which occurred just before the eruption, were also determined using the double-difference method. These hypocenters lie just under the vent ranging from 300 m to 800 m deep, suggesting that the shallowest part of the vent is broken during the swarm activity. These facts indicate that the hypocenter distribution before and after the eruption represents the magma supply path beneath Mt. Asama volcano. Before the eruption, long-period volcanic earthquakes were recorded using broadband seismographs located at the summit of Mt. Asama since October 17, 2003. The sources of these long-period events are located relatively shallow at a depth of

  16. Bayesian Event Tree (BET) approach to Near Real Time monitoring on active volcanoes within ASI-SRV project: Mt. Etna test case

    NASA Astrophysics Data System (ADS)

    Silvestri, Malvina; Musacchio, Massimo; Taroni, Matteo; Fabrizia Buongiorno, Maria; Dini, Luigi

    2010-05-01

    , therefore it can be useful in many practical aspects, as land use planning, and during volcanic emergencies. For this work we have used a part of data that come from the monitoring of the Etna volcano, in particular the ground deformation measured by GPS stations ( time series from 2002 to 2006 ), SO2 flux measured by COSPEC method ( time series from 1996 to 2009 ) and the number of flank and summit eruptions from 1970 to 2009. Moreover deformation pattern analyzed with the InSar technique applied on EO Radar data and further products derived by EO optical data complete the used data set. All these data have been inserted in BET, where they have been transformed by a numerical method, with a mathematical algorithm, into likelihood of eruption. The produced results will be disseminated through a WEB-GIS interface which will allow a multidisciplinary analysis improving the monitoring activity on Mt. Etna.

  17. A New Statistical Model for Eruption Forecasting at Open Conduit Volcanoes: an Application to Mt Etna and Kilauea Volcanoes

    NASA Astrophysics Data System (ADS)

    Passarelli, Luigi; Sanso, Bruno; Laura, Sandri; Marzocchi, Warner

    2010-05-01

    eruptions given by our model for Mt Etna volcano flank eruption are published on a internet website and are updated after any change in the eruptive activity.

  18. Spatial distribution of soil radon as a tool to recognize active faulting on an active volcano: the example of Mt. Etna (Italy).

    PubMed

    Neri, Marco; Giammanco, Salvatore; Ferrera, Elisabetta; Patanè, Giuseppe; Zanon, Vittorio

    2011-09-01

    This study concerns measurements of radon and thoron emissions from soil carried out in 2004 on the eastern flank of Mt. Etna, in a zone characterized by the presence of numerous seismogenic and aseismic faults. The statistical treatment of the geochemical data allowed recognizing anomaly thresholds for both parameters and producing distribution maps that highlighted a significant spatial correlation between soil gas anomalies and tectonic lineaments. The seismic activity occurring in and around the study area during 2004 was analyzed, producing maps of hypocentral depth and released seismic energy. Both radon and thoron anomalies were located in areas affected by relatively deep (5-10 km depth) seismic activity, while less evident correlation was found between soil gas anomalies and the released seismic energy. This study confirms that mapping the distribution of radon and thoron in soil gas can reveal hidden faults buried by recent soil cover or faults that are not clearly visible at the surface. The correlation between soil gas data and earthquakes depth and intensity can give some hints on the source of gas and/or on fault dynamics. PMID:21704438

  19. Spatial distribution of soil radon as a tool to recognize active faulting on an active volcano: the example of Mt. Etna (Italy).

    PubMed

    Neri, Marco; Giammanco, Salvatore; Ferrera, Elisabetta; Patanè, Giuseppe; Zanon, Vittorio

    2011-09-01

    This study concerns measurements of radon and thoron emissions from soil carried out in 2004 on the eastern flank of Mt. Etna, in a zone characterized by the presence of numerous seismogenic and aseismic faults. The statistical treatment of the geochemical data allowed recognizing anomaly thresholds for both parameters and producing distribution maps that highlighted a significant spatial correlation between soil gas anomalies and tectonic lineaments. The seismic activity occurring in and around the study area during 2004 was analyzed, producing maps of hypocentral depth and released seismic energy. Both radon and thoron anomalies were located in areas affected by relatively deep (5-10 km depth) seismic activity, while less evident correlation was found between soil gas anomalies and the released seismic energy. This study confirms that mapping the distribution of radon and thoron in soil gas can reveal hidden faults buried by recent soil cover or faults that are not clearly visible at the surface. The correlation between soil gas data and earthquakes depth and intensity can give some hints on the source of gas and/or on fault dynamics.

  20. The puzzle of Mt. Etna 2015 activity

    NASA Astrophysics Data System (ADS)

    Salerno, Giuseppe Giovanni; Caltabiano, Tommaso; Cannata, Andrea; Cannavo', Flavio; Currenti, Gilda; Di Grazia, Giuseppe; La Spina, Alessandro; Palano, Mimmo; Napoli, Rosalba; Sciotto, Mariangela; Spampinato, Letizia

    2016-04-01

    During 2015, Mt. Etna volcano activity consisted of a sequence of seismic and volcanic events indicative of a complex cause-effect relationship between volcanism and tectonics. Here we analyze in details all these events in order to figure out a possible and reliable causative mechanism able to explain the measured evidences by exploiting an extensive and multi-parametric dataset, including geochemical, volcanological, magnetic, seismic, and geodetic data. The integration of the different parameters allowed us to observe a long-lasting inflation episode abruptly interrupted by two vigorous short-term deflations and an intense dynamics of the northern sector of the volcano unstable flank. This last feature was characterized by two seismic swarms (Mmax = 3.6) occurring along the central sector of the Pernicana Fault and aseismic slip with intense deformation affecting the north-eastern edge of the unstable flank. This is not the first time in which the interaction between volcanism and tectonics has been observed at Mt. Etna although poorly constrained. In our case, the used multidisciplinary approach suggested us that in 2015 the eruptive activity was mainly triggered by the tectonic framework of the volcano unstable flank.

  1. Probabilistic Reasoning Over Seismic Time Series: Volcano Monitoring by Hidden Markov Models at Mt. Etna

    NASA Astrophysics Data System (ADS)

    Cassisi, Carmelo; Prestifilippo, Michele; Cannata, Andrea; Montalto, Placido; Patanè, Domenico; Privitera, Eugenio

    2016-07-01

    From January 2011 to December 2015, Mt. Etna was mainly characterized by a cyclic eruptive behavior with more than 40 lava fountains from New South-East Crater. Using the RMS (Root Mean Square) of the seismic signal recorded by stations close to the summit area, an automatic recognition of the different states of volcanic activity (QUIET, PRE-FOUNTAIN, FOUNTAIN, POST-FOUNTAIN) has been applied for monitoring purposes. Since values of the RMS time series calculated on the seismic signal are generated from a stochastic process, we can try to model the system generating its sampled values, assumed to be a Markov process, using Hidden Markov Models (HMMs). HMMs analysis seeks to recover the sequence of hidden states from the observations. In our framework, observations are characters generated by the Symbolic Aggregate approXimation (SAX) technique, which maps RMS time series values with symbols of a pre-defined alphabet. The main advantages of the proposed framework, based on HMMs and SAX, with respect to other automatic systems applied on seismic signals at Mt. Etna, are the use of multiple stations and static thresholds to well characterize the volcano states. Its application on a wide seismic dataset of Etna volcano shows the possibility to guess the volcano states. The experimental results show that, in most of the cases, we detected lava fountains in advance.

  2. Detecting hidden volcanic explosions from Mt. Cleveland Volcano, Alaska with infrasound and ground-couples airwaves

    USGS Publications Warehouse

    De Angelis, Slivio; Fee, David; Haney, Matthew; Schneider, David

    2012-01-01

    In Alaska, where many active volcanoes exist without ground-based instrumentation, the use of techniques suitable for distant monitoring is pivotal. In this study we report regional-scale seismic and infrasound observations of volcanic activity at Mt. Cleveland between December 2011 and August 2012. During this period, twenty explosions were detected by infrasound sensors as far away as 1827 km from the active vent, and ground-coupled acoustic waves were recorded at seismic stations across the Aleutian Arc. Several events resulting from the explosive disruption of small lava domes within the summit crater were confirmed by analysis of satellite remote sensing data. However, many explosions eluded initial, automated, analyses of satellite data due to poor weather conditions. Infrasound and seismic monitoring provided effective means for detecting these hidden events. We present results from the implementation of automatic infrasound and seismo-acoustic eruption detection algorithms, and review the challenges of real-time volcano monitoring operations in remote regions. We also model acoustic propagation in the Northern Pacific, showing how tropospheric ducting effects allow infrasound to travel long distances across the Aleutian Arc. The successful results of our investigation provide motivation for expanded efforts in infrasound monitoring across the Aleutians and contributes to our knowledge of the number and style of vulcanian eruptions at Mt. Cleveland.

  3. The occurrence of Mt Barca flank eruption in the evolution of the NW periphery of Etna volcano (Italy)

    NASA Astrophysics Data System (ADS)

    Branca, S.; Del Carlo, P.; Lo Castro, M. D.; de Beni, E.; Wijbrans, J.

    2009-01-01

    Geological surveys, tephrostratigraphic study, and 40Ar/39Ar age determinations have allowed us to chronologically constrain the geological evolution of the lower NW flank of Etna volcano and to reconstruct the eruptive style of the Mt Barca flank eruption. This peripheral sector of the Mt Etna edifice, corresponding to the upper Simeto valley, was invaded by the Ellittico volcano lava flows between 41 and 29 ka ago when the Mt Barca eruption occurred. The vent of this flank eruption is located at about 15 km away from the summit craters, close to the town of Bronte. The Mt Barca eruption was characterized by a vigorous explosive activity that produced pyroclastic deposits dispersed eastward and minor effusive activity with the emission of a 1.1-km-long lava flow. Explosive activity was characterized by a phreatomagmatic phase followed by a magmatic one. The geological setting of this peripheral sector of the volcano favors the interaction between the rising magma and the shallow groundwater hosted in the volcanic pile resting on the impermeable sedimentary basement. This process produced phreatomagmatic activity in the first phase of the eruption, forming a pyroclastic fall deposit made of high-density, poorly vesicular scoria lapilli and lithic clasts. Conversely, during the second phase, a typical strombolian fall deposit formed. In terms of hazard assessment, the possible occurrence of this type of highly explosive flank eruption, at lower elevation in the densely inhabited areas, increases the volcanic risk in the Etnean region and widens the already known hazard scenario.

  4. Dynamics of the eastern flank of Mt. Etna volcano (Italy) investigated by a dense GPS network

    NASA Astrophysics Data System (ADS)

    Bonforte, Alessandro; Puglisi, Giuseppe

    2006-05-01

    Mount Etna has developed at the intersection of two regional tectonic lineaments, the NNW-SSE trending Hybleo-Maltese escarpment, which separates the thick inland continental crust of the African platform from the Ionian Mesozoic oceanic crust, and the NE-SW Messina-Fiumefreddo fault that marks a rift zone between south Calabria and north-eastern Sicily, extending as far as the Mt. Etna area. All tectonic features affect, with outstanding surface features, the eastern side of the volcano. The eastern flank of the volcano is affected by a long-term motion toward ESE. In 1997, in order to increase the detail of the ground deformation pattern on the lower eastern flank of Mt. Etna, a new GPS network, the "Ionica" network, was installed on this sector of the volcano. This GPS network consists of 24 stations and covers the lower eastern flank of the volcano from the town of Catania to Taormina and from the coastline up to an altitude of about 1300 m. All the new stations consist in self-centring benchmarks; this kind of benchmark allows all station set-up errors to be avoided. Before the merging of the Ionica network to the frame of the global GPS network of Mt. Etna (in June 2001), three surveys were carried out on this network: in September 1997, August 1998 and January 2001. From the ground deformation pattern, it is possible to distinguish two different sectors, showing different characteristics of deformation. The southern part of the network shows a more uniform distribution of the vertical motion with a mean SE-ward horizontal component while the northern one shows an heterogeneous vertical motion with a ESE-ward horizontal component. Furthermore, a higher velocity is detected between 1997 and 1998, due to the additional stress induced by a shallow intrusion on the NW flank of the volcano. The model resulting from data inversions defines a wide sliding plane beneath the entire eastern flank of the volcano with a low dip angle. The expected velocity vectors fit

  5. Unraveling the volcanic tremor source: the Mt. Etna volcano case of study.

    NASA Astrophysics Data System (ADS)

    Zuccarello, Luciano; Cannata, Andrea; Di Grazia, Giuseppe; Trovato, Claudio; Lokmer, Ivan

    2016-04-01

    Although important steps have been made to develop techniques to locate the volcanic tremor sources, as well as to highlight relationships between changes in the volcanic tremor features and variations in the volcano activity, only a few attempts were made in order to constrain the volcanic tremor source mechanism. Indeed, the long lasting nature of volcanic tremor prevents the application of classical waveform inversion techniques used to model LP and VLP sources, especially in volcanoes where tremor is a continuous background signal (such as Etna and Stromboli). The study of volcanic tremor sources is important not only to improve our knowledge in the source processes leading to the volcanic tremor generation, but also to enhance our ability in reconstructing the geometry of the plumbing system. To get insights into the volcanic tremor source mechanism, we developed a new method based on the comparison between observed and theoretical amplitude values. Here we show preliminary results of these analyses, by using the volcanic tremor data recorded at Mt. Etna, thought a dense 3-C broadband seismic network. In particular, we chose some time intervals with the following features: i) high number of seismic stations properly working; ii) energetic volcanic tremor; iii) high quality of volcanic tremor source locations. The results obtained will shed further light on the source mechanism of volcanic tremor, a will provide a new method for constraining parameters that are relevant to monitor volcanoes and forecast their activity.

  6. Monitoring active volcanoes

    USGS Publications Warehouse

    Tilling, Robert I.

    1987-01-01

    One of the most spectacular, awesomely beautiful, and at times destructive displays of natural energy is an erupting volcano, belching fume and ash thousands of meters into the atmosphere and pouring out red-hot molten lava in fountains and streams. Countless eruptions in the geologic past have produced volcanic rocks that form much of the Earth's present surface. The gradual disintegration and weathering of these rocks have yielded some of the richest farmlands in the world, and these fertile soils play a significant role in sustaining our large and growing population. Were it not for volcanic activity, the Hawaiian Islands with their sugar cane and pineapple fields and magnificent landscapes and seascapes would not exist to support their residents and to charm their visitors. Yet, the actual eruptive processes are catastrophic and can claim life and property.

  7. Active submarine volcano sampled

    USGS Publications Warehouse

    Taylor, B.

    1983-01-01

    On June 4, 1982, two full dredge hauls of fresh lava were recovered from the upper flanks of Kavachi submarine volcano, Solomon Islands, in the western Pacific Ocean, from the water depths of 1,200 and 2,700 feet. the shallower dredge site was within 0.5 mile of the active submarine vent shown at the surface by an area of slick water, probably caused by gas emissions. Kavachi is a composite stratovolcano that has been observed to erupt every year or two for at least the last 30 years (see photographs). An island formed in 1952, 1961, 1965, and 1978; but, in each case, it rapidly eroded below sea level. The latest eruption was observed by Solair pilots during the several weeks up to and including May 18, 1982. 

  8. Carbon sources and biogeochemical processes in Monticchio maar lakes, Mt Vulture volcano (southern Italy): New geochemical constrains of active degassing of mantle derived fluids

    NASA Astrophysics Data System (ADS)

    Caracausi, A.; Nuccio, P. M.; Favara, R.; Grassa, F.

    2012-04-01

    Since the catastrophic releases of carbon dioxide from the African volcanic lakes Nyos and Monoun in the 1980s, the scientific community draw attention towards all those crater lakes able to accumulate massive amount of CO2, which could be catastrophically released following overturn of their deep waters. This implies a quantification of the gas accumulation rate into the lakes and the knowledge of recharge processes and their evolution in time. In fact the gaseous recharge in a lake occurs at alarming rates, when an active degassing of hazardous nature volatiles occurs into the lakes and the structure and dynamic of the lake permit the accumulation of gases into the water. The Monticchio lakes, LPM and LGM, occupies two maar craters formed during the last volcanic activity of Mt. Vulture occurred ˜ 140 000 years ago. LPM is a permanently stratified lake, with a thick deep volume of stagnant water and a shallower layer affected by seasonal overturn. On the contrary LGM is a monomittic lake with a complete overturn of the water during winter time. The major dissolved volatiles are methane and CO2. Dissolved helium is in trace amounts and its isotopic signature ranges between 6.1 and 5.3 Ra (Ra is the atmospheric 3He/4He isotopic ratio). These values are within the range of those measured in the olivine fluid inclusions (both of mantle xenoliths and dispersed in the pyroclastics) of LPM maar ejecta. During three years of investigations we observed that dissolved methane in the deep waters of LGM drastically decreases in wintertime as consequence of the complete overturn of the water. The isotopic signature of methane in the deepest portions of LGM (both sediment and water) is quite stable with time and highlights a biogenic origin, being produced both by acetate fermentation and by CO2-reduction in variable proportions. In contrast, a higher contribution of methane produced via CO2 reduction characterizes sediments at shallower depths. At LPM, there is a great

  9. Mount Rainier active cascade volcano

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Mount Rainier is one of about two dozen active or recently active volcanoes in the Cascade Range, an arc of volcanoes in the northwestern United States and Canada. The volcano is located about 35 kilometers southeast of the Seattle-Tacoma metropolitan area, which has a population of more than 2.5 million. This metropolitan area is the high technology industrial center of the Pacific Northwest and one of the commercial aircraft manufacturing centers of the United States. The rivers draining the volcano empty into Puget Sound, which has two major shipping ports, and into the Columbia River, a major shipping lane and home to approximately a million people in southwestern Washington and northwestern Oregon. Mount Rainier is an active volcano. It last erupted approximately 150 years ago, and numerous large floods and debris flows have been generated on its slopes during this century. More than 100,000 people live on the extensive mudflow deposits that have filled the rivers and valleys draining the volcano during the past 10,000 years. A major volcanic eruption or debris flow could kill thousands of residents and cripple the economy of the Pacific Northwest. Despite the potential for such danger, Mount Rainier has received little study. Most of the geologic work on Mount Rainier was done more than two decades ago. Fundamental topics such as the development, history, and stability of the volcano are poorly understood.

  10. Mantle CO2 degassing at Mt. Vulture volcano (Italy): Relationship between CO2 outgassing of volcanoes and the time of their last eruption

    NASA Astrophysics Data System (ADS)

    Caracausi, Antonio; Paternoster, Michele; Nuccio, Pasquale Mario

    2015-02-01

    Mantle volatiles are mainly lost from the Earth to the atmosphere through subaerial and submarine volcanism. Recent studies have shown that degassing of mantle volatiles also occurs from inactive volcanic areas and in tectonically active areas. A new challenge in Earth science is to quantify the mantle-derived flux of volatiles (e.g., CO2) which is important for understanding such diverse issues as the evolution of the atmosphere, the relationships between magma degassing and volcanic activity, gas pressure and seismogenic processes, and the hazards posed by volcanic lakes. Here we present a detailed study of mantle-derived CO2 budget from Mt. Vulture volcano in the Apennines, Italy, whose latest eruption occurred 141 ± 11 kyr ago. The relationship between δ13CCO2 and total dissolved carbon at Mt. Vulture volcano indicates that the emitted CO2 is a mixture of a biogenic end-member with an average δ13CCO2 of about - 17 ‰ and a mantle-derived CO2 end-member with δ13CCO2 values from - 3 ‰ to + 2 ‰. These values of mantle-derived δ13CCO2 are in the range of those for gas emitted from active volcanoes in the Mediterranean. We calculated the contribution of individual components (CO2 in groundwater, in lakes and from main pools) to the total CO2 budget in the area. We used new measurements of water flow, combined with literature data, to calculate the CO2 flux associated with groundwater, and measured the gas flux from the main pools on the volcanic edifice. Finally, we calculated the CO2 flow in the lakes based on the gradient concentration and eddy diffusivity. The total mantle-derived CO2 budget in the area is 4.85 ×108 molyr-1, which is more than double previous estimates. This is higher than those observed in younger volcanic systems elsewhere, thereby supporting the existence of actively degassing mantle melts below Mt. Vulture volcano. A structural map highlights the tectonic control on CO2 flow across the Mt. Vulture volcanic edifice. Indeed, the

  11. Full-wave Ambient Noise Tomography of Mt Rainier volcano, USA

    NASA Astrophysics Data System (ADS)

    Flinders, Ashton; Shen, Yang

    2015-04-01

    Mount Rainier towers over the landscape of western Washington (USA), ranking with Fuji-yama in Japan, Mt Pinatubo in the Philippines, and Mt Vesuvius in Italy, as one of the great stratovolcanoes of the world. Notwithstanding its picturesque stature, Mt Rainier is potentially the most devastating stratovolcano in North America, with more than 3.5 million people living beneath is shadow in the Seattle-Tacoma area. The primary hazard posed by the volcano is in the form of highly destructive debris flows (lahars). These lahars form when water and/or melted ice erode away and entrain preexisting volcanic sediment. At Mt Rainier these flows are often initiated by sector collapse of the volcano's hydrothermally rotten flanks and compounded by Mt Rainier's extensive snow and glacial ice coverage. It is therefore imperative to ascertain the extent of the volcano's summit hydrothermal alteration, and determine areas prone to collapse. Despite being one of the sixteen volcanoes globally designated by the International Association of Volcanology and Chemistry of the Earth's Interior as warranting detailed and focused study, Mt Rainier remains enigmatic both in terms of the shallow internal structure and the degree of summit hydrothermal alteration. We image this shallow internal structure and areas of possible summit alteration using ambient noise tomography. Our full waveform forward modeling includes high-resolution topography allowing us to accuratly account for the effects of topography on the propagation of short-period Rayleigh waves. Empirical Green's functions were extracted from 80 stations within 200 km of Mt Rainier, and compared with synthetic greens functions over multiple frequency bands from 2-28 seconds.

  12. Remote Sensing of Active Volcanoes

    NASA Astrophysics Data System (ADS)

    Francis, Peter; Rothery, David

    The synoptic coverage offered by satellites provides unparalleled opportunities for monitoring active volcanoes, and opens new avenues of scientific inquiry. Thermal infrared radiation can be used to monitor levels of activity, which is useful for automated eruption detection and for studying the emplacement of lava flows. Satellite radars can observe volcanoes through clouds or at night, and provide high-resolution topographic data. In favorable conditions, radar inteferometery can be used to measure ground deformation associated with eruptive activity on a centimetric scale. Clouds from explosive eruptions present a pressing hazard to aviation; therefore, techniques are being developed to assess eruption cloud height and to discriminate between ash and meterological clouds. The multitude of sensors to be launched on future generations of space platforms promises to greatly enhance volcanological studies, but a satellite dedicated to volcanology is needed to meet requirements of aviation safety and volcano monitoring.

  13. Time dependent modeling at Mt. Etna volcano: an application to the 2005-2013 time interval

    NASA Astrophysics Data System (ADS)

    Cannavo', Flavio; McCaffrey, Robert; Palano, Mimmo

    2015-04-01

    Following the 2004-05 eruption, Mt. Etna activity has been characterized by the occurrence of a number of eruptive episodes (2006, 2008 and 2012) and more than 35 paroxysmal events (mainly during the 2011-2012 time interval). In addition, continuous downslope motion of its eastern flank has affected the volcano. This seaward motion has been characterized by some episodic phases combined with the occurrence of multiple slow slip events (SSEs). In order to obtain a comprehensive view of the time evolution of these observed features and thus provide new insight into the ground deformation pattern of Mt. Etna, here we use time-dependent modeling of the three-component daily time series of all GNSS continuous stations installed on the volcanic edifice. All GNSS data spanning the 2005-2013 time interval were processed using the GAMIT/GLOBK software (Herring et al. 2010) following the strategy described in Gonzalez and Palano (2014). Estimated GNSS daily time series were referred to the "Etn@ref" reference frame (a local reference frame computed to isolate the Mt. Etna volcanic deformation from the background tectonic pattern; Palano et al. 2010). Using these daily time series as input we performed a time-dependent, non-linear inversion using the TDEFNODE code (McCaffrey, 2009). We used TDEFNODE to invert the time series to model simultaneously the steady tectonic kinematics plus the transient volcanic and tectonic sources, thus obtaining a realistic model of the complex area. Preliminary results allow us to track, over the considered time interval, the volume changes associated to the activity of a magmatic reservoir located at a depth of about 5 km b.s.l. beneath the upper western flank of the volcano, as well as the location and associated magnitude of four SSEs below the eastern flank. In addition, we attempted a preliminary subdivision of the southern and eastern flanks of Mt. Etna into four tectonic blocks which provide a reasonable representation of the observed

  14. Long period (LP) events on Mt Etna volcano (Italy): the influence of velocity structures on moment tensor inversion

    NASA Astrophysics Data System (ADS)

    Trovato, C.; Lokmer, I.; De Martin, F.; Aochi, H.

    2016-11-01

    Since a few decades volcanic long period (LP) events have been recorded on many active volcanoes and their study has been recognized as an important tool to characterize volcanic activity. LP event analyses through moment tensor (MT) inversions have led to kinematic descriptions of various source mechanisms. The main challenge in these inversions is to `strip out' the propagation effect in order to isolate the source; hence the velocity model used controls the accuracy of the retrieved source mechanism. We first carry out several synthetic tests of inversions on Mt Etna volcano (Italy). Four geological models with topography are considered with increasing complexity: the most complex model is used to generate synthetic data, while the other three models are used to calculate the Green's functions for inversions. The retrieved solutions from the three velocity models are similar. The MT solutions for a deeper source are well retrieved, while a shallower source test suffers from high uncertainties and strong misinterpretation of the source orientation. The homogeneous model gives the lowest misfit value, but source location and mechanism decomposition are inaccurate. When a complex model different from the true one is used, a high misfit value and a wrong solution is obtained. We then incorporate our findings into the MT inversion of an LP event recorded on Mt Etna in 2008. We obtain very different solutions among the three models in terms of source location and mechanism decomposition. The overall shape of the retrieved source time functions are similar, but some amplitude differences arise, especially for the homogeneous model. Our work highlights the importance of including the unconsolidated surface materials in the computation of Green's functions especially when dealing with shallow sources.

  15. Microbial community of a saline mud volcano at San Biagio-Belpasso, Mt. Etna (Italy).

    PubMed

    Yakimov, Michail M; Giuliano, Laura; Crisafi, Ermanno; Chernikova, Tatyana N; Timmis, Kenneth N; Golyshin, Peter N

    2002-05-01

    In San Biagio of Belpasso, approximately 20 km south of Mt. Etna, in the area of contact between volcanic and sedimentary formations, a number of small (3- 60 cm in diameter) active mud eruptions discharge CO2-rich gases, mud and NaCl brines. They can be described as mini-volcanoes owing to their typical conic shapes and continuously bubbling peak craters. Samples were collected from the active peak craters at a depth of 20 cm and DNA was immediately extracted and amplified with universal 16S rRNA gene-specific primers, followed by cloning procedure. A total of 140 bacterial clones obtained were screened and clustered by restriction fragment length polymorphism (RFLP) analysis. The pool of 16S rRNA sequences representing each RFLP cluster was subjected to phylogenetic analysis. All of the 33 sequences analysed were affiliated with the kingdom of Eubacteria; 28 sequences (77% of all clones) affiliated with the Proteobacteria, two sequences (19% of all clones) were affiliated with Actinobacteria and three sequences (4% of all clones) were affiliated with the Flexibacter-Cytophaga-Bacteroides division. The data obtained suggest that the microorganisms phylogenetically affiliated to autotrophic methane oxidizers and heterotrophic hydrocarbon degraders belonging to the gamma-subclass of Proteobacteria are major constituents of the microbial communities of the saline volcanic muds. Overall, the composition of the microbial community of the San Biagio mud volcano resembles the compositions of marine microbial communities, which might indicate that wind-blown seawater vapour acted as an inoculum for microbial community described in present work.

  16. Volcanoes.

    ERIC Educational Resources Information Center

    Tilling, Robert I.

    One of a series of general interest publications on science topics, this booklet provides a non-technical introduction to the subject of volcanoes. Separate sections examine the nature and workings of volcanoes, types of volcanoes, volcanic geological structures such as plugs and maars, types of eruptions, volcanic-related activity such as geysers…

  17. Holocene vertical deformation along the coastal sector of Mt. Etna volcano (eastern Sicily, Italy): Implications on the time-space constrains of the volcano lateral sliding

    NASA Astrophysics Data System (ADS)

    Branca, Stefano; De Guidi, Giorgio; Lanzafame, Gianni; Monaco, Carmelo

    2014-12-01

    A detailed survey of morphological and biological markers of paleo-shorelines has been carried out along the coastal sector of Mt. Etna volcano (eastern Sicily, Italy), in order to better define causes and timing of vertical deformation. We have mapped markers of raised Holocene shorelines, which are represented by beach rocks, wave-cut platforms, balanid, vermetid and algal rims. The timing of coastal uplift has been determined by radiocarbon dating of shells collected from the raised paleo-shorelines and, to correctly assess the total amount of tectonic uplift of the coast during the Late Holocene, we have compared the elevation-age data of sampled shells to the local curve of Holocene sea-level rise. Taking into account the nominal elevation of the associated paleo-shorelines, an uplift rate of 2.5-3.0 mm/year has been estimated for the last 6-7 ka. This general process of uplifting is only locally interrupted by subsidence related to flank sliding of the volcanic edifice, measured at docks and other manmade structures, and by acceleration along the hinge of an active anticline and at the footwall of an active fault. Based on this new data we suggest more precise time-space constraints for the dynamics of the lower eastern flank of Mt. Etna volcano.

  18. Basaltic volcanoes as large-scale aerators: the example of Mt. Etna

    NASA Astrophysics Data System (ADS)

    Moretti, R.; Metrich, N.; Aiuppa, A.; Allard, P.

    2008-12-01

    The recognition and simulation of the patterns of gas release from active volcanoes in relation to those of magma supply and transfer are a major geochemical goal. At basaltic volcanoes such as Mt. Etna (Sicily, Italy) this knowledge would greatly assist our comprehension of the mechanisms of magma rise and injection at different storage levels, from depth up to the shallow systems feeding lava fountains and flows. In this contribution we investigate the H2O-CO2-SO2-H2S-silicate melt system by integrating theoretical models on volcanic degassing with data from plume chemistry, fumarole sampling, chemistry and volatile contents of melt inclusions (MIs). Given an initial bulk composition, we show that the degassing processes behind this ensemble of data can be quantitatively assessed by carefully evaluating the interplay of 1) crystallization, hence phase proportions, 2) redox variables, 3) gas addition (flushing) occurring at different steps along the magmatic column. Because of pervasive CO2-flushing through the magma, we picture Mt. Etna as a big aerator, by analogy with gas absorption techniques in chemical process engineering. CO2-flushing is particularly efficient at P > 140 MPa, where the volatile influx generates a family of degassing paths that embrace the range of variability displayed by H2O, CO2 and S contents dissolved in MIs. The flushing mechanism can work under two extreme scenarios: in one case the rising volatile phase is completely blocked by the shallower magmas, whereas in the other one at each addition of deep gas the pre-existing gas phase is completely separated from the flushed magma. This study shows that equilibrium thermodynamics provides reasonable physico-chemical constraints to interpret the ensemble of data observed, without invoking diffusive regimes acting far from the equilibrium. This is a strong argument for the joint adoption of MI-based volatile contents and volatile-melt saturation algorithms. The results of this study are

  19. Mt. St. Helens Memories.

    ERIC Educational Resources Information Center

    Sharp, Len

    1992-01-01

    Provides a personal account of one science teacher's participation in a teacher workshop in which teachers learned about volcanic development, types of eruption, geomorphology, plate tectonics, volcano monitoring, and hazards created by volcanoes by examining Mt. St. Helens. Provides a graphic identifying volcanoes active since 1975. (MDH)

  20. A metallogenic survey of alkalic rocks of Mt. Somma-Vesuvius volcano

    USGS Publications Warehouse

    Paone, A.; Ayuso, R.A.; de Vivo, B.

    2001-01-01

    Somma-Vesuvius is an alkaline volcano whose products (pumice, scoria and lava) have alkaline (Na2O+K2O) contents between 6 and 16 wt%, Mg number <50, SiO2 59-47 wt% and MgO 0-7.8 wt% (more than 50% of the samples have a content <2 wt%). Immobile-element ratios (Th/Yb, Ta/Yb, Ce/Yb) indicate a shoshonitic character, while the K2O content (4-10 wt%) is characteristic of ultrapotassic rocks. The behavior of selected metals is discussed by grouping them on the basis of the stratigraphic sequence and differentiating the volcanic activity between plinian and interplinian (Rolandi et al., 1998; Ayuso et al., 1998). This allows observation of the variation within each formation from 25.000y. BP to the last historic eruptive cycle (1631-1944 AD). The main processes to explain the wide distribution of the data presented are fractional crystallization of a mantle-derived magma, magma mixing, and contamination with heterogeneous lower and/or upper crust. Variation diagrams distinguish different behavior for groups of metals: Ag (0.01-0.2 ppm), Mo (1-8.8 ppm), W (1.3-13 ppm), Pb (16-250 ppm), Sb (0.2-2.6 ppm), Sc (0.2-61 ppm), Li (15-140 ppm) and Be (1-31 ppm) increase with increasing differentiation and tend to correlate with the incompatible trace elements (Th, Hf, etc). Cu (10-380 ppm), Au (2-143 ppb), Co (0.7-35.1 ppm) and Fe (1.3-6.2 wt%) decrease towards advanced stage of differentiation. Iron also identifies three magmatic groups. The ratio Fe3+/Fe2+ ranges between 0.2 and 1.8, and Fe2O3/ (Fe2O3+FeO) ranges between 0.2 and 0.8, giving rise to an oxidized environment; exceptions are in the samples belonging to the interplinian formations: I, II, medieval and 1631-1994 AD. Fluorine ranges between 0.1 and 0.4 wt% for the complete Mt. Somma-Vesuvius activity, except for the Ottaviano and Avellino plinian (0.8 wt%) events. Chlorine has a wider range, from 0.1 wt% to 1.6 wt%. Mt Somma-Vesuvius has some features similar to those of mineralized alkaline magmatic systems which

  1. Episodic slow slip events and seaward flank motion at Mt. Etna volcano (Italy)

    NASA Astrophysics Data System (ADS)

    Palano, Mimmo

    2016-09-01

    Episodic aseismic slip events have recently been detected at a variety of tectonic and volcanic environments, sparking the curiosity of seismic and geodetic communities. Here, a sequence of 7 slow slip events occurring at Mt. Etna since mid-2009 has been analyzed. Observed displacement fields evidence that the sequence involves two contiguous sectors of the unstable eastern flank, delimited by the Timpe faults. The tectonic control played by these faults can also be recognized on the long-term (2003-2015) velocity field. Elastic modelling of the long-term velocity field infers a sub-horizontal plane slightly dipping eastward and located within the sedimentary basement at shallow depth. Slip distribution models for each slow-slip event highlight how the largest slip values were centred on the SE edge of the sub-horizontal plane during 4 events and on the NE edge during the remaining 3 ones. The recognized events do not appear correlated with volcanic activity, although there is a possible correlation between slow-slip events and inflating episodes of the volcano.

  2. Volcano Monitoring and Early Warning on MT Etna, Italy, Using Volcanic Tremor - Methods and Technical Aspects

    NASA Astrophysics Data System (ADS)

    D'Agostino, Marcello; Di Grazia, Giuseppe; Ferrari, Ferruccio; Langer, Horst; Messina, Alfio; Reitano, Danilo; Spampinato, Salvatore

    2013-04-01

    Recent activity on Mt Etna was characterized by 25 lava fountains occurred on Mt Etna in 2011 and the first semester of 2012. In summer 2012 volcanic activity in a milder form was noticed within the Bocca Nuova crater, before it came to an essential halt in August 2012. Together with previous unrests (e. g., in 2007-08) these events offer rich material for testing automatic data processing and alert issue in the context of volcano monitoring. Our presentation focuses on the seismic background radiation - volcanic tremor - which has a key role in the surveillance of Mt Etna. From 2006 on a multi-station alert system exploiting STA/LTA ratios, has been established in the INGV operative centre of Catania. Besides, also the frequency content has been found to change correspondingly to the type of volcanic activity, and can thus be exploited for warning purposes. We apply Self Organizing Maps and Fuzzy Clustering which offer an efficient way to visualize signal characteristics and its development with time. These techniques allow to identify early stages of eruptive events and automatically flag a critical status before this becomes evident in conventional monitoring techniques. Changes of tremor characteristics are related to the position of the source of the signal. Given the dense seismic network we can base the location of the sources on distribution of the amplitudes across the network. The locations proved to be extremely useful for warning throughout both a flank eruption in 2008 as well as the 2011 lava fountains. During all these episodes a clear migration of tremor sources towards the eruptive centres was revealed in advance. The location of the sources completes the picture of an imminent volcanic unrest and corroborates early warnings flagged by the changes of signal characteristics. Automatic real time data processing poses high demands on computational efficiency, robustness of the methods and stability of data acquisition. The amplitude based multi

  3. Magma evolution in the Ellittico volcano sequence outcropping at Serra Giannicola Grande, Mt. Etna, Italy.

    NASA Astrophysics Data System (ADS)

    Cristofolini, R.; de Rosa, R.; Ferlito, C.; Tripodo, M.

    2003-04-01

    The volcanic sequence examined here outcrops at Serra Giannicola Grande, along the south-western wall of the Valle del Bove (Mt. Etna Volcano), at an elevation between 2230 and 2700 m (Cristofolini et al., 2002). It is referred to the activity of the Ellittico volcanic complex (Ferlito &Cristofolini, 1989), and unconformably lies over on an erosional surface of the Cuvigghiuni synthem (Calvari et al., 1994). Petrological and geochimical investigations on lava flows, showed that: -The analyzed rocks have a Na-alkaline affinity and cover a compositional range from hawaiites to benmoreites and trachytes. -The common mineral association (pl+cpx+ol+mt) of Etnean lavas is present, both as phenocrysts and in groundmass; kaersutite as phenocryst phase isalso present in some of the samples. -The least differentiated lava flows, interbedded with volcanoclastic deposits in the middle part of the sequence, exhibit the widest compositional heterogeneity; they are referable to the existence of distinct magma batches, characterized by differing ascent rates and/or other processes, such as crustal contamination, occurring at shallow levels. It is noteworthy that mafic lavas differ in their contents of K (and Rb) and follow distinct trends of evolution. This suggests that magmas from at least two different sources were feeding the activity of the volcano. -The presence of the most differentiated lavas in the upper part of the sequence, is consistent with the presence of shallow reservoirs during the last stages of the Ellittico activity, where magmas could evolve due to crystal fractionation. The MELTS petrological code (Ghiorso &Sack, 1995) was used in order to quantify the evolution of the different magmas; this program simulates fractionation and assimilation processes in silicate melts under various physical and compositional conditions, and gives as a result compositions of residual liquids and of fractionated solid phases and their amounts. References Calvari, S., Groppelli

  4. Nitrogen multitemporal monitoring through mosses in urban areas affected by mud volcanoes around Mt. Etna, Italy.

    PubMed

    Bonanno, Giuseppe

    2013-10-01

    Nitrogen emissions were assessed by using mosses as bioindicators in a densely inhabited area affected by mud volcanoes. Such volcanoes, locally called Salinelle, are phenomena that occur around Mt. Etna (Sicily, Italy), and are interpreted as the surface outflow of a hydrothermal system located below Mt. Etna, which releases sedimentary fluids (hydrocarbons and Na-Cl brines) along with magmatic gases (mainly CO2 and He). To date, N emissions from such mud volcanoes have been only quantitatively assessed, and no biomonitoring campaigns are reported about the cumulative effects of these emissions. This study analyzed N concentrations in moss, water and soil samples, collected in a 4-year monitoring campaign. The bryophyte Bryum argenteum, a species widely adopted in surveys of atmospheric pollution, was used as a biological indicator. N concentrations in biomonitors showed relatively low values in the study sites. However, the results of this study suggest that N emissions from Salinelle may have an impact on surrounding ecosystems because N values in moss and water showed a significant correlation. N oxides, in particular, contribute to acidification of ecosystems, thus multitemporal biomonitoring is recommended, especially in those areas where N emitting sources are anthropogenic and natural.

  5. Constraining Volcano Source Rheology and Mechanisms: 3D Full Wavefield Simulations and Very High Resolution Observations From Mt Etna.

    NASA Astrophysics Data System (ADS)

    Bean, C. J.; O'Brien, G.; de Barros, L.; Murphy, S.; Lokmer, I.; Saccorotti, G.; Patane, D.; Metaxian, J.

    2009-05-01

    Recent field observation and laboratory experiments have demonstrated a broad range of deformation mechanisms in volcanic rocks, and a juxtaposition of brittle and ductile deformation in both space and time. On the other hand seismological observations of transient deformation at volcanoes yield an equally wide variety of signal types including Volcano Tectonic (VT), Long Period (LP), Very Long Period (VLP) and tremor. A clear goal is to find robust connections between these independent sets of observations, linking detailed field studies, well controlled laboratory experiments and volcano seismology. In volcano seismology VT events are usually interpreted as the brittle response of the edifice to stressing whereas LP and VLP events are thought to result from fluid-filled conduit dynamics. However, strong wave propagation path effects and a large number of possible source mechanisms make it difficult to find a quantitative interpretation of mechanism/rheology. Numerical simulations have a key role to play in making the connection between well-controlled laboratory experiments and the field. Furthermore, many of the features seen in real volcano seismograms can be reproduced in 3D full wavefield simulations of both wet (coupled multi phase fluids and solids) and dry (rupture propagation) models. Even in simulated data the underlying rheology/source mechanisms are difficult to determine from an inversion of the synthetic seismograms, especially for sparse data with poor velocity control. With this in mind a detailed field experiment was undertaken on Mt Etna in June 2008, comprising 30+ stations in the summit area. Aided by simulated data in realistic velocity models, this has given us an unprecedented picture of shallow LP activity on Etna. These high resolution observations will be compared with recent results from laboratory experiments and with numerical simulations in an effort to better constrain the rheology/mechanism of the sources.

  6. Microwave limb sounder measurement of stratospheric SO[sub 2] from the Mt. Pinatubo Volcano

    SciTech Connect

    Read, W.G.; Froidevaux, L.; Waters, J.W. )

    1993-06-18

    This paper presents measurements of sulfur dioxide densities in the stratosphere made by the microwave limb sounder (MLS) on the upper atmosphere research satellite. The SO[sub 2] came from the eruption of the Mt Pinatubo volcano which injected a massive quantity of gas into the stratosphere. The MLS is able to measure the decay rate of the gas densities based on its extended time and spatial coverage, and from this decay rate infer the OH densities in the stratosphere, since OH is the major reactive species which converts the SO[sub 2] into sulfuric acid.

  7. Intermediate-Term Declines in Seismicity at Mt. Wrangell and Mt. Veniaminof Volcanoes, Alaska, Following the November 3, 2002 Mw 7.9 Denali Fault Earthquake

    NASA Astrophysics Data System (ADS)

    Sanchez, J. J.; McNutt, S. R.

    2003-12-01

    On November 3, 2002 a Mw 7.9 earthquake ruptured segments of the Denali Fault and adjacent faults in interior Alaska providing a unique opportunity to look for intermediate-term (days to weeks) responses of Alaskan volcanoes to shaking from a large regional earthquake. The Alaska Volcano Observatory (AVO) monitors 24 volcanoes with seismograph networks. We examined one station per volcano, generally the closest to the vent (typically within 5 km) unless noise, or other factors made the data unusable. Data were digitally filtered between 0.8 and 5 Hz to enhance the signal-to-noise ratio. Data for the period four weeks before to four weeks after the Mw 7.9 earthquake were then plotted at a standard scale used for AVO routine monitoring. Mt. Veniaminof volcano, which has had recent mild eruptions and a rate of ten earthquakes per day on station VNNF, suffered a drop in seismicity by a factor of two after the earthquake; this lasted for 15 days. Wrangell, the closest volcano to the epicenter, had a background rate of about 16 earthquakes per day. Data from station WANC could not be measured for 3 days after the Mw 7.9 earthquake because the large number and size of aftershocks impeded identification of local earthquakes. For the following 30 days, however, its seismicity rate dropped by a factor of two. Seismicity then remained low for an additional 4 months at Wrangell, whereas that at Veniaminof returned to normal within weeks. The seismicity at both Mt. Veniaminof and Mt. Wrangell is dominated by low-frequency volcanic events. The detection thresholds for both seismograph networks are low and stations VNNF and WANC operated normally during the time of our study, thus we infer that the changes in seismicity may be related to the earthquake. It is known that Wrangell increased its heat output after the Mw 9.2 Alaska earthquake of 1964 and again after the Ms 7.1 St.Elias earthquake of 1979. The other volcanoes showed no changes in seismicity that can be attributable to

  8. Dark Oligotrophic Volcanic Ecosystems (DOVEs) in Fumarolic Ice Caves of Mt. Erebus Volcano

    NASA Astrophysics Data System (ADS)

    Staudigel, H.; Anitori, R.; Davis, R.; Connell, L.; Tebo, B. M.

    2011-12-01

    Dark Oligotrophic Volcanic Ecosystems (DOVEs) in the earth's crust may host substantial biomass sustained by chemolithoautotrophic metabolic reactions. It may serve as the base of the foodweb at the surface via hydrothermal circulation, venting pore fluids, cold seeps or gases, and offer a means for primary carbon fixation. When compared to other crustal oligotrophic environments, DOVEs are particularly relevant due to their considerable reductive potential, high permeability and the substantial chemical exchange facilitated by their hydrothermal systems. We studied terrestrial DOVEs in fumarolic ice caves on the summit plateau of Mt Erebus, an active volcano on Ross Island, Antarctica (http://erebuscaves.nmt.edu/). Most of the ice caves on Mt Erebus are relatively shallow and illuminated by natural light, but some are deep enough to afford complete darkness. Fumarole gases forming these caves are mostly atmospheric, enriched with water vapor and CO2. The fumaroles were studied in three caves, Warren, Warren West and Harry's Dream; these displayed, respectively, temperatures of 18°C, 2°C and 11°C at our sampling sites. Both Warren caves were completely dark, while Harry's Dream received continuous indirect light during the Austral summer, and offered a control to the two dark caves. The composition of the resident microbial communities was assessed using 16S rRNA and ITS libraries, while metabolic and functional characteristics were analyzed by culturing. The latter results are presented by Anitori et al. (this session). The three cave soils displayed very low (Warren, Warren West) or moderate division-level diversity, with distinct communities in each environment. Acidobacteria was the only phylum detected in all three caves, and was a major component of each library. The phototroph-containing phyla Cyanobacteria, Chloroflexi, and Chlorophyta (latter eukaryotic) were only seen in Harry's Dream. A number of phyla whose members are known to oxidize Mn(II) or Fe

  9. Active Deformation of Etna Volcano Combing IFSAR and GPS data

    NASA Technical Reports Server (NTRS)

    Lundgren, Paul

    1997-01-01

    The surface deformation of an active volcano is an important indicator of its eruptive state and its hazard potential. Mount Etna volcano in Sicily is a very active volcano with well documented eruption episodes.

  10. Evidences for higher nocturnal seismic activity at the Mt. Vesuvius

    NASA Astrophysics Data System (ADS)

    Mazzarella, Adriano; Scafetta, Nicola

    2016-07-01

    We analyze hourly seismic data measured at the Osservatorio Vesuviano Ovest (OVO, 1972-2014) and at the Bunker Est (BKE, 1999-2014) stations on the Mt. Vesuvius. The OVO record is complete for seismic events with magnitude M ≥ 1.9. We demonstrate that before 1996 this record presents a daily oscillation that nearly vanishes afterwards. To determine whether a daily oscillation exists in the seismic activity of the Mt. Vesuvius, we use the higher quality BKE record that is complete for seismic events with magnitude M ≥ 0.2. We demonstrate that BKE confirms that the seismic activity at the Mt. Vesuvius is higher during nighttime than during daytime. The amplitude of the daily oscillation is enhanced during summer and damped during winter. We speculate possible links with the cooling/warming diurnal cycle of the volcanic edifice, with external geomagnetic field and with magnetostriction, which stress the rocks. We find that the amplitude of the seismic daily cycle changes in time and has been increasing since 2008. Finally, we propose a seismic activity index to monitor the 24-hour oscillation that could be used to complement other methodologies currently adopted to determine the seismic status of the volcano to prevent the relative hazard.

  11. Italy: Mt. Etna

    Atmospheric Science Data Center

    2013-04-17

    article title:  Multi-angle Portrayals of Mt. Etna's Plume     View Larger Image ... (MISR) capture the energetic eruption of Sicily's Mount Etna volcano on October 29, 2002. Viewing Etna's eruptive activities at MISR's ...

  12. Endogenous growth of persistently active volcanoes

    NASA Astrophysics Data System (ADS)

    Francis, Peter; Oppenheimer, Clive; Stevenson, David

    1993-12-01

    LAVA lakes and active strombolian vents have persisted at some volcanoes for periods exceeding the historic record. They liberate prodigious amounts of volatiles and thermal energy but erupt little lava, a paradox that raises questions about how volcanoes grow. Although long-lasting surface manifestations can be sustained by convective exchange of magma with deeper reservoirs, residence times of magmas beneath several basaltic volcanoes are & sim10-100 years1,2, indicating that where surface activity continues for more than 100-1,000 years, the reservoirs are replenished by new magma. Endogenous growth of Kilauea volcano (Hawaii) through dyke intrusion and cumulate formation is a well-understood consequence of the steady supply of mantle-derived magma3,4. As we show here, inferred heat losses from the Halemaumau lava lake indicate a period of dominantly endogenous growth of Kilauea volcano during the nineteenth century. Moreover, heat losses and degassing rates for several other volcanoes, including Stromboli, also indicate cryptic influxes of magma that far exceed visible effluxes of lavas. We propose that persistent activity at Stromboli, and at other volcanoes in different tectonic settings, is evidence of endogenous growth, involving processes similar to those at Kilauea.

  13. 226Ra or 226Ra/Ba dating of Holocene volcanic rocks: application to Mt. Etna and Merapi volcanoes

    NASA Astrophysics Data System (ADS)

    Condomines, M.; Gauthier, P. J.; Tanguy, J. C.; Gertisser, R.; Thouret, J. C.; Berthommier, P.; Camus, G.

    2005-02-01

    This paper shows how 226Ra- 230Th disequilibria can be used to date Holocene volcanic rocks from some well selected volcanoes. A systematic study of these disequilibria on historical or well-dated volcanic samples is indeed first required to test the applicability of this method. Two examples are described here to illustrate its potential. In the case of Mt. Etna, the good correlation observed between ( 226Ra) 0 activities at the time of eruption and Th contents in lava flows from the last two millennia [M. Condomines, J.C. Tanguy, V. Michaud, Magma dynamics at Mt. Etna: constraints from U-Th-Ra-Pb radioactive disequilibria and Sr isotopes in historical lavas, Earth Planet. Sci. Lett. 132 (1995) 25-41] is used to infer the ages of several newly analysed lava flows. The calculated ages are in good agreement with those deduced from the archaeomagnetic curve describing the variation of the geomagnetic field direction in southern Italy [J.C. Tanguy, I. Bucur, J.F.C. Thompson, Geomagnetic secular variation in Sicily and revised ages of historic lavas from Mt. Etna, Nature 318 (1985) 453-455, J.C. Tanguy, M. Le Goff, V. Chillemi, A. Paiotti, C. Principe, S. La Delfa, G. Patane, Variation séculaire de la direction du champ géomagnétique enregistrée par les laves de l'Etna et du Vésuve pendant les deux derniers millénaires, C. R. Acad. Sci. Paris 329 (1999) 557-564, J.C. Tanguy, M. Le Goff, C. Principe, S. Arrighi, V. Chillemi, A. Paiotti, S. La Delfa, G. Patane, Archaeomagnetic dating of Mediterranean volcanics of the last 2100 years: validity and limits. Earth Planet. Sci. Lett. 211 (2003) 111-124]. We also present a whole set of new U-series data on historical, recent, and older samples from Merapi (Indonesia), and show that the ( 226Ra)/Ba ratio has probably maintained a quasi-steady state value during at least the past four millennia, and can be used to infer the ( 226Ra) 0/Ba ratio of old volcanics at the time of eruption, and thus their ages. Comparison with

  14. A volcano at work: the rapidly evolving landforms of Mt Etna documented through DEMs analysis

    NASA Astrophysics Data System (ADS)

    Tarquini, Simone; Favalli, Massimiliano; Fornaciai, Alessandro

    2016-04-01

    Volcanoes are characterized by rapid morphological changes in a continuously evolving landscape. In recent years, airborne LIDAR surveys have been repeatedly carried out to document the constructive and the destructive processes which modify the topography at Mount Etna (Italy), one of the most active volcanoes on Earth. In a few cases, time series of high resolution topographies have been acquired during ongoing effusive eruptions, and this extraordinary data allowed the systematic characterization of the morphology of active lava channels and the identification of a distinctive pulsating dynamic in lava flux. Furthermore, time series of topographies spaced several years allowed the quantification of the growth and of local collapses of summit craters, as well as the erosion of cinder cones formed during flank eruptions in 2001-2002. Overall, the availability of high resolution topographies boosted dramatically our understanding of volcanic processes, also allowing a better assessment of the related hazard. The present contribution is a review of several works spanning nearly a decade.

  15. Shallow magma-mingling-driven Strombolian eruptions at Mt. Yasur volcano, Vanuatu

    NASA Astrophysics Data System (ADS)

    Kremers, S.; Hanson, J. B.; Lavallee, Y.; Hess, K.-U.; Chevrel, M. O.; Wassermann, J.; Dingwell, D. B.

    2012-04-01

    Mt. Yasur volcano (Tanna, Vanuatu) has been increasingly recognized for its high-frequency Strombolian eruptions for the last 300 years. Currently, this activity takes place at three vents with highly varying recurrence rates, denoted as A, B and C from south to north, respectively. During a 6-week field campaign in August-September 2008, we installed four seismic and four infrasound arrays at site to record seismic and acoustic signals. Two Doppler-Radars measured the exit velocities of the erupted material, and a thermal camera was used to determine the temperature at the vent mouth. At the time of the fieldwork, the three active craters showed very different styles of activity. Crater A, the most active vent, had an eruption recurrence of under a minute. Crater B showed very irregular ash-venting with variable periodicity ranging between minutes and days, while crater C was producing the strongest eruptions approximately every 10 minutes. We sampled the eruptive products of craters A and C for further analysis in the lab. In total, three bombs were collected, two were juvenile and one exotic lithic material, in order to investigate the chemical, physical, rheological and textural variations in the erupted products from the different craters. The collected basaltic-andesite scoria bombs exhibit a relatively constant whole rock major element geochemistry (~56 wt.% SiO2). Petrographic texture and structure analysis revealed a large variation in porosity (~30 - 78 %) and microlite content. Both juvenile bombs revealed bimodal textures; that is, they contain regions of microlite-free glass (sideromelane) and regions of microlite-rich groundmass which suggests the occurrence of mingling and mixing of magma batches with different crystallization histories. In the exotic sample, almost no regions of sideromelane are observed; instead, the sample is nearly entirely crystallized. Interstitial glass chemistry from electron microprobe analysis shows a range of glass

  16. Continuous gravity observations at active volcanoes through superconducting gravimeters

    NASA Astrophysics Data System (ADS)

    Carbone, Daniele; Greco, Filippo

    2016-04-01

    Continuous gravity measurements at active volcanoes are usually taken through spring gravimeters that are easily portable and do not require much power to work. However, intrinsic limitations dictate that, when used in continuous, these instruments do not provide high-quality data over periods longer than some days. Superconducting gravimeters (SG), that feature a superconducting sphere in a magnetic field as the proof mass, provide better-quality data than spring gravimeters, but are bigger and need mains electricity to work, implying that they cannot be installed close to the active structures of high volcanoes. An iGrav SG was installed on Mt. Etna (Italy) in September 2014 and has worked almost continuously since then. It was installed about 6km from the active craters in the summit zone of the volcano. Such distance is normally too much to observe gravity changes due to relatively fast (minutes to days) volcanic processes. Indeed, mass redistributions in the shallowest part of the plumbing system induce short-wavelength gravity anomalies, centered below the summit craters. Nevertheless, thanks to the high precision and long-term stability of SGs, it was possible to observe low-amplitude changes over a wide range of timescales (minutes to months), likely driven by volcanic activity. Plans are in place for the implementation of a mini-array of SGs at Etna.

  17. Cognate xenoliths in Mt. Etna lavas: witnesses of the high-velocity body beneath the volcano

    NASA Astrophysics Data System (ADS)

    Corsaro, Rosa Anna; Rotolo, Silvio Giuseppe; Cocina, Ornella; Tumbarello, Gianvito

    2014-01-01

    Various xenoliths have been found in lavas of the 1763 ("La Montagnola"), 2001, and 2002-03 eruptions at Mt. Etna whose petrographic evidence and mineral chemistry exclude a mantle origin and clearly point to a cognate nature. Consequently, cognate xenoliths might represent a proxy to infer the nature of the high-velocity body (HVB) imaged beneath the volcano by seismic tomography. Petrography allows us to group the cognate xenoliths as follows: i) gabbros with amphibole and amphibole-bearing mela-gabbros, ii) olivine-bearing leuco-gabbros, iii) leuco-gabbros with amphibole, and iv) Plg-rich leuco gabbros. Geobarometry estimates the crystallization pressure of the cognate xenoliths between 1.9 and 4.1 kbar. The bulk density of the cognate xenoliths varies from 2.6 to 3.0 g/cm3. P wave velocities (V P ), calculated in relation to xenolith density, range from 4.9 to 6.1 km/s. The integration of mineralogical, compositional, geobarometric data, and density-dependent V P with recent literature data on 3D V P seismic tomography enabled us to formulate the first hypothesis about the nature of the HVB which, in the depth range of 3-13 km b.s.l., is likely made of intrusive gabbroic rocks. These are believed to have formed at the "solidification front", a marginal zone that encompasses a deep region (>5 km b.s.l.) of Mt. Etna's plumbing system, within which magma crystallization takes place. The intrusive rocks were afterwards fragmented and transported as cognate xenoliths by the volatile-rich and fast-ascending magmas of the 1763 "La Montagnola", 2001 and 2002-03 eruptions.

  18. Late Pleistocene glaciation of the Mt Giluwe volcano, Papua New Guinea

    USGS Publications Warehouse

    Barrows, T.T.; Hope, G.S.; Prentice, M.L.; Fifield, L.K.; Tims, S.G.

    2011-01-01

    The Mt Giluwe shield volcano was the largest area glaciated in Papua New Guinea during the Pleistocene. Despite minimal cooling of the sea surface during the last glacial maximum, glaciers reached elevations as low as 3200 m. To investigate changes in the extent of ice through time we have re-mapped evidence for glaciation on the southwest flank of Mt Giluwe. We find that an ice cap has formed on the flanks of the mountain on at least three, and probably four, separate occasions. To constrain the ages of these glaciations we present 39 new cosmogenic 36Cl exposure ages complemented by new radiocarbon dates. Direct dating of the moraines identifies that the maximum extent of glaciation on the mountain was not during the last glacial maximum as previously thought. In conjunction with existing potassium/argon and radiocarbon dating, we recognise four distinct glacial periods between 293-306 ka (Gogon Glaciation), 136-158 ka (Mengane Glaciation), centred at 62 ka (Komia Glaciation) and from >20.3-11.5 ka (Tongo Glaciation). The temperature difference relative to the present during the Tongo Glaciation is likely to be of the order of at least 5 ??C which is a minimum difference for the previous glaciations. During the Tongo Glaciation, ice was briefly at its maximum for less than 1000 years, but stayed near maximum levels for nearly 4000 years, until about 15.4 ka. Over the next 4000 years there was more rapid retreat with ice free conditions by the early Holocene. ?? 2011 Elsevier Ltd.

  19. Insights into the dynamics of Mt Etna volcano from gravity and DInSar observations

    NASA Astrophysics Data System (ADS)

    Del Negro, C.; Sansosti, E.; Greco, F.; Pepe, A.; Currenti, G.; Solaro, G.; Napoli, R.; Pepe, S.; Pistorio, A.

    2012-04-01

    18-years (September 1994 - October 2011) gravity and ground deformation sequences, recorded at Etna volcano along an East-West trending profile of 19 stations on the southern flank at a quasi-monthly sampling rate, are presented. Over the last two decades, frequent fountaining events and several flank eruptions occurred at Mt Etna. We use the SBAS DInSAR technique to analyze the temporal evolution of surface displacements by inverting a sequence of interferograms to form a deformation time series. Height changes, evaluated by DInSAR data during the entire period, show modest vertical variations unable to produce significant gravity changes. However, the gravity data set was corrected for the small height variations using the experimental free-air gravity gradients measured at two stations of the profile. The residual space-time gravity image displayed some gravity increase/decrease cycles, mostly affecting the central and eastern stations of the East-West profile. We attributed these gravity cycles to mass redistribution processes mainly located at a depth of 2-4 km bsl in a region recognized to be a preferential pathway of magma rising and an intermediate zone of magma storage/withdrawal. In the latter period 2008-2011, when several paroxysmal events occurred from the South East crater, the gravity and height deformation patterns show many similarities with the previous period 1995-2000 encompassing a long series of paroxysmal episodes that preceded the violent and dramatic explosive/effusive eruptions of 2001 and 2002-2003.

  20. Stable isotope ratios in meteoric recharge and groundwater at Mt. Vulture volcano, southern Italy

    NASA Astrophysics Data System (ADS)

    Paternoster, M.; Liotta, M.; Favara, R.

    2008-01-01

    SummaryA rain gauge network consisting of five sites located at different altitudes, ranging from 320 to 1285 m.a.s.l., was installed at Mt. Vulture volcano (southern Italy). Rain water samples were collected monthly over a two-year period and their isotopic composition (δ 18O and δD) was analyzed. During the same period, circulating groundwater was sampled from 24 springs and wells distributed throughout the study area. Monthly isotopic composition values were used to determine the local meteoric water line (LMWL). Its slope is slightly lower than the relationship defined by Longinelli and Selmo (Longinelli, A., Selmo, E., 2003. Isotopic composition of precipitation in Italy: a first overall map. J. Hydrol. 270, 75-88) for southern Italy. The groundwater samples analyzed were distributed essentially along the LMWL. The weighted local meteoric water line (WLMWL), defined through the mean values weighted by the rainfall amount, however, may define in a short range the meteoric end-member in the local hydrological cycle more precisely. Since most of the groundwater sampling locations do not show seasonal variations in their stable isotope values, the flow system appears to be relatively homogeneous. The mean altitude of the recharge by rainfall infiltration was estimated on the basis of the local vertical isotopic gradient δ 18O. A few springs, which show anomalous isotopic values, reveal more regional circulation systems, associated with tectonic structures responsible for the ascent of deeper water.

  1. Glacier-volcano interactions in the north crater of Mt. Wrangell, Alaska

    USGS Publications Warehouse

    Abston, Carl; Motyka, Roman J.; McNutt, Stephen; Luthi, Martin; Truffer, Martin

    2007-01-01

    Glaciological and related observations from 1961 to 2005 at the summit of Mt Wrangell (62.008 N, 144.028W; 4317 m a.s.l.), a massive glacier-covered shield volcano in south-central Alaska, show marked changes that appear to have been initiated by the Great Alaska Earthquake (MW = 9.2) of 27 March 1964. The 4 x 6 km diameter, ice-filled Summit Caldera with several post-caldera craters on its rim, comprises the summit region where annual snow accumulation is 1–2 m of water equivalent and the mean annual temperature, measured 10 m below the snow surface, is –20°C. Precision surveying, aerial photogrammetry and measurements of temperature and snow accumulation were used to measure the loss of glacier ice equivalent to about 0.03 km3 of water from the North Crater in a decade. Glacier calorimetry was used to calculate the associated heat flux, which varied within the range 20–140W m–2; total heat flow was in the range 20–100 MW. Seismicity data from the crater’s rim show two distinct responses to large earthquakes at time scales from minutes to months. Chemistry of water and gas from fumaroles indicates a shallow magma heat source and seismicity data are consistent with this interpretation.

  2. Seismic exploration of Fuji volcano with active sources in 2003

    NASA Astrophysics Data System (ADS)

    Oikawa, J.; Kagiyama, T.; Tanaka, S.; Miyamachi, H.; Tsutsui, T.; Ikeda, Y.; Katayama, H.; Matsuo, N.; Oshima, H.; Nishimura, Y.; Yamamoto, K.; Watanabe, T.; Yamazaki, F.

    2004-12-01

    the Tanzawa Range to the east. This uplifted body is formed by plate subduction and collision with the Izu Peninsula, and is believed to have influence at significant depth. This is considered to be the reason for the change in the geologic structure beneath Fuji volcano from west to east. The dome structure of the bedrock layer (second layer) directly beneath the summit is considered to have formed in the initial period of volcanic activity that formed Mt. Fuji, leading to the subsequent formation of Komitake volcano, Ko-Fuji volcano and the present day Fuji volcano.

  3. GlobVolcano pre-operational services for global monitoring active volcanoes

    NASA Astrophysics Data System (ADS)

    Tampellini, Lucia; Ratti, Raffaella; Borgström, Sven; Seifert, Frank Martin; Peltier, Aline; Kaminski, Edouard; Bianchi, Marco; Branson, Wendy; Ferrucci, Fabrizio; Hirn, Barbara; van der Voet, Paul; van Geffen, J.

    2010-05-01

    ), Stromboli and Volcano (Italy), Hilo (Hawai), Mt. St. Helens (United States), CTM (Coherent Target Monitoring): Cumbre Vieja (La Palma) To generate products either Envisat ASAR, Radarsat 1or ALOS PALSAR data have been used. Surface Thermal Anomalies Volcanic hot-spots detection, radiant flux and effusion rate (where applicable) calculation of high temperature surface thermal anomalies such as active lava flow, strombolian activity, lava dome, pyroclastic flow and lava lake can be performed through MODIS (Terra / Aqua) MIR and TIR channels, or ASTER (Terra), HRVIR/HRGT (SPOT4/5) and Landsat family SWIR channels analysis. ASTER and Landsat TIR channels allow relative radiant flux calculation of low temperature anomalies such as lava and pyroclastic flow cooling, crater lake and low temperature fumarolic fields. MODIS, ASTER and SPOT data are processed to detect and measure the following volcanic surface phenomena: Effusive activity Piton de la Fournaise (Reunion Island); Mt Etna (Italy). Lava dome growths, collapses and related pyroclastic flows Soufrière Hills (Montserrat); Arenal - (Costa Rica). Permanent crater lake and ephemeral lava lake Karthala (Comores Islands). Strombolian activity Stromboli (Italy). Low temperature fumarolic fields Nisyros (Greece), Vulcano (Italy), Mauna Loa (Hawaii). Volcanic Emission The Volcanic Emission Service is provided to the users by a link to GSE-PROMOTE - Support to Aviation Control Service (SACS). The aim of the service is to deliver in near-real-time data derived from satellite measurements regarding SO2 emissions (SO2 vertical column density - Dobson Unit [DU]) possibly related to volcanic eruptions and to track the ash injected into the atmosphere during a volcanic eruption. SO2 measurements are derived from different satellite instruments, such as SCIAMACHY, OMI and GOME-2. The tracking of volcanic ash is accomplished by using SEVIRI-MSG data and, in particular, the following channels VIS 0.6 and IR 3.9, and along with IR8.7, IR 10

  4. Factors determining forest diversity and biomass on a tropical volcano, Mt. Rinjani, Lombok, Indonesia.

    PubMed

    Dossa, Gbadamassi G O; Paudel, Ekananda; Fujinuma, Junichi; Yu, Haiying; Chutipong, Wanlop; Zhang, Yuan; Paz, Sherryl; Harrison, Rhett D

    2013-01-01

    Tropical volcanoes are an important but understudied ecosystem, and the relationships between plant species diversity and compositional change and elevation may differ from mountains created by uplift, because of their younger and more homogeneous soils. We sampled vegetation over an altitudinal gradient on Mt. Rinjani, Lombok, Indonesia. We modeled alpha- (plot) and beta- (among plot) diversity (Fisher's alpha), compositional change, and biomass against elevation and selected covariates. We also examined community phylogenetic structure across the elevational gradient. We recorded 902 trees and shrubs among 92 species, and 67 species of ground-cover plants. For understorey, subcanopy and canopy plants, an increase in elevation was associated with a decline in alpha-diversity, whereas data for ground-cover plants suggested a hump-shaped pattern. Elevation was consistently the most important factor in determining alpha-diversity for all components. The alpha-diversity of ground-cover vegetation was also negatively correlated with leaf area index, which suggests low light conditions in the understorey may limit diversity at lower elevations. Beta-diversity increased with elevation for ground-cover plants and declined at higher elevations for other components of the vegetation. However, statistical power was low and we could not resolve the relative importance to beta-diversity of different factors. Multivariate GLMs of variation in community composition among plots explained 67.05%, 27.63%, 18.24%, and 19.80% of the variation (deviance) for ground-cover, understorey, subcanopy and canopy plants, respectively, and demonstrated that elevation was a consistently important factor in determining community composition. Above-ground biomass showed no significant pattern with elevation and was also not significantly associated with alpha-diversity. At lower elevations communities had a random phylogenetic structure, but from 1600 m communities were phylogenetically clustered

  5. Factors determining forest diversity and biomass on a tropical volcano, Mt. Rinjani, Lombok, Indonesia.

    PubMed

    Dossa, Gbadamassi G O; Paudel, Ekananda; Fujinuma, Junichi; Yu, Haiying; Chutipong, Wanlop; Zhang, Yuan; Paz, Sherryl; Harrison, Rhett D

    2013-01-01

    Tropical volcanoes are an important but understudied ecosystem, and the relationships between plant species diversity and compositional change and elevation may differ from mountains created by uplift, because of their younger and more homogeneous soils. We sampled vegetation over an altitudinal gradient on Mt. Rinjani, Lombok, Indonesia. We modeled alpha- (plot) and beta- (among plot) diversity (Fisher's alpha), compositional change, and biomass against elevation and selected covariates. We also examined community phylogenetic structure across the elevational gradient. We recorded 902 trees and shrubs among 92 species, and 67 species of ground-cover plants. For understorey, subcanopy and canopy plants, an increase in elevation was associated with a decline in alpha-diversity, whereas data for ground-cover plants suggested a hump-shaped pattern. Elevation was consistently the most important factor in determining alpha-diversity for all components. The alpha-diversity of ground-cover vegetation was also negatively correlated with leaf area index, which suggests low light conditions in the understorey may limit diversity at lower elevations. Beta-diversity increased with elevation for ground-cover plants and declined at higher elevations for other components of the vegetation. However, statistical power was low and we could not resolve the relative importance to beta-diversity of different factors. Multivariate GLMs of variation in community composition among plots explained 67.05%, 27.63%, 18.24%, and 19.80% of the variation (deviance) for ground-cover, understorey, subcanopy and canopy plants, respectively, and demonstrated that elevation was a consistently important factor in determining community composition. Above-ground biomass showed no significant pattern with elevation and was also not significantly associated with alpha-diversity. At lower elevations communities had a random phylogenetic structure, but from 1600 m communities were phylogenetically clustered

  6. Factors Determining Forest Diversity and Biomass on a Tropical Volcano, Mt. Rinjani, Lombok, Indonesia

    PubMed Central

    Dossa, Gbadamassi G. O.; Paudel, Ekananda; Fujinuma, Junichi; Yu, Haiying; Chutipong, Wanlop; Zhang, Yuan; Paz, Sherryl; Harrison, Rhett D.

    2013-01-01

    Tropical volcanoes are an important but understudied ecosystem, and the relationships between plant species diversity and compositional change and elevation may differ from mountains created by uplift, because of their younger and more homogeneous soils. We sampled vegetation over an altitudinal gradient on Mt. Rinjani, Lombok, Indonesia. We modeled alpha- (plot) and beta- (among plot) diversity (Fisher's alpha), compositional change, and biomass against elevation and selected covariates. We also examined community phylogenetic structure across the elevational gradient. We recorded 902 trees and shrubs among 92 species, and 67 species of ground-cover plants. For understorey, subcanopy and canopy plants, an increase in elevation was associated with a decline in alpha-diversity, whereas data for ground-cover plants suggested a hump-shaped pattern. Elevation was consistently the most important factor in determining alpha-diversity for all components. The alpha-diversity of ground-cover vegetation was also negatively correlated with leaf area index, which suggests low light conditions in the understorey may limit diversity at lower elevations. Beta-diversity increased with elevation for ground-cover plants and declined at higher elevations for other components of the vegetation. However, statistical power was low and we could not resolve the relative importance to beta-diversity of different factors. Multivariate GLMs of variation in community composition among plots explained 67.05%, 27.63%, 18.24%, and 19.80% of the variation (deviance) for ground-cover, understorey, subcanopy and canopy plants, respectively, and demonstrated that elevation was a consistently important factor in determining community composition. Above-ground biomass showed no significant pattern with elevation and was also not significantly associated with alpha-diversity. At lower elevations communities had a random phylogenetic structure, but from 1600 m communities were phylogenetically clustered

  7. Experimental constraints on the origin of pahoehoe "cicirara" lavas at Mt. Etna Volcano (Sicily, Italy)

    NASA Astrophysics Data System (ADS)

    Vetere, F.; Mollo, S.; Giacomoni, P. P.; Iezzi, G.; Coltorti, M.; Ferlito, C.; Holtz, F.; Perugini, D.; Scarlato, P.

    2015-05-01

    We present results from phase equilibria experiments conducted on the most primitive pahoehoe "cicirara" trachybasaltic lava flow ever erupted at Mt. Etna Volcano. This lava is characterized by a pahoehoe morphology in spite of its high content of phenocrysts and microphenocrysts (>40 vol%) with the occurrence of centimetre-sized plagioclases (locally named cicirara for their chick-pea-like appearance). Our experiments have been performed at 400 MPa, 1100-1150 °C and using H2O and CO2 concentrations corresponding to the water-undersaturated crystallization conditions of Etnean magmas. Results show that olivine does not crystallize from the melt, whereas titanomagnetite is the liquidus phase followed by clinopyroxene or plagioclase as a function of melt-water concentration. This mineralogical feature contrasts with the petrography of pahoehoe cicirara lavas suggesting early crystallization of olivine and late formation of titanomagnetite after plagioclase and/or in close association with clinopyroxene. The lack of olivine produces MgO-rich melt compositions that do not correspond to the evolutionary behaviour of cicirara magmas. Moreover, in a restricted thermal path of 50 °C and over the effect of decreasing water concentrations, we observe abundant plagioclase and clinopyroxene crystallization leading to trace element enrichments unlikely for natural products. At the same time, the equilibrium compositions of our mineral phases are rather different from those of natural cicirara phenocrysts and microphenocrysts. The comparison between our water-undersaturated data and those from previous degassing experiments conducted on a similar Etnean trachybasaltic composition demonstrates that pahoehoe cicirara lavas originate from crystal-poor, volatile-rich magmas undergoing abundant degassing and cooling in the uppermost part of the plumbing system and at subaerial conditions where most of the crystallization occurs after the development of pahoehoe surface crusts.

  8. Monitoring volcano activity through Hidden Markov Model

    NASA Astrophysics Data System (ADS)

    Cassisi, C.; Montalto, P.; Prestifilippo, M.; Aliotta, M.; Cannata, A.; Patanè, D.

    2013-12-01

    During 2011-2013, Mt. Etna was mainly characterized by cyclic occurrences of lava fountains, totaling to 38 episodes. During this time interval Etna volcano's states (QUIET, PRE-FOUNTAIN, FOUNTAIN, POST-FOUNTAIN), whose automatic recognition is very useful for monitoring purposes, turned out to be strongly related to the trend of RMS (Root Mean Square) of the seismic signal recorded by stations close to the summit area. Since RMS time series behavior is considered to be stochastic, we can try to model the system generating its values, assuming to be a Markov process, by using Hidden Markov models (HMMs). HMMs are a powerful tool in modeling any time-varying series. HMMs analysis seeks to recover the sequence of hidden states from the observed emissions. In our framework, observed emissions are characters generated by the SAX (Symbolic Aggregate approXimation) technique, which maps RMS time series values with discrete literal emissions. The experiments show how it is possible to guess volcano states by means of HMMs and SAX.

  9. Dynamics of mild strombolian activity on Mt. Etna

    NASA Astrophysics Data System (ADS)

    Pering, T. D.; Tamburello, G.; McGonigle, A. J. S.; Aiuppa, A.; James, M. R.; Lane, S. J.; Sciotto, M.; Cannata, A.; Patanè, D.

    2015-07-01

    Here we report the first measurements of gas masses released during a rare period of strombolian activity at the Bocca Nuova crater, Mt. Etna, Sicily. UV camera data acquired for 195 events over an ≈ 27 minute period (27th July 2012) indicate erupted SO2 masses ranging from ≈ 0.1 to ≈ 14 kg per event, with corresponding total gas masses of ≈ 0.1 to 74 kg. Thus, the activity was characterised by more frequent and smaller events than typically associated with strombolian activity on volcanoes such as Stromboli. Events releasing larger measured gas masses were followed by relatively long repose periods before the following burst, a feature not previously reported on from gas measurement data. If we assume that gas transport within the magma can be represented by a train of rising gas pockets or slugs, then the high frequency of events indicates that these slugs must have been in close proximity. In this case the longer repose durations associated with the larger slugs would be consistent with interactions between adjacent slugs leading to coalescence, a process expedited close to the surface by rapid slug expansion. We apply basic modelling considerations to the measured gas masses in order to investigate potential slug characteristics governing the observed activity. We also cross correlated the acquired gas fluxes with contemporaneously obtained seismic data but found no relationship between the series in line with the mild form of manifest explosivity.

  10. Volcanic risk metrics at Mt Ruapehu, New Zealand: some background to a probabilistic eruption forecasting scheme and a cost/benefit analysis at an open conduit volcano

    NASA Astrophysics Data System (ADS)

    Jolly, Gill; Sandri, Laura; Lindsay, Jan; Scott, Brad; Sherburn, Steve; Jolly, Art; Fournier, Nico; Keys, Harry; Marzocchi, Warner

    2010-05-01

    The Bayesian Event Tree for Eruption Forecasting software (BET_EF) is a probabilistic model based on an event tree scheme that was created specifically to compute long- and short-term probabilities of different outcomes (volcanic unrest, magmatic unrest, eruption, vent location and eruption size) at long-time dormant and routinely monitored volcanoes. It is based on the assumption that upward movements of magma in a closed conduit volcano will produce detectable changes in the monitored parameters at the surface. In this perspective, the goal of BET_EF is to compute probabilities by merging information from geology, models, past data and present monitoring measurements, through a Bayesian inferential method. In the present study, we attempt to apply BET_EF to Mt Ruapehu, a very active and well-monitored volcano exhibiting the typical features of open conduit volcanoes. In such conditions, current monitoring at the surface is not necessarily able to detect short term changes at depth that may occur only seconds to minutes before an eruption. This results in so-called "blue sky eruptions" of Mt Ruapehu (for example in September 2007), that are volcanic eruptions apparently not preceded by any presently detectable signal in the current monitoring. A further complication at Mt Ruapehu arises from the well-developed hydrothermal system and the permanent crater lake sitting on top of the magmatic conduit. Both the hydrothermal system and crater lake may act to mask or change monitoring signals (if present) that magma produces deeper in the edifice. Notwithstanding these potential drawbacks, we think that an attempt to apply BET_EF at Ruapehu is worthwhile, for several reasons. First, with the exception of a few "blue sky" events, monitoring data at Mt Ruapehu can be helpful in forecasting major events, especially if a large amount of magma is intruded into the edifice and becomes available for phreatomagmatic or magmatic eruptions, as for example in 1995-96. Secondly, in

  11. 3D modelling of Mt. Talaga Bodas Crater (Indonesia) by using terrestrial laser scanner for volcano hazard mitigation

    NASA Astrophysics Data System (ADS)

    Gumilar, Irwan; Abidin, Hasanuddin Z.; Putra, Andreas D.; Haerani, Nia

    2015-04-01

    Indonesia is a country with many volcanoes. Each volcano in Indonesia typically has its own crater characteristics. One of them is the Mt.Talaga Bodas, located in Garut, West Java. Researches regarding the crater characteristics are necessary for volcanic disaster mitigation process. One of them is the modelling of the shape of the crater. One of the methods that can be used to model the volcanic crater is using Terrestrial Laser Scanner (TLS). This research aims to create a 3 dimensional (3D) model of the crater of the Mt. Talaga Bodas, that hopefully can be utilized for volcanic disaster mitigation. The methodology used in this research is by obtaining the scanning data using TLS and GPS measurements to obtain the coordinates of the reference points. The data processing methods consist of several steps, namely target to target registration, filterization, georeference, meshing point cloud, surface making, drawing, and 3D modelling. These steps were done using the Cyclone 7 software, and also using 3DS MAX for 3D modelling. The result of this data processing is a 3D model of the crater of the Mt. Talaga Bodas which is similar with the real shape. The calculation result shows that the height of the crater is 62.522 m, the diameter of the crater is 467.231 m, and the total area is 2961054.652 m2. The main obstacle in this research is the dense vegetation which becomes the noise and affects the crater model.

  12. Insights into Proximal-Medial Pyroclastic Density Current Deposits at a High-Risk Glaciated Volcano: Mt Ruapehu, New Zealand

    NASA Astrophysics Data System (ADS)

    Cowlyn, J.; Kennedy, B.; Gravley, D. M.; Cronin, S. J.; Pardo, N.; Wilson, T. M.; Leonard, G.; Townsend, D.; Dufek, J.

    2014-12-01

    Pyroclastic density currents (PDCs) are a destructive volcanic hazard. Quantifying the types, frequency and magnitudes of PDC events in the geological record is essential for effective risk management. However small-medium volume valley-confined PDC deposits have low preservation potential, especially when emplaced in active drainages or onto snow or ice. Where PDC deposits are preserved they can be difficult to distinguish from other surficial deposits and are frequently misinterpreted or overlooked. This is the case at Mt. Ruapehu; a much visited, high-risk active volcano in New Zealand with no historical PDCs. Through systematic field observations we identified several young proximal-medial andesitic PDC deposits exposed on Ruapehu's eastern flanks. The oldest deposits (Ohinewairua PDCs, <13.6 ka) are massive pumice-rich deposits that are preserved at least 7km from source (North Crater) and correlate with Ruapehu's largest plinian eruptions. Overlying these, the pumice-rich Pourahu PDC deposit reaches >10km from source (South Crater) and correlates with Ruapehu's last known plinian eruption (~11.6 ka). Several younger locally preserved PDC deposits (Tukino PDCs) with denser juvenile clasts represent proximal PDCs from smaller eruptions at South Crater. Finally, a variably welded, bedded deposit containing clasts of welded spatter is interpreted to represent multiple failures of near-vent (North Ruapehu) accumulations of erupted material. Here, PDC initiation appears to have been controlled by the topographic gradient and deposition rate, without requiring a collapsing eruption column. The Ruapehu deposits highlight the limited preservation of PDC deposits, which appears to be favoured at PDC margins. Lateral and vertical flow stratification means the resulting deposits may not then represent the bulk flow. Additionally, deposit textures, distributions, and associations with moraines indicate that many of Ruapehu's PDCs encountered glacial ice during transport

  13. Lifespans of Cascade Arc volcanoes

    NASA Astrophysics Data System (ADS)

    Calvert, A. T.

    2015-12-01

    Compiled argon ages reveal inception, eruptive episodes, ages, and durations of Cascade stratovolcanoes and their ancestral predecessors. Geologic mapping and geochronology show that most Cascade volcanoes grew episodically on multiple scales with periods of elevated behavior lasting hundreds of years to ca. 100 kyr. Notable examples include the paleomag-constrained, few-hundred-year-long building of the entire 15-20 km3 Shastina edifice at Mt. Shasta, the 100 kyr-long episode that produced half of Mt. Rainier's output, and the 30 kyr-long episode responsible for all of South and Middle Sister. Despite significant differences in timing and rates of construction, total durations of active and ancestral volcanoes at discrete central-vent locations are similar. Glacier Peak, Mt. Rainier, Mt. Adams, Mt. Hood, and Mt. Mazama all have inception ages of 400-600 ka. Mt. St. Helens, Mt. Jefferson, Newberry Volcano, Mt. Shasta and Lassen Domefield have more recent inception ages of 200-300 ka. Only the Sisters cluster and Mt. Baker have established eruptive histories spanning less than 50 kyr. Ancestral volcanoes centered 5-20 km from active stratocones appear to have similar total durations (200-600 kyr), but are less well exposed and dated. The underlying mechanisms governing volcano lifecycles are cryptic, presumably involving tectonic and plumbing changes and perhaps circulation cycles in the mantle wedge, but are remarkably consistent along the arc.

  14. Monitoring eruption activity using temporal stress changes at Mount Ontake volcano

    PubMed Central

    Terakawa, Toshiko; Kato, Aitaro; Yamanaka, Yoshiko; Maeda, Yuta; Horikawa, Shinichiro; Matsuhiro, Kenjiro; Okuda, Takashi

    2016-01-01

    Volcanic activity is often accompanied by many small earthquakes. Earthquake focal mechanisms represent the fault orientation and slip direction, which are influenced by the stress field. Focal mechanisms of volcano-tectonic earthquakes provide information on the state of volcanoes via stresses. Here we demonstrate that quantitative evaluation of temporal stress changes beneath Mt. Ontake, Japan, using the misfit angles of focal mechanism solutions to the regional stress field, is effective for eruption monitoring. The moving average of misfit angles indicates that during the precursory period the local stress field beneath Mt. Ontake was deviated from the regional stress field, presumably by stress perturbations caused by the inflation of magmatic/hydrothermal fluids, which was removed immediately after the expulsion of volcanic ejecta. The deviation of the local stress field can be an indicator of increases in volcanic activity. The proposed method may contribute to the mitigation of volcanic hazards. PMID:26892716

  15. Monitoring eruption activity using temporal stress changes at Mount Ontake volcano

    NASA Astrophysics Data System (ADS)

    Terakawa, Toshiko; Kato, Aitaro; Yamanaka, Yoshiko; Maeda, Yuta; Horikawa, Shinichiro; Matsuhiro, Kenjiro; Okuda, Takashi

    2016-02-01

    Volcanic activity is often accompanied by many small earthquakes. Earthquake focal mechanisms represent the fault orientation and slip direction, which are influenced by the stress field. Focal mechanisms of volcano-tectonic earthquakes provide information on the state of volcanoes via stresses. Here we demonstrate that quantitative evaluation of temporal stress changes beneath Mt. Ontake, Japan, using the misfit angles of focal mechanism solutions to the regional stress field, is effective for eruption monitoring. The moving average of misfit angles indicates that during the precursory period the local stress field beneath Mt. Ontake was deviated from the regional stress field, presumably by stress perturbations caused by the inflation of magmatic/hydrothermal fluids, which was removed immediately after the expulsion of volcanic ejecta. The deviation of the local stress field can be an indicator of increases in volcanic activity. The proposed method may contribute to the mitigation of volcanic hazards.

  16. Monitoring eruption activity using temporal stress changes at Mount Ontake volcano.

    PubMed

    Terakawa, Toshiko; Kato, Aitaro; Yamanaka, Yoshiko; Maeda, Yuta; Horikawa, Shinichiro; Matsuhiro, Kenjiro; Okuda, Takashi

    2016-01-01

    Volcanic activity is often accompanied by many small earthquakes. Earthquake focal mechanisms represent the fault orientation and slip direction, which are influenced by the stress field. Focal mechanisms of volcano-tectonic earthquakes provide information on the state of volcanoes via stresses. Here we demonstrate that quantitative evaluation of temporal stress changes beneath Mt. Ontake, Japan, using the misfit angles of focal mechanism solutions to the regional stress field, is effective for eruption monitoring. The moving average of misfit angles indicates that during the precursory period the local stress field beneath Mt. Ontake was deviated from the regional stress field, presumably by stress perturbations caused by the inflation of magmatic/hydrothermal fluids, which was removed immediately after the expulsion of volcanic ejecta. The deviation of the local stress field can be an indicator of increases in volcanic activity. The proposed method may contribute to the mitigation of volcanic hazards.

  17. Monitoring eruption activity using temporal stress changes at Mount Ontake volcano.

    PubMed

    Terakawa, Toshiko; Kato, Aitaro; Yamanaka, Yoshiko; Maeda, Yuta; Horikawa, Shinichiro; Matsuhiro, Kenjiro; Okuda, Takashi

    2016-01-01

    Volcanic activity is often accompanied by many small earthquakes. Earthquake focal mechanisms represent the fault orientation and slip direction, which are influenced by the stress field. Focal mechanisms of volcano-tectonic earthquakes provide information on the state of volcanoes via stresses. Here we demonstrate that quantitative evaluation of temporal stress changes beneath Mt. Ontake, Japan, using the misfit angles of focal mechanism solutions to the regional stress field, is effective for eruption monitoring. The moving average of misfit angles indicates that during the precursory period the local stress field beneath Mt. Ontake was deviated from the regional stress field, presumably by stress perturbations caused by the inflation of magmatic/hydrothermal fluids, which was removed immediately after the expulsion of volcanic ejecta. The deviation of the local stress field can be an indicator of increases in volcanic activity. The proposed method may contribute to the mitigation of volcanic hazards. PMID:26892716

  18. Mobility and fluxes of major, minor and trace metals during basalt weathering and groundwater transport at Mt. Etna volcano (Sicily)

    SciTech Connect

    Aiuppa, A.; Allard, P.; D'Alessandro, W.; Michel, A.; Parello, F.; Treuil, M.; Valenza, M.

    2000-06-01

    The concentrations and fluxes of major, minor and trace metals were determined in 53 samples of groundwaters from around Mt. Etna, in order to evaluate the conditions and extent of alkali basalt weathering by waters enriched in magma-derived CO{sub 2} and the contribution of aqueous transport to the overall metal discharge of the volcano. The authors show that gaseous input of magmatic volatile metals into the Etnean aquifer is small or negligible, being limited by cooling of the rising fluids. Basalt leaching by weakly acidic, CO{sub 2}-charged water is the overwhelming source of metals and appears to be more extensive in two sectors of the S-SW (Paterno) and E (Zafferana) volcano flanks, where out flowing groundwaters are the richest in metals and bicarbonate of magmatic origin. Thermodynamic modeling of the results allows evaluation of the relative mobility and chemical speciation of various elements during their partitioning between solid and liquid phases through the weathering process. At Mt. Etna, poorly mobile elements (Al, Th, Fe) are preferentially retained in the solid residue of weathering, while alkalis, alkaline earth and oxo-anion-forming elements (As, Se, Sb, Mo) are more mobile and released to the aqueous system. Transition metals display an intermediate behavior and are strongly dependent on either the redox conditions (Mn, Cr, V) or solid surface-related processes (V, Zn, Cu).

  19. Volcanoes

    ERIC Educational Resources Information Center

    Kunar, L. N. S.

    1975-01-01

    Describes the forces responsible for the eruptions of volcanoes and gives the physical and chemical parameters governing the type of eruption. Explains the structure of the earth in relation to volcanoes and explains the location of volcanic regions. (GS)

  20. Evaluation of the eruptive potential and probability in open conduit volcano (Mt Etna) based on soil CO2 flux measurements

    NASA Astrophysics Data System (ADS)

    De Gregorio, Sofia; Camarda, Marco

    2016-04-01

    The evaluation of the amount of magma that might be potentially erupted, i.e. the eruptive potential (EP), and the probability of eruptive event occurrence, i.e. eruptive probability (EPR) of active volcano is one of the most compelling and challenging topic addressed by the volcanology community in the last years. The evaluation of the EP in open conduit volcano is generally based on constant magma supply rate deduced by long-term series of eruptive rate. This EP computation gives good results on long-term (centuries) evaluations, but resulted less effective when short-term (years or months) estimations are needed. Actually the rate of magma supply can undergo changes both on long-term and short-term. At steady condition it can be supposed that the regular supply of magma determines an almost constant level of magma in the feeding system (FS) whereas episodic surplus of magma inputs, with respect the regular supply, can cause large variations in the magma level. Follow that the surplus of magma occasionally entered in the FS represents a supply of material that sooner or later will be disposed, i.e. it will be emitted. Afterwards the amount of surplus of magma inward the FS nearly corresponds to the amount of magma that must be erupted in order to restore the equilibrium. Further, larger is the amount of surplus of magma stored in the system higher is the energetic level of the system and its propensity to erupt or in other words its EPR. On the light of the above consideration herein, we present an innovative methodology to evaluate the EP based on the quantification of surplus of magma with respect the regular supply, progressively intruded in the FS. To estimate the surplus of magma supply we used soil CO2 emission data measured monthly at 130 sites in two peripheral areas of Mt Etna Volcano. Indeed as reported by many authors soil CO2 emissions in the areas are linked to magma supply dynamics and more, anomalous discharges of CO2 are ascribable to surplus of

  1. Edifice growth and collapse of the Pliocene Mt. Kenya: Evidence of large scale debris avalanches on a high altitude glaciated volcano

    NASA Astrophysics Data System (ADS)

    Schoorl, J. M.; Veldkamp, A.; Claessens, L.; van Gorp, W.; Wijbrans, J. R.

    2014-12-01

    The cyclic growth and destruction of the Late Cenozoic Stratovolcano Mt. Kenya have been reconstructed for its southeastern segment. At least three major debris avalanche deposits have been reconstructed and dated. The oldest deposits indicate an edifice collapse around 4.9 Ma (40Ar/39Ar), followed by a larger event around 4.1 Ma (40Ar/39Ar). The last and best preserved debris avalanche deposit, with still some morphological expression covering the whole 1214 km2 SE sector, occurred around 2.83 Ma (40Ar/39Ar). This very large debris avalanche event must have truncated the whole top of Mt. Kenya. Of the original typical hummocky relief, only local topographical depressions are still best visible and preserved. Using known geometric empirical parameters of the 3 preserved debris-avalanche deposits, the height of the sector collapse is estimated to be in the range of 5100-6500 m above the current height of 1000 m a.s.l. near the end lobe of the VDA deposits. This demonstrates that Mt. Kenya attained impressive altitudes during its main activity in the Pliocene, being one of the highest mountains in that time and was most probably covered by an ice cap. Correcting for the known net eastward tilting post eruptive uplift of approximately 500 m of the Mt. Kenya summit, our reconstruction indicates that an at least 5.6 to 7 km a.s.l. high active Mt. Kenya existed in the Pliocene landscape between 5.1 and 2.8 Ma. This volcano must have significantly contributed to regional environmental change, by catching rain on its eastern slopes and projecting a rain shadow towards the Kenya Rift valley in the west. The last major edifice collapse event around 2.8 Ma coincides with a major change in regional vegetation. This suggests that the truncating of Mt. Kenya may have caused significant changes in the local climate surrounding Mt. Kenya with possible implications for environmental change in the central Kenya Rift valley, the cradle of hominin evolution.

  2. Volcanoes

    SciTech Connect

    Decker, R.W.; Decker, B.

    1989-01-01

    This book describes volcanoes although the authors say they are more to be experienced than described. This book poses more question than answers. The public has developed interest and awareness in volcanism since the first edition eight years ago, maybe because since the time 120 volcanoes have erupted. Of those, the more lethal eruptions were from volcanoes not included in the first edition's World's 101 Most Notorious Volcanoes.

  3. Hybrid character and pre-eruptive events of Mt Amiata volcano (Italy) inferred from geochronological, petro-geochemical and isotopic data

    NASA Astrophysics Data System (ADS)

    Cadoux, Anita; Pinti, Daniele L.

    2009-01-01

    A new geochronological and geochemical study was carried out to better constrain the petrogenesis and eruptive history of Monte Amiata, a large Pleistocene trachydacitic volcano of Southern Tuscany. Previous studies suggested a magma mixing origin between calc-alkaline silicic melts from the Tuscan Magmatic Province (TMP) and potassic mafic melts like those found in the Roman Magmatic Province (RMP). Two eruptive episodes-the first at ca. 300 kyr, the second at ca. 200 kyr-were distinguished from the few available ages. However, both the involvement of a RMP-like melt as mafic end-member and the timing of volcanic activity remained to be ascertained. The K-Ar ages obtained on plagioclase, sanidine and glass separated from Mt Amiata volcanic rocks demonstrate the sanidine is the most suitable phase for K-Ar dating. Sanidine yields ages of 304-293 kyr for the basal trachydacitic unit (BTC), 298-280 kyr in the domes unit (DLC) and unexpected older ages of 312-308 kyr for the more mafic summit lava unit (OLL). A careful re-examination of the literature ages together with those obtained in this study shows that they tend to a common age of ca. 300 kyr whatever the volcanic unit. We interpret this as a reset of the K-Ar chronometer in response to a consequent recharge of the silicic magma reservoir by hot mafic melts. This recharge most probably triggered the first volcanic eruption of Mt Amiata magmas. In our model, we suppose an initially chemically-stratified magma chamber; the input of deep hot mafic melts reset the crystals clock and probably allowed the eruption of the huge amount of trachydacitic crystal mush. We propose that the controversial BTC unit could have emplaced during a non-explosive eruption if we consider either pre-eruption passive degassing or extrusion of the trachydacites as magmatic foam. First Pb isotopic data of mafic enclaves from the trachydacitic units, together with major and trace elements and new Sr and Nd data support the magma mixing as

  4. Making geochemical data representation simple: pattern classification applied to products of Mt Etna volcano

    NASA Astrophysics Data System (ADS)

    Corsaro, Rosa Anna; Falsaperla, Susanna; Langer, Horst

    2013-04-01

    We apply a pattern classification method based on Kohonen maps and fuzzy clustering to geochemical analyses of volcanic products erupted by Mt Etna during lava flows, Strombolian and lava-fountain activity. Two data sets are considered: the first one refer to volcanic products collected at Mt. Etna from 1995 to 2005; the second data set covers the time span from 2006 to 2012 during which important volcanic unrests (in 2006 and 2007-08) and 25 lava fountains (in 2011-12) occurred. For each sample, 13 major and trace elements are considered. The classifier provides an efficient identification of groups of volcanic products with similar geochemical composition. The potential benefits of the method for the visualization of multi-component characteristics of magma are presented. Unlike the many low-dimensional diagrams (78 possible combinations in conventional 2D graphs) required by classical analyses, our method offers the graphical visualization of the results in just a single picture, using a convenient color code. In addition, this graphical visualization allows us the rapid identification of the compositional features of each sample and their comparison with all products analyzed in the 16-year-long time span. This simplified representation of the multivariate data it is extremely useful to investigate on the development of geochemical properties of the erupted material in time. Using pattern classification on geochemical data collected at Etna from 1995-2005, Corsaro et al. (2013) highlight links between eruptive centers, which deliver a reliable picture of a multifaceted plumbing system in agreement with geochemical and geophysical evidence reported in the literature. Applying the classification method to the data collected from 2006 on, we analyze how the most recent eruptive products are related to this picture, investigating on time developments as well as similarities to data groups identified in the previous decade.

  5. Degassing Dynamics from Long-Period and Very-Long-Period Seismicity and Infrasound at Mt. Pagan Volcano

    NASA Astrophysics Data System (ADS)

    Lyons, J. J.; Haney, M. M.; Fee, D.; Werner, C. A.; Kern, C.; Kelly, P. J.

    2014-12-01

    Mt. Pagan is a small (570 m ASL), active basaltic cone filling a caldera that sits atop one of the largest (2160 km3) volcanoes in the Mariana Arc Front. A VEI 4 eruption in 1981 that forced the evacuation of the island was the most recent serious activity, although low-level activity persists with a robust degassing plume and occasional small ash explosions. A new monitoring network was installed in 2013, consisting of 7 intermediate band seismometers, 2 6-component infrasound arrays, and 2 web cameras. Additionally, 12 campaign broadband seismometers recorded for 10 months in 2013-2014. Crater-rim multi-GAS sampling and remote sensing of the volcanic plume indicate a shallowly degassing magmatic system producing ~600 tonnes/day of sulfur dioxide (SO2). The seismic activity to date is dominated by frequent long-period (LP) events (~1000 events/day) with energy peaked from 0.6-2 Hz. These events are accompanied by a 3 s very-long-period (VLP) signal in the infrasound. Continuous beamforming of waveforms from the infrasound arrays shows that degassing from the summit vent is an impressive source of nearly continuous, low frequency sound. The network has also recorded infrequent, extended (minutes duration), emergent seismo-acoustic signals associated with minor ash emissions. These small explosions are accompanied by VLP seismic signals with a period of 70 s and duration of ~200 s. In order to understand how the shallow conduit system produces nearly continuous degassing as well as discrete explosions, we performed full waveform inversions of the LP and VLP seismicity with a combination of campaign and permanent stations. The best-fit location for a 6 moment plus 3 force source mechanism lies at ~500 m beneath and at the western margin of the summit vent. The source time function is dominated by the diagonal components of the moment tensor with a minor contribution from the vertical single force. We suggest that these signals are caused by fluid transport through

  6. Living on Active Volcanoes - The Island of Hawai'i

    USGS Publications Warehouse

    Heliker, Christina; Stauffer, Peter H.; Hendley, James W.

    1997-01-01

    People on the Island of Hawai'i face many hazards that come with living on or near active volcanoes. These include lava flows, explosive eruptions, volcanic smog, damaging earthquakes, and tsunamis (giant seawaves). As the population of the island grows, the task of reducing the risk from volcano hazards becomes increasingly difficult. To help protect lives and property, U.S. Geological Survey (USGS) scientists at the Hawaiian Volcano Observatory closely monitor and study Hawai'i's volcanoes and issue timely warnings of hazardous activity.

  7. Trace element and isotopic variations from Mt. Vulture to Campanian volcanoes: constraints for slab detachment and mantle inflow beneath southern Italy

    NASA Astrophysics Data System (ADS)

    de Astis, G.; Kempton, P. D.; Peccerillo, A.; Wu, T. W.

    2006-03-01

    New Sr-Nd-Pb isotopic ratios and trace element data for volcanic mafic rocks outcropping along a E-W transect in southern Italy, from Mt. Vulture to Neapolitan volcanoes, are reported. The variation of LILE/HFSE, HFSE/HFSE and radiogenic isotopes along this transect indicates that all of these volcanoes contain both intra-plate and subduction-related signatures, with the former decreasing from Mt. Vulture to Campanian volcanoes. New data are also reported for the Paleocene alkaline rocks from Pietre Nere (Apulia foreland), which show isotopic ratios mostly overlapping the values for Mediterranean intra-plate volcanoes as well as the Eocene-Oligocene alkaline mafic lavas from the northern Adria plate. Pietre Nere provides evidence for an OIB mantle composition of FOZO-type, free of subduction influences, that is present beneath the Adria plate (Africa) before its collision with Europe. After this collision, and formation of the southern Apennines, westward inflow of mantle from the Adria plate to the Campanian area occurred, as a consequence of slab break off. Interaction of subduction components with inflowing Adria mantle generated hybrid sources beneath the Vulture-Campania area, which can explain the compositional features of both Mt. Vulture and the Campanian mafic rocks. Therefore, mafic magmas from these volcanoes represent variable degrees of mixing between different mantle components.

  8. Origin and transport of CH4 in two maar lakes fed by mantle-derived volatiles (Mt. Vulture volcano, Italy)

    NASA Astrophysics Data System (ADS)

    Caracausi, Antonio; Cosenza, Paolo; Favara, Rocco; Foresta Martin, Luigi; Galli, Nunzio; Grassa, Fausto; Nuccio, Pasquale Mario; Paternoster, Michele; Riccobono, Giuseppe

    2014-05-01

    It has been assessed that lakes contribute 6 to 16% to global CH4 emission in atmosphere. Accumulation of CH4 in the water is strongly dependent on the input of gas and the dynamic of the lake's water. Lakes located on tectonically and volcanically active areas (e.g., Kivu, Nyos) generally contain relevant amount of mantle-derived volatiles. This generated an open debate on the origin of CO2 and CH4 in volcanic lakes because the complex bio-geological cycling of these two gases. This study is a part of larger investigation carried out on two maar lakes (LPM and LGM) formed about 140.000 years ago during the last eruption of Mt. Vulture (Italy). In spite of it generally is considered to be extinct, both lakes are characterized by an active inflow of mantle-derived fluids (Caracausi et al., 2013). Although the two lakes are only 150 m apart, their respective dynamics are different being LPM a meromictic lake, while LGM a monomictic one (Caracausi et al., 2013). The stagnant waters of LPM are enriched in CO2 and CH4 but the total gas pressure is below the hydrostatic pressure, so that the transfer of gas towards the surface doesn't occur via bubbles. Vertical profiles at LPM reveal a marked decrease of the dissolved CH4 content in the shallower layers due to aerated water. The amount of CH4 dissolved in LGM water column shows seasonal variations: in autumn it is comparable to that of LPM at the same depth; in winter CH4 is fully released into atmosphere through overturn of waters. C and H isotopes of CH4 clearly indicate in both lakes an active production both by acetoclastic methanogenesis and by CO2 reduction although with different proportions. Historical reports describe intense episodic releases of gases from both lakes occurred up to about 200 years ago. Caracausi et al. (2013) highlight that these events could be caused by a release of mantle-derived CO2 accumulated in the crust or directly linked to magma degassing. In the present study the knowledge gained

  9. Active monitoring at an active volcano: amplitude-distance dependence of ACROSS at Sakurajima Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Yamaoka, Koshun; Miyamachi, Hiroki; Watanabe, Toshiki; Kunitomo, Takahiro; Michishita, Tsuyoshi; Ikuta, Ryoya; Iguchi, Masato

    2014-12-01

    First testing of volcanic activity monitoring with a system of continuously operatable seismic sources, named ACROSS, was started at Sakurajima Volcano, Japan. Two vibrators were deployed on the northwestern flank of the volcano, with a distance of 3.6 km from the main crater. We successfully completed the testing of continuous operation from 12 June to 18 September 2012, with a single frequency at 10.01 Hz and frequency modulation from 10 to 15 Hz. The signal was detected even at a station that is 28 km from the source, establishing the amplitude decay relation as a function of distance in the region in and around Sakurajima Volcano. We compare the observed amplitude decay with the prediction that was made before the deployment as a feasible study. In the prediction, we used the existing datasets by an explosion experiment in Sakurajima and the distance-dependent amplitude decay model that was established for the ACROSS source in the Tokai region. The predicted amplitude in Sakurajima is systematically smaller than that actually observed, but the dependence on distance is consistent with the observation. On the basis of the comparison of the noise level in Sakurajima Volcano, only 1-day stacking of data is necessary to reduce the noise to the level that is comparable to the signal level at the stations in the island.

  10. Seismic studies at the Mt. Hood Volcano, northern Cascade Range, Oregon

    USGS Publications Warehouse

    Green, Susan Molly; Weaver, Craig S.; Iyer, Hariharaiyer Mahadeva

    1979-01-01

    A sixteen station telemetered seismic network was established in the Mt. Hood, Oregon area to monitor local seismicity and to study crustal and upper mantle structure. The network was in operation 13 months, and recorded 10 local earthquakes, 25 regional events, and 300 teleseisms. A series of construction blasts were recorded and used to define an average upper crustal velocity of 5.4 km/s in the region. All local earthquakes occurred beneath Mt. Hood at shallow depths and roughly define a zone striking north-northwest beneath the mountain. The largest earthquake was a magnitude 3.4 event which had a strike-slip focal mechanism. The other events had magnitudes (ML) less than 2.0. P-wave travel time residuals from teleseismic events show a 0.5 second decrease in travel time from east to west across the Cascade Range. No travel time anomalies are associated directly with Mt. Hood.

  11. Evaluation of noise level and site response at Mt. Etna volcano and Aeolian Islands

    NASA Astrophysics Data System (ADS)

    D Amico, S.; Giampiccolo, E.; Maiolino, V.; Patanè, D.; Ursino, A.

    2003-04-01

    The aim of this work was to test the quality of the sites where the stations of the INGV-CT seismic network are installed. This because most of the installations will be soon improved with new broad-band sensors, which require a low level of background noise. Therefore, we investigated the noise level and estimated the site response at the seismic stations deployed at Mt. Etna and at Aeolian Islands, in order to evidence possible disturbs which can be related to anthropic activity, environmental factors and/or to the local soil conditions. Noise measurements were carried out using a portable digital seismic station equipped with a 3-component, 20 s sensor. The acquisition was performed both inside the vault structures where the remote stations are located and in proximity of them, on the outcropping terrain. The noise spectra were compared with the NLNM (New Low Noise Model) and NHNM (New High Noise Model) models described by Peterson (1993). A preliminary estimate of site response at each station, by applying the Nakamura (1989) technique, was also performed. The obtained results show, for some stations, higher noise levels mainly due to volcanic tremor and/or bad soil conditions. Moreover, in several cases, vault design need to be deeply reviewed and for some installations the substitution of the sites is required. References Nakamura, Y., (1989). A method for dynamic characteristics estimation of subsurface using microtremor on the ground surface. Quarterly R of Report RTRI, 30, 25-33. Peterson, J., (1993). Observations and modelling of background seismic noise. Open File Report 93-322, U. S. Geological Survey, Albuquerque, NM.

  12. July 1973 ground survey of active Central American volcanoes

    NASA Technical Reports Server (NTRS)

    Stoiber, R. E. (Principal Investigator); Rose, W. I., Jr.

    1973-01-01

    The author has identified the following significant results. Ground survey has shown that thermal anomalies of various sizes associated with volcanic activity at several Central American volcanoes should be detectable from Skylab. Anomalously hot areas of especially large size (greater than 500 m in diameter) are now found at Santiaguito and Pacaya volcanoes in Guatemala and San Cristobal in Nicaragua. Smaller anomalous areas are to be found at least seven other volcanoes. This report is completed after ground survey of eleven volcanoes and ground-based radiation thermometry mapping at these same points.

  13. Digital data set of volcano hazards for active Cascade Volcanos, Washington

    USGS Publications Warehouse

    Schilling, Steve P.

    1996-01-01

    Scientists at the Cascade Volcano Observatory have completed hazard assessments for the five active volcanos in Washington. The five studies included Mount Adams (Scott and others, 1995), Mount Baker (Gardner and others, 1995), Glacier Peak (Waitt and others, 1995), Mount Rainier (Hoblitt and others, 1995) and Mount St. Helens (Wolfe and Pierson, 1995). Twenty Geographic Information System (GIS) data sets have been created that represent the hazard information from the assessments. The twenty data sets have individual Open File part numbers and titles

  14. Aspects of historical eruptive activity and volcanic unrest at Mt. Tongariro, New Zealand: 1846-2013

    NASA Astrophysics Data System (ADS)

    Scott, Bradley J.; Potter, Sally H.

    2014-10-01

    The 6 August and 21 November 2012 eruptions from Upper Te Maari crater have heightened interest in past activity at Mt. Tongariro, New Zealand. Risks caused by volcanic hazards are increasingly being quantified by using probability estimates through expert elicitation, partly based on the frequency of past eruptions. To maximise the accuracy of these risk values at Mt. Tongariro, a historical eruption catalogue is required. This paper presents the findings of a detailed historical chronology of unrest and eruptions at Mt. Tongariro between 1846 AD and 2013 AD. It builds on the findings of previous researchers, highlighting that volcanic eruptions and unrest have occurred frequently from this volcano. Eruptions are now thought to have occurred at Mt. Tongariro in 1869, 1892, 1896-97, 1899, 1926, 1927, 1934 and 2012. Eruptions also potentially occurred in 1846, 1855, 1886, and 1928, in addition to frequent eruptions from neighbouring Mt. Ngauruhoe. The number of recognised eruptions during the 1896-97 episode has increased to 18, and the Red Crater area has been found to be more active than previously appreciated. Multiple episodes of unrest not resulting in eruptions have also been identified. New eruption recurrence rates are derived from this catalogue, with the baseline probability of the onset of an eruption episode calculated to be 0.07 per year (if 1896-97 and 2012 are considered as one episode each, and all others separately), and the maximum eruption rate within an eruption episode is 18 per year. These new data contribute towards risk assessments for future eruptions at Mt. Tongariro.

  15. Mobility and fluxes of major, minor and trace metals during basalt weathering and groundwater transport at Mt. Etna volcano (Sicily)

    NASA Astrophysics Data System (ADS)

    Aiuppa, Alessandro; Allard, Patrick; D'Alessandro, Walter; Michel, Agnes; Parello, Francesco; Treuil, Michel; Valenza, Mariano

    2000-06-01

    The concentrations and fluxes of major, minor and trace metals were determined in 53 samples of groundwaters from around Mt Etna, in order to evaluate the conditions and extent of alkali basalt weathering by waters enriched in magma-derived CO 2 and the contribution of aqueous transport to the overall metal discharge of the volcano. We show that gaseous input of magmatic volatile metals into the Etnean aquifer is small or negligible, being limited by cooling of the rising fluids. Basalt leaching by weakly acidic, CO 2-charged water is the overwhelming source of metals and appears to be more extensive in two sectors of the S-SW (Paternò) and E (Zafferana) volcano flanks, where out flowing groundwaters are the richest in metals and bicarbonate of magmatic origin. Thermodynamic modeling of the results allows to evaluate the relative mobility and chemical speciation of various elements during their partitioning between solid and liquid phases through the weathering process. The facts that rock-forming minerals and groundmass dissolve at different rates and secondary minerals are formed are taken into account. At Mt. Etna, poorly mobile elements (Al, Th, Fe) are preferentially retained in the solid residue of weathering, while alkalis, alkaline earth and oxo-anion-forming elements (As, Se, Sb, Mo) are more mobile and released to the aqueous system. Transition metals display an intermediate behavior and are strongly dependent on either the redox conditions (Mn, Cr, V) or solid surface-related processes (V, Zn, Cu). The fluxes of metals discharged by the volcanic aquifer of Etna range from 7.0 × 10 -3 t/a (Th) to 7.3 × 10 4 t/a (Na). They are comparable in magnitude to the summit crater plume emissions for a series of elements (Na, K, Ca, Mg, U, V, Li) with lithophile affinity, but are minor for volatile elements. Basalt weathering at Mt Etna also consumes about 2.1 × 10 5 t/a of magma-derived carbon dioxide, equivalent to ca. 7% of contemporaneous crater plume

  16. Global data collection and the surveillance of active volcanoes

    USGS Publications Warehouse

    Ward, P.L.

    1990-01-01

    Data relay systems on existing earth-orbiting satellites provide an inexpensive way to collect environmental data from numerous remote sites around the world. This technology could be used effectively for fundamental monitoring of most of the world's active volcanoes. Such global monitoring would focus attention on the most dangerous volcanoes that are likely to significantly impact the geosphere and the biosphere. ?? 1990.

  17. Volcanoes

    USGS Publications Warehouse

    Tilling, Robert I.; ,

    1998-01-01

    Volcanoes destroy and volcanoes create. The catastrophic eruption of Mount St. Helens on May 18, 1980, made clear the awesome destructive power of a volcano. Yet, over a time span longer than human memory and record, volcanoes have played a key role in forming and modifying the planet upon which we live. More than 80 percent of the Earth's surface--above and below sea level--is of volcanic origin. Gaseous emissions from volcanic vents over hundreds of millions of years formed the Earth's earliest oceans and atmosphere, which supplied the ingredients vital to evolve and sustain life. Over geologic eons, countless volcanic eruptions have produced mountains, plateaus, and plains, which subsequent erosion and weathering have sculpted into majestic landscapes and formed fertile soils.

  18. Principles of Volcano Risk Metrics: theory and the case study of Mt. Vesuvius and Campi Flegrei.

    NASA Astrophysics Data System (ADS)

    Marzocchi, W.; Woo, G.

    2009-04-01

    Despite volcanic risk having been defined quantitatively more than thirty years ago, it has been always managed without being effectively measured. Yet, the recent substantial progress in quantifying eruption probability paves the way for a new era of rational science-based volcano risk management, that we name Volcanic Risk Metrics (VRM). In this talk, we propose some principles of VRM, based on two main components: a probabilistic volcanic hazard assessment and eruption forecasting, and a cost/benefit analysis. In a nutshell, the method assists managers in decision-making under uncertainty, weighing appropriately the cost and benefit of actions to mitigate the effects of a threat having a specific probability of occurrence. The strategy has the potential to rationalize decision-making across a broad spectrum of volcanological questions: what areas should be covered by emergency plan? What early preparations should be made for a volcano crisis? When should the call for evacuation be made? The strategy has the paramount advantage of providing a set of quantitative and transparent 'rules' that can be established before a crisis, optimizing and clarifying decision-making procedures. It places volcanologists at the centre of decision-making, applying all their scientific knowledge and observational information to assist authorities in quantifying the positive and negative risk implications of any decision.

  19. Predicting and validating the tracking of a Volcanic Ash Cloud during the 2006 Eruption of Mt. Augustine Volcano

    SciTech Connect

    Webley, Peter W.; Atkinson, D.; Collins, Richard L.; Dean, K.; Fochesatto, J.; Sassen, Kenneth; Cahill, Catherine F.; Prata, A.; Flynn, Connor J.; Mizutani, K.

    2008-11-01

    On 11 January 2006, Mount Augustine volcano in southern Alaska began erupting after 20-year repose. The Anchorage Forecast Office of the National Weather Service (NWS) issued an advisory on 28 January for Kodiak City. On 31 January, Alaska Airlines cancelled all flights to and from Anchorage after multiple advisories from the NWS for Anchorage and the surrounding region. The Alaska Volcano Observatory (AVO) had reported the onset of the continuous eruption. AVO monitors the approximately 100 active volcanoes in the Northern Pacific. Ash clouds from these volcanoes can cause serious damage to an aircraft and pose a serious threat to the local communities, and to transcontinental air traffic throughout the Arctic and sub-Arctic region. Within AVO, a dispersion model has been developed to track the dispersion of volcanic ash clouds. The model, Puff, was used operational by AVO during the Augustine eruptive period. Here, we examine the dispersion of a volcanic ash cloud from Mount Augustine across Alaska from 29 January through the 2 February 2006. We present the synoptic meteorology, the Puff predictions, and measurements from aerosol samplers, laser radar (or lidar) systems, and satellites. UAF aerosol samplers revealed the presence of volcanic aerosols at the surface at sites where Puff predicted the ash clouds movement. Remote sensing satellite data showed the development of the ash cloud in close proximity to the volcano and a sulfur-dioxide cloud further from the volcano consistent with the Puff predictions. Lidars showed the presence of volcanic aerosol with consistent characteristics aloft over Alaska and were capable of detecting the aerosol, even in the presence of scattered clouds and where the cloud is too thin/disperse to be detected by remote sensing satellite data. The lidar measurements revealed the different trajectories of ash consistent with the Puff predictions. Dispersion models provide a forecast of volcanic ash cloud movement that might be

  20. The Mt. Perkins block, northwestern Arizona: An exposed cross section of a synextensional volcano in highly extended terrane

    SciTech Connect

    Faulds, J.E. . Dept. of Geology)

    1993-04-01

    Despite widespread and voluminous middle to late Tertiary volcanism in the Basin and Range province, relatively few volcanic centers have been located, especially in highly extended regions. Although large-magnitude tilting and structural dismemberment generally obscure conventional exposures of volcanic centers, they can potentially provide cross sectional views of major volcanic edifices. In the northern Colorado River extensional corridor, the steeply (90[degree]) W-tilted Mt. Perkins block incorporates a cross-sectional view of part of a major Miocene volcanic center. In ascending structural order from east to west, the Mt. Perkins block includes (a) a 15.96 Ma quartz monzonite to diorite pluton emplaced in Proterozoic gneiss, (b) a 20 km long, NNW-striking, gently to moderately (0--45[degree]) E-dipping felsic dike swarm (one dike dated at 14.7 Ma), (c) a nonconformity at the base of the Miocene volcanic section, (d) basaltic andesite flows and dacite flows and domes, (e) a 300--1,500 m thick section of rhyolite flows, surges, and tuffs bracketed between 16.4 and 14.4 Ma, and (f) capping basalt flows. Tilts decrease from 90 to 30 W between the base of the rhyolite section and upper basalt flows. Geologic and paleomagnetic data indicate 40--90 of W-tilting of the dike swarm and pluton. The felsic dike swarm invades the lower part of the volcanic section and terminates upward in the coeval sequence of rhyolites. In addition, the dike swarm and rhyolite section terminate along-strike in roughly the same area. Restoration places the rhyolites above the dike swarm, which in turn is situated directly above the pluton. These data indicate a genetic tie between at least the felsic dike swarm and thick sequence of rhyolites. Geochemical fingerprinting of the lavas, dike swarm, and pluton is underway to test the tilted volcano'' hypothesis.

  1. Did the Eruption of the Mt. Pinatubo Volcano Affect Cirrus Properties?

    NASA Technical Reports Server (NTRS)

    Luo, Zhengzhao; Rossow, William B.; Inoue, Toshiro; Stubenrauch, Claudia J.; Hansen, James E. (Technical Monitor)

    2001-01-01

    Some observations suggest that the volcanic aerosols produced by the Mt. Pinatubo eruption may have altered cirrus properties. We look for evidence that such modification of cirrus is extensive enough to be climatically significant by comparing three satellite-based cirrus datasets produced by the ISCCP (International Satellite Cloud Climatology Project) analysis, the 'split-window' analysis, and 3I analysis. Since the former two have not been compared in detail before, we conduct such a comparison here. When applied to AVHRR (Advanced Very High Resolution Radiometer) data, both the ISCCP and split-window analyses identify about 0.2 - 0.3 cirrus cloud amount in tropical latitudes; however, there are detailed differences of classification for about half of these clouds. The discrepancies are attributed to the simplified assumptions made by both methods. The latter two datasets are derived from infrared radiances, so they are much less sensitive to volcanic aerosols than the ISCCP analysis. After the Mt. Pinatubo eruption, the ISCCP results indicate a dramatic decrease of thin cirrus (cloud top pressure less than 440 mb and visible optical thickness less than 1.3) over ocean, accompanied by a comparable increase of altocumulus and cumulus clouds; over land, there are no significant changes. In contrast, results from the split-window and 3I analyses show little change in thin cirrus amount over either ocean or land that is associated with the volcanic eruption. The ISCCP results can, therefore, be understood as a misclassification of thin cirrus because the additional reflected sunlight by the volcanic aerosol makes the cirrus clouds appear to be optically thicker. Examination of the split-window signature and the infrared emissivities from 3I show no significant change in infrared emissivity (or optical thickness). These results indicate that the Mt. Pinatubo volcanic aerosol did not have a significant systematic effect on tropical cirrus properties, but rather

  2. Capturing the fingerprint of Etna volcano activity in gravity and satellite radar data.

    PubMed

    Del Negro, Ciro; Currenti, Gilda; Solaro, Giuseppe; Greco, Filippo; Pepe, Antonio; Napoli, Rosalba; Pepe, Susi; Casu, Francesco; Sansosti, Eugenio

    2013-10-30

    Long-term and high temporal resolution gravity and deformation data move us toward a better understanding of the behavior of Mt Etna during the June 1995 - December 2011 period in which the volcano exhibited magma charging phases, flank eruptions and summit crater activity. Monthly repeated gravity measurements were coupled with deformation time series using the Differential Synthetic Aperture Radar Interferometry (DInSAR) technique on two sequences of interferograms from ERS/ENVISAT and COSMO-SkyMed satellites. Combining spatiotemporal gravity and DInSAR observations provides the signature of three underlying processes at Etna: (i) magma accumulation in intermediate storage zones, (ii) magmatic intrusions at shallow depth in the South Rift area, and (iii) the seaward sliding of the volcano's eastern flank. Here we demonstrate the strength of the complementary gravity and DInSAR analysis in discerning among different processes and, thus, in detecting deep magma uprising in months to years before the onset of a new Etna eruption.

  3. High-K andesite petrogenesis and crustal evolution: Evidence from mafic and ultramafic xenoliths, Egmont Volcano (Mt. Taranaki) and comparisons with Ruapehu Volcano, North Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Price, Richard C.; Smith, Ian E. M.; Stewart, Robert B.; Gamble, John A.; Gruender, Kerstin; Maas, Roland

    2016-07-01

    This study uses the geochemistry and petrology of xenoliths to constrain the evolutionary pathways of host magmas at two adjacent andesitic volcanoes in New Zealand's North Island. Egmont (Mt. Taranaki) is located on the west coast of the North Island and Ruapehu lies 140 km to the east at the southern end of the Taupo Volcanic Zone, the principal locus of subduction-related magmatism in New Zealand. Xenoliths are common in the eruptives of both volcanoes but the xenoliths suites are petrographically and geochemically different. Ruapehu xenoliths are predominantly pyroxene-plagioclase granulites derived from Mesozoic meta-greywacke basement and the underlying oceanic crust. The xenolith population of Egmont Volcano is more complex. It includes sedimentary, metamorphic and plutonic rocks from the underlying basement but is dominated by coarse grained, mafic and ultramafic igneous rocks. Gabbroic xenoliths (Group 1) are composed of plagioclase, clinopyroxene and amphibole whereas ultramafic xenoliths are dominated by amphibole (Group 2) or pyroxene (Group 3) or, in very rare cases, olivine (Group 4). In Group 1 xenoliths plagioclase and clinopyroxene and in some cases amphibole show cumulate textures. Amphibole also occurs as intercumulate poikilitic crystals or as blebs or laminae replacing pyroxene. Some Group 2 xenoliths have cumulate textures but near monomineralic amphibole xenoliths are coarse grained with bladed or comb textures. Pyroxene in Group 3 xenoliths has a polygonal granoblastic texture that is commonly overprinted by veining and amphibole replacement. Group 1 and most Group 2 xenoliths have major, trace element and Sr, Nd and Pb isotope compositions indicating affinity with the host volcanic rocks. Geochemical variation can be modelled by assimilation fractional crystallisation (AFC) and fractional crystallisation (FC) of basaltic parents assuming an assimilant with the composition of average crystalline basement and Group 1 xenoliths have

  4. New formulae for estimating lava flow volumes at Mt. Etna Volcano, Sicily

    NASA Astrophysics Data System (ADS)

    Murray, J. B.; Stevens, N. F.

    A new data set of Etna lava flows erupted since 1868 has been compiled from eight topographic maps of the volcano published at intervals since then. Volumes of 59 flows or groups of flows were measured from topographic difference maps. Most of these volumes are likely to be considerably more accurate than those published previously. We cut the number of flow volumes down to 25 by selecting those examples for which the volume of an individual eruption could be derived with the highest accuracy. This refined data set was searched for high correlations between flow volume and more directly measurable parameters. Only two parameters showed a correlation coefficient of 70% or greater: planimetric flow area A (70%) and duration of the eruption D (79%). If only short duration (<18 days) flows were used, flow length cubed, L3, had a correlation coefficient of 98%. Using combinations of measured parameters, much more significant correlations with volume were found. Dh had a correlation coefficient of 90% (h is the hydrostatic head of magma above the vent), and , 92% (where W is mean width and E is the degree of topographic enclosure), and a combination of the two , 97%. These latter formulae were used to derive volumes of all eruptions back to 1868 to compare with those from the complete data set. Values determined from the formulae were, on average, lower by 16% (Dh), 7% ( , and 19% .

  5. Scaling explosive activity at Stromboli Volcano

    NASA Astrophysics Data System (ADS)

    marchetti, emanuele; ripepe, maurizio

    2013-04-01

    Ordinary explosive activity at Stromboli volcano is sometimes interrupted by Paroxysms and more often by Major Explosions. Major explosion represent a primary element of risk, given the large amount of material ejected, able to reach Pizzo Sopra la Fossa and the other summit trails, and the frequency of occurrence (2.1 events/year). However, while paroxysms are easy to be identified and there is a general consensous on their occurrence this does not necessarily hold for Major Explosions. Generally, Major Explosions are defined as based on the amount of material emitted and on the area covered by the ejecta dispersal, as well as on the properties of material emitted, but this is not always possible nor suitable for a near-real time information delivery to Civil Defence Authorities. With this purpose we have analyzed the seismic, tilt and infrasonic data collected at Stromboli since 2008 for a total database >400000 events to provide a geophysical classification of major explosions. We assumed that seismic (in the VLP band), ground tilt, and the acoustic excess pressure are efficient signals to discriminate different explosive energy. We show how ordinary activity is confined below a seismic VLP ground displacement of 8x10-6 m, a deformation of 0.25 μrad and an infrasonic excess pressure of 100 Pa. A separate cluster of events, characterized by tilt and seismic displacement significantly larger than these threshold are defined as Major Explosions. Here we propose these threshold can be used to quantitatively discriminate between ordinary activity and Major explosions. While above these precise threshold we have several explosions which can be considered as Major Explosions, the two paroxysms are associated to orders of magnitude (ground displacement of 10-3 m and tilt of 10 μrad) larger ground tilt and seismic VLP displacement. Besides our classification is suggesting the existence of a possible energy gap between Major and Paroxysms explosive dynamics which has

  6. An investigation of vegetation and other Earth resource/feature parameters using LANDSAT and other remote sensing data. 1: LANDSAT. 2: Remote sensing of volcanic emissions. [New England forest and emissions from Mt. St. Helens and Central American volcanoes

    NASA Technical Reports Server (NTRS)

    Birnie, R. W.; Stoiber, R. E. (Principal Investigator)

    1981-01-01

    A fanning technique based on a simplistic physical model provided a classification algorithm for mixture landscapes. Results of applications to LANDSAT inventory of 1.5 million acres of forest land in Northern Maine are presented. Signatures for potential deer year habitat in New Hampshire were developed. Volcanic activity was monitored in Nicaragua, El Salvador, and Guatemala along with the Mt. St. Helens eruption. Emphasis in the monitoring was placed on the remote sensing of SO2 concentrations in the plumes of the volcanoes.

  7. The pulmonary toxicity of an ash sample from the MT. St. Helens Volcano.

    PubMed

    Beck, B D; Brain, J D; Bohannon, D E

    1981-11-01

    Volcanic ash was collected from the Moses Lake region of Washington State after the 18 May 1980 eruption of Mt. St. Helens. The ash was tested in a short-term bioassay system using hamsters exposed by intratracheal instillation. One day after exposure the lungs were lavaged and the fluid collected was characterized using several parameters that represent different manifestations of lung injury: (a) in situ phagocytic ability of pulmonary macrophages; (b) the inflammatory response, as shown by polymorphonuclear neutrophil numbers and albumin levels in lung lavage fluid; and (c) release of cytoplasmic and lysosomal enzymes into the cell-free supernatant of lung-lavage fluid. The response to volcanic ash was elevated compared to controls, but was similar to the response to Al2O3, a dust considered to be relatively inert. In contrast, the response to alpha-quartz, a highly toxic fibrogenic dust, was significantly greater than the response to either volcanic ash or Al2O3 for most parameters measured. PMID:7318780

  8. The pulmonary toxicity of an ash sample from the Mt. St. Helens Volcano

    SciTech Connect

    Beck, B.D.; Brain, J.D.; Bohannon, D.E.

    1981-11-01

    Volcanic ash was collected from the Moses Lake region of Washington State after the 18 May 1980 eruption of Mt. St. Helens. The ash was tested in a short-term bioassay system using hamsters exposed by intratracheal instillation. One day after exposure the lungs were lavaged and the fluid collected was characterized using several parameters that represent different manifestations of lung injury: (a) in situ phagocytic ability of pulmonary macrophages; (b) the inflammatory response, as shown by polymorphonuclear neutrophil numbers and albumin levels in lung lavage fluid; and (c) release of cytoplasmic and lysosomal enzymes into the cell-free supernatant of lung-lavage fluid. The response to volcanic ash was elevated compared to controls, but was similar to the response to Al2O3, a dust considered to be relatively inert. In contrast, the response to alpha-quartz, a highly toxic fibrogenic dust, was significantly greater than the response to either volcanic ash or Al2O3 for most parameters measured.

  9. Deep to shallow crustal differentiation of within-plate alkaline magmatism at Mt. Bambouto volcano, Cameroon Line

    NASA Astrophysics Data System (ADS)

    Marzoli, Andrea; Aka, Festus T.; Merle, Renaud; Callegaro, Sara; N'ni, Jean

    2015-04-01

    At Mt. Bambouto, a continental stratovolcano of the Cameroon Line, magmatic activity lasted for over 20 Ma and was characterized by at least two caldera formation events. Here we present detailed mineral and whole-rock compositions of Mt. Bambouto basanites, hawaiites, trachytes and phonolites, with emphasis on caldera related volcanic rocks. These data show that differentiation took place within a complex magma plumbing system, with magma chambers occurring at different depths within the crust. Though differentiation was chiefly dominated by fractional crystallization, chemical mineral zoning of olivines, clinopyroxenes, and feldspars is also indicative of open-system processes such as magma mixing and magma chamber recharge. Chemical zoning is evident mainly in the outer 100 microns of the analyzed crystals, suggesting that magma mixing occurred shortly before eruption. The last caldera collapse at about 15 Ma also marked a clear change in the magma plumbing system. Before caldera collapse, Mt. Bambouto was characterized by a dominant production of peralkaline quartz trachytic magmas in shallow magma chambers. During this phase, evolved basic magmas (hawaiites) and strongly evolved alkaline magmas were formed in middle and upper crustal magma chambers, respectively. After emptying of the shallow quartz trachytic magma chamber and caldera collapse, magmas from the deep magmatic plumbing system were mobilized and partially mixed. This triggered eruptions of magmas on the caldera rims.

  10. Hydrothermal reservoir beneath Taal Volcano (Philippines): Implications to volcanic activity

    NASA Astrophysics Data System (ADS)

    Nagao, T.; Alanis, P. B.; Yamaya, Y.; Takeuchi, A.; Bornas, M. V.; Cordon, J. M.; Puertollano, J.; Clarito, C. J.; Hashimoto, T.; Mogi, T.; Sasai, Y.

    2012-12-01

    Taal Volcano is one of the most active volcanoes in the Philippines. The first recorded eruption was in 1573. Since then it has erupted 33 times resulting in thousands of casualties and large damages to property. In 1995, it was declared as one of the 15 Decade Volcanoes. Beginning in the early 1990s it has experienced several phases of abnormal activity, including seismic swarms, episodes of ground deformation, ground fissuring and hydrothermal activities, which continues up to the present. However, it has been noted that past historical eruptions of Taal Volcano may be divided into 2 distinct cycles, depending on the location of the eruption center, either at Main Crater or at the flanks. Between 1572-1645, eruptions occurred at the Main Crater, in 1707 to 1731, they occurred at the flanks. In 1749, eruptions moved back to the Main Crater until 1911. During the 1965 and until the end of the 1977 eruptions, eruptive activity once again shifted to the flanks. As part of the PHIVOLCS-JICA-SATREPS Project magnetotelluric and audio-magnetotelluric surveys were conducted on Volcano Island in March 2011 and March 2012. Two-dimensional (2-D) inversion and 3-D forward modeling reveals a prominent and large zone of relatively high resistivity between 1 to 4 kilometers beneath the volcano almost directly beneath the Main Crater, surrounded by zones of relatively low resistivity. This anomalous zone of high resistivity is hypothesized to be a large hydrothermal reservoir filled with volcanic fluids. The presence of this large hydrothermal reservoir could be related to past activities of Taal Volcano. In particular we believe that the catastrophic explosion described during the 1911 eruption was the result of the hydrothermal reservoir collapsing. During the cycle of Main Crater eruptions, this hydrothermal reservoir is depleted, while during a cycle of flank eruptions this reservoir is replenished with hydrothermal fluids.

  11. Erupting Volcano Mount Etna

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Expedition Five crew members aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting volcano Mt. Etna on the island of Sicily, Italy in October 2002. Triggered by a series of earthquakes on October 27, 2002, this eruption was one of Etna's most vigorous in years. This image shows the ash plume curving out toward the horizon. The lighter-colored plumes down slope and north of the summit seen in this frame are produced by forest fires set by flowing lava. At an elevation of 10,990 feet (3,350 m), the summit of the Mt. Etna volcano, one of the most active and most studied volcanoes in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.

  12. Temporary seismic networks on active volcanoes of Kamchatka (Russia)

    NASA Astrophysics Data System (ADS)

    Jakovlev, Andrey; Koulakov, Ivan; Abkadyrov, Ilyas; Shapiro, Nikolay; Kuznetsov, Pavel; Deev, Evgeny; Gordeev, Evgeny; Chebrov, Viktor

    2016-04-01

    We present details of four field campaigns carried out on different volcanoes of Kamchatka in 2012-2015. Each campaign was performed in three main steps: (i) installation of the temporary network of seismic stations; (ii) autonomous continuous registration of three component seismic signal; (III) taking off the network and downloading the registered data. During the first campaign started in September 2012, 11 temporary stations were installed over the Avacha group of volcanoes located 30 km north to Petropavlovsk-Kamchatsky in addition to the seven permanent stations operated by the Kamchatkan Branch of the Geophysical Survey (KBGS). Unfortunately, with this temporary network we faced with two obstacles. The first problem was the small amount of local earthquakes, which were detected during operation time. The second problem was an unexpected stop of several stations only 40 days after deployment. Nevertheless, after taking off the network in August 2013, the collected data appeared to be suitable for analysis using ambient noise. The second campaign was conducted in period from August 2013 to August 2014. In framework of the campaign, 21 temporary stations were installed over Gorely volcano, located 70 km south to Petropavlovsk-Kamchatsky. Just in time of the network deployment, Gorely Volcano became very seismically active - every day occurred more than 100 events. Therefore, we obtain very good dataset with information about thousands of local events, which could be used for any type of seismological analysis. The third campaign started in August 2014. Within this campaign, we have installed 19 temporary seismic stations over Tolbachik volcano, located on the south side of the Klyuchevskoy volcano group. In the same time on Tolbachik volcano were installed four temporary stations and several permanent stations operated by the KBGS. All stations were taking off in July 2015. As result, we have collected a large dataset, which is now under preliminary analysis

  13. Trace element biomonitoring using mosses in urban areas affected by mud volcanoes around Mt. Etna. The case of the Salinelle, Italy.

    PubMed

    Bonanno, Giuseppe; Lo Giudice, Rosa; Pavone, Pietro

    2012-08-01

    Trace element impact was assessed using mosses in a densely inhabited area affected by mud volcanoes. Such volcanoes, locally called Salinelle, are phenomena that occur around Mt. Etna (Sicily, Italy) and are interpreted as the surface outflow of a hydrothermal system located below Mt. Etna, releasing sedimentary fluids (hydrocarbons and NaCl brines) along with magmatic gases (mainly CO(2) and He). To date, scarce data are available about the presence of trace elements, and no biomonitoring campaigns are reported about the cumulative effects of such emissions. In this study, concentrations of Al, As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, V, and Zn were detected in the moss Bryum argenteum, in soil and water. Results showed that the trace element contribution of the Salinelle to the general pollution was significant for Al, Mn, Ni, and Zn. The comparison of trace concentrations in mosses from Salinelle and Etna showed that the mud volcanoes release a greater amount of Al and Mn, whereas similar values of Ni were found. Natural emissions of trace elements could be hazardous in human settlements, in particular, the Salinelle seem to play an important role in environmental pollution.

  14. Measuring thermal budgets of active volcanoes by satellite remote sensing

    NASA Technical Reports Server (NTRS)

    Glaze, L.; Francis, P. W.; Rothery, D. A.

    1989-01-01

    Thematic Mapper measurements of the total radiant energy flux Q at Lascar volcano in north Chile for December 1984 are reported. The results are consistent with the earlier suggestion that a lava lake is the source of a reported thermal budget anomaly, and with values for 1985-1986 that are much lower, suggesting that fumarolic activity was then a more likely heat source. The results show that satellite remote sensing may be used to monitor the activity of a volcano quantitatively, in a way not possible by conventional ground studies, and may provide a method for predicting eruptions.

  15. Volcanic Activities of Hakkoda Volcano after the 2011 Tohoku Earthquake

    NASA Astrophysics Data System (ADS)

    Yamamoto, M.; Miura, S.

    2014-12-01

    The 2011 Tohoku Earthquake of 11 March 2011 generated large deformation in and around the Japanese islands, and the large crustal deformation raises fear of further disasters including triggered volcanic activities. In this presentation, as an example of such potential triggered volcanic activities, we report the recent seismic activities of Hakkoda volcano, and discuss the relation to the movement of volcanic fluids. Hakkoda volcano is a group of stratovolcanoes at the northern end of Honshu Island, Japan. There are fumaroles and hot springs around the volcano, and phreatic eruptions from Jigoku-numa on the southwestern flank of Odake volcano, which is the highest peak of the volcanic group, were documented in its history. Since just after the occurrence of the Tohokui Earthquake, the seismicity around the volcano became higher, and the migration of hypocenters of volcano-tectonic (VT) earthquakes was observed.In addition to these VT earthquakes, long-period (LP) events started occurring beneath Odake at a depth of about 2-3 km since February, 2013, and subtle crustal deformation caused by deep inflation source was also detected by the GEONET GNSS network around the same time. The spectra of LP events are common between events irrespective of the magnitude of events, and they have several spectral peaks at 6-7 sec, 2-3 sec, 1 sec, and so on. These LP events sometimes occur like a swarm with an interval of several minutes. The characteristics of observed LP events at Hakkoda volcano are similar to those of LP events at other active volcanoes and hydrothermal area in the world, where abundant fluids exist. Our further analysis using far-field Rayleigh radiation pattern observed by NIED Hi-net stations reveals that the source of LP events is most likely to be a nearly vertical tensile crack whose strike is NE-SW direction. The strike is almost perpendicular to the direction of maximum extensional strain estimated from the geodetic analysis, and is almost parallel to

  16. Temperature induced phase transformations at Mt. Etna (Italy) volcano: implications for the mechanical weakening of the volcanic edifice under magmatic stresses

    NASA Astrophysics Data System (ADS)

    Vinciguerra, S.; Mollo, S.; Iarocci, A.; Iezzi, G.; Heap, M. J.

    2009-12-01

    Mt. Etna (Sicily, Italy) is one of the most active on Earth. Instability of the eastern and southern flanks, in terms of slow spreading and seismic activity of the volcano, is a dominant dynamic processes and is considered as a triggering mechanism of the eruptive activity. Extrusive lava flows were the subject of a number of laboratory studies aimed to investigate the evolution of physical parameters under cyclic loading. However, no temperature effects were investigated and more importantly only the shallow layers (~ 1.5km of depth) is made up of volcanites; the volcanic pile rests upon thick Mesozoic to Middle Pleistocene sedimentary sequences imbricated at the front of the Apennian-Maghrebian thrust belt. A variety of lithologies spanning from poorly consolidated terrigenous sediments to overconsolidated clays makes this sedimentary sequence and enhances the slow spreading detected. The tickest sequences are given from Triassic to Cretaceous carbonatic rocks (limestones and dolomites) and Creataceous to Pleistocene clays. Here we present a new dataset of Uniaxial Compressive Strength (UCS) and P-wave velocity measurements carried out at temperatures up to 800°C performed on both extrusive lava flows from the volcanic pile, a clay-limestone melanges (75 wt% calcite, 15 wt% quartz and 10 wt% kaolinite) and two limestones (95wt% and 99wt% calcite), which well represent the complexity of the sedimentary basement below Mt. Etna volcano. Measurements were carried out in a new experimental servo-controlled uniaxial apparatus allowing to simultaneously load samples at constant strain rate/stress and apply elevated temperatures (up to 1200°C). Results show that UCS values and P-wave velocities measured on the lava flows do not show significant changes up to 800°C, with average values of ~ 160-170MPa. On the contrary, UCS values and P-wave velocities relative to the marly limestone decrease from ~170 to ~90 MPa and from ~5.5 to ~4.0 Km s-1, by increasing temperatures

  17. Linking petrology and seismology at an active volcano.

    PubMed

    Saunders, Kate; Blundy, Jon; Dohmen, Ralf; Cashman, Kathy

    2012-05-25

    Many active volcanoes exhibit changes in seismicity, ground deformation, and gas emissions, which in some instances arise from magma movement in the crust before eruption. An enduring challenge in volcano monitoring is interpreting signs of unrest in terms of the causal subterranean magmatic processes. We examined over 300 zoned orthopyroxene crystals from the 1980-1986 eruption of Mount St. Helens that record pulsatory intrusions of new magma and volatiles into an existing larger reservoir before the eruption occurred. Diffusion chronometry applied to orthopyroxene crystal rims shows that episodes of magma intrusion correlate temporally with recorded seismicity, providing evidence that some seismic events are related to magma intrusion. These time scales are commensurate with monitoring signals at restless volcanoes, thus improving our ability to forecast volcanic eruptions by using petrology. PMID:22628652

  18. Linking petrology and seismology at an active volcano.

    PubMed

    Saunders, Kate; Blundy, Jon; Dohmen, Ralf; Cashman, Kathy

    2012-05-25

    Many active volcanoes exhibit changes in seismicity, ground deformation, and gas emissions, which in some instances arise from magma movement in the crust before eruption. An enduring challenge in volcano monitoring is interpreting signs of unrest in terms of the causal subterranean magmatic processes. We examined over 300 zoned orthopyroxene crystals from the 1980-1986 eruption of Mount St. Helens that record pulsatory intrusions of new magma and volatiles into an existing larger reservoir before the eruption occurred. Diffusion chronometry applied to orthopyroxene crystal rims shows that episodes of magma intrusion correlate temporally with recorded seismicity, providing evidence that some seismic events are related to magma intrusion. These time scales are commensurate with monitoring signals at restless volcanoes, thus improving our ability to forecast volcanic eruptions by using petrology.

  19. Analysis of active volcanoes from the Earth Observing System

    NASA Technical Reports Server (NTRS)

    Mouginis-Mark, Peter; Rowland, Scott; Crisp, Joy; Glaze, Lori; Jones, Kenneth; Kahle, Anne; Pieri, David; Zebker, Howard; Krueger, Arlin; Walter, Lou

    1991-01-01

    The Earth Observing System (EOS) scheduled for launch in 1997 and 1999 is briefly described, and the EOS volcanology investigation objectives are discussed. The volcanology investigation will include long- and short-term monitoring of selected volcanoes, the detection of precursor activity associated with unanticipated eruptions, and a detailed study of on-going eruptions. A variety of instruments on the EOS platforms will enable the study of local- and regional-scale thermal and deformational features of volcanoes, and the chemical and structural features of volcanic eruption plumes and aerosols.

  20. Volcano-seismic activity before and after the Maule 2010 Earthquake (Southern Chile): a comparison between Llaima and Villarrica volcanoes

    NASA Astrophysics Data System (ADS)

    Mora-Stock, C.; Thorwart, M.; Wunderlich, T.; Bredemeyer, S.; Rabbel, W.

    2012-04-01

    Llaima and Villarrica are two of the most actives volcanoes in the Southern Volcanic Zone in the Chilean Andes, with different type of activity and edifice. Llaima is a close vent volcano with constant seismic activity, while Villarrica is an open vent volcano with lava lake at the summit and constant degassing. The relation between volcano eruptions following a great earthquake has been studied in different cases around the world, and it has been the case for the 1960 Valdivia earthquake in southern Chile, where Llaima and Villarrica presented eruptions on the following months to years. This study is focused on characterizing the volcano-seismic activity in the months before and after the M8.8 Maule earthquake on the 27th February 2010. Time series for tremors, long period and volcano tectonic events were obtained from the catalogue of the Volcanic Observatory of the Southern Andes (OVDAS in Spanish) and from the continuous record of the SFB 574 temporary volcanic network. In Villarrica volcano, peaks of activity of tremor and long period events were observed months prior to and after the earthquake, followed by degassing activity, which is consistent with an increase in the activity related to fluids (gas and magma). While in Llaima volcano, a high increase in the volcano tectonic activity was observed directly after the earthquake, consistent with a possible structural adjustment response. The values for pressure change and normal stress were calculated for the Maule earthquake (M8.8) giving results two orders of magnitude lower in comparison to the ones obtained for Valdivia earthquake (M9.5). Finally, these changes in the seismic behavior had lasted over a year, than it is possible to state that the Maule earthquake affected Llaima and Villarrica in some way due to static stress, but given the location and the insufficient critical state of both edifices, it was not possible to generate a great eruption.

  1. CO2 driven weathering vs plume driven weathering as inferred from the groundwater of a persistently degassing basaltic volcano: Mt. Etna

    NASA Astrophysics Data System (ADS)

    Liotta, Marcello; D'Alessandro, Walter

    2016-04-01

    probably also at other volcanoes characterized by huge open-conduit degassing activity.

  2. Long-term eruptive activity at a submarine arc volcano.

    PubMed

    Embley, Robert W; Chadwick, William W; Baker, Edward T; Butterfield, David A; Resing, Joseph A; de Ronde, Cornel E J; Tunnicliffe, Verena; Lupton, John E; Juniper, S Kim; Rubin, Kenneth H; Stern, Robert J; Lebon, Geoffrey T; Nakamura, Ko-ichi; Merle, Susan G; Hein, James R; Wiens, Douglas A; Tamura, Yoshihiko

    2006-05-25

    Three-quarters of the Earth's volcanic activity is submarine, located mostly along the mid-ocean ridges, with the remainder along intraoceanic arcs and hotspots at depths varying from greater than 4,000 m to near the sea surface. Most observations and sampling of submarine eruptions have been indirect, made from surface vessels or made after the fact. We describe here direct observations and sampling of an eruption at a submarine arc volcano named NW Rota-1, located 60 km northwest of the island of Rota (Commonwealth of the Northern Mariana Islands). We observed a pulsating plume permeated with droplets of molten sulphur disgorging volcanic ash and lapilli from a 15-m diameter pit in March 2004 and again in October 2005 near the summit of the volcano at a water depth of 555 m (depth in 2004). A turbid layer found on the flanks of the volcano (in 2004) at depths from 700 m to more than 1,400 m was probably formed by mass-wasting events related to the eruption. Long-term eruptive activity has produced an unusual chemical environment and a very unstable benthic habitat exploited by only a few mobile decapod species. Such conditions are perhaps distinctive of active arc and hotspot volcanoes. PMID:16724063

  3. Long-term eruptive activity at a submarine arc volcano

    USGS Publications Warehouse

    Embley, R.W.; Chadwick, W.W.; Baker, E.T.; Butterfield, D.A.; Resing, J.A.; De Ronde, C. E. J.; Tunnicliffe, V.; Lupton, J.E.; Juniper, S.K.; Rubin, K.H.; Stern, R.J.; Lebon, G.T.; Nakamura, K.-I.; Merle, S.G.; Hein, J.R.; Wiens, D.A.; Tamura, Y.

    2006-01-01

    Three-quarters of the Earth's volcanic activity is submarine, located mostly along the mid-ocean ridges, with the remainder along intraoceanic arcs and hotspots at depths varying from greater than 4,000 m to near the sea surface. Most observations and sampling of submarine eruptions have been indirect, made from surface vessels or made after the fact. We describe here direct observations and sampling of an eruption at a submarine arc volcano named NW Rota-1, located 60 km northwest of the island of Rota (Commonwealth of the Northern Mariana Islands). We observed a pulsating plume permeated with droplets of molten sulphur disgorging volcanic ash and lapilli from a 15-m diameter pit in March 2004 and again in October 2005 near the summit of the volcano at a water depth of 555 m (depth in 2004). A turbid layer found on the flanks of the volcano (in 2004) at depths from 700 m to more than 1,400 m was probably formed by mass-wasting events related to the eruption. Long-term eruptive activity has produced an unusual chemical environment and a very unstable benthic habitat exploited by only a few mobile decapod species. Such conditions are perhaps distinctive of active arc and hotspot volcanoes. ?? 2006 Nature Publishing Group.

  4. First measurements of gas output from bubbling pools in a mud volcano at the periphery of Mt Etna (Italy): methodologies and implications for monitoring purposes

    NASA Astrophysics Data System (ADS)

    Federico, Cinzia; Giudice, Gaetano; Liuzzo, Marco; Pedone, Maria; Cosenza, Paolo; Riccobono, Giuseppe

    2014-05-01

    Gases and brines emitted in the southern sector of Mt Etna from mofettes, mud pools and mud volcanoes come from an hydrothermal reservoir hosted within the clayey formations of the sedimentary basement (Chiodini et al., 1996). The gas emitted consists mainly of CO2, with CH4, N2 and He as minor species. CO2 and He stable isotopes indicate a clear magmatic origin for these gases, and their compositional changes during either eruptive or rest periods closely parallel that of crater fumaroles (Paonita et al., 2012). Altough these manifestations are the most significant CO2 emitters outside the crater area, their mass output has never been measured. We present the first measurements of gas flux from several bubbling mud pools in a mud volcano located in the village of Paternò (Lon 14.89° Lat 37.57°), in the southern flank of the volcano. We performed gas measurements using a home-made apparatus, able to capture all the bubbles over an area of 0.4 m2. Over an area of about 7000 m2, we measured the flow rate of every single bubbling pool, providing that it had a minimum flux rate of 0.5 l/min. The maximum measured flow rate for a single pool was 15 l/min. A preliminary estimate of the total CO2 output over the whole mud volcano is in the order of few t/d. At the same time, we measured the chemical composition of emitted gases in various pools, characterised by different gas flow rates, to calculate the output of CO2 and verify the effect of eventual chemical fractionation processes upon gas chemistry. During the same campaign of direct measurements, we also used a commercial infrared laser unit (GasFinder 2.0 from Boreal Laser Ltd) for measurement of volcanic CO2 path-integrated concentrations along cross-sections of the atmospheric plumes in the area. The GasFinder was set as to measure CO2 concentrations at 1 Hz rate. During the field campaigns, the position of the GasFinder unit was sequentially moved so as to scan the plumes from different viewing directions and

  5. The role of regional tectonics, magma pressure and gravitational spreading in earthquakes of the eastern sector of Mt. Etna volcano (Italy)

    NASA Astrophysics Data System (ADS)

    Patanè, G.; Montalto, A.; Imposa, S.; Menza, S.

    1994-07-01

    Data concerning M ⩾ 3.3 earthquakes that occurred in the eastern sector of Mt. Etna volcano (Sicily, Italy) in the period 1984-1989 are here presented and discussed. Only events with reliable focal mechanisms and detailed macroseismic investigations have been considered. Instrumental information come from local seismic networks, both permanent and temporary, run by the University of Catania (UCT), the Seismological Observatory of Acireale (SOACR), the CNRS (Grenoble, France) and the Institut de Physique du Globe de Paris (IPG, France). Observations regarding the macroseismic effects have been collected by means of field recognitions mainly carried out by the authors. All available data are analyzed in light of the more recent interpretations on the kinematic behaviour of the shallowest structures of Etna, with particular reference to its eastern flank which, according to Borgia et al. (1992), is likely affected by a seaward gravitational migration, driven by the sliding of this sector of the volcanic apparatus over its clay-rich substratum. The results obtained support the hypothesis that the shallow seismicity of the eastern flank of Mt. Etna is related to a complex stress field due to the combined effects of: (a) the tectonics associated with the interaction between the African and Eurasian plates; (b) the rise of magma into the crust; and (c) the gravitative seaward sliding of the eastern sector of the volcano. In particular, we hypothesize that: (1) tectonic forces caused the end of the 1984 eruption, by means of a "locking mechanism"; (2) the increment of magma pressure at depth is periodically responsible for local re-orientation of the stress field acting on the volcano, which also produces earthquakes of high intensity; (3) shallow earthquakes ( z < = 5 km), showing eastward compression mechanism, could be related to the gravitational sliding of unbuttressed sectors of the volcanic body accompanying the emplacement of intrusive dykes.

  6. Numerical model of heat conduction in active volcanoes induced by magmatic activity

    NASA Astrophysics Data System (ADS)

    Atmojo, Antono Arif; Rosandi, Yudi

    2015-09-01

    We study the heat transfer mechanism of active volcanoes using the numerical thermal conduction model. A 2D model of volcano with its conduit filled by magma is considered, and acts as a constant thermal source. The temperature of the magma activity diffuses through the rock layers of the mountain to the surface. The conduction equation is solved using finite-difference method, with some adaptations to allow temperature to flow through different materials. Our model allows to simulate volcanoes having dikes, branch-pipes, and sills by constructing the domain appropriately, as well as layers with different thermal properties. Our research will show the possibility to monitor magma activity underneath a volcano by probing its surface temperature. The result of our work will be very useful for further study of volcanoes, eruption prediction, and volcanic disaster mitigation.

  7. Fault activation after vigorous eruption: the December 8, 2015 seismic swarm at Mt. Etna

    NASA Astrophysics Data System (ADS)

    Alparone, Salvatore; Bonforte, Alessandro; Guglielmino, Francesco; Maiolino, Vincenza; Puglisi, Giuseppe; Ursino, Andrea

    2016-04-01

    From December 2, 2015, volcanic activity suddenly occurred on Mt. Etna with very violent fire fountaining at central crater, known also as "Voragine". This activity continued with other intense episodes at the same crater during the three following days and involving also, in turn, all the other three summit craters. This sudden eruption produced a rapid deflation of the volcano and was followed, from December 8, by a seismic swarm, with almost eighty earthquakes during this day, located on the uppermost segment of the Pernicana-Provenzana fault system (PFS). This seismicity was characterized by shallow foci (from few hundred meters until 1.5 km below the sea level) and mainshock with 3.6 magnitude. In order to investigate and measure the dynamics controlling and accompanying the PFS activation, a dataset composed of C-Band Sentinel-1A data has been used for SAR Interferometry (InSAR) analysis. Some interferograms have been generated from ascending and descending orbits in order to analyze both short- and long-term deformation. The availability of GPS data allowed comparing and integrating them with InSAR for ground truth and modeling aims. The surface kinematics and modeling obtained by DInSAR and GPS data and integration have been compared to the distribution of the seismicity and related focal mechanisms in order to define the fault geometry and motion. Moreover, essential constraints have been achieved about the PFS dynamic and its relationship with the intense volcanic activity occurred.

  8. 2011 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Maharrey, J. Zebulon; Neal, Christina A.

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near three separate volcanic centers in Alaska during 2011. The year was highlighted by the unrest and eruption of Cleveland Volcano in the central Aleutian Islands. AVO annual summaries no longer report on activity at Russian volcanoes.

  9. Eruption of Alkaline Basalts Prior to the Calc-alkaline Lavas of Mt. Cleveland Volcano, Aleutian Arc, Alaska

    NASA Astrophysics Data System (ADS)

    Bridges, D. L.; Nicolaysen, K. P.

    2005-12-01

    Mt. Cleveland is a 1,730 m stratovolcano, located on Chuginadak Island, that has erupted at least 23 times historically, with the latest occurring in August 2005. Major, trace, and REE analyses of 63 samples from Mt. Cleveland, including 8 from proximal cinder cones and 4 from andesitic domes on the lower flanks, identify two distinct lava suites. Modern Cleveland (MC) basalts to dacites (50.5-66.7 wt.% SiO2) exhibit a calc-alkaline differentiation trend. Major element trends suggest crystal fractionation of plagioclase +/- ortho- and clinopyroxene in MC lavas and olivine in cinder cone deposits. Resorption textures on plagioclase and olivine phenocrysts and multiple populations of plagioclase predominate throughout the MC suite suggesting magma mixing is a major process at Cleveland. Frothy white xenoliths of plagioclase + quartz + biotite are encased in glass and erupted as small pumiceous fragments in 2001. The partial resorption of the xenocrysts indicates assimilation is also an active crustal process at Cleveland. MC trace element spider diagrams exhibit a typical arc pattern in which HFS elements including Nb are depleted, and Pb and LIL elements are enriched. Th/La, Sm/La, and Sr, Nd, Pb, and Hf isotopic ratios indicate both a North Pacific MORB and a sediment component in the source of modern Cleveland lavas, consistent with sediment flux estimates of 90 to 95 m3/m/yr and an updip sediment thickness of 1300 to 1400 meters. Average 206Pb/204Pb, 207Pb/204Pb, 87Sr/86Sr, and 143Nd/144Nd values for the calc-alkaline suite are 18.93, 15.58, 0.70345, and 0.51303 respectively. The second suite consists of 3 olivine-rich, mildly alkaline basalts (48.5-49.4 wt.% SiO2), of older stratigraphic position than MC lavas representing deposits from an older phase of activity (ancestral Cleveland, AC). La/Yb, Sr/Y, and Th/Nb ratios indicate lower degrees of partial melting, relative to MC lavas, and suggests presence of garnet in the source region. The AC lavas, however, are

  10. Catalog of earthquake hypocenters at Redoubt Volcano and Mt. Spurr, Alaska: October 12, 1989 - December 31, 1990

    USGS Publications Warehouse

    Power, John A.; March, Gail D.; Lahr, John C.; Jolly, Arthur D.; Cruse, Gina R.

    1993-01-01

    Following a 23 year period of quiescence, Redoubt Volcano erupted between December 14,1989 and April 21,1990. The eruption was accompanied by thousands of earthquakes (Alaska Volcano Observatory Staff, 1990). Throughout the eruption sequence, data from the PC/AT system provided the primary means of determining earthquake hypocenters. This report catalogs the earthquake hypocenters and magnitudes calculated from data collected between October 12, 1989 and December 31, 1990 on the PC/AT acquisition system, provides station locations, statistics, and calibrations, and outlines which stations were recorded and used in triggering the PC/AT system.

  11. Contrahelicase activity of the mitochondrial transcription termination factor mtDBP

    PubMed Central

    Polosa, Paola Loguercio; Deceglie, Stefania; Roberti, Marina; Gadaleta, Maria Nicola; Cantatore, Palmiro

    2005-01-01

    The sea urchin mitochondrial D-loop binding protein (mtDBP) is a transcription termination factor that is able to arrest bidirectionally mitochondrial RNA chain elongation. The observation that the mtDBP binding site in the main non-coding region is located in correspondence of the 3′ end of the triplex structure, where the synthesis of heavy strand mitochondrial (mt) DNA is either prematurely terminated or allowed to continue, raised the question whether mtDBP could also regulate mtDNA replication. By using a helicase assay in the presence of the replicative helicase of SV40, we show that mtDBP is able to inhibit the enzyme thus acting as a contrahelicase. The impairing activity of mtDBP is bidirectional as it is independent of the orientation of the protein binding site. The inhibition is increased by the presence of the guanosine-rich sequence that flanks mtDBP binding site. Finally, a mechanism of abrogation of mtDBP contrahelicase activity is suggested that is based on the dissociation of mtDBP from DNA caused by the passage of the RNA polymerase through the protein–DNA complex. All these findings favour the view that mtDBP, besides serving as transcription termination factor, could also act as a negative regulator of mtDNA synthesis at the level of D-loop expansion. PMID:16006625

  12. Deep structure and origin of active volcanoes in China

    NASA Astrophysics Data System (ADS)

    Zhao, D.

    2010-12-01

    Recent geophysical studies have provided important constraints on the deep structure and origin of the active intraplate volcanoes in Mainland China. Magmatism in the western Pacific arc and back-arc areas is caused by the corner flow in the mantle wedge and dehydration of the subducting slab (e.g., Zhao et al., 2009a), while the intraplate magmatism in China has different origins. The active volcanoes in Northeast China (such as the Changbai and Wudalianchi) are caused by hot upwelling in the big mantle wedge (BMW) above the stagnant slab in the mantle transition zone and deep slab dehydration as well (Zhao et al., 2009b). The Tengchong volcano in Southwest China is caused by a similar process in the BMW above the subducting Burma microplate (or Indian plate) (Lei et al., 2009a). The Hainan volcano in southernmost China is a hotspot fed by a lower-mantle plume which may be associated with the Pacific and Philippine Sea slabs' deep subduction in the east and Indian slab's deep subduction in the west down to the lower mantle (Lei et al., 2009b; Zhao, 2009). The stagnant slab finally collapses down to the bottom of the mantle, which can trigger the upwelling of hot mantle materials from the lower mantle to the shallow mantle beneath the subducting slabs and may cause the slab-plume interactions (Zhao, 2009). References Lei, J., D. Zhao, Y. Su, 2009a. Insight into the origin of the Tengchong intraplate volcano and seismotectonics in southwest China from local and teleseismic data. J. Geophys. Res. 114, B05302. Lei, J., D. Zhao, B. Steinberger et al., 2009b. New seismic constraints on the upper mantle structure of the Hainan plume. Phys. Earth Planet. Inter. 173, 33-50. Zhao, D., 2009. Multiscale seismic tomography and mantle dynamics. Gondwana Res. 15, 297-323. Zhao, D., Z. Wang, N. Umino, A. Hasegawa, 2009a. Mapping the mantle wedge and interplate thrust zone of the northeast Japan arc. Tectonophysics 467, 89-106. Zhao, D., Y. Tian, J. Lei, L. Liu, 2009b. Seismic

  13. Capturing the fingerprint of Etna volcano activity in gravity and satellite radar data

    PubMed Central

    Negro, Ciro Del; Currenti, Gilda; Solaro, Giuseppe; Greco, Filippo; Pepe, Antonio; Napoli, Rosalba; Pepe, Susi; Casu, Francesco; Sansosti, Eugenio

    2013-01-01

    Long-term and high temporal resolution gravity and deformation data move us toward a better understanding of the behavior of Mt Etna during the June 1995 – December 2011 period in which the volcano exhibited magma charging phases, flank eruptions and summit crater activity. Monthly repeated gravity measurements were coupled with deformation time series using the Differential Synthetic Aperture Radar Interferometry (DInSAR) technique on two sequences of interferograms from ERS/ENVISAT and COSMO-SkyMed satellites. Combining spatiotemporal gravity and DInSAR observations provides the signature of three underlying processes at Etna: (i) magma accumulation in intermediate storage zones, (ii) magmatic intrusions at shallow depth in the South Rift area, and (iii) the seaward sliding of the volcano's eastern flank. Here we demonstrate the strength of the complementary gravity and DInSAR analysis in discerning among different processes and, thus, in detecting deep magma uprising in months to years before the onset of a new Etna eruption. PMID:24169569

  14. Fiber Bragg grating strain sensors to monitor and study active volcanoes

    NASA Astrophysics Data System (ADS)

    Sorrentino, Fiodor; Beverini, Nicolò; Carbone, Daniele; Carelli, Giorgio; Francesconi, Francesco; Gambino, Salvo; Giacomelli, Umberto; Grassi, Renzo; Maccioni, Enrico; Morganti, Mauro

    2016-04-01

    Stress and strain changes are among the best indicators of impending volcanic activity. In volcano geodesy, borehole volumetric strain-meters are mostly utilized. However, they are not easy to install and involve high implementation costs. Advancements in opto-electronics have allowed the development of low-cost sensors, reliable, rugged and compact, thus particularly suitable for field application. In the framework of the EC FP7 MED-SUV project, we have developed strain sensors based on the fiber Bragg grating (FBG) technology. In comparison with previous implementation of the FBG technology to study rock deformations, we have designed a system that is expected to offer a significantly higher resolution and accuracy in static measurements and a smooth dynamic response up to 100 Hz, implying the possibility to observe seismic waves. The system performances are tailored to suit the requirements of volcano monitoring, with special attention to power consumption and to the trade-off between performance and cost. Preliminary field campaigns were carried out on Mt. Etna (Italy) using a prototypal single-axis FBG strain sensor, to check the system performances in out-of-the-lab conditions and in the harsh volcanic environment (lack of mains electricity for power, strong diurnal temperature changes, strong wind, erosive ash, snow and ice during the winter time). We also designed and built a FBG strain sensor featuring a multi-axial configuration which was tested and calibrated in the laboratory. This instrument is suitable for borehole installation and will be tested on Etna soon.

  15. Capturing the fingerprint of Etna volcano activity in gravity and satellite radar data.

    PubMed

    Del Negro, Ciro; Currenti, Gilda; Solaro, Giuseppe; Greco, Filippo; Pepe, Antonio; Napoli, Rosalba; Pepe, Susi; Casu, Francesco; Sansosti, Eugenio

    2013-01-01

    Long-term and high temporal resolution gravity and deformation data move us toward a better understanding of the behavior of Mt Etna during the June 1995 - December 2011 period in which the volcano exhibited magma charging phases, flank eruptions and summit crater activity. Monthly repeated gravity measurements were coupled with deformation time series using the Differential Synthetic Aperture Radar Interferometry (DInSAR) technique on two sequences of interferograms from ERS/ENVISAT and COSMO-SkyMed satellites. Combining spatiotemporal gravity and DInSAR observations provides the signature of three underlying processes at Etna: (i) magma accumulation in intermediate storage zones, (ii) magmatic intrusions at shallow depth in the South Rift area, and (iii) the seaward sliding of the volcano's eastern flank. Here we demonstrate the strength of the complementary gravity and DInSAR analysis in discerning among different processes and, thus, in detecting deep magma uprising in months to years before the onset of a new Etna eruption. PMID:24169569

  16. Active Volcano Monitoring using a Space-based Hyperspectral Imager

    NASA Astrophysics Data System (ADS)

    Cipar, J. J.; Dunn, R.; Cooley, T.

    2010-12-01

    Active volcanoes occur on every continent, often in close proximity to heavily populated areas. While ground-based studies are essential for scientific research and disaster mitigation, remote sensing from space can provide rapid and continuous monitoring of active and potentially active volcanoes [Ramsey and Flynn, 2004]. In this paper, we report on hyperspectral measurements of Kilauea volcano, Hawaii. Hyperspectral images obtained by the US Air Force TacSat-3/ARTEMIS sensor [Lockwood et al, 2006] are used to obtain estimates of the surface temperatures for the volcano. ARTEMIS measures surface-reflected light in the visible, near-infrared, and short-wave infrared bands (VNIR-SWIR). The SWIR bands are known to be sensitive to thermal radiation [Green, 1996]. For example, images from the NASA Hyperion hyperspectral sensor have shown the extent of wildfires and active volcanoes [Young, 2009]. We employ the methodology described by Dennison et al, (2006) to obtain an estimate of the temperature of the active region of Kilauea. Both day and night-time images were used in the analysis. To improve the estimate, we aggregated neighboring pixels. The active rim of the lava lake is clearly discernable in the temperature image, with a measured temperature exceeding 1100o C. The temperature decreases markedly on the exterior of the summit crater. While a long-wave infrared (LWIR) sensor would be ideal for volcano monitoring, we have shown that the thermal state of an active volcano can be monitored using the SWIR channels of a reflective hyperspectral imager. References: Dennison, Philip E., Kraivut Charoensiri, Dar A. Roberts, Seth H. Peterson, and Robert O. Green (2006). Wildfire temperature and land cover modeling using hyperspectral data, Remote Sens. Environ., vol. 100, pp. 212-222. Green, R. O. (1996). Estimation of biomass fire temperature and areal extent from calibrated AVIRIS spectra, in Summaries of the 6th Annual JPL Airborne Earth Science Workshop, Pasadena, CA

  17. Dike propagation in active volcanoes: importance, evidence, models and perspectives

    NASA Astrophysics Data System (ADS)

    Acocella, V.

    2011-12-01

    Most eruptions are fed by dikes; therefore, better knowledge of dike propagation is crucial to improve our understanding of how magma is transferred and extruded at volcanoes. Dike pattern data from a few tens of active volcanic edifices show how dike propagation in a volcano is not a random process; rather, it depends from the following factors (listed in order of importance): the presence of relief, the shape of the edifice, the proximity to the surface, and regional tectonic control. Relief enhances the development of radial dikes, which may also cluster following volcano elongation or regional patterns. Dikes approaching the surface of volcanic edifices, regardless of their initial orientation, reorient to become radial (parallel to the maximum gravitational stress); in presence of scarps, dikes reorient subparallel to the scarp (perpendicular to the minimum gravitational stress). These relationships have been also observed or inferred during eruptions at Etna, Stromboli, Vesuvio (Italy), Erta Ale (Afar) and Faial (Azores). While numerical modelling of dike propagation remains challenging, analogue models of dike emplacement have been performed over a few decades, also supporting part of the above-described evidence. Analogue models have been mostly conducted injecting air or water within gelatine and, recently, injecting vegetable oil within sand. More sophisticated analogue modelling is foreseen for the future, using a more appropriate scaling, a larger sensitivity and providing a more quantitative approach in capturing relationships. More in general, future research on dikes should be devoted towards identifying dike propagation paths, dike arrest mechanisms, and likely locations of vent formation at specific volcanoes, to better aid hazards assessment.

  18. Venus lives!. [evidence for active volcanoes

    NASA Technical Reports Server (NTRS)

    Wood, Charles A.; Francis, Peter W.

    1988-01-01

    Observational evidence which supports the contention that Venus is a volcanically and tectonically active planet is discussed. It is argued that, although there are no observations to date that would prove that Venus has been volcanically active during the last decade, planetological studies presented evidence for youthful volcanic mountains on Venus: the surface of the northern quarter of Venus is considered to be younger than 1 Gy, and some units are likely to be much younger. Because of the small sizes of likely volcanic manifestations and the long intervals expected between eruptions, it is unlikely that any direct evidence of eruptions will be detected with existing and planned spacecraft. It is suggested that future studies of the dynamics and the chemical mixing of the Venusian atmosphere might supply an unequivocal evidence for active volcanism on this planet.

  19. Study of Seismic Activity at Ceboruco Volcano, Mexico

    NASA Astrophysics Data System (ADS)

    Nunez-Cornu, F. J.; Escudero, C. R.; Rodríguez Ayala, N. A.; Suarez-Plascencia, C.

    2013-12-01

    Many societies and their economies endure the disastrous consequences of destructive volcanic eruptions. The Ceboruco stratovolcano (2,280 m.a.s.l.) is located in Nayarit, Mexico, at the west of the Mexican volcanic belt and towards the Sierra de San Pedro southeast, which is a key communication point for coast of Jalisco and Nayarit and the northwest of Mexico. It last eruptive activity was in 1875, and during the following five years it presents superficial activity such as vapor emissions, ash falls and riodacitic composition lava flows along the southeast side. Although surface activity has been restricted to fumaroles near the summit, Ceboruco exhibits regular seismic unrest characterized by both low frequency seismic events and volcano-tectonic earthquakes. From March 2003 until July 2008 a three-component short-period seismograph Marslite station with a Lennartz 3D (1Hz) was deployed in the south flank (CEBN) and within 2 km from the summit to monitoring the seismic activity at the volcano. The LF seismicity recorded was classified using waveform characteristics and digital analysis. We obtained four groups: impulsive arrivals, extended coda, bobbin form, and wave package amplitude modulation earthquakes. The extended coda is the group with more earthquakes and present durations of 50 seconds. Using the moving particle technique, we read the P and S wave arrival times and estimate azimuth arrivals. A P-wave velocity of 3.0 km/s was used to locate the earthquakes, most of the hypocenters are below the volcanic edifice within a circular perimeter of 5 km of radius and its depths are calculated relative to the CEBN elevation as follows. The impulsive arrivals earthquakes present hypocenters between 0 and 1 km while the other groups between 0 and 4 km. Results suggest fluid activity inside the volcanic building that could be related to fumes on the volcano. We conclude that the Ceboruco volcano is active. Therefore, it should be continuously monitored due to the

  20. Interagency collaboration on an active volcano: a case study at Hawai‘i Volcanoes National Park

    USGS Publications Warehouse

    Kauahikaua, James P.; Orlando, Cindy

    2014-01-01

    Because Kilauea and Mauna Loa are included within the National Park, there is a natural intersection of missions for the National Park Service (NPS) and the U.S. Geological Survey (USGS). HAVO staff and the USGS Hawaiian Volcano Observatory scientists have worked closely together to monitor and forecast multiple eruptions from each of these volcanoes since HAVO’s founding in 1916.

  1. A Broadly-Based Training Program in Volcano Hazards Monitoring at the Center for the Study of Active Volcanoes

    NASA Astrophysics Data System (ADS)

    Thomas, D. M.; Bevens, D.

    2015-12-01

    The Center for the Study of Active Volcanoes, in cooperation with the USGS Volcano Hazards Program at HVO and CVO, offers a broadly based volcano hazards training program targeted toward scientists and technicians from developing nations. The program has been offered for 25 years and provides a hands-on introduction to a broad suite of volcano monitoring techniques, rather than detailed training with just one. The course content has evolved over the life of the program as the needs of the trainees have changed: initially emphasizing very basic monitoring techniques (e.g. precise leveling, interpretation of seismic drum records, etc.) but, as the level of sophistication of the trainees has increased, training in more advanced technologies has been added. Currently, topics of primary emphasis have included volcano seismology and seismic networks; acquisition and modeling of geodetic data; methods of analysis and monitoring of gas geochemistry; interpretation of volcanic deposits and landforms; training in LAHARZ, GIS mapping of lahar risks; and response to and management of volcanic crises. The course also provides training on public outreach, based on CSAV's Hawaii-specific hazards outreach programs, and volcano preparedness and interactions with the media during volcanic crises. It is an intensive eight week course with instruction and field activities underway 6 days per week; it is now offered in two locations, Hawaii Island, for six weeks, and the Cascades volcanoes of the Pacific Northwest, for two weeks, to enable trainees to experience field conditions in both basaltic and continental volcanic environments. The survival of the program for more than two decades demonstrates that a need for such training exists and there has been interaction and contribution to the program by the research community, however broader engagement with the latter continues to present challenges. Some of the reasons for this will be discussed.

  2. 2013 Mt. Etna Pyroclastic Activity through the ADCP Recordings of NEMO-SN1 Multidisciplinary Seafloor Observatory

    NASA Astrophysics Data System (ADS)

    Lo Bue, N.; Sgroi, T.; Giovinetti, G.; Marinaro, G.; Favali, P.

    2014-12-01

    The Acoustic Doppler Current Profiler (ADCP) is one of the most useful sensor used to measure speed and direction of sea currents in the water column. More often ADCPs are being also used to monitor concentration of suspended matter in rivers or in marine environments by the analysis of the acoustic backscatter intensity. In the framework of the European Research Infrastructure EMSO (European Multidisciplinary Seafloor and water-column Observatory, www.emso-eu.org), its cabled node, the NEMO-SN1 multidisciplinary seafloor observatory, was deployed in the Western Ionian Sea (Southern Italy) at a depth of 2100 m, about 25 km off-shore Eastern Sicily close to the submarine slope of the Mt. Etna volcano. Starting from February 2013, the Mt. Etna was interested by thirteen different parossistic events producing intense eruption followed by pyroclastic fallout that reached distances of tens kilometres from the eruptive centre. Four of these events affected the ESE sector with a consequent fallout in the Western Ionian Sea and they were detected by NEMO-SN1. In fact, its scientific payload also included an ADCP (RDI WorkHorse 600 kHz) with the main aim to monitor the hydrodynamic conditions of about 30 metres of the water column above the station. Surprisingly, this sensor offered spectacular recordings of the Mt. Etna pyroclastic activity occurred on 2013 wich affected the ESE sector. This work aims to present new records of pyroclastic fallout associated to explosive events observed at sea bottom by the analysis of backscatter signal of the ADCP. A multidisciplinary approach taking into account the Mt. Etna eruptive activity as well as the local oceanographic dynamic is necessary to describe marine processes involved in volcanic ash sedimentation.

  3. Active tectonic features and structural dynamics of the summit area of Mt. Etna (Italy) revealed by soil CO2 and soil temperature surveying

    NASA Astrophysics Data System (ADS)

    Giammanco, Salvatore; Melián, Gladys; Neri, Marco; Hernández, Pedro A.; Sortino, Francesco; Barrancos, José; López, Manuela; Pecoraino, Giovannella; Perez, Nemesio M.

    2016-02-01

    This work presents the results of an extensive geochemical survey aimed at measuring soil CO2 effluxes and soil temperatures over a large portion of Mt. Etna's summit area, coupled with an updated structural survey of the same area. The main goals of this study were i) to find concealed or hidden volcano-tectonic structures in the studied area by detecting anomalous soil gas emissions, ii) to investigate the origin of the emitted gas and the mechanism of gas and heat transport to the surface, iii) to produce a structural model based both on the surface geology and on the soil gas data and, lastly, iv) to contribute to the assessment of hazard from slope failure and crater collapses at Mt. Etna. The results revealed many concealed structural lines that followed the major directions of structural weakness in the summit area of Mt. Etna, mostly due to a combined action of gravitational spreading of the volcano and magma intrusions. Both recent and old volcano-tectonic lines were found to act as pathways for the leakage of magmatic gases to the surface. An important role in driving magmatic gases to the surface is also played by fracturing and faulting due to caldera-forming collapses and smaller crater collapses. Correlation between soil CO2 emissions and soil temperature allowed discriminating areas of active shallow hydrothermal circulation along deep fractures (characterized by high values of both parameters, but mostly soil temperature) from those affected by undeveloped fractures that did not reach the surface (characterized by high CO2 emissions at low temperature). The former corresponded to weak zones of the volcano edifice that were frequently site of past eruptions, indicating that those areas keep a high potential for future opening of eruptive fissures. The latter were likely related to sites where new eruptive fissures may open in the near future due to backward propagation of extensional tectonic stress.

  4. Patterns in Seismicity at Mt St Helens and Mt Unzen

    NASA Astrophysics Data System (ADS)

    Lamb, Oliver; De Angelis, Silvio; Lavallee, Yan

    2014-05-01

    Cyclic behaviour on a range of timescales is a well-documented feature of many dome-forming volcanoes. Previous work on Soufrière Hills volcano (Montserrat) and Volcán de Colima (Mexico) revealed broad-scale similarities in behaviour implying the potential to develop general physical models of sub-surface processes [1]. Using volcano-seismic data from Mt St Helens (USA) and Mt Unzen (Japan) this study explores parallels in long-term behaviour of seismicity at two dome-forming systems. Within the last twenty years both systems underwent extended dome-forming episodes accompanied by large Vulcanian explosions or dome collapses. This study uses a suite of quantitative and analytical techniques which can highlight differences or similarities in volcano seismic behaviour, and compare the behaviour to changes in activity during the eruptive episodes. Seismic events were automatically detected and characterized on a single short-period seismometer station located 1.5km from the 2004-2008 vent at Mt St Helens. A total of 714 826 individual events were identified from continuous recording of seismic data from 22 October 2004 to 28 February 2006 (average 60.2 events per hour) using a short-term/long-term average algorithm. An equivalent count will be produced from seismometer recordings over the later stages of the 1991-1995 eruption at MT Unzen. The event count time-series from Mt St Helens is then analysed using Multi-taper Method and the Short-Term Fourier Transform to explore temporal variations in activity. Preliminary analysis of seismicity from Mt St Helens suggests cyclic behaviour of subannual timescale, similar to that described at Volcán de Colima and Soufrière Hills volcano [1]. Frequency Index and waveform correlation tools will be implemented to analyse changes in the frequency content of the seismicity and to explore their relations to different phases of activity at the volcano. A single station approach is used to gain a fine-scale view of variations in

  5. Aerial monitoring in active mud volcano by UAV technique

    NASA Astrophysics Data System (ADS)

    Pisciotta, Antonino; Capasso, Giorgio; Madonia, Paolo

    2016-04-01

    UAV photogrammetry opens various new applications in the close range domain, combining aerial and terrestrial photogrammetry, but also introduces low-cost alternatives to the classical manned aerial photogrammetry. Between 2014 and 2015 tree aerial surveys have been carried out. Using a quadrotor drone, equipped with a compact camera, it was possible to generate high resolution elevation models and orthoimages of The "Salinelle", an active mud volcanoes area, located in territory of Paternò (South Italy). The main risks are related to the damages produced by paroxysmal events. Mud volcanoes show different cyclic phases of activity, including catastrophic events and periods of relative quiescence characterized by moderate activity. Ejected materials often are a mud slurry of fine solids suspended in liquids which may include water and hydrocarbon fluids, the bulk of released gases are carbon dioxide, with some methane and nitrogen, usually pond-shaped of variable dimension (from centimeters to meters in diameter). The scope of the presented work is the performance evaluation of a UAV system that was built to rapidly and autonomously acquire mobile three-dimensional (3D) mapping data in a volcanic monitoring scenario.

  6. Remote sensing for active volcano monitoring in Barren Island, India

    SciTech Connect

    Bhattacharya, A.; Reddy, C.S.S.; Srivastav, S.K. )

    1993-08-01

    The Barren Island Volcano, situated in the Andaman Sea of the Bay of Bengal, erupted recently (March, 1991) after a prolonged period of quiescence of about 188 years. This resumed activity coincides with similar outbreaks in the Philippines and Japan, which are located in an identical tectonic environment. This study addresses (1) remote sensing temporal monitoring of the volcanic activity, (2) detecting hot lava and measuring its pixel-integrated and subpixel temperatures, and (3) the importance of SWIR bands for high temperature volcanic feature detection. Seven sets of TM data acquired continuously from 3 March 1991 to 8 July 1991 have been analyzed. It is concluded that detectable pre-eruption warming took place around 25 March 1991 and volcanic activity started on 1 April 1991. It is observed that high temperature features, such as an erupting volcano, can register emitted thermal radiance in SWIR bands. Calculation of pixel-integrated and sub-pixel temperatures related to volcanic vents has been made, using the dual-band method. 6 refs.

  7. Using the Landsat Thematic Mapper to detect and monitor active volcanoes - An example from Lascar volcano, northern Chile

    NASA Technical Reports Server (NTRS)

    Francis, P. W.; Rothery, D. A.

    1987-01-01

    The Landsat Thematic Mapper (TM) offers a means of detecting and monitoring thermal features of active volcanoes. Using the TM, a prominent thermal anomaly has been discovered 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 Sept. 16, 1986. TM data acquired on Oct. 27, 1986, revealed significant changes within the crater area. 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. 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.

  8. Magmatic activity inferred from tree activity at Mt. Etna

    NASA Astrophysics Data System (ADS)

    Cherubini, P.; Houlié, N.; Noetzli, M.; Appert, T.; Cullotta, S.

    2008-12-01

    Volcanic activity can be detected using optical imagery focused on signal tree-growth anomalies (i.e., NDVI) (Houlié et al., 2006). Theses anomalous tree-growth signals maybe caused by changes in environmental conditions, but their actual causes still remain challenging to identify. We hypothesize that the possible factors involved can only be: 1) carbon dioxide degassing from the soil, 2) increase in soil temperature, 3) increase in water availability. As the correlation between tree growth seems established during the pre- eruptive activity for selected areas, we still don;t know if wether the trees have the capability to store to information and preserve it for a long time or not.We sampled cores from trees growing along the North Eastern rift zone flank of Etna, near Piano Provenzana (Sicily, Italy). Trees close to the fracture show larger activity while all trees might respond to a single stimulating source . We present here the results of this study and discuss the results under the light of the eruptive activity catalog during the last century.

  9. Volcanoes: Coming Up from Under.

    ERIC Educational Resources Information Center

    Science and Children, 1980

    1980-01-01

    Provides specific information about the eruption of Mt. St. Helens in March 1980. Also discusses how volcanoes are formed and how they are monitored. Words associated with volcanoes are listed and defined. (CS)

  10. Heterogeneous δ18O in the mantle wedge beneath Medicine Lake and Mt. Shasta volcanoes (California): ancient or modern subduction signature?

    NASA Astrophysics Data System (ADS)

    Martin, E.; Bindeman, I.; Grove, T.

    2008-12-01

    This study presents new analyses of O-isotopes in olivine phenocrysts from most primitive high alumina olivine tholeiite (HAOT) from Medicine Lake volcano (MLV; California) with MgO > 8%. The measured δ18OOl-values range from 4.69‰ to 5.49‰, with an average of 5.07‰ (n = 12), which is low relatively to the mantle olivine values (5.2‰±±0.2‰). We compare these data to O-isotopes measured in olivine phenocrysts from the most primitive lavas from Mount Shasta, which show high δ18OOl-values relatively to the olivine mantle value, 5.89-6.08‰ in HAOT (n = 2), 5.31-5.81‰ in basaltic andesite (BA; n = 7) and 5.54-5.85‰ in primitive magnesian andesite (PMA; n = 5). The primitive crystal poor nature of these lavas, Mg# > 0.65, and the fact that we analyzed olivine, the first mineral to crystallize in these lavas, allow us a good assessment to mantle-derived magmas. The HOAT are known to be generated by nearly anhydrous melting of spinel peridotite, which makes them a good indicator of the composition of the mantle unaffected by the present day subduction fluids. Therefore it appears that the mantle beneath MLV has a low- to mantle-like δ18OOl with variation of up to 0.8‰. However, beneath Mt Shasta the mantle has a relatively high δ18OOl and more homogeneous (based on two samples). Overall, it appears that the arc mantle of the South Cascade segment is heterogeneous with more than 1.3‰ variation in δ18OOl. The question that we address here is: Is the high-δ18O signature measured in olivine phenocrysts from BA and PMA from Mt Shasta come from the preexisting mantle source itself or from the present subduction fluids? If we consider BA and PMA to be generated by high-δ18O fluids flux melting in the present subduction environment, how can we explain high-δ18O values measured in HAOT? The heterogeneous character of the mantle in the South Cascades could be due to ancient subduction fluids more and more depleted during the slab dehydration that fluxed

  11. International Global Atmospheric Chemistry Programme global emissions inventory activity: Sulfur emissions from volcanoes, current status

    SciTech Connect

    Benkovitz, C.M.

    1995-07-01

    Sulfur emissions from volcanoes are located in areas of volcanic activity, are extremely variable in time, and can be released anywhere from ground level to the stratosphere. Previous estimates of global sulfur emissions from all sources by various authors have included estimates for emissions from volcanic activity. In general, these global estimates of sulfur emissions from volcanoes are given as global totals for an ``average`` year. A project has been initiated at Brookhaven National Laboratory to compile inventories of sulfur emissions from volcanoes. In order to complement the GEIA inventories of anthropogenic sulfur emissions, which represent conditions circa specific years, sulfur emissions from volcanoes are being estimated for the years 1985 and 1990.

  12. Automated system for magnetic monitoring of active volcanoes

    NASA Astrophysics Data System (ADS)

    Del Negro, Ciro; Napoli, Rosalba; Sicali, Antonino

    2002-01-01

    In order to provide a basis for short-term decision-making in the forecasting and monitoring of volcanic activity, we developed an entirely automated system of data acquisition and reduction for magnetic data. The system (Mag-Net) is designed to provide monitoring and analysis of magnetic data on Etna volcano at large distances from the central observatory. The Mag-Net system uses data from an array of continuously recording remote stations spread over the volcanic area and linked by mobile phone to the control center at the local observatory. At this location a computer receives the data and performs data sorting and reduction as well as limited evaluation to detect abnormal behavior or breakdown of remote sensors. Communication software, called MagTalk, is also designed to provide data to distant users. With a view to using continuous magnetic observations in advanced analysis techniques for volcano monitoring, the Mag-Net system also delivers two graphical user interface based applications to provide an interpretation capability. The former, called MADAP, speeds up all the data reduction processes in order to evaluate the reliability of magnetic signals. The latter, called VMM, is a procedure for modeling magnetic fields associated with tectonic and volcanic activity to facilitate the identification and interpretation of the sources of a wide spectrum of magnetic signals.

  13. Quantitative measurements of active Ionian volcanoes in Galileo NIMS data

    NASA Astrophysics Data System (ADS)

    Saballett, Sebastian; Rathbun, Julie A.; Lopes, Rosaly M. C.; Spencer, John R.

    2016-10-01

    Io is the most volcanically active body in our solar system. The spatial distribution of volcanoes a planetary body's surface gives clues into its basic inner workings (i.e., plate tectonics on earth). Tidal heating is the major contributor to active surface geology in the outer solar system, and yet its mechanism is not completely understood. Io's volcanoes are the clearest signature of tidal heating and measurements of the total heat output and how it varies in space and time are useful constraints on tidal heating. Hamilton et al. (2013) showed through a nearest neighbor analysis that Io's hotspots are globally random, but regionally uniform near the equator. Lopes-Gautier et al. (1999) compared the locations of hotspots detected by NIMS to the spatial variation of heat flow predicted by two end-member tidal heating models. They found that the distribution of hotspots is more consistent with tidal heating occurring in asthenosphere rather than the mantle. Hamilton et al. (2013) demonstrate that clustering of hotspots also supports a dominant role for asthenosphere heating. These studies were unable to account for the relative brightness of the hotspots. Furthermore, studies of the temporal variability of Ionian volcanoes have yielded substantial insight into their nature. The Galileo Near Infrared Mapping Spectrometer (NIMS) gave us a large dataset from which to observe active volcanic activity. NIMS made well over 100 observations of Io over an approximately 10-year time frame. With wavelengths spanning from 0.7 to 5.2 microns, it is ideally suited to measure blackbody radiation from surfaces with temperatures over 300 K. Here, we report on our effort to determine the activity level of each hotspot observed in the NIMS data. We decide to use 3.5 micron brightness as a proxy for activity level because it will be easy to compare to, and incorporate, ground-based observations. We fit a 1-temperature blackbody to spectra in each grating position and averaged the

  14. Crustal contamination and crystal entrapment during polybaric magma evolution at Mt. Somma-Vesuvius volcano, Italy: Geochemical and Sr isotope evidence

    USGS Publications Warehouse

    Piochi, M.; Ayuso, R.A.; de Vivo, B.; Somma, R.

    2006-01-01

    New major and trace element analyses and Sr-isotope determinations of rocks from Mt. Somma-Vesuvius volcano produced from 25 ky BP to 1944 AD are part of an extensive database documenting the geochemical evolution of this classic region. Volcanic rocks include silica undersaturated, potassic and ultrapotassic lavas and tephras characterized by variable mineralogy and different crystal abundance, as well as by wide ranges of trace element contents and a wide span of initial Sr-isotopic compositions. Both the degree of undersaturation in silica and the crystal content increase through time, being higher in rocks produced after the eruption at 472 AD (Pollena eruption). Compositional variations have been generally thought to reflect contributions from diverse types of mantle and crust. Magma mixing is commonly invoked as a fundamental process affecting the magmas, in addition to crystal fractionation. Our assessment of geochemical and Sr-isotopic data indicates that compositional variability also reflects the influence of crustal contamination during magma evolution during upward migration to shallow crustal levels and/or by entrapment of crystal mush generated during previous magma storage in the crust. Using a variant of the assimilation fractional crystallization model (Energy Conservation-Assimilation Fractional Crystallization; [Spera and Bohrson, 2001. Energy-constrained open-system magmatic processes I: General model and energy-constrained assimilation and fractional crystallization (EC-AFC) formulation. J. Petrol. 999-1018]; [Bohrson, W.A. and Spera, F.J., 2001. Energy-constrained open-system magmatic process II: application of energy-constrained assimilation-fractional crystallization (EC-AFC) model to magmatic systems. J. Petrol. 1019-1041]) we estimated the contributions from the crust and suggest that contamination by carbonate rocks that underlie the volcano (2 km down to 9-10 km) is a fundamental process controlling magma compositions at Mt. Somma

  15. Deciphering lava flow post-eruption differentiation processes by means of geochemical and isotopic variations: A case study from Mt. Etna volcano

    NASA Astrophysics Data System (ADS)

    Mollo, Silvio; Scarlato, Piergiorgio; Lanzafame, Gabriele; Ferlito, Carmelo

    2013-03-01

    We report results from geochemical and isotopic analyses conducted on nine samples collected from the vertical section of a pahoehoe lava flow unit from Mt. Etna volcano. Textural observations in the field show that, during lava emplacement, volatile exsolution and degassing allowed the nucleation and growth of bubbles, which subsequently rose from the base towards the uppermost lava crust. The amount of phenocrysts is low (about 12 vol.%) and their compositions are comparable to intratelluric crystals analyzed for from historical and recent products. In contrast, from the basal zone to the uppermost lava crust, groundmass microlites are characterized by progressively more primitive compositions, i.e., olivines and clinopyroxenes show increasing Mg#, plagioclases are enriched in anorthite, and the ulvospinel content in titanomagnetites increases. Calculations based on thermodynamic models, thermometers and oxygen barometers indicate that, during post-eruption conditions, crystals formed at higher crystallization temperatures with increasing vertical height. The redox state of the melt progressively increased from the base towards the uppermost crust of the lava flow as is attested by increasing Fe2O3/FeO ratios in clinopyroxene and titanomagnetite. The lowest fO2 is recorded at the basal zone and suggests that this part of the lava was inaccessible to diffusion of atmospheric oxygen at the time of emplacement; whereas, the highest fO2 measured for the uppermost lava crust testifies to post-eruptive hydrogen loss, mainly transported by carrier gas phases. Whole-rock analyses of lava samples also indicate higher Fe2O3/FeO ratios with increasing vertical height as well as substantial enrichments in MgO and transitional elements. Results from both mass balance and Rayleigh fractionation calculations show that about 6 vol.% of titanomagnetite and olivine microlites accumulated in the upper parts of the lava flow during emplacement. At the same time, due to progressive

  16. Catalogue of satellite photography of the active volcanoes of the world

    NASA Technical Reports Server (NTRS)

    Heiken, G.

    1976-01-01

    A catalogue is presented of active volcanoes as viewed from Earth-orbiting satellites. The listing was prepared of photographs, which have been screened for quality, selected from the earth resources technology satellite (ERTS) and Skylab, Apollo and Gemini spacecraft. There is photography of nearly every active volcano in the world; the photographs are particularly useful for regional studies of volcanic fields.

  17. Observing ground surface change series at active volcanoes in Indonesia using backscattering intensity of SAR data

    NASA Astrophysics Data System (ADS)

    Saepuloh, Asep; Trianaputri, Mila Olivia

    2015-04-01

    Indonesia contains 27 active volcanoes passing the West through the East part. Therefore, Indonesia is the most hazard front due to the volcanic activities. To obtain the new precursory signals leading to the eruptions, we applied remote sensing technique to observe ground surface change series at the summit of Sinabung and Kelud volcanoes. Sinabung volcano is located at Karo Region, North Sumatra Province. This volcano is a strato volcano type which is re-activated in August 2010. The eruption continues to the later years by ejecting volcanic products such as lava, pyroclastic flow, and ash fall deposits. This study is targeted to observe ground surface change series at the summit of Sinabung volcano since 2007 to 2011. In addition, we also compared the summit ground surface changes after the eruptions of Kelud volcano in 2007. Kelud volcano is also strato volcano type which is located at East Java, Indonesia. The Synthetic Aperture Radar (SAR) remotely sensed technology makes possible to observe rapidly a wide ground surface changes related to ground surface roughness. Detection series were performed by extracting the backscattering intensity of the Phased Array type L-band Synthetic Aperture Radar (PALSAR) onboard the Advanced Land Observing Satellite (ALOS). The intensity values were then calculated using a Normalized Radar Cross-Section (NRCS). Based on surface roughness criterion at the summit of Sinabung volcano, we could observe the ground surface changes prior to the early eruption in August 2010. The continuous increment of NRCS values showed clearly at window size 3×3 pixel of the summit of Sinabung volcano. The same phenomenon was also detected at the summit of Kelud volcano after the 2007 eruptions. The detected ground surface changes were validated using optical Landsat-8, backscattering intensity ratio for volcanic products detection, and radial component of a tilt-meter data.

  18. Volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory 1993

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.; Doukas, Michael P.

    1996-01-01

    During 1993, the Alaska Volcano Observatory (AVO) responded to episodes of eruptive activity or false alarms at nine volcanic centers in the state of Alaska. Additionally, as part of a formal role in KVERT (the Kamchatkan Volcano Eruption Response Team), AVO staff also responded to eruptions on the Kamchatka Peninsula, details of which are summarized in Miller and Kurianov (1993). In 1993, AVO maintained seismic instrumentation networks on four volcanoes of the Cook Inlet region--Spurr, Redoubt, Iliamna, and Augustine--and two stations at Dutton Volcano near King Cove on the Alaska Peninsula. Other routine elements of AVO's volcano monitoring program in Alaska include periodic airborne measurement of volcanic SO2 and CO2 at Cook Inlet volcanoes (Doukas, 1995) and maintenance of a lightning detection system in Cook Inlet (Paskievitch and others, 1995).

  19. A Benthic Invertebrate Survey of Jun Jaegyu Volcano: An active undersea volcano in Antarctic Sound, Antarctica

    NASA Astrophysics Data System (ADS)

    Quinones, G.; Brachfeld, S.; Gorring, M.; Prezant, R. S.; Domack, E.

    2005-12-01

    Jun Jaegyu volcano, an Antarctic submarine volcano, was dredged in May 2004 during cruise 04-04 of the RV Laurence M. Gould to determine rock, sediment composition and marine macroinvertebrate diversity. The objectives of this study are to examine the benthic assemblages and biodiversity present on a young volcano. The volcano is located on the continental shelf of the northeastern Antarctic Peninsula, where recent changes in surface temperature and ice shelf stability have been observed. This volcano was originally swath-mapped during cruise 01-07 of the Research Vessel-Ice Breaker Nathaniel B. Palmer. During LMG04-04 we also studied the volcano using a SCUD video camera, and performed temperature surveys along the flanks and crest. Both the video and the dredge indicate a seafloor surface heavily colonized by benthic organisms. Indications of fairly recent lava flows are given by the absence of marine life on regions of the volcano. The recovered dredge material was sieved, and a total of thirty-three invertebrates were extracted. The compilation of invertebrate community data can subsequently be compared to other benthic invertebrate studies conducted along the peninsula, which can determine the regional similarity of communities over time, their relationship to environmental change and health, if any, and their relationship to geologic processes in Antarctic Sound. Twenty-two rock samples, all slightly weathered and half bearing encrusted organisms, were also analyzed using inductively coupled plasma-optical emission spectrometry (ICP-OES). Except for one conglomerate sample, all are alkali basalts and share similar elemental compositions with fresh, unweathered samples from the volcano. Two of the encrusted basalt samples have significantly different compositions than the rest. We speculate this difference could be due to water loss during sample preparation, loss of organic carbon trapped within the vesicles of the samples and/or elemental uptake by the

  20. Linking subsurface to surface degassing at active volcanoes: A thermodynamic model with applications to Erebus volcano

    NASA Astrophysics Data System (ADS)

    Iacovino, Kayla

    2015-12-01

    Volcanic plumbing systems are the pathways through which volatiles are exchanged between the deep Earth and the atmosphere. The interplay of a multitude of processes occurring at various depths in the system dictates the composition and quantity of gas eventually erupted through volcanic vents. Here, a model is presented as a framework for interpreting surface volcanic gas measurements in terms of subsurface degassing processes occurring throughout a volcanic plumbing system. The model considers all possible sources of fluid from multiple depths, including degassing of dissolved volatiles during crystallization and/or decompression as recorded in melt inclusions plus any co-existing fluid phase present in a magma reservoir. The former is achieved by differencing melt inclusion volatile contents between groups of melt inclusions saturated at discrete depths. The latter is calculated using a thermodynamic model, which computes the composition of a C-O-H-S fluid in equilibrium with a melt given a minimum of five thermodynamic parameters commonly known for natural systems (T, P, fO2, either fH2 or one parameter for H2O, and either fS2 or one parameter for CO2). The calculated fluids are thermodynamically decompressed and run through a mixing model, which finds all possible mixtures of subsurface fluid that match the chemistry of surface gas within ±2.0 mol%. The method is applied to Mount Erebus (Antarctica), an active, intraplate volcano whose gas emissions, which emanate from an active phonolitic lava lake, have been well quantified by FTIR, UV spectroscopy, and multi-gas sensors over the last several decades. In addition, a well-characterized suite of lavas and melt inclusions, and petrological interpretations thereof, represent a wealth of knowledge about the shallow, intermediate, and deep parts of the Erebus plumbing system. The model has been used to calculate the compositions of seven C-O-H-S fluids that originate from four distinct regions within the Erebus

  1. The recent seismo-volcanic activity at Deception Island volcano

    NASA Astrophysics Data System (ADS)

    Ibáñez, Jesús M.; Almendros, Javier; Carmona, Enrique; Martínez-Arévalo, Carmen; Abril, Miguel

    2003-06-01

    This paper reviews the recent seismic studies carried out at Deception Island, South Shetland Islands, Antarctica, which was monitored by the Argentinean and Spanish Antarctic Programs since 1986. Several types of seismic network have been deployed temporarily during each Antarctic summer. These networks have consisted of a variety of instruments, including radio-telemetered stations, autonomous digital seismic stations, broadband seismometers, and seismic arrays. We have identified two main types of seismic signals generated by the volcano, namely pure seismo-volcanic signals, such as volcanic tremor and long-period (LP) events, and volcano-tectonic (VT) earthquakes. Their temporal distributions are far from homogeneous. Volcanic tremors and LP events usually occur in seismic swarms lasting from a few hours to some days. The number of LP events in these swarms is highly variable, from a background level of less than 30/day to a peak activity of about 100 events/h. The occurrence of VT earthquakes is even more irregular. Most VT earthquakes at Deception Island have been recorded during two intense seismic crises, in 1992 and 1999, respectively. Some of these VT earthquakes were large enough to be felt by researchers working on the island. Analyses of both types of seismic events have allowed us to derive source locations, establish seismic source models, analyze seismic attenuation, calculate the energy and stress drop of the seismic sources, and relate the occurrence of seismicity to the volcanic activity. Pure seismo-volcanic signals are modelled as the consequence of hydrothermal interactions between a shallow aquifer and deeper hot materials, resulting in the resonance of fluid-filled fractures. VT earthquakes constitute the brittle response to changes in the distribution of stress in the volcanic edifice. The two VT seismic series are probably related to uplift episodes due to deep injections of magma that did not reach the surface. This evidence, however

  2. Evolution of Deformation Studies on Active Hawaiian Volcanoes

    USGS Publications Warehouse

    Decker, Robert; Okamura, Arnold; Miklius, Asta; Poland, Michael

    2008-01-01

    Everything responds to pressure, even rocks. Deformation studies involve measuring and interpreting the changes in elevations and horizontal positions of the land surface or sea floor. These studies are variously referred to as geodetic changes or ground-surface deformations and are sometimes indexed under the general heading of geodesy. Deformation studies have been particularly useful on active volcanoes and in active tectonic areas. A great amount of time and energy has been spent on measuring geodetic changes on Kilauea and Mauna Loa Volcanoes in Hawai`i. These changes include the build-up of the surface by the piling up and ponding of lava flows, the changes in the surface caused by erosion, and the uplift, subsidence, and horizontal displacements of the surface caused by internal processes acting beneath the surface. It is these latter changes that are the principal concern of this review. A complete and objective review of deformation studies on active Hawaiian volcanoes would take many volumes. Instead, we attempt to follow the evolution of the most significant observations and interpretations in a roughly chronological way. It is correct to say that this is a subjective review. We have spent years measuring and recording deformation changes on these great volcanoes and more years trying to understand what makes these changes occur. We attempt to make this a balanced as well as a subjective review; the references are also selective rather than exhaustive. Geodetic changes caused by internal geologic processes vary in magnitude from the nearly infinitesimal - one micron or less, to the very large - hundreds of meters. Their apparent causes also are varied and include changes in material properties and composition, atmospheric pressure, tidal stress, thermal stress, subsurface-fluid pressure (including magma pressure, magma intrusion, or magma removal), gravity, and tectonic stress. Deformation is measured in units of strain or displacement. For example, tilt

  3. Recent Seismic and Geodetic Activity at Multiple Volcanoes in the Ecuadorean Andes

    NASA Astrophysics Data System (ADS)

    Hernandez, S.; Ruiz, M. C.; McCausland, W. A.; Prejean, S. G.; Mothes, P. A.; Bell, A. F.; Hidalgo, S.; Barrington, C.; Yepez, M.; Aguaiza, S.; Plain, M.

    2015-12-01

    The state of volcanic activity often fluctuates between periods of repose and unrest. The transition time between a period of repose and unrest, or vice versa for an open system, can occur within a matter of hours or days. Because of this short time scale, real-time seismic and geodetic (e.g. tiltmeter, GPS) monitoring networks are crucial for characterizing the state of activity of a volcano. In the Ecuadorean Andes, 5 volcanoes demonstrate long-term (Tungurahua, Reventador, and Guagua Pichincha) or recently reactivated (Cotopaxi, Chiles-Cerro Negro) seismic and geodetic activity. The Instituto Geofisico regularly characterizes volcano seismicity into long period, very long period, volcano-tectonic, and tremor events. Significant recent changes at these volcanoes include: rigorous reactivation of glacier-capped Cotopaxi, drumbeat seismicity absent a dome extrusion at Tungurahua, and regularly reoccurring (~7 day recurrence interval), shallow seismic swarms at Guagua Pichincha. These volcanoes locate along both the Western and Eastern Cordillera of the Ecuadorean Andes and, where data are available, manifest important variations in chemical composition, daily gas flux, and surficial deformation. We summarize the long-term geophysical parameters measured at each volcano and place recent changes in each parameter in a larger magmatic and hydrothermal context. All of the studied volcanoes present significant societal hazards to local and regional communities.

  4. Sangay volcano, Ecuador: structural development, present activity and petrology

    NASA Astrophysics Data System (ADS)

    Monzier, Michel; Robin, Claude; Samaniego, Pablo; Hall, Minard L.; Cotten, Jo; Mothes, Patricia; Arnaud, Nicolas

    1999-05-01

    Sangay (5230 m), the southernmost active volcano of the Andean Northern Volcanic Zone (NVZ), sits ˜130 km above a >32-Ma-old slab, close to a major tear that separates two distinct subducting oceanic crusts. Southwards, Quaternary volcanism is absent along a 1600-km-long segment of the Andes. Three successive edifices of decreasing volume have formed the Sangay volcanic complex during the last 500 ka. Two former cones (Sangay I and II) have been largely destroyed by sector collapses that resulted in large debris avalanches that flowed out upon the Amazon plain. Sangay III, being constructed within the last avalanche amphitheater, has been active at least since 14 ka BP. Only the largest eruptions with unusually high Plinian columns are likely to represent a major hazard for the inhabited areas located 30 to 100 km west of the volcano. However, given the volcano's relief and unbuttressed eastern side, a future collapse must be considered, that would seriously affect an area of present-day colonization in the Amazon plain, ˜30 km east of the summit. Andesites greatly predominate at Sangay, there being few dacites and basalts. In order to explain the unusual characteristics of the Sangay suite—highest content of incompatible elements (except Y and HREE) of any NVZ suite, low Y and HREE values in the andesites and dacites, and high Nb/La of the only basalt found—a preliminary five-step model is proposed: (1) an enriched mantle (in comparison with an MORB source), or maybe a variably enriched mantle, at the site of the Sangay, prior to Quaternary volcanism; (2) metasomatism of this mantle by important volumes of slab-derived fluids enriched in soluble incompatible elements, due to the subduction of major oceanic fracture zones; (3) partial melting of this metasomatized mantle and generation of primitive basaltic melts with Nb/La values typical of the NVZ, which are parental to the entire Sangay suite but apparently never reach the surface and subordinate

  5. Seismicity study of volcano-tectonic in and around Tangkuban Parahu active volcano in West Java region, Indonesia

    NASA Astrophysics Data System (ADS)

    Ry, Rexha V.; Priyono, A.; Nugraha, A. D.; Basuki, A.

    2016-05-01

    Tangkuban Parahu is one of the active volcano in Indonesia located about 15 km northern part of Bandung city. The objective of this study is to investigate the seismic activity in the time periods of January 2013 to December 2013. First, we identified seismic events induced by volcano-tectonic activities. These micro-earthquake events were identified as having difference of P-wave and S-wave arrival times less than three seconds. Then, we constrained its location of hypocenter to locate the source of the activities. Hypocenter determination was performed using adaptive simulated annealing method. Using these results, seismic tomographic inversions were conducted to image the three-dimensional velocity structure of Vp, Vs, and the Vp/Vs ratio. In this study, 278 micro-earthquake events have been identified and located. Distribution of hypocenters around Tangkuban Parahu volcano forms an alignment structure and may be related to the stress induced by magma below, also movement of shallow magma below Domas Crater. Our preliminary tomographic inversion results indicate the presences of low Vp, high Vs, and low Vp/Vs ratio that associate to accumulated young volcanic eruption products and hot material zones.

  6. 2013 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Dixon, James P.; Cameron, Cheryl; McGimsey, Robert G.; Neal, Christina A.; Waythomas, Chris

    2015-08-14

    The Alaska Volcano Observatory (AVO) responded to eruptions, volcanic unrest or suspected unrest, and seismic events at 18 volcanic centers in Alaska during 2013. Beginning with the 2013 AVO Summary of Events, the annual description of the AVO seismograph network and activity, once a stand-alone publication, is now part of this report. Because of this change, the annual summary now contains an expanded description of seismic activity at Alaskan volcanoes. Eruptions occurred at three volcanic centers in 2013: Pavlof Volcano in May and June, Mount Veniaminof Volcano in June through December, and Cleveland Volcano throughout the year. None of these three eruptive events resulted in 24-hour staffing at AVO facilities in Anchorage or Fairbanks.

  7. 2013 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Dixon, James P.; Cameron, Cheryl; McGimsey, Robert G.; Neal, Christina A.; Waythomas, Chris

    2015-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, volcanic unrest or suspected unrest, and seismic events at 18 volcanic centers in Alaska during 2013. Beginning with the 2013 AVO Summary of Events, the annual description of the AVO seismograph network and activity, once a stand-alone publication, is now part of this report. Because of this change, the annual summary now contains an expanded description of seismic activity at Alaskan volcanoes. Eruptions occurred at three volcanic centers in 2013: Pavlof Volcano in May and June, Mount Veniaminof Volcano in June through December, and Cleveland Volcano throughout the year. None of these three eruptive events resulted in 24-hour staffing at AVO facilities in Anchorage or Fairbanks.

  8. Identifying hazard parameter to develop quantitative and dynamic hazard map of an active volcano in Indonesia

    NASA Astrophysics Data System (ADS)

    Suminar, Wulan; Saepuloh, Asep; Meilano, Irwan

    2016-05-01

    Analysis of hazard assessment to active volcanoes is crucial for risk management. The hazard map of volcano provides information to decision makers and communities before, during, and after volcanic crisis. The rapid and accurate hazard assessment, especially to an active volcano is necessary to be developed for better mitigation on the time of volcanic crises in Indonesia. In this paper, we identified the hazard parameters to develop quantitative and dynamic hazard map of an active volcano. The Guntur volcano in Garut Region, West Java, Indonesia was selected as study area due population are resided adjacent to active volcanoes. The development of infrastructures, especially related to tourism at the eastern flank from the Summit, are growing rapidly. The remote sensing and field investigation approaches were used to obtain hazard parameters spatially. We developed a quantitative and dynamic algorithm to map spatially hazard potential of volcano based on index overlay technique. There were identified five volcano hazard parameters based on Landsat 8 and ASTER imageries: volcanic products including pyroclastic fallout, pyroclastic flows, lava and lahar, slope topography, surface brightness temperature, and vegetation density. Following this proposed technique, the hazard parameters were extracted, indexed, and calculated to produce spatial hazard values at and around Guntur Volcano. Based on this method, the hazard potential of low vegetation density is higher than high vegetation density. Furthermore, the slope topography, surface brightness temperature, and fragmental volcanic product such as pyroclastics influenced to the spatial hazard value significantly. Further study to this proposed approach will be aimed for effective and efficient analyses of volcano risk assessment.

  9. Embedded ARM system for volcano monitoring in remote areas: application to the active volcano on Deception Island (Antarctica).

    PubMed

    Peci, Luis Miguel; Berrocoso, Manuel; Fernández-Ros, Alberto; García, Alicia; Marrero, José Manuel; Ortiz, Ramón

    2014-01-01

    This paper describes the development of a multi-parameter system for monitoring volcanic activity. The system permits the remote access and the connection of several modules in a network. An embedded ARM™ processor has been used, allowing a great flexibility in hardware configuration. The use of a complete Linux solution (Debian™) as Operating System permits a quick, easy application development to control sensors and communications. This provides all the capabilities required and great stability with relatively low energy consumption. The cost of the components and applications development is low since they are widely used in different fields. Sensors and commercial modules have been combined with other self-developed modules. The Modular Volcano Monitoring System (MVMS) described has been deployed on the active Deception Island (Antarctica) volcano, within the Spanish Antarctic Program, and has proved successful for monitoring the volcano, with proven reliability and efficient operation under extreme conditions. In another context, i.e., the recent volcanic activity on El Hierro Island (Canary Islands) in 2011, this technology has been used for the seismic equipment and GPS systems deployed, thus showing its efficiency in the monitoring of a volcanic crisis.

  10. Embedded ARM System for Volcano Monitoring in Remote Areas: Application to the Active Volcano on Deception Island (Antarctica)

    PubMed Central

    Peci, Luis Miguel; Berrocoso, Manuel; Fernández-Ros, Alberto; García, Alicia; Marrero, José Manuel; Ortiz, Ramón

    2014-01-01

    This paper describes the development of a multi-parameter system for monitoring volcanic activity. The system permits the remote access and the connection of several modules in a network. An embedded ARM™™ processor has been used, allowing a great flexibility in hardware configuration. The use of a complete Linux solution (Debian™) as Operating System permits a quick, easy application development to control sensors and communications. This provides all the capabilities required and great stability with relatively low energy consumption. The cost of the components and applications development is low since they are widely used in different fields. Sensors and commercial modules have been combined with other self-developed modules. The Modular Volcano Monitoring System (MVMS) described has been deployed on the active Deception Island (Antarctica) volcano, within the Spanish Antarctic Program, and has proved successful for monitoring the volcano, with proven reliability and efficient operation under extreme conditions. In another context, i.e., the recent volcanic activity on El Hierro Island (Canary Islands) in 2011, this technology has been used for the seismic equipment and GPS systems deployed, thus showing its efficiency in the monitoring of a volcanic crisis. PMID:24451461

  11. Embedded ARM system for volcano monitoring in remote areas: application to the active volcano on Deception Island (Antarctica).

    PubMed

    Peci, Luis Miguel; Berrocoso, Manuel; Fernández-Ros, Alberto; García, Alicia; Marrero, José Manuel; Ortiz, Ramón

    2014-01-01

    This paper describes the development of a multi-parameter system for monitoring volcanic activity. The system permits the remote access and the connection of several modules in a network. An embedded ARM™ processor has been used, allowing a great flexibility in hardware configuration. The use of a complete Linux solution (Debian™) as Operating System permits a quick, easy application development to control sensors and communications. This provides all the capabilities required and great stability with relatively low energy consumption. The cost of the components and applications development is low since they are widely used in different fields. Sensors and commercial modules have been combined with other self-developed modules. The Modular Volcano Monitoring System (MVMS) described has been deployed on the active Deception Island (Antarctica) volcano, within the Spanish Antarctic Program, and has proved successful for monitoring the volcano, with proven reliability and efficient operation under extreme conditions. In another context, i.e., the recent volcanic activity on El Hierro Island (Canary Islands) in 2011, this technology has been used for the seismic equipment and GPS systems deployed, thus showing its efficiency in the monitoring of a volcanic crisis. PMID:24451461

  12. A Modality-Specific Feedforward Component of Choice-Related Activity in MT.

    PubMed

    Smolyanskaya, Alexandra; Haefner, Ralf M; Lomber, Stephen G; Born, Richard T

    2015-07-01

    The activity of individual sensory neurons can be predictive of an animal's choices. These decision signals arise from network properties dependent on feedforward and feedback inputs; however, the relative contributions of these inputs are poorly understood. We determined the role of feedforward pathways to decision signals in MT by recording neuronal activity while monkeys performed motion and depth tasks. During each session, we reversibly inactivated V2 and V3, which provide feedforward input to MT that conveys more information about depth than motion. We thus monitored the choice-related activity of the same neuron both before and during V2/V3 inactivation. During inactivation, MT neurons became less predictive of decisions for the depth task but not the motion task, indicating that a feedforward pathway that gives rise to tuning preferences also contributes to decision signals. We show that our data are consistent with V2/V3 input conferring structured noise correlations onto the MT population. PMID:26139374

  13. Risk-Free Volcano Observations Using an Unmanned Autonomous Helicopter: seismic observations near the active vent of Sakurajima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Ohminato, T.; Kaneko, T.; Koyama, T.; Yasuda, A.; Watanabe, A.; Takeo, M.; Honda, Y.; Kajiwara, K.; Kanda, W.; Iguchi, M.; Yanagisawa, T.

    2010-12-01

    Observations in the vicinity of summit area of active volcanoes are important not only for understanding physical processes in the volcanic conduit but also for eruption prediction and volcanic hazards mitigation. It is, however, challenging to install observation sensors near active vents because of the danger of sudden eruptions. We need safe and efficient ways of installing sensors near the summit of active volcanoes. We have been developing an volcano observation system based on an unmanned autonomous vehicle (UAV) for risk-free volcano observations. Our UAV is an unmanned autonomous helicopter manufactured by Yamaha-Motor Co., Ltd. The UAV is 3.6m long and weighs 84kg with maximum payload of 10kg. The UAV can aviate autonomously along a previously programmed path within a meter accuracy using real-time kinematics differential GPS equipment. The maximum flight time and distance from the operator are 90 minutes and 5km, respectively. We have developed various types of volcano observation techniques adequate for the UAV, such as aeromagnetic survey, taking infrared and visible images from onboard high-resolution cameras, volcanic ash sampling in the vicinity of active vents. Recently, we have developed an earthquake observation module (EOM), which is exclusively designed for the UAV installation in the vicinity of active volcanic vent. In order to meet the various requirements for UAV installation, the EOM is very compact, light-weight (5-6kg), and is solar-powered. It is equipped with GPS for timing, a communication device using cellular-phone network, and triaxial accelerometers. Our first application of the EOM installation using the UAV is one of the most active volcanoes in Japan, Sakurajima volcano. Since 2006, explosive eruptions have been continuing at the reopened Showa crater at the eastern flank near the summit of Sakurajima. Entering the area within 2 km from the active craters is prohibited, and thus there were no observation station in the vicinity

  14. Mt. St. Helens

    NASA Technical Reports Server (NTRS)

    2001-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1 Movie

    This 3-D anaglyph image of Mt. St. Helens volcano combines the nadir-looking and back-looking band 3 images of ASTER. To view the image in stereo, you will need blue-red glasses. Make sure to look through the red lens with your left eye. Figure 1: This ASTER image of Mt. St. Helens volcano in Washington was acquired on August 8, 2000 and covers an area of 37 by 51 km. Mount Saint Helens, a volcano in the Cascade Range of southwestern Washington that had been dormant since 1857, began to show signs of renewed activity in early 1980. On 18 May 1980, it erupted with such violence that the top of the mountain was blown off, spewing a cloud of ash and gases that rose to an altitude of 19 kilometers. The blast killed about 60 people and destroyed all life in an area of some 180 square kilometers (some 70 square miles), while a much larger area was covered with ash and debris. It continues to spit forth ash and steam intermittently. As a result of the eruption, the mountain's elevation decreased from 2,950 meters to 2,549 meters. The image is centered at 46.2 degrees north latitude, 122.2 degrees west longitude.

    Movie: The simulated fly-over was produced by draping ASTER visible and near infrared image data over a digital topography model, created from ASTER's 3-D stereo bands. The color was computer enhanced to create a natural color image, where the vegetation appears green. The topography has been exaggerated 2 times to enhance the appearance of the relief.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  15. Geochemical insight into differences in the physical structures and dynamics of two adjacent maar lakes at Mt. Vulture volcano (southern Italy)

    NASA Astrophysics Data System (ADS)

    Caracausi, A.; Nicolosi, M.; Nuccio, P. M.; Favara, R.; Paternoster, M.; Rosciglione, A.

    2013-05-01

    report on the first geochemical investigation of the Monticchio maar lakes (Mt. Vulture volcano, southern Italy) covering an annual cycle that aimed at understanding the characteristic features of the physical structures and dynamics of the two lakes. We provide the first detailed description of the lakes based on high-resolution conductivity-temperature-depth (CTD) profiles, chemical and isotopic (H and O) compositions of the water, and the amounts of dissolved gases (e.g., He, Ar, CH4, and CO2). The combined data set reveals that the two lakes, which are separated by less than 200 m, exhibit different dynamics: one is a meromictic lake, where the waters are rich in biogenic and mantle-derived gases, while the other is a monomictic lake, which exhibits complete turnover of the water in winter and the release of dissolved gases. Our data strongly suggest that the differences in the dynamics of the two lakes are due to different density profiles affected by dissolved solutes, mainly Fe, which is strongly enriched in the deep water of the meromictic lake. A conceptual model of water balance was constructed based on the correlation between the chemical composition of the water and the hydrogen isotopic signature. Gas-rich groundwaters that feed both of the lakes and evaporation processes subsequently modify the water chemistry of the lakes. Our data highlight that no further potential hazardous accumulation of lethal gases is expected at the Monticchio lakes. Nevertheless, geochemical monitoring is needed to prevent the possibility of vigorous gas releases that have previously occurred in historical time.

  16. Virtual Investigations of an Active Deep Sea Volcano

    NASA Astrophysics Data System (ADS)

    Sautter, L.; Taylor, M. M.; Fundis, A.; Kelley, D. S.; Elend, M.

    2013-12-01

    Axial Seamount, located on the Juan de Fuca spreading ridge 300 miles off the Oregon coast, is an active volcano whose summit caldera lies 1500 m beneath the sea surface. Ongoing construction of the Regional Scale Nodes (RSN) cabled observatory by the University of Washington (funded by the NSF Ocean Observatories Initiative) has allowed for exploration of recent lava flows and active hydrothermal vents using HD video mounted on the ROVs, ROPOS and JASON II. College level oceanography/marine geology online laboratory exercises referred to as Online Concept Modules (OCMs) have been created using video and video frame-captured mosaics to promote skill development for characterizing and quantifying deep sea environments. Students proceed at their own pace through a sequence of short movies with which they (a) gain background knowledge, (b) learn skills to identify and classify features or biota within a targeted environment, (c) practice these skills, and (d) use their knowledge and skills to make interpretations regarding the environment. Part (d) serves as the necessary assessment component of the laboratory exercise. Two Axial Seamount-focused OCMs will be presented: 1) Lava Flow Characterization: Identifying a Suitable Cable Route, and 2) Assessing Hydrothermal Vent Communities: Comparisons Among Multiple Sulfide Chimneys.

  17. Cyclic activity of the LUSI mud volcano (East Java, Indonesia)

    NASA Astrophysics Data System (ADS)

    Vanderkluysen, L.; Clarke, A. B.; Hartnett, H. E.

    2011-12-01

    Mud volcanoes often release fluids in a pulsating fashion, with periodic timescales ranging from minutes to days. These oscillations, common in natural systems of multi-phase fluid flow, are thought to result from some combination of complex feedback mechanisms between conduit and source geometry, and such factors as: fluid compressibility, viscosity and density, changes in lithostatic stresses, reservoir pressure, or vent conditions. The LUSI mud volcano is in a densely populated district of the Sidoarjo regency (East Java, Indonesia), and has been erupting since May 2006. Crisis management workers and local residents have reported observations of pulsating eruptive cycles lasting a few hours during the first two years of the eruption, and possibly beyond. Since 2010, however, the activity has shifted to individual transient eruptions recurring at intervals of a few minutes. In the summer of 2011, we documented this cyclic behavior at LUSI using a combination of high-resolution time-lapse photography, webcam, and thermal infrared imagery. The imagery reveals that hot mud and gases were released from three individual sources within the 150 m wide vent pond. The mud, consisting of at least 70% water, is erupted at temperatures close to boiling. Released gases consist principally of water vapor, carbon dioxide and methane. Eruptions ejected mud some 20 m above the vent in an unsteady fountain and formed 50 m-high plumes of hot gas. Pulses, on average 50 s in duration, were characterized by sharp onsets and exponential decays in intensity. We observed explosion periods ranging from 1 to 3 minutes during this campaign, the median period was 100 s, and pulses were separated by periods of apparent quiescence. Each vent was characterized by a different dominant period, indicating that parameters controlling activity vary among the vents. Potential conceptual eruptive models are gas accumulation and release, slug flow, or oscillations in pressure at depth to account for

  18. Interpreting Low Spatial Resolution Thermal Data from Active Volcanoes on Io and the Earth

    NASA Technical Reports Server (NTRS)

    Keszthelyi, L.; Harris, A. J. L.; Flynn, L.; Davies, A. G.; McEwen, A.

    2001-01-01

    The style of volcanism was successfully determined at a number of active volcanoes on Io and the Earth using the same techniques to interpret thermal remote sensing data. Additional information is contained in the original extended abstract.

  19. Shallow outgassing changes disrupt steady lava lake activity, Kilauea Volcano

    NASA Astrophysics Data System (ADS)

    Patrick, M. R.; Orr, T. R.; Swanson, D. A.; Lev, E.

    2015-12-01

    Persistent lava lakes are a testament to sustained magma supply and outgassing in basaltic systems, and the surface activity of lava lakes has been used to infer processes in the underlying magmatic system. At Kilauea Volcano, Hawai`i, the lava lake in Halema`uma`u Crater has been closely studied for several years with webcam imagery, geophysical, petrological and gas emission techniques. The lava lake in Halema`uma`u is now the second largest on Earth, and provides an unprecedented opportunity for detailed observations of lava lake outgassing processes. We observe that steady activity is characterized by continuous southward motion of the lake's surface and slow changes in lava level, seismic tremor and gas emissions. This normal, steady activity can be abruptly interrupted by the appearance of spattering - sometimes triggered by rockfalls - on the lake surface, which abruptly shifts the lake surface motion, lava level and gas emissions to a more variable, unstable regime. The lake commonly alternates between this a) normal, steady activity and b) unstable behavior several times per day. The spattering represents outgassing of shallowly accumulated gas in the lake. Therefore, although steady lava lake behavior at Halema`uma`u may be deeply driven by upwelling of magma, we argue that the sporadic interruptions to this behavior are the result of shallow processes occurring near the lake surface. These observations provide a cautionary note that some lava lake behavior is not representative of deep-seated processes. This behavior also highlights the complex and dynamic nature of lava lake activity.

  20. ETINDE. Improving the role of a methodological approach and ancillary ethnoarchaeological data application for place vulnerability and resilience to a multi-hazard environment: Mt. Cameroon volcano case study [MIA-VITA project -FP7-ENV-2007-1

    NASA Astrophysics Data System (ADS)

    Ilaria Pannaccione Apa, Maria; Kouokam, Emmanuel; Mbe Akoko, Robert; Peppoloni, Silvia; Fabrizia Buongiorno, Maria; Thierry, Pierre

    2013-04-01

    The FP7 MIA-VITA [Mitigate and assess risk from volcanic impact on terrain and human activities] project has been designed to address multidisciplinary aspects of volcanic threat assessment and management from prevention to crisis management recovery. In the socio-economic analysis carried out at Mt. Cameroon Bakweri and Bakossi ethnic groups, ancillary ethnoarchaeological information has been included to point out the cultural interaction between the volcano and its residents. In 2009-2011, ethnoanthropological surveys and interviews for data collection were carried out at Buea, Limbe, West Coast, Tiko and Muyuka sub-divisions adjacent to Mt. Cameroon. One of the outstanding, results from the Bakweri and Bakossi cultural tradition study: natural hazards are managed and produced by supernatural forces, as: Epasa Moto, God of the Mountain (Mt. Cameroon volcano) and Nyango Na Nwana , Goddess of the sea (Gulf of Guinea). In the case of Mount Cameroon, people may seek the spirit or gods of the mountain before farming, hunting and most recently the undertaking of the Mount Cameroon annual race are done. The spirit of this mountain must be seek to avert or stop a volcanic eruption because the eruption is attributed to the anger of the spirit. Among the Northern Bakweri, the association of spirits with the mountain could also be explained in terms of the importance of the mountain to the people. Most of their farming and hunting is done on the Mountain. Some forest products, for instance, wood for building and furniture is obtained from the forest of the mountain; this implies that the people rely on the Mountain for food, game and architecture/furniture etc. In addition, the eruption of the mountain is something which affects the people. It does not only destroy property, it frustrates people and takes away human lives when it occurs. Because of this economic importance of the Mountain and its unexpected and unwanted eruption, the tendency is to believe that it has some

  1. Mt. Spurr's 1992 eruptions

    USGS Publications Warehouse

    1993-01-01

    On 27 June, 1992, the Crater Peak vent on the south side of Mt. Spurr awoke from 39 years of dormancy and burst into sub-plinian eruption after 10 months of elevated seismicity. Two more eruptions followed in August and September. The volcano lies 125 km west of Anchorage, Alaska's largest city and an important international hub for air travel. The Alaska Volcano Observatory (AVO) was able to warn communities and the aviation industry well in advance of these eruptions.

  2. Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow

    PubMed Central

    Katsuyama, Narumi; Usui, Nobuo; Taira, Masato

    2016-01-01

    A moving cast shadow is a powerful monocular depth cue for motion perception in depth. For example, when a cast shadow moves away from or toward an object in a two-dimensional plane, the object appears to move toward or away from the observer in depth, respectively, whereas the size and position of the object are constant. Although the cortical mechanisms underlying motion perception in depth by cast shadow are unknown, the human MT complex (hMT+) is likely involved in the process, as it is sensitive to motion in depth represented by binocular depth cues. In the present study, we examined this possibility by using a functional magnetic resonance imaging (fMRI) technique. First, we identified the cortical regions sensitive to the motion of a square in depth represented via binocular disparity. Consistent with previous studies, we observed significant activation in the bilateral hMT+, and defined functional regions of interest (ROIs) there. We then investigated the activity of the ROIs during observation of the following stimuli: 1) a central square that appeared to move back and forth via a moving cast shadow (mCS); 2) a segmented and scrambled cast shadow presented beside the square (sCS); and 3) no cast shadow (nCS). Participants perceived motion of the square in depth in the mCS condition only. The activity of the hMT+ was significantly higher in the mCS compared with the sCS and nCS conditions. Moreover, the hMT+ was activated equally in both hemispheres in the mCS condition, despite presentation of the cast shadow in the bottom-right quadrant of the stimulus. Perception of the square moving in depth across visual hemifields may be reflected in the bilateral activation of the hMT+. We concluded that the hMT+ is involved in motion perception in depth induced by moving cast shadow and by binocular disparity. PMID:27597999

  3. Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow.

    PubMed

    Katsuyama, Narumi; Usui, Nobuo; Taira, Masato

    2016-01-01

    A moving cast shadow is a powerful monocular depth cue for motion perception in depth. For example, when a cast shadow moves away from or toward an object in a two-dimensional plane, the object appears to move toward or away from the observer in depth, respectively, whereas the size and position of the object are constant. Although the cortical mechanisms underlying motion perception in depth by cast shadow are unknown, the human MT complex (hMT+) is likely involved in the process, as it is sensitive to motion in depth represented by binocular depth cues. In the present study, we examined this possibility by using a functional magnetic resonance imaging (fMRI) technique. First, we identified the cortical regions sensitive to the motion of a square in depth represented via binocular disparity. Consistent with previous studies, we observed significant activation in the bilateral hMT+, and defined functional regions of interest (ROIs) there. We then investigated the activity of the ROIs during observation of the following stimuli: 1) a central square that appeared to move back and forth via a moving cast shadow (mCS); 2) a segmented and scrambled cast shadow presented beside the square (sCS); and 3) no cast shadow (nCS). Participants perceived motion of the square in depth in the mCS condition only. The activity of the hMT+ was significantly higher in the mCS compared with the sCS and nCS conditions. Moreover, the hMT+ was activated equally in both hemispheres in the mCS condition, despite presentation of the cast shadow in the bottom-right quadrant of the stimulus. Perception of the square moving in depth across visual hemifields may be reflected in the bilateral activation of the hMT+. We concluded that the hMT+ is involved in motion perception in depth induced by moving cast shadow and by binocular disparity. PMID:27597999

  4. Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow.

    PubMed

    Katsuyama, Narumi; Usui, Nobuo; Taira, Masato

    2016-01-01

    A moving cast shadow is a powerful monocular depth cue for motion perception in depth. For example, when a cast shadow moves away from or toward an object in a two-dimensional plane, the object appears to move toward or away from the observer in depth, respectively, whereas the size and position of the object are constant. Although the cortical mechanisms underlying motion perception in depth by cast shadow are unknown, the human MT complex (hMT+) is likely involved in the process, as it is sensitive to motion in depth represented by binocular depth cues. In the present study, we examined this possibility by using a functional magnetic resonance imaging (fMRI) technique. First, we identified the cortical regions sensitive to the motion of a square in depth represented via binocular disparity. Consistent with previous studies, we observed significant activation in the bilateral hMT+, and defined functional regions of interest (ROIs) there. We then investigated the activity of the ROIs during observation of the following stimuli: 1) a central square that appeared to move back and forth via a moving cast shadow (mCS); 2) a segmented and scrambled cast shadow presented beside the square (sCS); and 3) no cast shadow (nCS). Participants perceived motion of the square in depth in the mCS condition only. The activity of the hMT+ was significantly higher in the mCS compared with the sCS and nCS conditions. Moreover, the hMT+ was activated equally in both hemispheres in the mCS condition, despite presentation of the cast shadow in the bottom-right quadrant of the stimulus. Perception of the square moving in depth across visual hemifields may be reflected in the bilateral activation of the hMT+. We concluded that the hMT+ is involved in motion perception in depth induced by moving cast shadow and by binocular disparity.

  5. Analysis of Active Lava Flows on Kilauea Volcano, Hawaii, Using SIR-C Radar Correlation Measurements

    NASA Technical Reports Server (NTRS)

    Zebker, H. A.; Rosen, P.; Hensley, S.; Mouginis-Mark, P. J.

    1995-01-01

    Precise eruption rates of active pahoehoe lava flows on Kilauea volcano, Hawaii, have been determined using spaceborne radar data acquired by the Space Shuttle Imaging Radar-C (SIR-C). Measurement of the rate of lava flow advance, and the determination of the volume of new material erupted in a given period of time, are among the most important observations that can be made when studying a volcano.

  6. Use of SAR data to study active volcanoes in Alaska

    USGS Publications Warehouse

    Dean, K.G.; Engle, K.; Lu, Zhiming; Eichelberger, J.; Neal, T.; Doukas, M.

    1996-01-01

    Synthetic Aperture Radar (SAR) data of Westdahl, Veniaminof, and Novarupta volcanoes in the Aleutian Arc of Alaska were analyzed to investigate recent surface volcanic processes. These studies support ongoing monitoring and research by the Alaska Volcano Observatory (AVO) in the North Pacific Ocean Region. Landforms and possible crustal deformation before, during, or after eruptions were detected and analyzed using data from the European Remote Sensing Satellites (ERS), Japanese Earth Resources Satellite (JERS) and the U. S. Seasat platforms. Field observations collected by scientists from the AVO were used to verify the results from the analysis of SAR data.

  7. Use of SAR data to study active volcanoes in Alaska

    USGS Publications Warehouse

    Dean, K.G.; Engle, K.; Lu, Zhiming; Eichelberger, J.; Near, T.; Doukas, M.

    1996-01-01

    Synthetic Aperture Radar (SAR) data of the Westdahl, Veniaminof, and Novarupta volcanoes in the Aleutian Arc of Alaska were analysed to investigate recent surface volcanic processes. These studies support ongoing monitoring and research by the Alaska Volcano Observatory (AVO) in the North Pacific Ocean Region. Landforms and possible crustal deformation before, during, or after eruptions were detected and analysed using data from the European Remote Sensing Satellites (ERS), the Japanese Earth Resources Satellite (JERS) and the US Seasat platforms. Field observations collected by scientists from the AVO were used to verify the results from the analysis of SAR data.

  8. Dynamics of magma supply at Mt. Etna volcano (Southern Italy) as revealed by textural and compositional features of plagioclase phenocrysts

    NASA Astrophysics Data System (ADS)

    Viccaro, Marco; Giacomoni, Pier Paolo; Ferlito, Carmelo; Cristofolini, Renato

    2010-04-01

    A systematic study of textural and compositional zoning (An% and FeO variation) in plagioclase phenocrysts of historic (pre-1971) and recent (post-1971) lavas at Mount Etna was made through back-scattered electron (BSE) images and electron microprobe analyses (EMP). The textures considered include oscillatory zoning and several types of dissolution, resorption and growth textures at the phenocryst cores and/or rims. Two patterns of oscillation were recognized from the combined An-FeO variation: 1) Low Amplitude-High Frequency (LAHF) and 2) High Amplitude-Low Frequency (HALF). The first pattern is interpreted here as due to kinetic effects at the plagioclase/melt interface which developed during crystallization in closed reservoirs. The second, which sometimes involves thin dissolution surfaces marked by irregular edges, angular unconformities and complex dissolution-regrowth patterns, might imply crystallization in a more dynamic regime, probably driven by chemical and physical gradients of the system (e.g., convection in a steadily degassing open-conduit). Dissolution and resorption textures at the core vary from patchy (exclusive to plagioclases within pre-1971 lavas) to strongly sieved, and can be related to increasing rates of decompression under H 2O-undersaturated conditions. Thick sieve-textured envelopes at the phenocryst rims, generally coupled with marked An-FeO increase, result from mixing with more primitive and volatile-rich magmas. In the same crystals from recent activity, An and, to a lesser extent, FeO increase, consistent with the mixing of H 2O-rich magmas similar in their mafic character to the resident magma (cryptic mixing). Two types of growth textures were also recognized at the crystal rims: 1) stripes of regularly-shaped melt inclusions and 2) swallow-tailed, skeletal crystals. In the first instance, the concordant An-FeO decrease suggests crystallization caused by fast ascent-related decompression accompanied by volatile loss. In the

  9. Real-time measurements of Hg0 and H2S at La Solfatara Crater (Campi Flegrei, Southern Italy) and Mt. Amiata volcano (Siena, Central Italy): a new geochemical approach to estimate the distribution of air contaminants

    NASA Astrophysics Data System (ADS)

    Cabassi, J.; Calabrese, S.; Tassi, F.; Venturi, S.; Capecchiacci, F.; Di Lonardo, C.; D'Alessandro, W.; Vaselli, O.

    2014-12-01

    The emission of Hg and H2S from natural and anthropogenic sources may have a great environmental impact in urban areas as well as in the surroundings of active and passive degassing volcanoes. Mercury is present in the atmosphere mainly in its elemental form (Hg0~98 %), which has a relatively high volatility, low solubility and chemical inertness. Hydrogen sulfide, one of the most abundant gas species in volcanic fluids, is highly poisoning and corrosive. In this study, an innovative real-time method for the measurements of Hg0 and H2S concentrations in air was carried out at La Solfatara Crater, a hydrothermally altered tuff-cone nested in the town of Pozzuoli (Southern Italy), and at Mt. Amiata volcano (Central Italy), where a world-class Hg mining district abandoned in the seventies and a presently-exploited geothermal field for the production of electrical energy occur. The main aims were (i) to test this new methodological approach and (ii) to investigate Hg0 and H2S concentrations and the chemical-physical parameters regulating their spatial distribution in polluted areas. A portable Zeeman atomic absorption spectrometer with high frequency modulation of light polarization (Lumex RA-915M) was used in combination with a pulsed fluorescence gas analyzer (Thermo Scientific Model 450i) to measure Hg0 and H2S, respectively. The instruments were synchronized and set at high-frequency acquisition (10 sec and 1 min, respectively). Measurements were carried out along pathways (up to 12 km long) at an average speed of <10 km/h and coupled with GPS data and meteorological parameters. In selected sites, passive samplers were positioned to determine the time-integrated Hg0 and H2S concentrations to be compared with the real-time measurements. The results indicate that this approach is highly efficient and effective in providing reliable and reproducible Hg0 and H2S concentrations and can be used to identify and characterize gas emitters in different environments.

  10. Morne aux Diables. a potentially active volcano in northern Dominica, Lesser Antilles

    NASA Astrophysics Data System (ADS)

    Rheubottom, A. N.; Smith, A. L.; Roobol, M. J.

    2005-12-01

    The island of Dominica, which is located near the center of the Lesser Antilles island arc, comprises at least 8 potentially active volcanoes. One of these is Morne aux Diables, an isolated composite cone situated at the extreme northern end of the island. Age dating suggests that the main cone building activity occurred between 1.5 and 1.0 million years ago. Exposed on the volcano's flanks however are a number of unconsolidated valley-fill block and ash flow deposits suggesting more recent activity. One of these deposits, on the north-east flank of the volcano, has been recently dated at > 46,000 years B.P. Other evidence of potential activity from this center includes the presence of warm (27°C), acidic (pH 1.6), sulfate-rich springs on the summit of the volcano, hot springs on the coast, and the occurrence in 2002 and 2003 of shallow earthquake swarms partially located beneath the volcano. Morne aux Diables is dominantly composed of deposits of block and ash flows and associated domes from Pelean-style activity, however, semi-vesicular andesite block and ash flows and surges (Asama-style activity) and pumiceous lapilli falls (Plinian-style activity) are locally abundant. The Pelean domes are located both in the summit region and along the southern flanks of the volcano. Petrologically, the volcano is composed of a monotonous series of porphyritic andesites and dacites containing phenocrysts of plagioclase+augite-hypersthene with very sparse crystals of hornblende and quartz. Petrological models suggest the Morne aux Diables andesites and dacites can be produced by fractional crystallization of basaltic magma (such as those erupted from centers such as Morne Anglais and Morne Plat Pays in the south). Minor variations within this suite of andesites and dacites can be related to upper crustal fractionation of phenocryst phases.

  11. Case Studies of Airborne Electromagnetic Survey of Volcanoes

    NASA Astrophysics Data System (ADS)

    Seto, S.; Takahara, T.; Kinoshita, A.; Mizuno, H.; Kawato, K.; Okumura, M.; Kageura, R.

    2015-12-01

    At Mt. Ontake in 1984 and Mt. Kurikoma in 2008, parts of the volcanoes collapsed and large-scale sediment disasters occurred. These events were unrelated to volcanic eruption. We conducted case studies using airborne electromagnetic surveys to investigate the slopes likely to cause landslides on such volcanoes. The surveys were conducted by using a helicopter carrying survey instruments; this method of non-contact investigation acquires specific electrical resistance data by electromagnetic induction. Airborne electromagnetic surveys were conducted of 15 active volcanoes where volcanic events could have serious social implications. These case studies extracted data showing only roughly the areas that were at risk of collapse, but this was the first time that such data on slopes likely to cause landslides and on estimated collapse depths were obtained. It remains necessary to find a method of extracting precise data on the slopes likely to induce landslides on each volcano. First, we collected the results of the volcano surveys and categorized the properties of the collapsed slopes as cap rock type, extended collapse type, or landslide type on the basis of the topography, geological information, and specific electrical resistivity structure. Second, we investigated whether the properties of each volcano were the same as these typified ones. We also defined a collapse range based mainly on the topography and geological properties and also on the collapse depth, which was based on the specific electrical resistivity structure. We revealed that we could use the defined collapse range and depth to estimate the sediment volume of the slopes that were likely to induce landslides. Several cases, including Mt. Hokkaido Komagatake, Mt. Azuma, Mt. Asama, and Mt. Ontake, will be introduced in this presentation.

  12. 2010 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; Herrick, Julie; Girina, O.A.; Chibisova, Marina; Rybin, Alexander; McGimsey, Robert G.; Dixon, Jim

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest or suspected unrest at 12 volcanic centers in Alaska during 2010. The most notable volcanic activity consisted of intermittent ash emissions from long-active Cleveland volcano in the Aleutian Islands. AVO staff also participated in hazard communication regarding eruptions or unrest at seven volcanoes in Russia as part of an ongoing collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  13. The expanding roles of 1-methyl-tryptophan (1-MT): in addition to inhibiting kynurenine production, 1-MT activates the synthesis of melatonin in skin cells.

    PubMed

    Moreno, Ana C R; Clara, Renan O; Coimbra, Janine B; Júlio, Ariane R; Albuquerque, Renata C; Oliveira, Edson M; Maria-Engler, Silvya S; Campa, Ana

    2013-10-01

    Indoleamine 2,3-dioxygenase 1 (IDO1), the rate-limiting enzyme of tryptophan catabolism, has been strongly associated with the progression of malignancy and poor survival in melanoma patients. As a result, IDO1 is a leading target for interventions aimed at restoring melanoma immune surveillance. Here, in a scenario involving the tryptophan catabolism, we report that melatonin biosynthesis is driven by 1-methyl-tryptophan (1-MT), a competitive inhibitor of IDO1, in human fibroblasts, melanocytes and melanoma cells. In addition to melatonin biosynthesis, 1-MT induced the expression of tryptophan hydroxylase, arylalkylamine-N-acetyltransferase and hydroxyindole O-methyltransferase mRNA in fibroblasts and melanocytes. We observed a great variability in the levels of IDO1 mRNA expression and kynurenine release between skin cells and melanoma cell lines in response to interferon-γ, a classical IDO1 inducer. In this setting, melatonin was shown to downregulate kynurenine production. Furthermore, in a condition of low basal activity of IDO1, it was observed that 1-MT, as well melatonin, inhibited the proliferation of human melanoma cells. Taken together, our results suggest that 1-MT may serve as more than just a tool to disrupt tumor immune escape (via the inhibition of IDO1) because it was shown to act directly on the proliferation of human melanoma cells and induce melatonin biosynthesis in the tumor milieu. Moreover, 1-MT-mediated inhibition of IDO occurs in normal skin and melanoma cells, which addresses the possibility that all cells in the skin microenvironment can be targeted by 1-MT. Our findings provide innovative approaches into understanding tumor therapy related to the control of tryptophan metabolism by 1-MT.

  14. Vestibular activation differentially modulates human early visual cortex and V5/MT excitability and response entropy.

    PubMed

    Seemungal, Barry M; Guzman-Lopez, Jessica; Arshad, Qadeer; Schultz, Simon R; Walsh, Vincent; Yousif, Nada

    2013-01-01

    Head movement imposes the additional burdens on the visual system of maintaining visual acuity and determining the origin of retinal image motion (i.e., self-motion vs. object-motion). Although maintaining visual acuity during self-motion is effected by minimizing retinal slip via the brainstem vestibular-ocular reflex, higher order visuovestibular mechanisms also contribute. Disambiguating self-motion versus object-motion also invokes higher order mechanisms, and a cortical visuovestibular reciprocal antagonism is propounded. Hence, one prediction is of a vestibular modulation of visual cortical excitability and indirect measures have variously suggested none, focal or global effects of activation or suppression in human visual cortex. Using transcranial magnetic stimulation-induced phosphenes to probe cortical excitability, we observed decreased V5/MT excitability versus increased early visual cortex (EVC) excitability, during vestibular activation. In order to exclude nonspecific effects (e.g., arousal) on cortical excitability, response specificity was assessed using information theory, specifically response entropy. Vestibular activation significantly modulated phosphene response entropy for V5/MT but not EVC, implying a specific vestibular effect on V5/MT responses. This is the first demonstration that vestibular activation modulates human visual cortex excitability. Furthermore, using information theory, not previously used in phosphene response analysis, we could distinguish between a specific vestibular modulation of V5/MT excitability from a nonspecific effect at EVC.

  15. Hydrothermal changes related to earthquake activity at Mud Volcano, Yellowstone National Park, Wyoming

    SciTech Connect

    Pitt, A.M.; Hutchinson, R.A.

    1982-04-10

    The Mud Volcano hydrothermal area in Yellowstone National Park is near the intersection of a 20-km-long zone of northeast trending normal faults with the eastern resurgent dome within the 600,000-year-odd Yellowstone caldera. Recent crustal uplift along the northeast trending axis of the caldera is at a maximum (700 mm since 1923) near the Mud Volcano area. From 1973 through April 1978, less than 10 earthquakes (largest M 2.4) were located within 3 km of the Mud Volcano area. In May 1978, earthquakes began occurring beneath the hydrothermal area at depths of 1 to 5 km. The seismic activity continued until the end of November with intense swarms (100 events per hour) occurring on October 23 and November 7. The largest event (M 3.1) occured on November 14 and at least 8 events were M 2.5 or larger. In December 1978, heat flux in the Mud Volcano hydrothermal features began increasing along a 2-km-long northeast trending zone. Existing mud cauldrons became more active, new mud cauldrons and fumeroles were formed, and vegetation (primarily lodgepole pine) was killed by increased soil temperature. The increase in heat flux continued through July 1979 then gradually declined, reaching the early 1978 level by June 1980. The spatial and temporal association of earthquakes and increased hydrothermal activity at Mud Volcano suggests that the seismic activity expanded preexisting fracture systems, premitting increased fluid flow from depths of several kilometers.

  16. Volcano Deformation and Modeling on Active Volcanoes in the Philippines from ALOS InSAR Time Series

    NASA Astrophysics Data System (ADS)

    Morales Rivera, Anieri M.; Amelung, Falk; Eco, Rodrigo

    2015-05-01

    Bulusan, Kanlaon, and Mayon volcanoes have erupted over the last decade, and Taal caldera showed signs of volcanic unrest within the same time range. Eruptions at these volcanoes are a threat to human life and infrastructure, having over 1,000,000 people living within 10 km from just these 4 volcanic centers. For this reason, volcano monitoring in the Philippines is of extreme importance. We use the ALOS-1 satellite from the Japanese Aerospace Exploration Agency (JAXA) to make an InSAR time series analysis over Bulusan, Kanlaon, Mayon, and Taal volcanoes for the 2007-2011 period. Time-dependent deformation was detected at all of the volcanoes. Deformation related to changes in pressurization of the volcanic systems was found on Taal caldera and Bulusan volcanoes, with best fitting Mogi sources located at half-space depths of 3.07 km and 0.5 km respectively.

  17. Active volcanoes observed through Art: the contribution offered by the social networks

    NASA Astrophysics Data System (ADS)

    Neri, Marco; Neri, Emilia

    2015-04-01

    Volcanoes have always fascinated people for the wild beauty of their landscapes and also for the fear that they arouse with their eruptive actions, sometimes simply spectacular, but other times terrifying and catastrophic for human activities. In the past, volcanoes were sometimes imagined as a metaphysical gateway to the otherworld; they have inspired the creation of myths and legends ever since three thousand years ago, also represented by paintings of great artistic impact. Modern technology today offers very sophisticated and readily accessed digital tools, and volcanoes continue to be frequently photographed and highly appreciated natural phenomena. Moreover, in recent years, the spread of social networks (Facebook, Twitter, YouTube, Instagram, etc.) have made the widespread dissemination of graphic contributions even easier. The result is that very active and densely inhabited volcanoes such as Etna, Vesuvius and Aeolian Islands, in Italy, have become among the most photographed subjects in the world, providing a popular science tool with formidable influence and usefulness. The beauty of these landscapes have inspired both professional artists and photographers, as well as amateurs, who compete in the social networks for the publication of the most spectacular, artistic or simply most informative images. The end result of this often frantic popular scientific activity is at least two-fold: on one hand, it provides geoscientists and science communicators a quantity of documentation that is almost impossible to acquire through the normal systems of volcano monitoring, while on the other it raises awareness and respect for the land among the civil community.

  18. Ambient Noise Tomography at Bezymianny Volcano, Kamchatka

    NASA Astrophysics Data System (ADS)

    Shuler, A. E.; Ekström, G.; West, M.; Senyukov, S.

    2008-12-01

    Bezymianny Volcano is an active stratovolcano located in the Kluychevskoy volcanic group on the Kamchatka Peninsula in eastern Russia. Since its dramatic sector collapse eruption in 1956, the volcano's activity has been characterized by nearly twice annual plinian eruptions accompanying ongoing lava-dome growth. Its frequent eruptions and similarity to Mt. St. Helens have made it the target of a multifaceted geologic and geophysical project supported by the NSF Partners in Research and Education (PIRE) program. Since mid- 2006, the volcano has been monitored by a broadband seismic array that is currently composed of 8 stations within 10 kilometers of the active dome. In this project, we use continuous data from these stations to investigate the static and dynamic structure of the volcano. Using methods similar to those used by Brenguier et al. (2007, 2008), we estimate the Green's function for each pair of stations by cross-correlating day-long time series of ambient noise. Paths with high signal-to-noise ratios can be used to estimate group velocity dispersion curves. From these measurements, we work towards constructing the first velocity model of this volcano. Furthermore, we begin to test whether measurements of ambient noise can be used to monitor changes inside the volcano prior to eruptive activity. These problems will continue to be addressed as more data becomes available in future field seasons.

  19. Volcanoes: Nature's Caldrons Challenge Geochemists.

    ERIC Educational Resources Information Center

    Zurer, Pamela S.

    1984-01-01

    Reviews various topics and research studies on the geology of volcanoes. Areas examined include volcanoes and weather, plate margins, origins of magma, magma evolution, United States Geological Survey (USGS) volcano hazards program, USGS volcano observatories, volcanic gases, potassium-argon dating activities, and volcano monitoring strategies.…

  20. 2009 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Girina, Olga A.; Chibisova, Marina; Rybin, Alexander

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest, and reports of unusual activity at or near eight separate volcanic centers in Alaska during 2009. The year was highlighted by the eruption of Redoubt Volcano, one of three active volcanoes on the western side of Cook Inlet and near south-central Alaska's population and commerce centers, which comprise about 62 percent of the State's population of 710,213 (2010 census). AVO staff also participated in hazard communication and monitoring of multiple eruptions at ten volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  1. Seismically Articulating Kilauea Volcano's Active Conduits, Rift Zones, and Faults through HVO's Second Fifty Years

    NASA Astrophysics Data System (ADS)

    Okubo, P.; Nakata, J.; Klein, F.; Koyanagi, R.; Thelen, W.

    2011-12-01

    While seismic monitoring of active Hawaiian volcanoes began 100 years ago, the build-up of the U. S. Geological Survey's (USGS) Hawaiian Volcano Observatory (HVO) seismographic network to its current configuration began in 1955, when Jerry Eaton established remote stations that telemetered data via landline to recorders at HVO. With network expansion through the 1960's, earthquake location and cataloging capabilities have evolved to afford a computer processed seismic catalog now spanning fifty years. Location accuracy and catalog completeness to smaller magnitudes have increased. Research and insights developed using HVO's seismic record have exploited the ability to seismically monitor volcanic activity at depth, to identify active regions within the volcanoes on the basis of computed hypocentral locations, to infer regions of magma storage by recognizing different families of volcanic earthquakes, and to forecast volcanic activity in both short and longer term from seismicity patterns. HVO's seismicity catalog was central to calculations of probabilistic seismic hazards. The ability to develop and implement additional analytical and interpretive capabilities has kept pace with improvements in both field and laboratory hardware and software. While the basic capabilities continue as part of HVO's core monitoring, additional interpretive capabilities now include adding details of volcanic and earthquake source regions, and viewing seismic data in juxtaposition with other observatory data streams. As HVO looks to its next century of volcano studies, research and development continue to shape the future. Broadband seismic recording at HVO has enabled extensive study by Chouet, Dawson, and co-workers of the relationship of very-long-period seismic sources beneath Kilauea's summit caldera to magma supply and transport. Recent upgrades have improved the ability to use these data in seismic cataloging and research. Data processing upgrades have bolstered the ability to

  2. SO2 degassing at Tungurahua volcano (Ecuador) between 2007 and 2013: Transition from continuous to episodic activity

    NASA Astrophysics Data System (ADS)

    Hidalgo, Silvana; Battaglia, Jean; Arellano, Santiago; Steele, Alexander; Bernard, Benjamin; Bourquin, Julie; Galle, Bo; Arrais, Santiago; Vásconez, Freddy

    2015-06-01

    We present continuous SO2 measurements performed at Tungurahua volcano with a permanent network of 4 scanning DOAS instruments between 2007 and 2013. The volcano has been erupting since September 1999, but on the contrary to the first years of eruption when the activity was quasi-continuous, the activity transitioned in late 2008 towards the occurrence of distinct eruptive phases separated by periods of quiescence. During our study period we distinguish 11 phases lasting from 17 to 527 days separated by quiescence periods of 26 to 184 days. We propose a new routine to quantify the SO2 emissions when data from a dense DOAS monitoring network are available. This routine consists in summing all the highest validated SO2 measurements among all stations during the 10 h of daily working-time to obtain a daily observed SO2 mass. Since measurement time is constant at Tungurahua the "observed" amounts can be expressed in tons per 10 h and can easily be converted to a daily average flux or mass per day. Our results provide time series having an improved correlation on a long time scale with the eruptive phases and with quiescence periods. A total of 1.25 Mt (1.25 × 109 kg) of SO2 has been released by Tungurahua during the study period, with 95% of these emissions occurring during phases of activity and only 5% during quiescence. This shows a contrast with previous volcanic behaviour when passive degassing dominated the total SO2 emissions. SO2 average daily mass emission rates are of 73 ± 56 t/d during quiescent periods, 735 ± 969 t/d during long-lasting phases and 1424 ± 1224 t/d during short-lasting phases. Degassing during the different eruptive phases displays variable patterns. However, two contrasting behaviours can be distinguished for the onset of eruptive phases with both sudden and progressive onsets being observed. The first is characterised by violent opening of the conduit by high energy Vulcanian explosions; and the second by a progressive, in crescendo

  3. Evaluating life-safety risk of fieldwork at New Zealand's active volcanoes

    NASA Astrophysics Data System (ADS)

    Deligne, Natalia; Jolly, Gill; Taig, Tony; Webb, Terry

    2014-05-01

    Volcano observatories monitor active or potentially active volcanoes. Although the number and scope of remote monitoring instruments and methods continues to grow, in-person field data collection is still required for comprehensive monitoring. Fieldwork anywhere, and especially in mountainous areas, contains an element of risk. However, on volcanoes with signs of unrest, there is an additional risk of volcanic activity escalating while on site, with potentially lethal consequences. As an employer, a volcano observatory is morally and sometimes legally obligated to take reasonable measures to ensure staff safety and to minimise occupational risk. Here we present how GNS Science evaluates life-safety risk for volcanologists engaged in fieldwork on New Zealand volcanoes with signs of volcanic unrest. Our method includes several key elements: (1) an expert elicitation for how likely an eruption is within a given time frame, (2) quantification of, based on historical data when possible, given a small, moderate, or large eruption, the likelihood of exposure to near-vent processes, ballistics, or surge at various distances from the vent, and (3) estimate of fatality rate given exposure to these volcanic hazards. The final product quantifies hourly fatality risk at various distances from a volcanic vent; various thresholds of risk (for example, zones with more than 10-5 hourly fatality risk) trigger different levels of required approval to undertake work. Although an element of risk will always be present when conducting fieldwork on potentially active volcanoes, this is a first step towards providing objective guidance for go/no go decisions for volcanic monitoring.

  4. Lymphocytic infiltration and immune activation in metallothionein promoter-exendin-4 (MT-Exendin) transgenic mice.

    PubMed

    Baggio, Laurie L; Holland, Dianne; Wither, Joan; Drucker, Daniel J

    2006-06-01

    Glucagon-like peptide 1 (GLP-1) exhibits considerable potential for the treatment of type 2 diabetes because of its effects on stimulation of insulin secretion and the inhibition of gastric emptying, appetite, and glucagon secretion. However, native GLP-1 undergoes rapid enzymatic inactivation, prompting development of long-acting degradation-resistant GLP-1 receptor agonists such as exendin-4 (Ex-4). To study the consequences of sustained exposure to Ex-4, we generated metallothionein promoter-exendin-4 (MT-Exendin) mice that continuously express a proexendin-4 transgene in multiple murine tissues. We now report that MT-Exendin mice develop extensive tissue lymphocytic infiltration with increased numbers of CD4(+) and CD8a(+) cells in the liver and/or kidney and increased numbers of B220(+) cells present in the pancreas and liver. MT-Exendin mice generate antibodies directed against Ex-4, exendin NH(2)-terminal peptide (ENTP), and proexendin-4 as well as antibodies that cross-react with native GLP-1. Furthermore, lymphocytes isolated from MT-Exendin mice proliferate in response to proexendin-4 but not after exposure to Ex-4 or ENTP. These findings demonstrate that expression of a proexendin-4 transgene may be associated with activation of humoral and cellular immune responses in mice.

  5. Infrasound Monitoring of the Volcanic Activities of Japanese Volcanoes in Korea

    NASA Astrophysics Data System (ADS)

    Lee, H. I.; Che, I. Y.; Shin, J. S.

    2015-12-01

    Since 1999 when our first infrasound array station(CHNAR) has been installed at Cheolwon, Korea Institute of Geoscience and Mineral Resources(KIGAM) is continuously observing infrasound signals with an infrasound array network, named KIN(Korean Infrasound Network). This network is comprised of eight seismo-acoustic array stations(BRDAR, YPDAR, KMPAR, CHNAR, YAGAR, KSGAR, ULDAR, TJIAR). The aperture size of the smallest array is 300m and the largest is about 1.4km. The number of infrasound sensors are between 4(TJIAR) and 18(YAGAR), and 1~5 seismometers are collocated with infrasound sensors. Many interesting infrasound signals associated with different type of sources, such as blasting, large earthquake, bolide, volcanic explosion are detected by KIN in the past 15 years. We have analyzed the infrasound signals possibly associated with the japanese volcanic explosions with reference to volcanic activity report published by Japanese Meteorological Agency. Analysis results of many events, for example, Asama volcano explosion in 2004 and Shinmoe volcano in 2011, are well matched with the official report. In some cases, however, corresponding infrasound signals are not identified. By comparison of the infrasound signals from different volcanoes, we also found that the characteristics of signals are distinguishing. It may imply that the specific volcano has its own unique fingerprint in terms of infrasound signal. It might be investigated by long-term infrasound monitoring for a specific volcano as a ground truth generating repetitive infrasound signal.

  6. Hydrogochemical tools for monitoring active volcanoes: Applications to El Chichón volcano, México.

    NASA Astrophysics Data System (ADS)

    Armienta, M. A.; de La Cruz-Reyna, S.; Ramos, S.; Morton, O.; Ceniceros, N.; Aguayo, A.; Cruz, O.

    2010-03-01

    In 1982, a series of eruptions resulted in the worst disaster linked with volcanic activity in México. The characteristics of the phenomena together with a lack of prevention measures resulted in approximately 2000 deaths. An important aspect to prevent disasters is a thorough knowledge and monitoring of the potentially destructive natural phenomena. Monitoring the activity of dormant or active volcanoes by various methods is thus a key measure to estimate the hazard and design adequate risk reduction measures. Despite of the 1982 volcanic disaster, until only a few years, hydrogeochemical monitoring was the only regular surveillance of El Chichón post-eruptive activity. The first samples of the crater-lake water were collected by Casadevall et al. in 1983. Since 1985, a systematic sampling and chemical analyses program has been carried out by the Geophysics Institute in collaboration with local authorities from the State of Chiapas. Chemical analyses of main ions and Rare Earth elements (REE) are performed in the Laboratorio de Química Analítica and Laboratorio ICP-MS of the Instituto de Geofísica, UNAM. Results are interpreted considering the physico-chemical changes that may be recognized as precursors of volcanic activity. The problem is difficult because at least two main water reservoirs feed the crater lake; besides, dissolution of acid volcanic gases, water-rock interactions and geochemical processes among dissolved species have resulted in a complex chemical behavior of the lake-water along the years. The calculated degree of neutralization, pH values, and chloride and sulfate concentrations of samples taken at different dates result in a classification of the volcano as active or inactive according to the method developed by Varekamp. A pH of 0.5, very high conductivity and a temperature of about 50°C characterized the first years following the eruptions. An overall decrease on the temperature and ionic concentrations, along with a less acid p

  7. What do the Mt. Wilson stars tell us about solar activity?

    NASA Astrophysics Data System (ADS)

    Schröder, K.-P.; Mittag, M.; Hempelmann, A.; González-Pérez, J. N.; Schmitt, J. H. M. M.

    2013-06-01

    We relate the evolutionary status and mass of the Mt. Wilson project stars with the type and strength of stellar activity as established in decades of monitoring their chromospheric Ca II K line emission. We specifically derive their positions in the Hertzsprung-Russell-diagram (HRD) from Hipparcos parallaxes and SIMBAD B - V data, considering and correcting for the effects of different individual stellar metallicities, and place different activity groups of the Mt. Wilson stars on a common set of Z = 0.02 evolution tracks to obtain a quantitative picture of their relative evolutionary status and mass distribution. We find that, first, the downturn in stellar activity does not depend on absolute age but instead decreases with the relative age as stars advance on the main sequence and thus confirm theoretical expectations, while the most active of the irregularly variable stars are found to scatter around the zero-age main-sequence (ZAMS). Moderately active stars, both with clear cycles like the Sun and those without a dominant activity period, populate the 2nd quarter of main-sequence (MS) evolution. Almost inactive stars are mostly in their 3rd quarter of MS evolution and seem to represent stellar analogues of the solar Maunder minimum state. Totally inactive stars are all in the final quarter of their MS evolution and make up for over 70% of the Mt. Wilson stars that far evolved (the remainders being only weakly active). Most of these are more massive and younger than the Sun. Accordingly, less massive stars did not have enough time to significantly decrease their activity, since they generally evolve more slowly. We find, second, that the Sun is near an apparent upper mass limit for cyclic activity on the MS, because there are no cyclic MS stars much above one solar mass, at least not in the Mt. Wilson sample. Once put in proper perspective with the other Mt. Wilson stars, the Sun indeed ought to be approaching a gradual transition from moderate cyclic activity

  8. Methods of InSAR atmosphere correction for volcano activity monitoring

    USGS Publications Warehouse

    Gong, W.; Meyer, F.; Webley, P.W.; Lu, Zhiming

    2011-01-01

    When a Synthetic Aperture Radar (SAR) signal propagates through the atmosphere on its path to and from the sensor, it is inevitably affected by atmospheric effects. In particular, the applicability and accuracy of Interferometric SAR (InSAR) techniques for volcano monitoring is limited by atmospheric path delays. Therefore, atmospheric correction of interferograms is required to improve the performance of InSAR for detecting volcanic activity, especially in order to advance its ability to detect subtle pre-eruptive changes in deformation dynamics. In this paper, we focus on InSAR tropospheric mitigation methods and their performance in volcano deformation monitoring. Our study areas include Okmok volcano and Unimak Island located in the eastern Aleutians, AK. We explore two methods to mitigate atmospheric artifacts, namely the numerical weather model simulation and the atmospheric filtering using Persistent Scatterer processing. We investigate the capability of the proposed methods, and investigate their limitations and advantages when applied to determine volcanic processes. ?? 2011 IEEE.

  9. Remote sensing and tectonic analysis of active volcanoes in continental arcs

    NASA Astrophysics Data System (ADS)

    Wessels, Rick Lee

    Variations in arc volcano spatial distribution and morphology are influenced by the crustal structure beneath the arc. In Colombia and Ecuador, most of the active volcanoes lie on or near regional arc-parallel fault zones, and many of the major volcanoes are aligned or elongated parallel to the faults. Two dominant volcano-fault geometry patterns exist: (1) From north to south, the orientation of the fractures and volcano-shapes changes along the arc from primarily north-northwest trending to east-northeast trending; and (2) From west to east, the fault and volcano alignment patterns vary from north-northwest trends at the outer edges of the arc to east-northeast trending in the middle of the arc. The fault and volcano orientation patterns are related to the age and type of crust being faulted during oblique subduction. The regionally active strike-slip faults in the Northern Andes and other arcs provide long-lasting paths for magma ascent that penetrate much deeper through the lithosphere than the secondary features. Local zones of extension and pre-existing fractures in the last several kilometers of lithosphere provide the plumbing that diverts magma slightly away from the primary linear volcanic front. The dissertation also describes a technique for merging multiple remote sensing data sets over the extremely rough terrain of silicic volcanoes. The major focus of this work was on overcoming coregistration errors from geometric distortion induced by local topography. The geometric distortion was compensated for by first creating an accurate base image with a combination of global positioning system (GPS) ground control, high resolution digital elevation models (DEM), and orthorectified aerial photographs. The individual sensor data were then rectified to the new reference base using triangulation geocoding. The final multi-layered, geocoded product is being used to enhance an existing thermal infrared technique for mapping complex textural patterns in silicic

  10. 78 FR 65963 - Foreign-Trade Zone 44-Mt. Olive, New Jersey; Authorization of Production Activity; Givaudan...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-04

    ... notice in the Federal Register inviting public comment (78 FR 39707, 07-02-2013). The FTZ Board has... Foreign-Trade Zones Board Foreign-Trade Zone 44--Mt. Olive, New Jersey; Authorization of Production Activity; Givaudan Fragrances Corporation (Fragrance and Flavor Products); Mt. Olive, New Jersey On June...

  11. Dante's Volcano

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This video contains two segments: one a 0:01:50 spot and the other a 0:08:21 feature. Dante 2, an eight-legged walking machine, is shown during field trials as it explores the inner depths of an active volcano at Mount Spurr, Alaska. A NASA sponsored team at Carnegie Mellon University built Dante to withstand earth's harshest conditions, to deliver a science payload to the interior of a volcano, and to report on its journey to the floor of a volcano. Remotely controlled from 80-miles away, the robot explored the inner depths of the volcano and information from onboard video cameras and sensors was relayed via satellite to scientists in Anchorage. There, using a computer generated image, controllers tracked the robot's movement. Ultimately the robot team hopes to apply the technology to future planetary missions.

  12. Dante's volcano

    NASA Astrophysics Data System (ADS)

    1994-09-01

    This video contains two segments: one a 0:01:50 spot and the other a 0:08:21 feature. Dante 2, an eight-legged walking machine, is shown during field trials as it explores the inner depths of an active volcano at Mount Spurr, Alaska. A NASA sponsored team at Carnegie Mellon University built Dante to withstand earth's harshest conditions, to deliver a science payload to the interior of a volcano, and to report on its journey to the floor of a volcano. Remotely controlled from 80-miles away, the robot explored the inner depths of the volcano and information from onboard video cameras and sensors was relayed via satellite to scientists in Anchorage. There, using a computer generated image, controllers tracked the robot's movement. Ultimately the robot team hopes to apply the technology to future planetary missions.

  13. Formation of a Phyllosilicate-, K-feldspar-, and Sulfate-Bearing Hematite Ridge on Mauna Kea Volcano, Hawaii, Under Hydrothermal, Acid-Sulfate Conditions: Process and Mineralogical Analog for the Hematite Ridge on Mt. Sharp, Gale Crater, Mars.

    NASA Astrophysics Data System (ADS)

    Ming, D. W.; Morris, R. V.; Adams, M. E.; Catalano, J. G.; Graff, T. G.; Arvidson, R. E.; Guinness, E. A.; Hamilton, J. C.; Mertzman, S. A.; Fraeman, A.

    2015-12-01

    The Mars Science Laboratory rover Curiosity is currently moving upslope on Mt. Sharp in Gale Crater toward a hematite-bearing ridge. This hematite exposure was originally detected in CRISM spectra and subsequently mapped as part of a ~200 m wide, 6.5 km long ridge extending roughly parallel to the base of Mt. Sharp. CRISM spectra in the region suggest that hematite, smectite, and hydrated sulfates occur as secondary phases in lower layers of Mt. Sharp, separated by an unconformity from overlying anhydrous strata. A potential process and mineralogical analog is a hematite-bearing and weathering-resistant stratum (ridge) is exposed on the Puu Poliahu cinder cone on Mauna Kea (MK) volcano, Hawaii. The MK ridge is the product of hydrothermal alteration of basaltic precursors under acid-sulfate conditions. We are acquiring chemical and mineralogical (VNIR, Mid-IR, and backscatter Moessbauer spectroscopy, and transmission XRD) data on the MK ridge area that correspond to rover and orbiting spacecraft measurements at Gale Crater and elsewhere. The hematite-bearing stratum does not have detectable sulfate minerals by XRD, and hematite is variably present as up to mm-sized black crystals which, together with associated trioctahedral smectite and K-feldspar (from XRD), imply hydrothermal conditions. Adjacent to the MK hematite-bearing stratum are sulfates (jarosite and alunite) that are evidence for aqueous alteration under acid-sulfate conditions, and more soluble sulfates are absent but such phases would not persist if formed because of annual precipitation. Dioctahedral smectite is associated with red hematite and alunite-rich samples. The black and red hematite zones have the highest and lowest MgO/Al2O3 and K2O/Na2O ratios, respectively. Hematite, smectite, jarosite, and K-feldspar have been detected by Curiosity XRD downslope from the Mt. Sharp hematite ridge. MK field work and samples were obtained with PISCES partnership and OMKM, MKMB, BLNR, and KKMC permissions.

  14. Inside active volcanoes; an exhibit on the move!

    USGS Publications Warehouse

    Fiske, R.S.

    1990-01-01

    All of us are aware of the emphasis currently being placed in the United States on science education and public understanding of science. Most of this emphasis is directed toward mass audiences through book publications, school curricula, and television programs; sadly, most of it deals with non-earth science topics. In an effort to take advantage of this awakened consciousness and to highlight the earth sciences, the Smithsonian Institution and the U.S Geological Survey joined forces to prepare a traveling exhibit on volcanoes that is currently touring the country. This note will serve to bring you up to date on the progress of this exhibit as it reaches the mid-point of its tour. 

  15. 4D volcano gravimetry

    USGS Publications Warehouse

    Battaglia, Maurizio; Gottsmann, J.; Carbone, D.; Fernandez, J.

    2008-01-01

    Time-dependent gravimetric measurements can detect subsurface processes long before magma flow leads to earthquakes or other eruption precursors. The ability of gravity measurements to detect subsurface mass flow is greatly enhanced if gravity measurements are analyzed and modeled with ground-deformation data. Obtaining the maximum information from microgravity studies requires careful evaluation of the layout of network benchmarks, the gravity environmental signal, and the coupling between gravity changes and crustal deformation. When changes in the system under study are fast (hours to weeks), as in hydrothermal systems and restless volcanoes, continuous gravity observations at selected sites can help to capture many details of the dynamics of the intrusive sources. Despite the instrumental effects, mainly caused by atmospheric temperature, results from monitoring at Mt. Etna volcano show that continuous measurements are a powerful tool for monitoring and studying volcanoes.Several analytical and numerical mathematical models can beused to fit gravity and deformation data. Analytical models offer a closed-form description of the volcanic source. In principle, this allows one to readily infer the relative importance of the source parameters. In active volcanic sites such as Long Valley caldera (California, U.S.A.) and Campi Flegrei (Italy), careful use of analytical models and high-quality data sets has produced good results. However, the simplifications that make analytical models tractable might result in misleading volcanological inter-pretations, particularly when the real crust surrounding the source is far from the homogeneous/ isotropic assumption. Using numerical models allows consideration of more realistic descriptions of the sources and of the crust where they are located (e.g., vertical and lateral mechanical discontinuities, complex source geometries, and topography). Applications at Teide volcano (Tenerife) and Campi Flegrei demonstrate the

  16. Methanogenic activity and diversity in the centre of the Amsterdam Mud Volcano, Eastern Mediterranean Sea.

    PubMed

    Lazar, Cassandre Sara; John Parkes, R; Cragg, Barry A; L'Haridon, Stephane; Toffin, Laurent

    2012-07-01

    Marine mud volcanoes are geological structures emitting large amounts of methane from their active centres. The Amsterdam mud volcano (AMV), located in the Anaximander Mountains south of Turkey, is characterized by intense active methane seepage produced in part by methanogens. To date, information about the diversity or the metabolic pathways used by the methanogens in active centres of marine mud volcanoes is limited. (14)C-radiotracer measurements showed that methylamines/methanol, H(2)/CO(2) and acetate were used for methanogenesis in the AMV. Methylotrophic methanogenesis was measured all along the sediment core, Methanosarcinales affiliated sequences were detected using archaeal 16S PCR-DGGE and mcrA gene libraries, and enrichments of methanogens showed the presence of Methanococcoides in the shallow sediment layers. Overall acetoclastic methanogenesis was higher than hydrogenotrophic methanogenesis, which is unusual for cold seep sediments. Interestingly, acetate porewater concentrations were extremely high in the AMV sediments. This might be the result of organic matter cracking in deeper hotter sediment layers. Methane was also produced from hexadecanes. For the most part, the methanogenic community diversity was in accordance with the depth distribution of the H(2)/CO(2) and acetate methanogenesis. These results demonstrate the importance of methanogenic communities in the centres of marine mud volcanoes.

  17. Methanogenic activity and diversity in the centre of the Amsterdam Mud Volcano, Eastern Mediterranean Sea.

    PubMed

    Lazar, Cassandre Sara; John Parkes, R; Cragg, Barry A; L'Haridon, Stephane; Toffin, Laurent

    2012-07-01

    Marine mud volcanoes are geological structures emitting large amounts of methane from their active centres. The Amsterdam mud volcano (AMV), located in the Anaximander Mountains south of Turkey, is characterized by intense active methane seepage produced in part by methanogens. To date, information about the diversity or the metabolic pathways used by the methanogens in active centres of marine mud volcanoes is limited. (14)C-radiotracer measurements showed that methylamines/methanol, H(2)/CO(2) and acetate were used for methanogenesis in the AMV. Methylotrophic methanogenesis was measured all along the sediment core, Methanosarcinales affiliated sequences were detected using archaeal 16S PCR-DGGE and mcrA gene libraries, and enrichments of methanogens showed the presence of Methanococcoides in the shallow sediment layers. Overall acetoclastic methanogenesis was higher than hydrogenotrophic methanogenesis, which is unusual for cold seep sediments. Interestingly, acetate porewater concentrations were extremely high in the AMV sediments. This might be the result of organic matter cracking in deeper hotter sediment layers. Methane was also produced from hexadecanes. For the most part, the methanogenic community diversity was in accordance with the depth distribution of the H(2)/CO(2) and acetate methanogenesis. These results demonstrate the importance of methanogenic communities in the centres of marine mud volcanoes. PMID:22458514

  18. Tissue-specific mtDNA abundance from exome data and its correlation with mitochondrial transcription, mass and respiratory activity.

    PubMed

    D'Erchia, Anna Maria; Atlante, Anna; Gadaleta, Gemma; Pavesi, Giulio; Chiara, Matteo; De Virgilio, Caterina; Manzari, Caterina; Mastropasqua, Francesca; Prazzoli, Gian Marco; Picardi, Ernesto; Gissi, Carmela; Horner, David; Reyes, Aurelio; Sbisà, Elisabetta; Tullo, Apollonia; Pesole, Graziano

    2015-01-01

    Eukaryotic cells contain a population of mitochondria, variable in number and shape, which in turn contain multiple copies of a tiny compact genome (mtDNA) whose expression and function is strictly coordinated with the nuclear one. mtDNA copy number varies between different cell or tissues types, both in response to overall metabolic and bioenergetics demands and as a consequence or cause of specific pathological conditions. Here we present a novel and reliable methodology to assess the effective mtDNA copy number per diploid genome by investigating off-target reads obtained by whole-exome sequencing (WES) experiments. We also investigate whether and how mtDNA copy number correlates with mitochondrial mass, respiratory activity and expression levels. Analyzing six different tissues from three age- and sex-matched human individuals, we found a highly significant linear correlation between mtDNA copy number estimated by qPCR and the frequency of mtDNA off target WES reads. Furthermore, mtDNA copy number showed highly significant correlation with mitochondrial gene expression levels as measured by RNA-Seq as well as with mitochondrial mass and respiratory activity. Our methodology makes thus feasible, at a large scale, the investigation of mtDNA copy number in diverse cell-types, tissues and pathological conditions or in response to specific treatments. PMID:25446395

  19. Volcano Infrasound

    NASA Astrophysics Data System (ADS)

    Johnson, J. B.; Fee, D.; Matoza, R. S.

    2013-12-01

    Open-vent volcanoes generate prodigious low frequency sound waves that tend to peak in the infrasound (<20 Hz) band. These long wavelength (> ~20 m) atmospheric pressure waves often propagate long distances with low intrinsic attenuation and can be well recorded with a variety of low frequency sensitive microphones. Infrasound records may be used to remotely monitor eruptions, identify active vents or track gravity-driven flows, and/or characterize source processes. Such studies provide information vital for both scientific study and volcano monitoring efforts. This presentation proposes to summarize and standardize some of the terminology used in the still young, yet rapidly growing field of volcano infrasound. Herein we suggest classification of typical infrasound waveform types, which include bimodal pulses, blast (or N-) waves, and a variety of infrasonic tremors (including broadband, harmonic, and monotonic signals). We summarize various metrics, including reduced pressure, intensity, power, and energy, in which infrasound excess pressures are often quantified. We also describe the spectrum of source types and radiation patterns, which are typically responsible for recorded infrasound. Finally we summarize the variety of propagation paths that are common for volcano infrasound radiating to local (<10 km), regional (out to several hundred kilometers), and global distances. The effort to establish common terminology requires community feedback, but is now timely as volcano infrasound studies proliferate and infrasound becomes a standard component of volcano monitoring.

  20. SO2 Emission from Active Volcanoes Measured Simultaneously by COSPEC and mini-DOAS

    NASA Astrophysics Data System (ADS)

    Barrancos, José; Roselló, José I.; Calvo, David; Padrón, Eleazar; Melián, Gladys; Hernández, Pedro A.; Pérez, Nemesio M.; Millán, Millán M.; Galle, Bo

    2008-01-01

    We measured SO2 emission rate from six volcanoes in Latin America (Santa Ana, El Salvador; San Cristóbal and Masaya, Nicaragua; Arenal and Poás, Costa Rica; Tungurahua and Sierra Negra, Ecuador) and from Mt. Etna, Italy, using two different remote sensing techniques: COSPEC (COrrelation SPECtrometer) and miniDOAS (miniaturized Differential Optical Absorption Spectroscopy). One of the goals of this study was to evaluate the differences in SO2 emission rates obtained by these two methods. The observed average SO2 emission rates measured during this study were 2688 t· d -1 from Tungurahua in July 2006, 2375 t· d -1 in September 2005 and 480 t· d -1 in February 2006 from Santa Ana, 1200 t· d -1 in May 2005 from Etna, 955 t· d -1 in March 2006 and 1165 t· d -1 in December 2006 from Masaya, 5400 t· d -1 of March 7, 2006 and 265 t· d -1 in March 2006 from San Cristobal, 113 t· d -1 in April 2006 from Arenal, 104 t· d -1 in April 2006 from Poás and 11 t· d -1 in July 2006 from Sierra Negra volcano. Most of the observed relative differences of SO2 emission measurements from COSPEC and miniDOAS were lower than 10%.

  1. Eruptive history, current activity and risk estimation using geospatial information in the Colima volcano, Mexico

    NASA Astrophysics Data System (ADS)

    Suarez-Plascencia, C.; Camarena-Garcia, M.; Nunez-Cornu, F. J.; Flores-Peña, S.

    2013-12-01

    Colima volcano, also known as Volcan de Fuego (19 30.696 N, 103 37.026 W), is located on the border between the states of Jalisco and Colima, and is the most active volcano in Mexico. In January 20, 1913, Colima had its biggest explosion of the twentieth century, with VEI 4, after the volcano had been dormant for almost 40 years. In 1961, a dome reached the northeastern edge of the crater and started a new lava flow, and from this date maintains constant activity. In February 10, 1999, a new explosion occurred at the summit dome. The activity during the 2001-2005 period was the most intense, but did not exceed VEI 3. The activity resulted in the formation of domes and their destruction after explosive events. The explosions originated eruptive columns, reaching altitudes between 4,500 and 9,000 masl, further pyroclastic flows reaching distances up to 3.5 km from the crater. During the explosive events, ash emissions were generated in all directions reaching distances up to 100 km, slightly affecting the nearby villages: Tuxpan, Tonila, Zapotlan, Cuauhtemoc, Comala, Zapotitlan de Vadillo and Toliman. During 2005 to July 2013, this volcano has had an intense effusive-explosive activity; similar to the one that took place during the period of 1890 through 1905. That was before the Plinian eruption of 1913, where pyroclastic flows reached a distance of 15 km from the crater. In this paper we estimate the risk of Colima volcano through the analysis of the vulnerability variables, hazard and exposure, for which we use: satellite imagery, recurring Fenix helicopter over flights of the state government of Jalisco, the use of the images of Google Earth and the population census 2010 INEGI. With this information and data identified changes in economic activities, development, and use of land. The expansion of the agricultural frontier in the lower sides of the volcano Colima, and with the advancement of traditional crops of sugar cane and corn, increased the growth of

  2. Bilayer Membrane Modulation of Membrane Type 1 Matrix Metalloproteinase (MT1-MMP) Structure and Proteolytic Activity.

    PubMed

    Cerofolini, Linda; Amar, Sabrina; Lauer, Janelle L; Martelli, Tommaso; Fragai, Marco; Luchinat, Claudio; Fields, Gregg B

    2016-01-01

    Cell surface proteolysis is an integral yet poorly understood physiological process. The present study has examined how the pericellular collagenase membrane-type 1 matrix metalloproteinase (MT1-MMP) and membrane-mimicking environments interplay in substrate binding and processing. NMR derived structural models indicate that MT1-MMP transiently associates with bicelles and cells through distinct residues in blades III and IV of its hemopexin-like domain, while binding of collagen-like triple-helices occurs within blades I and II of this domain. Examination of simultaneous membrane interaction and triple-helix binding revealed a possible regulation of proteolysis due to steric effects of the membrane. At bicelle concentrations of 1%, enzymatic activity towards triple-helices was increased 1.5-fold. A single mutation in the putative membrane interaction region of MT1-MMP (Ser466Pro) resulted in lower enzyme activation by bicelles. An initial structural framework has thus been developed to define the role(s) of cell membranes in modulating proteolysis. PMID:27405411

  3. Bilayer Membrane Modulation of Membrane Type 1 Matrix Metalloproteinase (MT1-MMP) Structure and Proteolytic Activity

    PubMed Central

    Cerofolini, Linda; Amar, Sabrina; Lauer, Janelle L.; Martelli, Tommaso; Fragai, Marco; Luchinat, Claudio; Fields, Gregg B.

    2016-01-01

    Cell surface proteolysis is an integral yet poorly understood physiological process. The present study has examined how the pericellular collagenase membrane-type 1 matrix metalloproteinase (MT1-MMP) and membrane-mimicking environments interplay in substrate binding and processing. NMR derived structural models indicate that MT1-MMP transiently associates with bicelles and cells through distinct residues in blades III and IV of its hemopexin-like domain, while binding of collagen-like triple-helices occurs within blades I and II of this domain. Examination of simultaneous membrane interaction and triple-helix binding revealed a possible regulation of proteolysis due to steric effects of the membrane. At bicelle concentrations of 1%, enzymatic activity towards triple-helices was increased 1.5-fold. A single mutation in the putative membrane interaction region of MT1-MMP (Ser466Pro) resulted in lower enzyme activation by bicelles. An initial structural framework has thus been developed to define the role(s) of cell membranes in modulating proteolysis. PMID:27405411

  4. Discovery of an Active Submarine Mud Volcano Along the Nootka Fault West of Vancouver Island

    NASA Astrophysics Data System (ADS)

    Riedel, M.; Riedel, M.; Kelly, D. S.; Delaney, J. R.; Spence, G. D.; Hyndman, R. D.; Hyndman, R. D.; Mayer, L.; Calder, B.; Lilley, M. D.; Olson, E. O.; Schrenk, M. O.; Coffin, R.

    2001-12-01

    Submarine mud volcanoes are a common feature in margin environments, but few of them have been documented in the Northeast Pacific. However, during a Hydrosweep bathymetric survey in July, 2001, and a follow-on sub-surface seismic survey in August two mud volcanoes were imaged along the Nootka Fault, 16-18 km west of Vancouver Island at a water depth of 2500 m. The southern volcano, called Maquinna, lies directly along the southern expression of the left lateral, strike slip Nootka Fault. It is 1.5 km across, has a breached caldera and two small summit craters, and it stands about 30 m above the seafloor. The base is bounded by a narrow moat, partially filled by Holocene sediments that are flat lying; older, underlying sediments show steep downwarping towards the sides of the volcano. Subsurface imaging shows a dramatic loss of reflectivity beneath the volcano mound, which may indicate significant mobilization of material. However, a very bright reflector is seen at about 400 m depth below the volcano. This reflector is too deep for stability of methane clathrate, and is interpreted as a zone of high fluid content. A CTD vertical cast above the summit of the volcano showed strong, co-registered thermal, particulate, and oxygen anomalies that extend 50 m up into the overlying water column. These data indicate that the volcano is actively venting warm hydrothermal fluids. The fluids are depleted in CO2, contain background concentrations of CH4, but show elevated H2 concentrations above ocean background water. Microscopic examination of the Nootka hydrothermal samples shows that they contain dense and morphologically diverse microbial communities in comparison to background seawater with cell densities of 106 cells/ml. Enrichment culturing indicates that these communities include both anaerobic and aerobic organisms, some of which are thermophilic with optimal growth temperatures in excess of 50 deg C. Some of these cultures can use methane oxidation as an energy

  5. BrO/SO2 ratios at Popocatepetl volcano during increased activity in 2012

    NASA Astrophysics Data System (ADS)

    Fickel, M.; Delgado Granados, H.

    2012-12-01

    Since its reactivation in 1994 after many decades of inactivity, Popocatepetl volcano has been showing long periods of quiescent degassing and some events of intensified activity in connection with dome building and destruction processes. During a period of increased activity of the volcano, which began in April 2012, mobile ultraviolet DOAS measurements and stationary DOAS scans were performed to quantify SO2 fluxes and BrO/SO2 ratios within the volcanic plume. The results of these measurements are presented in the context of the volcanic activity, which consisted of increased emission of gas and ash and Vulcanian type explosions. In general, SO2 emissions were high during the period April-June 2012 and so the BrO emissions, however, the BrO/SO2 ratios did not change strongly before, during and after the increased activity.

  6. Prokaryotic community structure and diversity in the sediments of an active submarine mud volcano (Kazan mud volcano, East Mediterranean Sea).

    PubMed

    Pachiadaki, Maria G; Lykousis, Vasilios; Stefanou, Euripides G; Kormas, Konstantinos A

    2010-06-01

    We investigated 16S rRNA gene diversity at a high sediment depth resolution (every 5 cm, top 30 cm) in an active site of the Kazan mud volcano, East Mediterranean Sea. A total of 242 archaeal and 374 bacterial clones were analysed, which were attributed to 38 and 205 unique phylotypes, respectively (> or = 98% similarity). Most of the archaeal phylotypes were related to ANME-1, -2 and -3 members originating from habitats where anaerobic oxidation of methane (AOM) occurs, although they occurred in sediment layers with no apparent AOM (below the sulphate depletion depth). Proteobacteria were the most abundant and diverse bacterial group, with the Gammaproteobacteria dominating in most sediment layers and these were related to phylotypes involved in methane cycling. The Deltaproteobacteria included several of the sulphate-reducers related to AOM. The rest of the bacterial phylotypes belonged to 15 known phyla and three unaffiliated groups, with representatives from similar habitats. Diversity index H was in the range 0.56-1.73 and 1.47-3.82 for Archaea and Bacteria, respectively, revealing different depth patterns for the two groups. At 15 and 20 cm below the sea floor, the prokaryotic communities were highly similar, hosting AOM-specific Archaea and Bacteria. Our study revealed different dominant phyla in proximate sediment layers. PMID:20370830

  7. Trace elements in scalp hair of children chronically exposed to volcanic activity (Mt. Etna, Italy).

    PubMed

    Varrica, D; Tamburo, E; Dongarrà, G; Sposito, F

    2014-02-01

    The aim of this survey was to use scalp hair as a biomonitor to evaluate the environmental exposure to metals and metalloids of schoolchildren living around the Mt. Etna area, and to verify whether the degree of human exposure to trace elements is subject to changes in local environmental factors. Twenty trace elements were determined in 376 samples of scalp hair from schoolboys (11-13 years old) of both genders, living in ten towns located around the volcanic area of Mt. Etna (Sicily). The results were compared with those (215 samples) from children living in areas of Sicily characterized by a different geological setting (reference site). As, U and V showed much higher concentrations at the volcanic site whereas Sr was particularly more abundant at the reference site. Linear Discriminant Analysis (LDA) indicated an Etna factor, made up of V, U and Mn, and a second factor, concerning the reference site, characterized by Ni and Sr, and to a lesser extent by Mo and Cd. Significant differences in element concentrations were also observed among three different sectors of Mt. Etna area. Young people living in the Mt. Etna area are naturally exposed to enhanced intakes of some metals (V, U, Mn) and non-metals (e.g., As) than individuals of the same age residing in other areas of Sicily, characterized by different lithologies and not influenced by volcanic activity. The petrographic nature of local rocks and the dispersion of the volcanic plume explain the differences, with ingestion of water and local food as the most probable exposure pathways.

  8. Mt. Etna, Italy

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On Sunday, November 3, 2002, Mt. Etna's ash-laden plume was imaged by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. The plume is seen blowing toward the south-southeast, over the city and airport of Catania, Sicily. The previous day, the plume was blowing toward the northwest, and posed no hazard to Catania. The current eruption of Mt. Etna, Europe's most active volcano, began on October 27. These sorts of observations from space may help civil defense authorities mitigate hazards from active eruptions. Space data may also help scientists evaluate the behavior and effects volcanic eruptions have on our global climate system.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. science team leader; Bjorn Eng of JPL is the project manager. The Terra mission is part of NASA's Earth Science

  9. Magnetic precursors to the 2013 eruptive activity at Popocatepetl Volcano, Mexico

    NASA Astrophysics Data System (ADS)

    Martin, A.; Gonzalez, E.; Cifuentes-Nava, G.; HernaNdez-Quintero, J.; Flores, A.

    2013-12-01

    Popocateptl volcano, 60km from Mexico City, has been erupting since 1994 with periods of more intense activity. Volcanomagnetic signals at Popocatepetl have been correlated with different volcanic phenomena especially ascent of several magma batches in pulses lasting several hours that precede increasing seismicity at the volcano. Data from the TL magnetic station on the northern flank of the volcano at 4000masl and from the CPX station at the same altitude on the southwestern flank are processed with the data from the TEO base station (weighted differences) in order to remove signals not associated with the volcano. Short term negative volcanic anomalies around 10nT preceded sharp increases in seismicity and copious ash emission during April and May 2013. They were correlated with periods of harmonic tremor and interpreted as new ascending magma batches, below the Curie point. A longer term descending magnetic trend from February on, is of thermomagnetic origen and is associated with the more mafic andesite compositions of the ash which contain higher MgO and are consistent with influx of deeper magma at higher magmatic temperatures. Sharp positive magnetic peaks are related both with explosions and seismic events, while sustained steps of positive anomalies are related with dome growth and cooling

  10. Active Volcanoes of the Kurile Islands: A Reference Guide for Aviation Users

    USGS Publications Warehouse

    Neal, Christina A.; Rybin, Alexander; Chibisova, Marina; Miller, Edward

    2008-01-01

    Introduction: The many volcanoes of the remote and mostly uninhabited Kurile Island arc (fig. 1; table 1) pose a serious hazard for air traffic in the North Pacific. Ash clouds from Kurile eruptions can impact some of the busiest air travel routes in the world and drift quickly into airspace managed by three countries: Russia, Japan, and the United States. Prevailing westerly winds throughout the region will most commonly send ash from any Kurile eruption directly across the parallel North Pacific airways between North America and Asia (Kristine A. Nelson, National Weather Service, oral commun., 2006; fig. 1). This report presents maps showing locations of the 36 most active Kurile volcanoes plotted on Operational Navigational Charts published by the Defense Mapping Agency (map sheets ONC F-10, F-11, and E-10; figs. 1, 2, 3, 4). These maps are intended to assist aviation and other users in the identification of restless Kurile volcanoes. A regional map is followed by three subsections of the Kurile volcanic arc (North, Central, South). Volcanoes and selected primary geographic features are labeled. All maps contain schematic versions of the principal air routes and selected air navigational fixes in this region.

  11. A Scientific Excursion: Volcanoes.

    ERIC Educational Resources Information Center

    Olds, Henry, Jr.

    1983-01-01

    Reviews an educationally valuable and reasonably well-designed simulation of volcanic activity in an imaginary land. VOLCANOES creates an excellent context for learning information about volcanoes and for developing skills and practicing methods needed to study behavior of volcanoes. (Author/JN)

  12. 2007 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Dixon, James P.; Malik, Nataliya; Chibisova, Marina

    2011-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near nine separate volcanic centers in Alaska during 2007. The year was highlighted by the eruption of Pavlof, one of Alaska's most frequently active volcanoes. Glaciated Fourpeaked Mountain, a volcano thought to have been inactive in the Holocene, produced a phreatic eruption in the autumn of 2006 and continued to emit copious amounts of steam and volcanic gas into 2007. Redoubt Volcano showed the first signs of the unrest that would unfold in 2008-09. AVO staff also participated in hazard communication and monitoring of multiple eruptions at seven volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  13. 2008 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.; Dixon, James P.; Cameron, Cheryl E.; Nuzhdaev, Anton A.; Chibisova, Marina

    2011-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest or suspected unrest at seven separate volcanic centers in Alaska during 2008. Significant explosive eruptions at Okmok and Kasatochi Volcanoes in July and August dominated Observatory operations in the summer and autumn. AVO maintained 24-hour staffing at the Anchorage facility from July 12 through August 28. Minor eruptive activity continued at Veniaminof and Cleveland Volcanoes. Observed volcanic unrest at Cook Inlet's Redoubt Volcano presaged a significant eruption in the spring of 2009. AVO staff also participated in hazard communication regarding eruptions or unrest at nine volcanoes in Russia as part of a collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  14. TIMP-2 Interaction with MT1-MMP Activates the AKT Pathway and Protects Tumor Cells from Apoptosis

    PubMed Central

    Valacca, Cristina; Tassone, Evelyne; Mignatti, Paolo

    2015-01-01

    Membrane-type 1 matrix metalloproteinase (MT1-MMP), a transmembrane proteinase with an extracellular catalytic domain and a short cytoplasmic tail, degrades a variety of extracellular matrix (ECM) components. In addition, MT1-MMP activates intracellular signaling through proteolysis-dependent and independent mechanisms. We have previously shown that binding of tissue inhibitor of metalloproteinases-2 (TIMP-2) to MT1-MMP controls cell proliferation and migration, as well as tumor growth in vivo by activating the Ras—extracellular signal regulated kinase-1 and -2 (ERK1/2) pathway through a mechanism that requires the cytoplasmic but not the proteolytic domain of MT1-MMP. Here we show that in MT1-MMP expressing cells TIMP-2 also induces rapid and sustained activation of AKT in a dose- and time-dependent manner and by a mechanism independent of the proteolytic activity of MT1-MMP. Fibroblast growth factor receptor-1 mediates TIMP-2 induction of ERK1/2 but not of AKT activation; however, Ras activation is necessary to transduce the TIMP-2-activated signal to both the ERK1/2 and AKT pathways. ERK1/2 and AKT activation by TIMP-2 binding to MT1-MMP protects tumor cells from apoptosis induced by serum starvation. Conversely, TIMP-2 upregulates apoptosis induced by three-dimensional type I collagen in epithelial cancer cells. Thus, TIMP-2 interaction with MT1-MMP provides tumor cells with either pro- or anti-apoptotic signaling depending on the extracellular environment and apoptotic stimulus. PMID:26331622

  15. Evidence for an early gene duplication event in the evolution of the mitochondrial transcription factor B family and maintenance of rRNA methyltransferase activity in human mtTFB1 and mtTFB2.

    PubMed

    Cotney, Justin; Shadel, Gerald S

    2006-11-01

    Most metazoans have two nuclear genes encoding orthologues of the well-characterized Saccharomyces cerevisiae mitochondrial transcription factor B (sc-mtTFB). This class of transcription factors is homologous to the bacterial KsgA family of rRNA methyltransferases, which in Escherichia coli dimethylates adjacent adenine residues in a stem-loop of the 16S rRNA. This posttranscriptional modification is conserved in most metazoan cytoplasmic and mitochondrial rRNAs. Homo sapiens mitochondrial transcription factor B1 (h-mtTFB1) possesses this enzymatic activity, implicating it as a dual-function protein involved in mitochondrial transcription and translation. Here we demonstrate that h-mtTFB2 also has rRNA methyltransferase activity but is a less efficient enzyme than h-mtTFB1. In contrast, sc-mtTFB has no detectable rRNA methyltransferase activity, correlating with the lack of the corresponding modification in the mitochondrial rRNA of budding yeast. Based on these results, and reports that Drosophila melanogaster mtTFB1 and mtTFB2 do not have completely overlapping functions, we propose a model for human mtDNA regulation that takes into account h-mtTFB1 and h-mtTFB2 likely having partially redundant transcription factor and rRNA methyltransferase functions. Finally, phylogenetic analyses of this family of proteins strongly suggest that the presence of two mtTFB homologues in metazoans is the result of a gene duplication event that occurred early in eukaryotic evolution prior to the divergence of fungi and metazoans. This model suggests that, after the gene duplication event, differential selective pressures on the rRNA methyltransferase and transcription factor activities of mtTFB genes occurred, with extreme cases culminating in the loss of one of the paralogous genes in certain species.

  16. 1996 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.

    1997-01-01

    During 1996, the Alaska Volcano Observatory (AVO) responded to eruptive activity, anomalous seismicity, or suspected volcanic activity at 10 of the approximately 40 active volcanic centers in the state of Alaska. As part of a formal role in KVERT (the Kamchatkan Volcano Eruption Response Team), AVO staff also disseminated information about eruptions and other volcanic unrest at six volcanic centers on the Kamchatka Peninsula and in the Kurile Islands, Russia.

  17. Dueling Volcanoes: How Activity Levels At Kilauea Influence Eruptions At Mauna Loa

    NASA Astrophysics Data System (ADS)

    Trusdell, F.

    2011-12-01

    The eruption of Kilauea at Pu`u `O`o is approaching its 29th anniversary. During this time, Mauna Loa has slowly inflated following its most recent eruption in 1984. This is Mauna Loa's longest inter-eruptive interval observed in HVO's 100 years of operation. When will the next eruption of Mauna Loa take place? Is the next eruption of Mauna Loa tied to the current activity at Kilauea? Historically, eruptive periods at Kilauea and Mauna Loa volcanoes appear to be inversely correlated. In the past, when Mauna Loa was exceptionally active, Kilauea Volcano was in repose, recovery, or in sustained lava lake activity. Swanson and co-workers (this meeting) have noted that explosive activity on Kilauea, albeit sporadic, was interspersed between episodes of effusive activity. Specifically, Swanson and co-workers note as explosive the time periods between 300 B.C.E.-1000 C.E and 1500-1800 C.E. They also point to evidence for low magma supply to Kilauea during these periods and few flank eruptions. During the former explosive period, Mauna Loa was exceedingly active, covering approximately 37% of its surface or 1882 km2, an area larger than Kilauea. This period is also marked by summit activity at Mauna Loa sustained for 300 years. In the 1500-1800 C.E. period, Mauna Loa was conspicuously active with 29 eruptions covering an area of 446 km2. In the late 19th and early 20th century, Kilauea was dominated by nearly continuous lava-lake activity. Meanwhile Mauna Loa was frequently active from 1843 C.E. to 1919 C.E., with 24 eruptions for an average repose time of 3.5 years. I propose that eruptive activity at one volcano may affect eruptions at the other, due to factors that impact magma supply, volcanic plumbing, and flank motion. This hypothesis is predicated on the notion that when the rift zones of Kilauea, and in turn its mobile south flank, are active, Mauna Loa's tendency to erupt is diminished. Kilauea's rift zones help drive the south flank seaward, in turn, as Mauna

  18. Active Source Seismic Experiment Peers Under Soufrière Hills Volcano

    NASA Astrophysics Data System (ADS)

    Voight, Barry; Sparks, R. S. J.; Hammond, J.; Shalev, E.; Malin, P.; Kenedi, C.; Minshull, T. A.; Paulatto, M.; Mattioli, G.; Hidayat, D.; Widiwijayanti, C.

    2010-07-01

    Characterizing internal structures of active volcanoes remains an enigmatic issue in geosciences. Yet studies of such structures can greatly improve hazard assessments, helping scientists to better monitor seismic signatures, geodetic deformation, and gas emissions, data that can be used to improve models and forecasts of future eruptions. Several passive seismic tomography experiments—which use travel times of seismic waves from natural earthquakes to image underground structures—have been conducted at active volcanoes (Hawaii's Kilauea, Washington's Mount St. Helens, Italy's Etna, and Japan's Unzen), but an inhomogeneous distribution of earthquakes compromises resolution. Further, if volcanic earthquakes are dominantly shallow at a given location, passive methods are limited to studying only shallow features. Thus, active source experiments—where seismic waves from the explosion of deliberately set charges are used to image below the surface—hold great potential to illuminate structures not readily seen through passive measures.

  19. Rapid response of a hydrologic system to volcanic activity: Masaya volcano, Nicaragua

    USGS Publications Warehouse

    Pearson, S.C.P.; Connor, C.B.; Sanford, W.E.

    2008-01-01

    Hydrologic systems change in response to volcanic activity, and in turn may be sensitive indicators of volcanic activity. Here we investigate the coupled nature of magmatic and hydrologic systems using continuous multichannel time series of soil temperature collected on the flanks of Masaya volcano, Nicaragua, one of the most active volcanoes in Central America. The soil temperatures were measured in a low-temperature fumarole field located 3.5 km down the flanks of the volcano. Analysis of these time series reveals that they respond extremely rapidly, on a time scale of minutes, to changes in volcanic activity also manifested at the summit vent. These rapid temperature changes are caused by increased flow of water vapor through flank fumaroles during volcanism. The soil temperature response, ~5 °C, is repetitive and complex, with as many as 13 pulses during a single volcanic episode. Analysis of the frequency spectrum of these temperature time series shows that these anomalies are characterized by broad frequency content during volcanic activity. They are thus easily distinguished from seasonal trends, diurnal variations, or individual rainfall events, which triggered rapid transient increases in temperature during 5% of events. We suggest that the mechanism responsible for the distinctive temperature signals is rapid change in pore pressure in response to magmatism, a response that can be enhanced by meteoric water infiltration. Monitoring of distal fumaroles can therefore provide insight into coupled volcanic-hydrologic-meteorologic systems, and has potential as an inexpensive monitoring tool.

  20. Long-range infrasound monitoring of eruptive volcanoes.

    NASA Astrophysics Data System (ADS)

    Marchetti, Emanuele; Innocenti, Lorenzo; Ulivieri, Giacomo; Lacanna, Giorgio; Ripepe, Maurizio

    2016-04-01

    The efficient long-range propagation in the atmosphere makes infrasound of active volcanoes extremely promising and opens new perspectives for volcano monitoring at large scale. In favourable propagation conditions, long-range infrasound observations can be used to track the occurrence and the duration of volcanic eruptions also at remote non-monitored volcanoes, but its potential to infer volcanic eruptive source term is still debated. We present results of comparing five years of infrasound of eruptive activity at Mt.Etna volcano (Italy) recorded both at local (~5 km) and at regional distances (~600 km) from the source. Infrasound of lava fountains at Etna volcano, occurring in between 2010 and 2015, are analysed in terms of the local and regional wavefield record, and by comparing to all available volcanic source terms (i.e. plume height and mass eruption rates). Besides, the potential of near real-time notification of ongoing volcanic activity at Etna volcano at a regional scale is investigated. In particular we show how long range infrasound, in the case of Etna volcano, can be used to promptly deliver eruption notification and reliability is constrained by the results of the local array. This work is performed in the framework of the H2020 ARISE2 project funded by the EU in the period 2015-2018.

  1. Geothermal activity and energy of the Yakedake volcano, Gifu-Nagano, Japan

    SciTech Connect

    Iriyama, Jun

    1996-12-31

    The temperature of the most active solfatara in the summit crater of the Yakedake volcano (altitude 2,455 m Gifu-Nagano, Japan) was 92.2 and 129.4{degrees}C in September 1995 and in October 1994, respectively. The temperature of solfatara in the northern summit dome at an altitude of 2,240 to 2,270 m ranged from 68.2 to 92.5{degrees}C in September 1995. The water sample from a crater pond, Shoga-ike, located on the summit, showed a pH and electrical conductivity of 4.38 and 42.2 {mu}S/cm in October 1991, 4.35 and 42.4 {mu}S/cm in September 1992, 4.11 and 76.6 {mu}S/cm in October 1994, and 4.30 and 45.1 {mu}S/cm in September 1995, respectively. In 1960, the water sample from the same pond showed the pH and electrical conductivity of 3.7 and 80.8 {mu}S/cm, respectively. Although the values of pH and electrical conductivity in 1994 approached to the values at the volcano`s pre-eruption in 1960, the eruption in the summit dome did not occur in 1995. However, a large steam explosion occurred in the Nakanoyu area of the southeastern Mountainside of the volcano. The geothermal energy within the summit dome at an altitude of 2,050 to 2,455 m of the Yakedake volcano is calculated, using new data, to be about 4.8 x 10{sup 17} J, which represents a thermal power output of 5.1 x 10{sup 2} MW{sub th} averaged over 30 yrs.

  2. Areal distribution, thickness, mass, volume, and grain size of tephra-fall deposits from the 1992 eruptions of Crater Peak vent, Mt. Spurr Volcano, Alaska

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Riley, Colleen M.

    2001-01-01

    The Crater Peak flank vent of Mount Spurr volcano erupted June 27, August 18, and September 16- 17, 1992. The three eruptions were similar in intensity (vulcanian to subplinian eruption columns reaching up to 14 km Above Sea Level) and duration (3.5 to 4.0 hours) and produced tephra-fall deposits (12, 14, 15 x 10 6 m3 Dense Rock Equivalent [DRE]) discernible up to 1,000 km downwind. The June 27 ash cloud traveled north over the rugged, ice- and snow-covered Alaska Range. The August 18 ash cloud was carried southeastward over Anchorage, across Prince William Sound, and down the southeastern shoreline of the Gulf of Alaska. The September 16-17 ash plume was directed eastward over the Talkeetna and Wrangell mountains and into the Yukon Territory of Canada. Over 50 mass-per-unit-area (MPUA) samples were collected for each of the latter two fall deposits at distances ranging from about 2 km to 370 km downwind from the volcano. Only 10 (mostly proximal) samples were collected for the June fall deposit due to inaccessible terrain and funding constraints. MPUA data were plotted and contoured (isomass lines) to graphically display the distribution of each fall deposit. For the August and September eruptions, fallout was concentrated along a narrow (30 to 50 km wide) belt. The fallout was most concentrated (100,000 to greater than 250,000 g/m2) within about 80 km of the volcano. Secondary maxima occur at 200 km (2,620 g/m2) and 300 km (4,659 g/m2), respectively, down axis for the August and September deposits. The maxima contain bimodal grain size distributions (with peaks at 88.4 and 22.1 microns) indicating aggregation within the ash cloud. Combined tephra-volume for the 1992 Mount Spurr eruptions (41 x 10 6 m3 DRE) is comparable to that (tephra-fall only) of the 1989-90 eruptions of nearby Redoubt volcano (31-49 x 106 m3 DRE).

  3. Phthalimide neovascular factor 1 (PNF1) modulates MT1-MMP activity in human microvascular endothelial cells.

    PubMed

    Wieghaus, Kristen A; Gianchandani, Erwin P; Neal, Rebekah A; Paige, Mikell A; Brown, Milton L; Papin, Jason A; Botchwey, Edward A

    2009-07-01

    We are creating synthetic pharmaceuticals with angiogenic activity and potential to promote vascular invasion. We previously demonstrated that one of these molecules, phthalimide neovascular factor 1 (PNF1), significantly expands microvascular networks in vivo following sustained release from poly(lactic-co-glycolic acid) (PLAGA) films. In addition, to probe PNF1 mode of action, we recently applied a novel pathway-based compendium analysis to a multi-timepoint, controlled microarray data set of PNF1-treated (vs. control) human microvascular endothelial cells (HMVECs), and we identified induction of tumor necrosis factor-alpha (TNF-alpha) and, subsequently, transforming growth factor-beta (TGF-beta) signaling networks by PNF1. Here we validate this microarray data set with quantitative real-time polymerase chain reaction (RT-PCR) analysis. Subsequently, we probe this data set and identify three specific TGF-beta-induced genes with regulation by PNF1 conserved over multiple timepoints-amyloid beta (A4) precursor protein (APP), early growth response 1 (EGR-1), and matrix metalloproteinase 14 (MMP14 or MT1-MMP)-that are also implicated in angiogenesis. We further focus on MMP14 given its unique role in angiogenesis, and we validate MT1-MMP modulation by PNF1 with an in vitro fluorescence assay that demonstrates the direct effects that PNF1 exerts on functional metalloproteinase activity. We also utilize endothelial cord formation in collagen gels to show that PNF1-induced stimulation of endothelial cord network formation in vitro is in some way MT1-MMP-dependent. Ultimately, this new network analysis of our transcriptional footprint characterizing PNF1 activity 1-48 h post-supplementation in HMVECs coupled with corresponding validating experiments suggests a key set of a few specific targets that are involved in PNF1 mode of action and important for successful promotion of the neovascularization that we have observed by the drug in vivo. PMID:19326468

  4. Analysis of the seismicity activity of the volcano Ceboruco, Nayarit, Mexico

    NASA Astrophysics Data System (ADS)

    Rodriguez-Ayala, N. A.; Nunez-Cornu, F. J.; Escudero, C. R.; Zamora-Camacho, A.; Gomez, A.

    2014-12-01

    The Ceboruco is a stratovolcano is located in the state of Nayarit,Mexico (104 ° 30'31 .25 "W, 21 ° 7'28 .35" N, 2280msnm). This is an volcano active, as part of the Trans-Mexican Volcanic Belt, Nelson (1986) reports that it has had activity during the last 1000 years has averaged eruptions every 125 years or so, having last erupted in 1870, currently has fumarolic activity. In the past 20 years there has been an increase in the population and socio-economic activities around the volcano (Suárez Plascencia, 2013); which reason the Ceboruco study has become a necessity in several ways. Recent investigations of seismicity (Rodríguez Uribe et al., 2013) have classified the earthquakes in four families Ceboruco considering the waveform and spectral features. We present analysis included 57 days of seismicity from March to October 2012, in the period we located 97 events with arrivals of P and S waves clear, registered in at least three seasons, three components of the temporal network Ceboruco volcano.

  5. Long-term explosive degassing and debris flow activity at West Mata submarine volcano

    NASA Astrophysics Data System (ADS)

    Dziak, R. P.; Bohnenstiehl, D. R.; Baker, E. T.; Matsumoto, H.; Caplan-Auerbach, J.; Embley, R. W.; Merle, S. G.; Walker, S. L.; Lau, T.-K.; Chadwick, W. W.

    2015-03-01

    West Mata is a 1200 m deep submarine volcano where explosive boninite eruptions were observed in 2009. The acoustic signatures from the volcano's summit eruptive vents Hades and Prometheus were recorded with an in situ (~25 m range) hydrophone during ROV dives in May 2009 and with local (~5 km range) moored hydrophones between December 2009 and August 2011. The sensors recorded low frequency (1-40 Hz), short duration explosions consistent with magma bubble bursts from Hades, and broadband, 1-5 min duration signals associated with episodes of fragmentation degassing from Prometheus. Long-term eruptive degassing signals, recorded through May 2010, preceded a several month period of declining activity. Degassing episodes were not recorded acoustically after early 2011, although quieter effusive eruption activity may have continued. Synchronous optical measurements of turbidity made between December 2009 and April 2010 indicate that turbidity maxima resulted from occasional south flank slope failures triggered by the collapse of accumulated debris during eruption intervals.

  6. Seismicity at Uturuncu Volcano, Bolivia: Volcano-Tectonic Earthquake Swarms Triggered by the 2010 Maule, Chile Earthquake and Non-Triggered Background Activity

    NASA Astrophysics Data System (ADS)

    Christensen, D. H.; Chartrand, Z. A.; Jay, J.; Pritchard, M. E.; West, M. E.; McNutt, S. R.

    2010-12-01

    We find that the 270 ky dormant Uturuncu Volcano in SW Bolivia exhibits relatively high rates of shallow, volcano-tectonic seismicity that is dominated by swarm-like activity. We also document that the 27 February 2010 Mw 8.8 Maule, Chile earthquake triggered an exceptionally high rate of seismicity in the seconds to days following the main event. Although dormant, Uturuncu is currently being studied due to its large-scale deformation rate of 1-2 cm/yr uplift as revealed by InSAR. As part of the NASA-funded Andivolc project to investigate seismicity of volcanoes in the central Andes, a seismic network of 15 stations (9 Mark Products L22 short period and 6 Guralp CMG40T intermediate period sensors) with an average spacing of about 10 km was installed at Uturuncu from April 2009 to April 2010. Volcano-tectonic earthquakes occur at an average rate of about 3-4 per day, and swarms of 5-60 events within a span of minutes to hours occur a few times per month. Most of these earthquakes are located close to the summit at depths near and above sea level. The largest swarm occurred on 28 September 2009 and consisted of 60 locatable events over a time span of 28 hours. The locations of volcano-tectonic earthquakes at Uturuncu are oriented in a NW-SE trend, which matches the dominant orientation of regional faults and suggests a relationship between the fault system at Uturuncu and the regional tectonics of the area; a NW-SE trending fault beneath Uturuncu may serve to localize stresses that are accumulating over the broad area of uplift. Based on automated locations, the maximum local magnitude of these events is approximately M = 4 and the average magnitude is approximately M = 2. An initial estimate of the b-value is about b = 1.2. The Mw 8.8 Maule earthquake on 27 February 2010 triggered hundreds of local volcano-tectonic events at Uturuncu. High-pass filtering of the long period surface waves reveals that the first triggered events occurred with the onset of the Rayleigh

  7. Simultaneous use of various sensors for thermal monitoring of active volcanoes - an application of Kalman filtering

    NASA Astrophysics Data System (ADS)

    Zaksek, K.; Hort, M. K.

    2009-12-01

    Thermal remote sensing is a valuable tool for monitoring active volcanoes. One can detect thermal anomalies originating from a volcano by comparing signals in mid and thermal infrared spectra. Once a thermal anomaly is detected, it has to be characterized in order to evaluate the activity status of volcano. The usual procedure is to compute temperature and area of the thermal anomaly using the dual band method proposed by Dozier (1981). More recent work, however, has shown that radiant flux (can be derived from the temperature and area or directly from measured radiances) is a more robust parameter for volcano characterization. Atmosphere, satellite viewing angle and sensor characteristics have a significant influence on the thermal anomaly characterization. Some of the influences are easy to correct using standard remote sensing preprocessing techniques, however, some noise still remains in data. In addition, satellites in polar orbits have long revisit times and thus they might fail to detect short volcanic events. It would therefore desirable to use data from different satellites in order to a) reduce uncertainties and b) improve temporal resolution. If one tries to simultaneously use data from different instruments, the measurements are often not comparable. Fortunately, there are statistical techniques that allow the combination of measurements from different sources that have different levels of accuracy. A suitable method for such a data fusion is Kalman filter. It is a recursive operator that returns the optimal estimation of a system state in a chosen time. Here we applied the Kalman filter to reduce noise and increase the temporal resolution of volcano radiant flux measurements from simultaneous MODIS and AVHRR measurements. As the evolution of the volcanic activity is difficult to predict we did not apply a physical model for the system state transition; we used a stochastic based model. A main challenge was to define the process noise covariance matrix

  8. Esmeralda Bank: Geochemistry of an active submarine volcano in the Mariana Island Arc

    NASA Astrophysics Data System (ADS)

    Stern, Robert J.; Bibee, L. D.

    1984-05-01

    Esmeralda Bank is the southernmost active volcano in the Izu-Volcano-Mariana Arc. This submarine volcano is one of the most active vents in the western Pacific. It has a total volume of about 27 km3, rising to within 30 m of sea level. Two dredge hauls from Esmeralda recovered fresh, nearly aphyric, vesicular basalts and basaltic andesites and minor basaltic vitrophyre. These samples reflect uniform yet unusual major and trace element chemistries. Mean abundances of TiO2 (1.3%) and FeO* (12.6%) are higher and CaO (9.2%) and Al2O3 (15.1%) are lower than rocks of similar silica content from other active Mariana Arc volcanoes. Mean incompatible element ratios K/Rb (488) and K/Ba (29) of Esmeralda rocks are indistinguishable from those of other Mariana Arc volcanoes. On a Ti-Zr plot, Esmeralda samples plot in the field of oceanic basalts while other Mariana Arc volcanic rocks plot in the field for island arcs. Incompatible element ratios K/Rb and K/Ba and isotopic compositions of Sr (87Sr/86Sr=0.70342 0.70348), Nd (ɛND=+7.6 to +8.1), and O(δ18O=+5.8 to +5.9) are incompatible with models calling for the Esmeralda source to include appreciable contributions from pelagic sediments or fresh or altered abyssal tholeiite from subduction zone melting. Instead, incompatible element and isotopic ratios of Esmeralda rocks are similar to those of intra-plate oceanic islands or “hot-spot” volcanoes in general and Kilauean tholeiites in particular. The conclusion that the source for Esmeralda lavas is an ocean-island type mantle reservoir is preferred. Esmeralda Bank rare earth element patterns are inconsistent with models calling for residual garnet in the source region, but are adequately modelled by 7 10% equilibrium partial melting of spinel lherzolite. This is supported by consideration of the results of melting experiments at 20 kbars, 1,150° C with CO2 and H2O as important volatile components. These experiments further indicate that low MgO (4.1%), MgO/FeO*(0.25) and

  9. Active normal faulting along the Mt. Morrone south-western slopes (central Apennines, Italy)

    NASA Astrophysics Data System (ADS)

    Gori, Stefano; Giaccio, Biagio; Galadini, Fabrizio; Falcucci, Emanuela; Messina, Paolo; Sposato, Andrea; Dramis, Francesco

    2011-01-01

    In the present work we analyse one of the active normal faults affecting the central Apennines, i.e. the Mt. Morrone normal fault system. This tectonic structure, which comprises two parallel, NW-SE trending fault segments, is considered as potentially responsible for earthquakes of magnitude ≥ 6.5 and its last activation probably occurred during the second century AD. Structural observations performed along the fault planes have allowed to define the mainly normal kinematics of the tectonic structure, fitting an approximately N 20° trending extensional deformation. Geological and geomorphological investigations performed along the whole Mt. Morrone south-western slopes permitted us to identify the displacement of alluvial fans, attributed to Middle and Late Pleistocene by means of tephro-stratigraphic analyses and geomorphological correlations with dated lacustrine sequences, along the western fault branch. This allowed to evaluate in 0.4 ± 0.07 mm/year the slip rate of this segment. On the other hand, the lack of synchronous landforms and/or deposits that can be correlated across the eastern fault segment prevented the definition of the slip rate related to this fault branch. Nevertheless, basing on a critical review of the available literature dealing with normal fault systems evolution, we hypothesised a total slip rate of the fault system in the range of 0.4 ± 0.07 to 0.8 ± 0.09 mm/year. Moreover, basing on the length at surface of the Mt. Morrone fault system (i.e. 22-23 km) we estimated the maximum expected magnitude of an earthquake that might originate along this tectonic structure in the order of 6.6-6.7.

  10. Spreading and collapse of big basaltic volcanoes

    NASA Astrophysics Data System (ADS)

    Puglisi, Giuseppe; Bonforte, Alessandro; Guglielmino, Francesco; Peltier, Aline; Poland, Michael

    2016-04-01

    Among the different types of volcanoes, basaltic ones usually form the most voluminous edifices. Because volcanoes are growing on a pre-existing landscape, the geologic and structural framework of the basement (and earlier volcanic landforms) influences the stress regime, seismicity, and volcanic activity. Conversely, the masses of these volcanoes introduce a morphological anomaly that affects neighboring areas. Growth of a volcano disturbs the tectonic framework of the region, clamps and unclamps existing faults (some of which may be reactivated by the new stress field), and deforms the substratum. A volcano's weight on its basement can trigger edifice spreading and collapse that can affect populated areas even at significant distance. Volcano instability can also be driven by slow tectonic deformation and magmatic intrusion. The manifestations of instability span a range of temporal and spatial scales, ranging from slow creep on individual faults to large earthquakes affecting a broad area. In the frame of MED-SVU project, our work aims to investigate the relation between basement setting and volcanic activity and stability at three Supersite volcanoes: Etna (Sicily, Italy), Kilauea (Island of Hawaii, USA) and Piton de la Fournaise (La Reunion Island, France). These volcanoes host frequent eruptive activity (effusive and explosive) and share common features indicating lateral spreading and collapse, yet they are characterized by different morphologies, dimensions, and tectonic frameworks. For instance, the basaltic ocean island volcanoes of Kilauea and Piton de la Fournaise are near the active ends of long hotspot chains while Mt. Etna has developed at junction along a convergent margin between the African and Eurasian plates and a passive margin separating the oceanic Ionian crust from the African continental crust. Magma supply and plate velocity also differ in the three settings, as to the sizes of the edifices and the extents of their rift zones. These

  11. Cellular immune responses and phagocytic activity of fishes exposed to pollution of volcano mud.

    PubMed

    Risjani, Yenny; Yunianta; Couteau, Jerome; Minier, Christophe

    2014-05-01

    Since May 29, 2006, a mud volcano in the Brantas Delta of the Sidoarjo district has emitted mud that has inundated nearby villages. Pollution in this area has been implicated in detrimental effects on fish health. In fishes, leukocyte and phagocytic cells play a vital role in body defenses. We report for the first time the effect of "LUSI" volcano mud on the immune systems of fish in the Brantas Delta. The aim of this study was to find biomarkers to allow the evaluation of the effects of volcanic mud and anthropogenic pollution on fish health in the Brantas Delta. The study took places at the Brantas Delta, which was polluted by volcano mud, and at reference sites in Karangkates and Pasuruan. Leukocyte numbers were determined using a Neubauer hemocytometer and a light microscope. Differential leukocyte counts were determined using blood smears stained with May Grunwald-Giemsa, providing neutrophil, lymphocyte and monocyte counts. Macrophages were taken from fish kidney, and their phagocytic activity was measured. In vitro analyses revealed that leukocyte and differential leukocyte counts (DLC) were higher in Channa striata and Chanos chanos caught from the polluted area. Macrophage numbers were higher in Oreochromis mossambicus than in the other species, indicating that this species is more sensitive to pollution. In areas close to volcanic mud eruption, all specimens had lower phagocytic activity. Our results show that immune cells were changed and phagocytic activity was reduced in the polluted area indicating cytotoxicity and alteration of the innate immune system in fishes exposed to LUSI volcano mud and anthropogenic pollution.

  12. Cellular immune responses and phagocytic activity of fishes exposed to pollution of volcano mud.

    PubMed

    Risjani, Yenny; Yunianta; Couteau, Jerome; Minier, Christophe

    2014-05-01

    Since May 29, 2006, a mud volcano in the Brantas Delta of the Sidoarjo district has emitted mud that has inundated nearby villages. Pollution in this area has been implicated in detrimental effects on fish health. In fishes, leukocyte and phagocytic cells play a vital role in body defenses. We report for the first time the effect of "LUSI" volcano mud on the immune systems of fish in the Brantas Delta. The aim of this study was to find biomarkers to allow the evaluation of the effects of volcanic mud and anthropogenic pollution on fish health in the Brantas Delta. The study took places at the Brantas Delta, which was polluted by volcano mud, and at reference sites in Karangkates and Pasuruan. Leukocyte numbers were determined using a Neubauer hemocytometer and a light microscope. Differential leukocyte counts were determined using blood smears stained with May Grunwald-Giemsa, providing neutrophil, lymphocyte and monocyte counts. Macrophages were taken from fish kidney, and their phagocytic activity was measured. In vitro analyses revealed that leukocyte and differential leukocyte counts (DLC) were higher in Channa striata and Chanos chanos caught from the polluted area. Macrophage numbers were higher in Oreochromis mossambicus than in the other species, indicating that this species is more sensitive to pollution. In areas close to volcanic mud eruption, all specimens had lower phagocytic activity. Our results show that immune cells were changed and phagocytic activity was reduced in the polluted area indicating cytotoxicity and alteration of the innate immune system in fishes exposed to LUSI volcano mud and anthropogenic pollution. PMID:24631200

  13. Ground survey of active Central American volcanoes in November - December 1973

    NASA Technical Reports Server (NTRS)

    Stoiber, R. E. (Principal Investigator); Rose, W. I., Jr.

    1974-01-01

    The author has identified the following significant results. Thermal anomalies at two volcanoes, Santiaguito and Izalco, have grown in size in the past six months, based on repeated ground survey. Thermal anomalies at Pacaya volcano have became less intense in the same period. Large (500 m diameter) thermal anomalies exist at 3 volcanoes presently, and smaller scale anomalies are found at nine other volcanoes.

  14. Multi-variable X-band radar observation and tracking of ash plume from Mt. Etna volcano on November 23, 2013 event

    NASA Astrophysics Data System (ADS)

    Montopoli, Mario; Vulpiani, Gianfranco; Riccci, Matteo; Corradini, Stefano; Merucci, Luca; Marzano, Frank S.

    2015-04-01

    Ground based weather radar observations of volcanic ash clouds are gaining momentum after recent works which demonstrated their potential use either as stand alone tool or in combination with satellite retrievals. From an operational standpoint, radar data have been mainly exploited to derive the height of ash plume and its temporal-spatial development, taking into account the radar limitation of detecting coarse ash particles (from approximately 20 microns to 10 millimeters and above in terms of particle's radius). More sophisticated radar retrievals can include airborne ash concentration, ash fall rate and out-flux rate. Marzano et al. developed several volcanic ash radar retrieval (VARR) schemes, even though their practical use is still subject to a robust validation activity. The latter is made particularly difficult due to the lack of field campaigns with multiple observations and the scarce repetition of volcanic events. The radar variable, often used to infer the physical features of actual ash clouds, is the radar reflectivity named ZHH. It is related to ash particle size distribution and it shows a nice power law relationship with ash concentration. This makes ZHH largely used in radar-volcanology studies. However, weather radars are often able to detect Doppler frequency shifts and, more and more, they have a polarization-diversity capability. The former means that wind speed spectrum of the ash cloud is potentially inferable, whereas the latter implies that variables other than ZHH are available. Theoretically, these additional radar variables are linked to the degree of eccentricity of ash particles, their orientation and density as well as the presence of strong turbulence effects. Thus, the opportunity to refine the ash radar estimates so far developed can benefit from the thorough analysis of radar Doppler and polarization diversity. In this work we show a detailed analysis of Doppler shifts and polarization variables measured by the X band radar

  15. Alaska Volcano Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Murray, Tom; Read, Cyrus

    2008-01-01

    Steam plume from the 2006 eruption of Augustine volcano in Cook Inlet, Alaska. Explosive ash-producing eruptions from Alaska's 40+ historically active volcanoes pose hazards to aviation, including commercial aircraft flying the busy North Pacific routes between North America and Asia. The Alaska Volcano Observatory (AVO) monitors these volcanoes to provide forecasts of eruptive activity. AVO is a joint program of the U.S. Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). AVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Augustine volcano and AVO at http://www.avo.alaska.edu.

  16. Io’s active volcanoes during the New Horizons era: Insights from New Horizons imaging

    NASA Astrophysics Data System (ADS)

    Rathbun, J. A.; Spencer, J. R.; Lopes, R. M.; Howell, R. R.

    2014-03-01

    In February 2007, the New Horizons spacecraft flew by the Jupiter system, obtaining images of Io, the most volcanically active body in the Solar System. The Multicolor Visible Imaging Camera (MVIC), a four-color (visible to near infrared) camera, obtained 17 sets of images. The Long-Range Reconnaissance Imager (LORRI), a high-resolution panchromatic camera, obtained 190 images, including many of Io eclipsed by Jupiter. We present a complete view of the discrete point-like emission sources in all images obtained by these two instruments. We located 54 emission sources and determined their brightnesses. These observations, the first that observed individual Ionian volcanoes on short timescales of seconds to minutes, demonstrate that the volcanoes have stable brightnesses on these timescales. The active volcanoes Tvashtar (63N, 124W) and E. Girru (22N, 245W) were observed by both LORRI and MVIC, both in the near-infrared (NIR) and methane (CH4) filters. Tvashtar was additionally observed in the red filter, which allowed us to calculate a color temperature of approximately 1200 K. We found that, with some exceptions, most of the volcanoes frequently active during the Galileo era continued to be active during the New Horizons flyby. We found that none of the seven volcanoes observed by New Horizons multiple times over short timescales showed substantial changes on the order of seconds and only one, E. Girru exhibited substantial variation over minutes to days, increasing by 25% in just over an hour and decreasing by a factor of 4 over 6 days. Observations of Tvashtar are consistent with a current eruption similar to previously observed eruptions and are more consistent with the thermal emission of a lava flow than the fire fountains inferred from the November 1999 observations. These data also present new puzzles regarding Ionian volcanism. Since there is no associated surface change or low albedo feature that could be identified nearby, the source of the emission from

  17. Estimating eruption temperature from thermal emission spectra of lava fountain activity in the Erta'Ale (Ethiopia) volcano lava lake: Implications for observing Io's volcanoes

    USGS Publications Warehouse

    Davies, A.G.; Keszthelyi, L.; McEwen, A.S.

    2011-01-01

    We have analysed high-spatial-resolution and high-temporal-resolution temperature measurements of the active lava lake at Erta'Ale volcano, Ethiopia, to derive requirements for measuring eruption temperatures at Io's volcanoes. Lava lakes are particularly attractive targets because they are persistent in activity and large, often with ongoing lava fountain activity that exposes lava at near-eruption temperature. Using infrared thermography, we find that extracting useful temperature estimates from remote-sensing data requires (a) high spatial resolution to isolate lava fountains from adjacent cooler lava and (b) rapid acquisition of multi-color data. Because existing spacecraft data of Io's volcanoes do not meet these criteria, it is particularly important to design future instruments so that they will be able to collect such data. Near-simultaneous data at more than two relatively short wavelengths (shorter than 1 ??m) are needed to constrain eruption temperatures. Resolving parts of the lava lake or fountains that are near the eruption temperature is also essential, and we provide a rough estimate of the required image scale. ?? 2011 by the American Geophysical Union.

  18. Estimating eruption temperature from thermal emission spectra of lava fountain activity in the Erta'Ale (Ethiopia) volcano lava lake: Implications for observing Io's volcanoes

    USGS Publications Warehouse

    Davies, Ashley G.; Keszthelyi, Laszlo P.; McEwen, Alfred S.

    2011-01-01

    We have analysed high-spatial-resolution and high-temporal-resolution temperature measurements of the active lava lake at Erta'Ale volcano, Ethiopia, to derive requirements for measuring eruption temperatures at Io's volcanoes. Lava lakes are particularly attractive targets because they are persistent in activity and large, often with ongoing lava fountain activity that exposes lava at near-eruption temperature. Using infrared thermography, we find that extracting useful temperature estimates from remote-sensing data requires (a) high spatial resolution to isolate lava fountains from adjacent cooler lava and (b) rapid acquisition of multi-color data. Because existing spacecraft data of Io's volcanoes do not meet these criteria, it is particularly important to design future instruments so that they will be able to collect such data. Near-simultaneous data at more than two relatively short wavelengths (shorter than 1 μm) are needed to constrain eruption temperatures. Resolving parts of the lava lake or fountains that are near the eruption temperature is also essential, and we provide a rough estimate of the required image scale.

  19. Estimating eruption temperature from thermal emission spectra of lava fountain activity in the Erta'Ale (Ethiopia) volcano lava lake: Implications for observing Io's volcanoes

    NASA Astrophysics Data System (ADS)

    Davies, Ashley Gerard; Keszthelyi, Laszlo; McEwen, Alfred S.

    2011-11-01

    We have analysed high-spatial-resolution and high-temporal-resolution temperature measurements of the active lava lake at Erta'Ale volcano, Ethiopia, to derive requirements for measuring eruption temperatures at Io's volcanoes. Lava lakes are particularly attractive targets because they are persistent in activity and large, often with ongoing lava fountain activity that exposes lava at near-eruption temperature. Using infrared thermography, we find that extracting useful temperature estimates from remote-sensing data requires (a) high spatial resolution to isolate lava fountains from adjacent cooler lava and (b) rapid acquisition of multi-color data. Because existing spacecraft data of Io's volcanoes do not meet these criteria, it is particularly important to design future instruments so that they will be able to collect such data. Near-simultaneous data at more than two relatively short wavelengths (shorter than 1 μm) are needed to constrain eruption temperatures. Resolving parts of the lava lake or fountains that are near the eruption temperature is also essential, and we provide a rough estimate of the required image scale.

  20. Understanding how active volcanoes work: a contribution from synchrotron X-ray computed microtomography

    NASA Astrophysics Data System (ADS)

    Polacci, M.; Baker, D. R.; Mancini, L.

    2009-04-01

    Volcanoes are complex systems that require the integration of many different geoscience disciplines to understand their behaviour and to monitor and forecast their activity. In the last two decades an increasing amount of information on volcanic processes has been obtained by studying the textures and compositions of volcanic rocks. Five years ago we started a continuing collaboration with the SYRMEP beamline of Elettra Sincrotrone, a third generation synchrotron light source near Trieste, Italy, with the goal of performing high-resolution, phase-contrast X-ray tomographic scans and reconstructing 3-D digital volumes of volcanic specimens. These volumes have been then used for the visualization of the internal structure of rocks and for the quantification of rock textures (i.e., vesicle and crystal volume fraction, individual vesicle volumes and shapes, vesicle connectivity, vesicle volume distributions, permeability simulations etc.). We performed tomographic experiments on volcanic products erupted from different hazardous volcanic systems in Italy and around the world: Campi Flegrei, Stromboli, Etna (Southern Italy), Villarrica (Chile), Yasur and Ambrym (Vanuatu Islands). As an example, we used the results of these studies to constrain the dynamics of vesiculation and degassing in basaltic (Polacci et al., 2006; Burton et al., 2007; Colò et al., 2007; Andronico et al., 2008; Polacci et al., 2008a) and trachytic (Piochi et al., 2008) magmas. A better knowledge of how gas is transported and lost from magmas has led us in turn to draw new implications on the eruptive style of these active, hazardous volcanoes (Polacci et al., 2008b). Work in progress consists of optimizing our procedure by establishing a precise protocol that will enable us to quantitatively study the 3-D texture and composition of rocks in a statistically representative way. Future work will concentrate on the study of the spatial relations between phases (crystals, vesicles and glass) in rocks

  1. SO2 emissions from persistently active explosive volcanoes: can we estimate their contribution using satellite instruments?

    NASA Astrophysics Data System (ADS)

    Smekens, J.; Clarke, A. B.

    2010-12-01

    The scientific community has long since recognized the importance of sulfur dioxide (SO2) on climate change. The most universally accepted theory is that large amounts of SO2 injected into the atmosphere will react to form sulfate aerosols that reflect sunlight, thereby decreasing global temperature. This cooling effect has been observed after large eruptions throughout the geologic and historic records. The exact effect of SO2 on global climate though is still poorly understood. Estimates of global volcanic SO2 emissions rely primarily on two sets of data: ground-based measurements of SO2 fluxes using COSPEC or DOAS and more recently satellite observations. Both of these usually represent ‘snapshots’ of the gas emissions and at only a few places is continuous monitoring and data acquisition possible. Because continuous data are so rare, many assumptions have to be made when trying to estimate the global volcanic SO2 input to the atmosphere. This is especially true when it comes to frequently exploding volcanoes. Most of their background activity is very low in intensity or the gas plume may simply not reach the stratosphere, both of which make it impossible for satellite instruments to detect it. On the other hand, while individual explosions produce plumes big enough to be detected by satellite instruments, they are often not captured from the ground because no continuous monitoring is in place. Therefore neither satellite nor ground-based data fully represents the total SO2 emissions of these volcanoes. We have analyzed satellite data for several persistently active explosive volcanic centers in an attempt to determine whether their SO2 emissions are detectable and to what extent we can quantify them. We used data from the Ozone Monitoring Instrument (OMI), which operates in the UV spectrum, the Moderate Resolution Imaging Spectroradiometer (MODIS) and, when available, the Advanced Spaceborne Thermal Emission Radiometer (ASTER), both of which operate in the

  2. 1997 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Wallace, Kristi L.

    1999-01-01

    The Alaska Volcano Observatory (AVO) monitors over 40 historically active volcanoes along the Aleutian Arc. Twenty are seismically monitored and for the rest, the AVO monitoring program relies mainly on pilot reports, observations of local residents and ship crews, and daily analysis of satellite images. In 1997, AVO responded to eruptive activity or suspect volcanic activity at 11 volcanic centers: Wrangell, Sanford, Shrub mud volcano, Iliamna, the Katmai group (Martin, Mageik, Snowy, and Kukak volcanoes), Chiginagak, Pavlof, Shishaldin, Okmok, Cleveland, and Amukta. Of these, AVO has real-time, continuously recording seismic networks at Iliamna, the Katmai group, and Pavlof. The phrase “suspect volcanic activity” (SVA), used to characterize several responses, is an eruption report or report of unusual activity that is subsequently determined to be normal or enhanced fumarolic activity, weather-related phenomena, or a non-volcanic event. In addition to responding to eruptive activity at Alaska volcanoes, AVO also disseminated information for the Kamchatkan Volcanic Eruption Response Team (KVERT) about the 1997 activity of 5 Russian volcanoes--Sheveluch, Klyuchevskoy, Bezymianny, Karymsky, and Alaid (SVA). This report summarizes volcanic activity and SVA in Alaska during 1997 and the AVO response, as well as information on the reported activity at the Russian volcanoes. Only those reports or inquiries that resulted in a “significant” investment of staff time and energy (here defined as several hours or more for reaction, tracking, and follow-up) are included. AVO typically receives dozens of reports throughout the year of steaming, unusual cloud sightings, or eruption rumors. Most of these are resolved quickly and are not tabulated here as part of the 1997 response record.

  3. Activity of Earthquakes with Similar Waveforms Around Ontake Volcano, Central Japan

    NASA Astrophysics Data System (ADS)

    Yamawaki, T.; Yamazaki, F.; Tadokoro, K.

    2005-12-01

    Ontake volcano area is known for its very high seismicity. Swarm activity has been repeatedly observed since 1976. The volcano erupted in 1979 and a large earthquake with a magnitude of 6.8 occurred in 1984 in the southeastern part of the volcano. A dense seismic network has been constructed for monitoring in this area. Recent studies using leveling survey reveal uplift above the swarm area. Earthquakes with similar waveforms (similar earthquakes) have been observed mainly at geothermal areas and plate boundaries. It is possible to use them to detect temporal change of crustal structure due to large earthquakes or volcanic eruptions using repeating similar earthquakes. With a view to use them as a monitoring tool, we search for similar earthquakes in Ontake area and examine temporal change of observed seismic waveforms. We use ~3300 events which occurred in this area from January 1999 to August 2000. First we pick up event pairs of which hypocenters are manually determined within 4 km. Then we calculate cross-correlation coefficients at each station from the waveform pairs band-pass-filtered at 4 to 8 Hz. The calculation uses 15-second time window that contains both P- and S-waves. We define similar earthquake pairs as event pairs with cross-correlation coefficients larger than 0.9 at more than 8 stations. Such event pairs are distributed mainly in earthquake clusters located to the east and southeastern flank of the volcano. The similar earthquakes have magnitude ranging from 1 to 2 and focal depths of 1 to 7 km. Occurrence intervals of the most pairs are very short, between a few hours and a few days. A few pairs have intervals of several months. But repeating groups with nearly the same interval have not been found due probably to the short data period. We will further analyze using expanded data period and area.

  4. Evidence for a seismic activity mainly constituted of hybrid events at Cayambe volcano, Ecuador. Interpretation in a iced-domes volcano context

    NASA Astrophysics Data System (ADS)

    Guillier, Bertrand; Chatelain, Jean-Luc

    2006-06-01

    The high activity level of Hybrid Events (HE) detected beneath the Cayambe volcano since 1989 has been more thoroughly investigated with data from a temporary array. The unusual HE spectral content allows separating a high-frequency signal riding on a low-frequency one, with a probable single source. HEs are interpreted as high frequency VT events, produced by the interaction between magmatic heat and an underground water system fed by thaw water from the summital glacier, which trigger simultaneous low-frequency fluid resonance in the highly fractured adjacent medium. Pure VTs are interpreted as 'aborted' HEs occurring probably in the oldest and coldest part of the volcano complex. To cite this article: B. Guillier, J.-L. Chatelain, C. R. Geoscience 338 (2006).

  5. Combining Infrasound and Imaging Techniques to Characterize and Quantify Eruptive Activity at Karymsky Volcano, Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Fee, D.; Lopez, T. M.; Rowell, C.; Matoza, R. S.; Szuberla, C.; Prata, F.; Firstov, P.; Makhmudov, E.

    2012-12-01

    Changes in atmospheric pressure at volcanic vents caused by the rapid release and expansion of volcanic material (e.g., gas, ash, lava) produce low frequency sound waves known as infrasound. Because of the direct link between the infrasound source and the eruption and emission of volcanic material, complementary direct and remote observations of gas, ash, and other eruptive phenomena can be combined with infrasound measurements to characterize and quantify volcanic activity. Here we present coincident measurements collected over two 10-day periods at Karymsky Volcano in August 2011 and July 2012 of infrasound, SO2, thermal radiation, ash (2011 only), and visual imagery. Infrasound and audible (up to 250 Hz) acoustic data were recorded using arrays of portable digital microphones. SO2 emissions were measured using both a scanning FLYSPEC ultraviolet spectrometer system as well as a CyClops infrared camera equipped with broadband, 8.6, 10, and 11 micron filters permitting detection and quantification of both SO2 and ash. A FLIR infrared camera was utilized to record high temporal resolution thermal observations of the volcanic emissions and hot eruption deposits. Lastly, visual imagery was taken with an HD camcorder. Correlations between this multiparameter dataset allow a better understanding of both the infrasound data and eruptive activity. Karymsky Volcano is one of the most active and dynamic volcanoes in Kamchatka, Russia, with activity during our experiments consisting of vigorous degassing, frequent ash explosions, apparent vent sealing, and intermittent explosive magmatic eruptions. This varied activity produced diverse acoustic and emissions signals. Large explosive eruptions in 2011 are preceded by vent sealing and produce high-amplitude infrasound with occasional visible shock waves. Vigorous gas jetting is also observed and accompanied by elevated SO2 emissions and low infrasound levels. The gas jetting produced clear audible sound (~20-100 Hz) that

  6. Chemical evolution of thermal springs at Arenal Volcano, Costa Rica: Effect of volcanic activity, precipitation, seismic activity, and Earth tides

    NASA Astrophysics Data System (ADS)

    López, D. L.; Bundschuh, J.; Soto, G. J.; Fernández, J. F.; Alvarado, G. E.

    2006-09-01

    Arenal Volcano in NW Costa Rica, Central America has been active during the last 37 years. However, only relatively low temperature springs have been identified on its slopes with temperatures less than around 60 °C. The springs are clustered on the NE and NW slopes of the volcano, close to contacts between the recent and older volcanic products or at faults that intercept the volcano. This volcano is located in a rain forest region with annual rainfall averaging around 5 m. During the last 15 years, the temperature and chemical composition of 4 hot springs and 2 cold springs have been monitored approximately every 3 months. In addition, two more thermal sites were identified recently and sampled, as well as two boreholes located on a fault NE of the volcano. Scatter plots of chemical species such as Cl and B suggest that the waters in these discharges belong to the same aquifer with a saline end member similar to Río Tabacón at the beginning of the study period (1990) and the deeper borehole (B-2) in 2004. The waters of Quebrada Bambú and Quebrada Fría represent a more dilute end member. Both long-term (over the 15 years) and short-term or seasonal decreases in concentration and steady or decreasing temperature are noted in NW springs. Springs located at the NE show increasing temperatures and ion concentrations, except for bicarbonate that has decreased in concentration for all the springs. This behavior is likely associated with a shallow source for the solutes and heat for this aquifer. To the NW the early lavas and pyroclastic flows have been cooling down, decreasing the contribution of leaching products to the infiltrating waters. To the NE, pyroclastic flows to the N during the last decade are contributing increasing concentrations of solutes and heat throughout water infiltration and circulation within the faults and the surficial drainage that has a NE regional trend. For the short-term or seasonal variations, concentrations of chemical constituents

  7. Methanogenic diversity and activity in hypersaline sediments of the centre of the Napoli mud volcano, Eastern Mediterranean Sea.

    PubMed

    Lazar, Cassandre Sara; Parkes, R John; Cragg, Barry A; L'Haridon, Stéphane; Toffin, Laurent

    2011-08-01

    Submarine mud volcanoes are a significant source of methane to the atmosphere. The Napoli mud volcano, situated in the brine-impacted Olimpi Area of the Eastern Mediterranean Sea, emits mainly biogenic methane particularly at the centre of the mud volcano. Temperature gradients support the suggestion that Napoli is a cold mud volcano with moderate fluid flow rates. Biogeochemical and molecular genetic analyses were carried out to assess the methanogenic activity rates, pathways and diversity in the hypersaline sediments of the centre of the Napoli mud volcano. Methylotrophic methanogenesis was the only significant methanogenic pathway in the shallow sediments (0-40 cm) but was also measured throughout the sediment core, confirming that methylotrophic methanogens could be well adapted to hypersaline environments. Hydrogenotrophic methanogenesis was the dominant pathway below 50 cm; however, low rates of acetoclastic methanogenesis were also present, even in sediment layers with the highest salinity, showing that these methanogens can thrive in this extreme environment. PCR-DGGE and methyl coenzyme M reductase gene libraries detected sequences affiliated with anaerobic methanotrophs (mainly ANME-1) as well as Methanococcoides methanogens. Results show that the hypersaline conditions in the centre of the Napoli mud volcano influence active biogenic methane fluxes and methanogenic/methylotrophic diversity. PMID:21382146

  8. Methanogenic diversity and activity in hypersaline sediments of the centre of the Napoli mud volcano, Eastern Mediterranean Sea.

    PubMed

    Lazar, Cassandre Sara; Parkes, R John; Cragg, Barry A; L'Haridon, Stéphane; Toffin, Laurent

    2011-08-01

    Submarine mud volcanoes are a significant source of methane to the atmosphere. The Napoli mud volcano, situated in the brine-impacted Olimpi Area of the Eastern Mediterranean Sea, emits mainly biogenic methane particularly at the centre of the mud volcano. Temperature gradients support the suggestion that Napoli is a cold mud volcano with moderate fluid flow rates. Biogeochemical and molecular genetic analyses were carried out to assess the methanogenic activity rates, pathways and diversity in the hypersaline sediments of the centre of the Napoli mud volcano. Methylotrophic methanogenesis was the only significant methanogenic pathway in the shallow sediments (0-40 cm) but was also measured throughout the sediment core, confirming that methylotrophic methanogens could be well adapted to hypersaline environments. Hydrogenotrophic methanogenesis was the dominant pathway below 50 cm; however, low rates of acetoclastic methanogenesis were also present, even in sediment layers with the highest salinity, showing that these methanogens can thrive in this extreme environment. PCR-DGGE and methyl coenzyme M reductase gene libraries detected sequences affiliated with anaerobic methanotrophs (mainly ANME-1) as well as Methanococcoides methanogens. Results show that the hypersaline conditions in the centre of the Napoli mud volcano influence active biogenic methane fluxes and methanogenic/methylotrophic diversity.

  9. Degassing Dynamics at Stromboli Volcano: Insights From Infrasonic Activity

    NASA Astrophysics Data System (ADS)

    Marchetti, E.; Ripepe, M.; Ulivieri, G.; Delle Donne, D.

    2006-12-01

    Infrasound at Stromboli consists on transients related to explosions and on small amplitude intermittent pulses associated with "active" over-pressurized degassing of the magma column. Degassing of a magmatic system is generally understood as a quasi-steady "non-explosive" passive mechanism, when the slow exsolution process allows the continuous compensation of the gas pressure. In contrast infrasound indicates that degassing can occur also in over-pressurized condition, associated to the bursting of small gas pockets at the magma free-surface. This intermittent release of gas induces in the atmosphere small (< 0.1 x105 Pa at the source) infrasonic pulses and occurs almost regularly every ~1-2 s. The permanent small aperture 5-elements infrasonic array at Stromboli is monitoring both explosions and degassing providing position, over-pressure and occurrence of the source and revealing the complex and complete behavior of the magma column. Log-linear amplitude distribution of infrasonic data shows 2 different trends of decay suggesting that degassing and explosions are driven by a different gas dynamics. Moreover, infrasound location indicates that over-pressurized degassing is active only in one vent at once. Location of the puffing is stable in a single vent over hours-to-days periods, or it can shift from vent to vent with smooth or abrupt transitions. The stability in the position of the puffing within the crater terrace is suggesting that the over-pressurized gas bubble flow is following only one preferential segment of the feeding conduits at once. The stable location of the bursting bubbles, however, may change from time to time and without any apparent evidence or trigger mechanisms, leading to a sharp change in the rising path of gas bubbles. This gas bubble behavior seems to be consistent with experimental and numerical studies on the flow of particles and drops at pipe bifurcations. Over-pressurized gas bursting could reflect higher gas flux regimes in the

  10. Peculiar Active-Tectonic Landscape Within the Sanctuary of Zeus at Mt. Lykaion (Peloponnese, Greece)

    NASA Astrophysics Data System (ADS)

    Davis, G. H.

    2008-12-01

    The Sanctuary of Zeus (Mt. Lykaion) lies in the Peloponnese within the Pindos fold and thrust belt. It is the object of investigation of the Mt. Lykaion Excavation and Survey (http://lykaionexcavation.org/). Mt. Lykaion is a thrust klippe, on the summit of which is an upper sanctuary marked by an ash altar, temenos, and column bases. Earliest objects recovered from the ash altar go back to 3000 BCE, leading Dr. David Romano (University of Pennsylvania), a principal leader of the project, to conclude that worship of divinities on the summit is ancient. Detailed structural geological mapping reveals one dimension of the "power" of the site. Crisscrossing the upper sanctuary are scree bands that mark the traces of active normal faults, which are expressions of tectonic stretching of the Aegean region. The scree bands, composed of cinder-block-sized limestone blocks, range up to 10 m in outcrop breadth, 100 m in length, and 5 m in thickness. Though discontinuous, most of the scree bands lie precisely on the traces of through-going faults, which cut and displace the sedimentary formations of the Pindos group. Some cut the thrust fault, whose elliptical trace defines the Lykaion klippe. What makes the scree bands of this active-tectonic landscape "peculiar" is that there are no cliffs from which the scree descends. Rather, the bands of scree occur along flanks of smooth, rounded hillslopes and ridges. The scree bands coincide with modest steps in the topography, ranging from tens of centimeters to several tens of meters. The specific bedrock formation where the bands are best developed is an Upper Cretaceous limestone whose average platy-bedding thickness (approximately 20 cm) matches closely the average joint spacing. The limestone has little mechanical integrity. It cannot support itself as a scarp footwall and instead collapses into a pile of scree, whose upper-surface inclination conforms to a stable angle of repose. Evidence of the contemporary nature of this

  11. NIK regulates MT1-MMP activity and promotes glioma cell invasion independently of the canonical NF-κB pathway

    PubMed Central

    Duran, C L; Lee, D W; Jung, J-U; Ravi, S; Pogue, C B; Toussaint, L G; Bayless, K J; Sitcheran, R

    2016-01-01

    A growing body of evidence implicates the noncanonical NF-κB pathway as a key driver of glioma invasiveness and a major factor underlying poor patient prognoses. Here, we show that NF-κB-inducing kinase (NIK/MAP3K14), a critical upstream regulator of the noncanonical NF-κB pathway, is both necessary and sufficient for cell-intrinsic invasion, as well as invasion induced by the cytokine TWEAK, which is strongly associated with tumor pathogenicity. NIK promotes dramatic alterations in glioma cell morphology that are characterized by extensive membrane branching and elongated pseudopodial protrusions. Correspondingly, NIK increases the phosphorylation, enzymatic activity and pseudopodial localization of membrane type-1 matrix metalloproteinase (MT1-MMP/MMP14), which is associated with enhanced tumor cell invasion of three-dimensional collagen matrices. Moreover, NIK regulates MT1-MMP activity in cells lacking the canonical NF-κB p65 and cRel proteins. Finally, increased expression of NIK is associated with elevated MT1-MMP phosphorylation in orthotopic xenografts and co-expression of NIK and MT1-MMP in human tumors is associated with poor glioma patient survival. These data reveal a novel role of NIK to enhance pseudopodia formation, MT1-MMP enzymatic activity and tumor cell invasion independently of p65. Collectively, our findings underscore the therapeutic potential of approaches targeting NIK in highly invasive tumors. PMID:27270613

  12. Volcano Observations Using an Unmanned Autonomous Helicopter : seismic and GPS observations near the active summit area of Sakurajima and Kirishima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Ohminato, T.; Kaneko, T.; Koyama, T.; Watanabe, A.; Takeo, M.; Iguchi, M.; Honda, Y.

    2012-04-01

    Observations in the vicinity of summit area of active volcanoes are very important from various viewpoints such as understanding physical processes in the volcanic conduit. It is, however, highly difficult to install observation sensors near active vents because of the risk of sudden eruptions. We have been developing a safe volcano observation system based on an unmanned aerial vehicle (UAV). As an UAV, we adopted an unmanned autonomous helicopter manufactured by Yamaha-Motor Co., Ltd. We have also developed earthquake observation modules and GPS receiver modules that are exclusively designed for UAV installation at summit areas of active volcanoes. These modules are light weight, compact size, and solar powered. For data transmission, a commercial cellular-phone network is used. Our first application of the sensor installation by the UAV is Sakurajima, one of the most active volcanos in Japan. In November 2009, 2010, and 2011, we installed up to four seismic sensors within 2km from the active summit crater. In the 2010 and 2011 operations, we succeeded in pulling up and collecting the sensor modules by using the UAV. In the 2011 experiment, we installed two GPS receivers near the summit area of Sakurajima volcano. We also applied the UAV installation to another active volcano, Shinmoedake in Kirishima volcano group. Since the sub-plinian eruption in February 2011, entering the area 3km from the summit of Shinmoe-dake has been prohibited. In May and November 2011, we installed seismic sensors and GPS receivers in the off-limit zone. Although the ground coupling of the seismic modules is not perfect due to the way they are installed, the signal-to-noise ratio of the seismic signals recorded by these modules is fairly good. Despite the low antenna height of 50 cm from the ground surface, the location errors in horizontal and vertical GPS components are 1cm and 3cm, respectively. For seismic signals associated with eruptions at Sakurajima from November 2010 to

  13. International Collaboration on Building Local Technical Capacities for Monitoring Volcanic Activity at Pacaya Volcano, Guatemala.

    NASA Astrophysics Data System (ADS)

    Escobar-Wolf, R. P.; Chigna, G.; Morales, H.; Waite, G. P.; Oommen, T.; Lechner, H. N.

    2015-12-01

    Pacaya volcano is a frequently active and potentially dangerous volcano situated in the Guatemalan volcanic arc. It is also a National Park and a major touristic attraction, constituting an important economic resource for local municipality and the nearby communities. Recent eruptions have caused fatalities and extensive damage to nearby communities, highlighting the need for risk management and loss reduction from the volcanic activity. Volcanic monitoring at Pacaya is done by the Instituto Nacional de Sismologia, Vulcanologia, Meteorologia e Hidrologia (INSIVUMEH), instrumentally through one short period seismic station, and visually by the Parque Nacional Volcan de Pacaya y Laguna de Calderas (PNVPLC) personnel. We carry out a project to increase the local technical capacities for monitoring volcanic activity at Pacaya. Funding for the project comes from the Society of Exploration Geophysicists through the Geoscientists Without Borders program. Three seismic and continuous GPS stations will be installed at locations within 5 km from the main vent at Pacaya, and one webcam will aid in the visual monitoring tasks. Local educational and outreach components of the project include technical workshops on data monitoring use, and short thesis projects with the San Carlos University in Guatemala. A small permanent exhibit at the PNVPLC museum or visitor center, focusing on the volcano's history, hazards and resources, will also be established as part of the project. The strategy to involve a diverse group of local collaborators in Guatemala aims to increase the chances for long term sustainability of the project, and relies not only on transferring technology but also the "know-how" to make that technology useful. Although not a primary research project, it builds on a relationship of years of joint research projects at Pacaya between the participants, and could be a model of how to increase the broader impacts of such long term collaboration partnerships.

  14. Morphometric, acoustic and lithofacies characterization of mud volcanoes in the Eastern Mediterranean: Toward a new approach and classification to constrain the regional distribution and activity of mud volcanoes?

    NASA Astrophysics Data System (ADS)

    Flore, Mary; Sébastien, Migeon; Elia, d'Acremont; Alain, Rabaute; Silvia, Ceramicola; Daniel, Praeg; Christian, Blanpied

    2015-04-01

    On continental margins, several types of seabed features recording fluid circulation within the sediment column have already been recognized, including mud volcanoes, pockmarks, carbonates pavements and/or mounds and brine lakes. They can be associated to (a) thermogenic or biogenic fluids migrating along tectonic conduits, (b) dissociation of gas hydrates, or (c) dewatering of turbidite channels and mass-transport deposits. Although fluid-escape structures have been analyzed for the last two decades using diverse and complementary data, many questions are still debated about their morphologies/architectures, origin and formation, their temporal dynamic and the impact of the geodynamical context on their location/formation. In the Eastern Mediterranean, fluid seepages and in particular mud volcanoes, were identified in three geodynamical contexts including active margins (Calabrian accretionary prism and Mediterranean ridge) and highly-sedimented passive margin (Nil deep-sea fan). In this study, we follow a new approach allowing to (1) better quantify a broad set of morphological parameters that characterize the seabed fluid-escape structures, (2) propose an advance classification of these structures, the final goal being to test whether one or several morphological types of fluid-escape structures can be characteristic of one tectonic and sedimentological setting in the Eastern Mediterranean basin. To achieve this classification based on geophysical and geological analysis (morphometry, reflectivity, seismic r and lithofacies features), we used a broad homogenous dataset at the scale of the Eastern Mediterranean, including multibeam bathymetry, acoustic backscatter, 2D/3D seismic reflection, and sediment cores description and analysis. More than 500 mud volcano-like structures were identified based on one criterion or on the association of several criteria, while 40 of them were clearly proved to be mud volcanoes by coring. These structures exhibit different

  15. Implications for future activity of Grímsvötn volcano, Iceland, from compositional time series of historical tephra

    NASA Astrophysics Data System (ADS)

    Carpentier, Marion; Sigmarsson, Olgeir; Larsen, Gudrun

    2014-05-01

    The nature of future eruptions of active volcanoes is hard to predict. Improved understanding of the past volcanic activity is probably the best way to infer future eruptive scenarios. The most active volcano in Iceland, Grímsvötn, last erupted in 2011 with consequences for habitants living close to the volcano and aviation in the North-Atlantic. In an effort to better understand the magmatic system of the volcano, we have investigated the compositions of 23 selected tephra layers representing the last 8 centuries of volcanic activity at Grímsvötn. The tephra was collected in the ablation area of outlet glaciers from Vatnajökull ice cap. The ice-conserved tephra are less prone to alteration than those exposed in soil sections. Major element analyses are indistinguishable and of quartz-normative tholeiite composition, and Sr and Nd isotope ratios are constant. In contrast, both trace element concentrations (Th range from 0.875 ppm to 1.37 ppm and Ni from 28.5 ppm to 56.6 ppm) in the basalts and Pb isotopes show small but significant variations. The high-precision analyses of Pb isotope ratios allow the identification of tephra samples (3 in total) with more radiogenic ratios than the bulk of the samples. The tephra of constant isotope ratios show linear increase in incompatible element concentrations with time. The rate of increasing concentrations permits exploring possible future scenarios assuming that the magmatic system beneath the volcano follows the established historical evolution. Assuming similar future behaviour of the magma system beneath Grímsvötn volcano, the linear increase in e.g. Th concentration suggests that the volcano is likely to principally produce basalts for the next 500-1000 years. Evolution of water concentration will most likely follow those of incompatible elements with consequent increases in explosiveness of future Grímsvötn eruptions.

  16. What drives centuries-long polygenetic scoria cone activity at Barren Island volcano?

    NASA Astrophysics Data System (ADS)

    Sheth, Hetu

    2014-12-01

    Barren Island in the Andaman Sea is an active mafic stratovolcano, which had explosive and effusive eruptions, followed by caldera formation, in prehistoric time (poorly dated). A scoria cone within the caldera, marking volcanic resurgence, was active periodically from 1787 to 1832 (the historic eruptions). Since 1991, the same scoria cone has produced six eruptions, commonly including lava flows. Links between Barren Island's eruptions and giant earthquakes (such as the 26 December 2004 Great Sumatra megathrust earthquake) have been suggested, though there is no general correlation between them. The ≥ 227-year-long activity of the scoria cone, named here Shanku ("cone"), is normally driven by purely magmatic processes. I present a "source to surface" model for Barren Island and Shanku, including the source region, deeper and shallow magma chambers, volcanotectonics, dyking from magma chambers, and eruptions and eruptive style as controlled by crustal stresses, composition and volatile content. Calculations show that dykes ~ 0.5 m thick and a few hundred meters long, originating from shallow-level magma chambers (~ 5 km deep), are suitable feeders of the Shanku eruptions. Shanku, a polygenetic scoria cone (at least 13 eruptions since 1787), has three excellent analogues, namely Anak Krakatau (40 eruptions since 1927), Cerro Negro (23 eruptions since 1850), and Yasur (persistent activity for the past hundreds of years). This is an important category of volcanoes, gradational between small "monogenetic" scoria cones and larger "polygenetic" volcanoes.

  17. Source mechanism of very-long-period signals accompanying dome growth activity at Merapi volcano, Indonesia

    USGS Publications Warehouse

    Hidayat, D.; Chouet, B.; Voight, B.; Dawson, P.; Ratdomopurbo, A.

    2002-01-01

    Very-long-period (VLP) pulses with period of 6-7s, displaying similar waveforms, were identified in 1998 from broadband seismographs around the summit crater. These pulses accompanied most of multiphase (MP) earthquakes, a type of long-period event locally defined at Merapi Volcano. Source mechanisms for several VLP pulses were examined by applying moment tensor inversion to the waveform data. Solutions were consistent with a crack striking ???70?? and dipping ???50?? SW, 100m under the active dome, suggest pressurized gas transport involving accumulation and sudden release of 10-60 m3 of gas in the crack over a 6s interval.

  18. The Qartaba Structure: An Active Backthrust In Central Mt-Lebanon.

    NASA Astrophysics Data System (ADS)

    Elias, Ata Richard

    2016-04-01

    The Qartaba structure in central Mt-Lebanon is a 15x5km box fold running parallel to the restraining bend of the sinsitral Yammouneh Fault, the main fault of the central segment of the Dead Sea Transform. The Qartaba structure has long been described as a "horst" and associated with Mesozoic normal faulting. However, the Qartaba anticline is suitably oriented with the direction of maximum compression along the restraining bend. Jurassic carbonate rocks form the core of this anticline culminating at ~1953m asl to the east, of the highest structural elevation of the Mt-Lebanon range indicating important tectonic uplift rate. The fold is asymmetric. The western limb is steep and bordered by the Lebanese Flexure, a prominent continuous monocline of Upper Jurassic to Mid Cretaceous rocks, running along the western flank of Mt-Lebanon. The eastern limb of the anticline has a very steep dip, and forms a 200m high cliff well marked in the topography. Its Jurassic layers are almost vertical and end up overhanging Lower Cretaceous beds. Our study suggest that the Qartaba structure is a growing anticline, built by active thrusting over a west dipping thrust fault that cuts the surface at the base of the eastern limb of the anticline. The fault plane can be seen dipping 30-35 degrees to the west. At depth, this thrust is likely to connect with the blind thrust ramp of the Mt-Lebanon Flexure. The Qartaba backthrust with a dip to the west, is opposite to the general vergence of similar structures in the area. On some of the segments of the steep cliff forming the faulted eastern limb, a fresh scarp with smooth and polished surfaces bearing vertical slickensides can be followed over ~700m along the base of the cliff. It corresponds with the location of the thrust fault tip. Talus accumulation over the steep eastern limb covers most of the cliff base, and may be masking further extent of this scarp. We interpret this scarp as the freeface of a co-seismic rupture on the underlying

  19. 1995 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.

    1996-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptive activity or suspected volcanic activity (SVA) at 6 volcanic centers in 1995: Mount Martin (Katmai Group), Mount Veniaminof, Shishaldin, Makushin, Kliuchef/Korovin, and Kanaga. In addition to responding to eruptive activity at Alaska volcanoes, AVO also disseminated information for the Kamchatkan Volcanic Eruption Response Team (KVERT) on the 1995 eruptions of 2 Russian volcanoes: Bezymianny and Karymsky. This report summarizes volcanic activity in Alaska during 1995 and the AVO response, as well as information on the 2 Kamchatkan eruptions. Only those reports or inquiries that resulted in a "significant" investment of staff time and energy (here defined as several hours or more for reaction, tracking, and follow-up) are included. AVO typically receives dozens of phone calls throughout the year reporting steaming, unusual cloud sightings, or eruption rumors. Most of these are resolved quickly and are not tabulated here as part of the 1995 response record.

  20. Active Source Tomography of Stromboli Volcano (Italy): Results From the 2006 Seismic Experiment.

    NASA Astrophysics Data System (ADS)

    Zuccarello, L.; Patanè, D.; Cocina, O.; Castellano, M.; Sgroi, T.; Favali, P.; de Gori, P.

    2008-12-01

    Stromboli island, located in the Southern Tyrrhenian sea, is the emerged part (about 900 m a.s.l.) of a 3km-high strato-volcano. Its persistent Strombolian activity, documented for over 2000 years, is sometimes interrupted by lava effusions or major explosions. Despite the amount of recent published geophysical studies aimed to clarifying eruption dynamics, the spatial extend and geometrical characteristics of the plumbing system remain poorly understood. In fact, the knowledge of the inner structure and the zones of magma storage is limited to the upper few hundreds meters of the volcanic edifice and P- and S-waves velocity models are available only in restricted areas. In order to obtain a more suitable internal structural and velocity models of the volcano, from 25 November to 2 December 2006, a seismic tomography experiment through active seismics using air-gun sources was carried out and the final Vp model is here presented. The data has been inverted for the Vp structure by using the code Simulps13q, considering a 3D grid of nodes spaced 0.5 km down to 2 km depth, beneath the central part of volcano. The results show a relatively high velocity zones located both in the inner part of the volcanic structure, at about 1km b.s.l. and in the last 200-300 m a.s.l. in correspondence with the volcanic conduit. Slower zones were located around the summit craters in agreement with volcanological and petrological informations for the area. The relatively high velocity zones could suggest the presence of intrusive bodies related to the plumbing system.

  1. Water chemistry of lakes related to active and inactive Mexican volcanoes

    NASA Astrophysics Data System (ADS)

    Armienta, María Aurora; Vilaclara, Gloria; De la Cruz-Reyna, Servando; Ramos, Silvia; Ceniceros, Nora; Cruz, Olivia; Aguayo, Alejandra; Arcega-Cabrera, Flor

    2008-12-01

    Water chemistry of crater lakes, maars and water reservoirs linked to some Mexican volcanoes within and outside the Mexican Volcanic Belt has been determined for several years and examined regarding environmental and volcanic factors. All the analyzed lakes are relatively small with a maximum depth of 65 m, and are located in regions with different climates, from semi-arid to very humid, with altitudes ranging from 100 to more than 4000 m a.s.l. Crater lakes in active volcanoes (El Chichón, Popocatépetl) have very low pH, moderate to high temperatures and major ion concentrations varying with the level of volcanic unrest. Lakes in sub-arid and temperate-arid regions (like maars in Puebla and Guanajuato states) show high alkalinity and pH, with bicarbonate/carbonate, chloride, sodium and magnesium as predominant ions. Lakes located in humid climates (Central Michoacán and Veracruz state) have low mineralization and near-neutral pH values. In general, conservative dissolved ions and conductivity appear to be mostly controlled by precipitation/evaporation and by the ionic concentration of groundwater inputs. Calcium, magnesium, sulfate concentrations and pH are strongly influenced by volcanic-rock or volcanic gas interactions with water. The influence of low-level volcanic activity on crater lakes may be obscured by water-rock interactions, and climatic factors. One of the aims of this paper is to define the relative influence of these factors searching for a reference frame to recognize the early volcanic precursors in volcano-related lakes.

  2. Gas flux measurements of episodic bimodal eruptive activity at Karymsky volcano (Kamchatka, Russia)

    NASA Astrophysics Data System (ADS)

    Arellano, S.; Galle, B.; Melnikov, D.

    2012-04-01

    Volcanoes of intermediate magmatic composition commonly exhibit episodes of intermittent gas and ash emission of variable duration. Due to the multiple conditions present at each system, different mechanisms have been proposed to account for the observed activity, and without key measurements at hand, a definite understanding of the situation might not be singled out. Karymsky, the most active volcano of Central Kamchatka, has presented a remarkably stable pattern of bimodal eruption since a few weeks after its violent reactivation in 1996. Periods of quasi-periodic explosive emissions with typical recurrence intervals of 3-10 min are alternated with episodes of semi-continuous discharge which intensity has a typical modulation at a frequency of 1 Hz. Geophysical studies at Karymsky have identified the main visual, seismic and acoustic features of these two eruption modalities. From these observations, the time scales of the processes have been defined and relevant models have been formulated, according to which the two modes are controlled by the rheological properties of an intruding gas-saturated magma batch and a shallow gas-depleted magma plug. Explosions are explained as the consequence of the formation of temporary sealing, overpressure buildup and vent clearance. Clearly, direct measurements of the gas emission rate are the key parameter to test such models. In this work, we report on the results of a field campaign for SO2 gas measurements carried out at Karymsky during 10-14 September 2011. We deployed 2 NOVAC-type, scanning DOAS systems as well as 1 rapid wide-Field of View mini-DOAS plume tracker. With this setup, we derived time-resolved SO2 flux, plume height, direction and speed, and detected pulses of increasing emission with high temporal resolution. We observed phases of explosive and quiescent degassing with variable amounts of ash emission and detected intensity changes of the associated acoustic signals. The repose time intervals between these

  3. Observing active deformation of volcanoes in North America: Geodetic data from the Plate Boundary Observatory and associated networks

    NASA Astrophysics Data System (ADS)

    Puskas, C. M.; Phillips, D. A.; Mattioli, G. S.; Meertens, C. M.; Hodgkinson, K. M.; Crosby, C. J.; Enders, M.; Feaux, K.; Mencin, D.; Baker, S.; Lisowski, M.; Smith, R. B.

    2013-12-01

    The EarthScope Plate Boundary Observatory (PBO), operated by UNAVCO, records deformation of the geologically diverse North America western plate boundary, with subnetworks of instruments concentrated at selected active and potentially active volcanoes. These sensors record deformation and earthquakes and allow monitoring agencies and researchers to analyze changes in ground motion and seismicity. The intraplate volcanoes at Yellowstone and Long Valley are characterized by uplift/subsidence cycles, high seismicity, and hydrothermal activity but there have been no historic eruptions at either volcano. PBO maintains dense GPS networks of 20-25 stations at each of these volcanoes, with an additional 5 boreholes at Yellowstone containing tensor strainmeters, short-period seismometers, and borehole tiltmeters. Subduction zone volcanoes in the Aleutian Arc have had multiple historic eruptions, and PBO maintains equipment at Augustine (8 GPS), Akutan (8 GPS, 4 tiltmeters), and Unimak Island (14 GPS, 8 tiltmeters). The Unimak stations are at the active Westdahl and Shishaldin edifices and the nearby, inactive Isanotski volcano. In the Cascade Arc, PBO maintains networks at Mount St. Helens (15 GPS, 4 borehole strainmeters and seismometers, 8 borehole tiltmeters), Shasta (7 GPS, 1 borehole strainmeter and seismometer), and Lassen Peak (8 GPS). Data from many of these stations in the Pacific Northwest and California are also provided as realtime streams of raw and processed data. Real-time GPS data, along with high-rate GPS data, will be an important new resource for detecting and studying future rapid volcanic deformation events and earthquakes. UNAVCO works closely with the USGS Volcano Hazards Program, archiving data from USGS GPS stations in Alaska, Cascadia, and Long Valley. The PBO and USGS networks combined provide more comprehensive coverage than PBO alone, particularly of the Cascade Arc, where the USGS maintains a multiple instruments near each volcano. Ground

  4. Active hydrocarbon (methane) seepage at the Alboran Sea mud volcanoes indicated by specific lipid biomarkers.

    NASA Astrophysics Data System (ADS)

    Lopez-Rodriguez, C.; Stadnitskaia, A.; De Lange, G. J.; Martínez-Ruiz, F.; Comas, M.; Sinninghe Damsté, J. S.

    2012-04-01

    Mud volcanoes (MVs) and pockmark fields are known to occur in the Alboran Basin (Westernmost Mediterranean). These MVs occur above a major sedimentary depocenter that includes up to 7 km thick early Miocene to Holocene sequences. MVs located on the top of diapiric structures that originated from undercompacted Miocene clays and olistostromes. Here we provide results from geochemical data-analyses of four gravity cores acquired in the Northern Mud Volcano Field (north of the 36°N): i.e. Perejil, Kalinin and Schneiderś Heart mud expulsion structures. Extruded materials include different types of mud breccias. Specific lipid biomarkers (n-alkanes, hopanes, irregular isoprenoid hydrocarbons and Dialkyl Glycerol Diethers (DGDs) were analysed by gas chromatography (GC) and gas chromatography mass spectrometry (GC-MS). Determination of Glycerol Dialkyl Glycerol Tetraethers (GDGTs) by high performance liquid chromatography-spectrometry (HPLC-MS), and analysis of biomarker δ13C values were performed in selected samples. Lipid biomarker analysis from the three MVs revealed similar n-alkane distributions in all mud breccia intervals, showing significant hydrocarbon-derived signals and the presence of thermally immature organic-matter admixture. This suggests that similar strata fed these MVs. The hemipelagic drapes reveal comparable n-alkane distributions, suggesting that significant upward diffusion of fluids occurs. Distributions of GDGTs are generally accepted as usefull biomarkers to locate the anaerobic oxidation of methane (AOM) in marine sediments. However, our GDGT profiles only reflect the marine thaumarchaeotal signature. There seems to be no archaea producing specific GDGTs involved in AOM in the recovered interval. Evidence of recent activity (i.e., methane gas-bubbling and chemosynthetic fauna at the Perejil MV) and the presence of specific lipid biomarker related with methanotropic archaea (Irregular Isoprenoids and DGDs), however, suggest the existence of

  5. Lateral Dispersion of Volcanic Ash From the Flanks of an Actively Erupting Submarine Volcano

    NASA Astrophysics Data System (ADS)

    Walker, S. L.; Baker, E. T.; Resing, J. A.; Lebon, G. T.; Lupton, J. E.; Greene, R. R.

    2006-12-01

    NW Rota-1 is an actively erupting submarine volcano along the Mariana Arc, rising some 2500 m from the local seafloor. Eruptions at Brimstone Pit, located about 30 m below the summit on the south side of the volcano at 550 m water depth, have been directly observed since 2004. Water column surveys (using CTD-O vertical cast and tow methods) in 2003, 2004 and 2006 mapped the distribution of both persistent and variable particle plumes over the summit and down the flanks. In all years, there was a non-buoyant laterally dispersing plume over the summit that was optically intense and very thin (25-30 m plume maximum), measurable up to 2-3 km from the summit. The plume was most intense in 2003 and 2004 with dNTU values reaching 5 (the upper limit of the optical backscatter sensor). High concentrations of particulate sulfur in the plume contribute to these unusually intense optical signals, as sulfur particles are efficient optical backscatters. The plume maxima depth has steadily declined over 3 years: 460 m in 2003, 485 m in 2004, and 505-530 m in 2006. In 2003, both hydrothermal and volcanic components were detected in the plume, so it is not certain that the 2003 data represent pre-eruption conditions. Deeper layers of turbidity were absent in 2003, but were observed in multiple layers surrounding the volcano in 2004 and 2006 from depths of about 700 m extending to >2500 m, and were detectable at distances up to 18 km from the summit. Microscopy and chemical analysis indicates that the particles in these layers are overwhelmingly glass fragments rather than hydrothermal precipitates. Over the scale of 3-6 days, repeat tows showed significant decreases in particle concentrations, implying some of the particles settled rapidly from these plumes. The most likely source of these layers is gravity flow of volcanic ash down the flanks, fed by violent eruptions at the summit. Detachment from the seafloor may be controlled by turbulence from current flow or internal waves

  6. Vailulu'u Seamount, Samoa: Life and death on an active submarine volcano.

    PubMed

    Staudigel, Hubert; Hart, Stanley R; Pile, Adele; Bailey, Bradley E; Baker, Edward T; Brooke, Sandra; Connelly, Douglas P; Haucke, Lisa; German, Christopher R; Hudson, Ian; Jones, Daniel; Koppers, Anthony A P; Konter, Jasper; Lee, Ray; Pietsch, Theodore W; Tebo, Bradley M; Templeton, Alexis S; Zierenberg, Robert; Young, Craig M

    2006-04-25

    Submersible exploration of the Samoan hotspot revealed a new, 300-m-tall, volcanic cone, named Nafanua, in the summit crater of Vailulu'u seamount. Nafanua grew from the 1,000-m-deep crater floor in <4 years and could reach the sea surface within decades. Vents fill Vailulu'u crater with a thick suspension of particulates and apparently toxic fluids that mix with seawater entering from the crater breaches. Low-temperature vents form Fe oxide chimneys in many locations and up to 1-m-thick layers of hydrothermal Fe floc on Nafanua. High-temperature (81 degrees C) hydrothermal vents in the northern moat (945-m water depth) produce acidic fluids (pH 2.7) with rising droplets of (probably) liquid CO(2). The Nafanua summit vent area is inhabited by a thriving population of eels (Dysommina rugosa) that feed on midwater shrimp probably concentrated by anticyclonic currents at the volcano summit and rim. The moat and crater floor around the new volcano are littered with dead metazoans that apparently died from exposure to hydrothermal emissions. Acid-tolerant polychaetes (Polynoidae) live in this environment, apparently feeding on bacteria from decaying fish carcasses. Vailulu'u is an unpredictable and very active underwater volcano presenting a potential long-term volcanic hazard. Although eels thrive in hydrothermal vents at the summit of Nafanua, venting elsewhere in the crater causes mass mortality. Paradoxically, the same anticyclonic currents that deliver food to the eels may also concentrate a wide variety of nektonic animals in a death trap of toxic hydrothermal fluids. PMID:16614067

  7. Kilauea's Explosive Past: Understanding Violent Explosions at Hawai'i's most Active Volcano

    NASA Astrophysics Data System (ADS)

    Weaver, S. J.; Houghton, B. F.; Swanson, D.

    2010-12-01

    A sequence of explosions that occurred from Kilauea caldera around 1790 A.D. includes the most deadly pyroclastic eruptions recorded in the USA. The products, the upper part of the Keanakāko`i tephra formation, are believed to be responsible for the deaths of a Hawaiian war party on the summit of the volcano. Little is known about the parent eruptions or even how many explosions there were in or around 1790; also, no hazard maps exist at Kilauea for this type of violent yet short-lived activity, with few clear precursors. The c. 1790 deposits show both marked sectoral changes and also, on a finer length scale, rapid lateral variability over distances of less than 1 kilometer. In the southern sector, they form a series of striking alternating coarse-grained beds, cross-bedded pyroclastic density current deposits (pdc) and accretionary-lapilli-bearing fine ashes. This study focuses primarily on the coarse-grained units, which are largely absent west and east of the caldera. Through characterization of the beds in the field and analysis of grain size and dispersal data, the size and intensity of these eruptions have been defined. The coarse-grained units include both pyroclastic fall and pdc deposits. Unusually, only bedding characteristics, (and not grain size or dispersal) unequivocally distinguish between these two transport processes. This study offers a clearer, more quantitative picture of the c. 1790 events and advances the understanding of how explosive eruptions can occur at an otherwise gently effusive volcano. It also constrains the dynamics associated with these events and improves volcanic hazard mitigation at Kilauea and shield volcanoes worldwide.

  8. The weathering and element fluxes from active volcanoes to the oceans: a Montserrat case study

    NASA Astrophysics Data System (ADS)

    Jones, Morgan T.; Hembury, Deborah J.; Palmer, Martin R.; Tonge, Bill; Darling, W. George; Loughlin, Susan C.

    2011-04-01

    The eruptions of the Soufrière Hills volcano on Montserrat (Lesser Antilles) from 1995 to present have draped parts of the island in fresh volcaniclastic deposits. Volcanic islands such as Montserrat are an important component of global weathering fluxes, due to high relief and runoff and high chemical and physical weathering rates of fresh volcaniclastic material. We examine the impact of the recent volcanism on the geochemistry of pre-existing hydrological systems and demonstrate that the initial chemical weathering yield of fresh volcanic material is higher than that from older deposits within the Lesser Antilles arc. The silicate weathering may have consumed 1.3% of the early CO2 emissions from the Soufrière Hills volcano. In contrast, extinct volcanic edifices such as the Centre Hills in central Montserrat are a net sink for atmospheric CO2 due to continued elevated weathering rates relative to continental silicate rock weathering. The role of an arc volcano as a source or sink for atmospheric CO2 is therefore critically dependent on the stage it occupies in its life cycle, changing from a net source to a net sink as the eruptive activity wanes. While the onset of the eruption has had a profound effect on the groundwater around the Soufrière Hills center, the geochemistry of springs in the Centre Hills 5 km to the north appear unaffected by the recent volcanism. This has implications for the potential risk, or lack thereof, of contamination of potable water supplies for the island's inhabitants.

  9. Vailulu’u Seamount, Samoa: Life and death on an active submarine volcano

    PubMed Central

    Staudigel, Hubert; Hart, Stanley R.; Pile, Adele; Bailey, Bradley E.; Baker, Edward T.; Brooke, Sandra; Connelly, Douglas P.; Haucke, Lisa; German, Christopher R.; Hudson, Ian; Jones, Daniel; Koppers, Anthony A. P.; Konter, Jasper; Lee, Ray; Pietsch, Theodore W.; Tebo, Bradley M.; Templeton, Alexis S.; Zierenberg, Robert; Young, Craig M.

    2006-01-01

    Submersible exploration of the Samoan hotspot revealed a new, 300-m-tall, volcanic cone, named Nafanua, in the summit crater of Vailulu’u seamount. Nafanua grew from the 1,000-m-deep crater floor in <4 years and could reach the sea surface within decades. Vents fill Vailulu’u crater with a thick suspension of particulates and apparently toxic fluids that mix with seawater entering from the crater breaches. Low-temperature vents form Fe oxide chimneys in many locations and up to 1-m-thick layers of hydrothermal Fe floc on Nafanua. High-temperature (81°C) hydrothermal vents in the northern moat (945-m water depth) produce acidic fluids (pH 2.7) with rising droplets of (probably) liquid CO2. The Nafanua summit vent area is inhabited by a thriving population of eels (Dysommina rugosa) that feed on midwater shrimp probably concentrated by anticyclonic currents at the volcano summit and rim. The moat and crater floor around the new volcano are littered with dead metazoans that apparently died from exposure to hydrothermal emissions. Acid-tolerant polychaetes (Polynoidae) live in this environment, apparently feeding on bacteria from decaying fish carcasses. Vailulu’u is an unpredictable and very active underwater volcano presenting a potential long-term volcanic hazard. Although eels thrive in hydrothermal vents at the summit of Nafanua, venting elsewhere in the crater causes mass mortality. Paradoxically, the same anticyclonic currents that deliver food to the eels may also concentrate a wide variety of nektonic animals in a death trap of toxic hydrothermal fluids. PMID:16614067

  10. The activity of the Colima volcano and morphological changes in the summit between 2004 and 2013

    NASA Astrophysics Data System (ADS)

    Suarez-Plascencia, C.; Nunez-Cornu, F. J.; Camarena Garcia, M. A.

    2013-05-01

    Colima Volcano, located in the West of the Volcanic Mexican Belt (19° 30.696 N, 103° 37.026 W), has shown a new cycle of explosive activity beginning May 30 1999, and reaching its maximum in March-April of 2005 and January 2013. In the 2005 the explosive activity increased gradually, having the largest event on May 23, when a new dome was created. Hours later this dome was destroyed by a strong explosion, forming an ash column 5.6 km high with subsequent pyroclastic flows that reached a distance of 4.2 km flowing along the ravines of the South sector. On May 30 the most intense explosion in 1999 occurred, when the plume reached heights in excess of 4.4 km above the crater, and pyroclastic flows were created. On the same year in July two explosive events occurred of characteristics similar to those in May. These constant explosions caused continuous morphological changes in the summit, the most significant being the collapse of the North and South walls of the crater, in the first week of June of 2005, and the creation of a new crater in July. In 2006 the most significant explosive activity took place during April, May and July, when the eruptive columns reached heights of more than 1500 meters above the crater, occasionally forming small pyroclastic flows. In May of 2007 morphological changes were observed in the summit. Among them a crater explosion on the East side, a dome was formed on the West side, with 20 m in high and 50 m in diameter. Since the end of 2008 to December of 2012 the volcano remained calm, with a dome diameter of 220 m and height of 60 m, in January 2013 three explosions occurred, destroying the dome and throwing a volume of 1.5 million cubic meters. The eruptive column reached a height of 3000 above the crater. It reported light ashfall to the NE to 100 km away from the volcano. The explosive events continue to date, but they have diminished in size and intensity. This activity was similar to the one observed in 1902-1903 and reported by

  11. Monitoring Monitoring Evolving Activity at Popocatepetl Volcano, Mexico, 2000-2001

    NASA Astrophysics Data System (ADS)

    Martin-DelPozzo, A.; Aceves, F.; Bonifaz, R.; Humberto, S.

    2001-12-01

    After 6 years of small eruptions, activity at Mexico's 5,452m high Popocatepetl Volcano in central Mexico, peaked in the December 2000-January 2001 eruptions. Precursors included an important increase in seismicity as well as in magmatic components of spring water and small scale deformation which resulted in growth of a new crater dome from January 16 on. Evacuation of the towns nearest the volcano over Christmas was decided because of the possibility of pyroclastic flows. During the previous years, crater dome growth, contraction and explosive clearing has dominated the activity. The January 22 eruption produced an eruption column approximately 17km high with associated pyroclastic flows. Ejecta was composed of both basic and evolved scoria and pumice and dome lithics. A large proportion of the juvenile material was intermediate between these 2 endmenbers (59-63percent SiO2 and 3.5 to 5.5 MgO) consistent with a small basic pulse entering a more evolved larger batch of magma. The January eruption left a large pit which has been partially infilled by another crater dome this August 2001.

  12. Relationship between fumarole gas composition and eruptive activity at Galeras Volcano, Colombia

    SciTech Connect

    Fischer, T.P.; Williams, S.N.; Arehart, G.B.; Sturchio, N.C.

    1996-06-01

    Forecasting volcanic eruptions is critical to the mitigation of hazards for the millions of people living dangerously close to active volcanoes. Volcanic gases collected over five years from Galeras Volcano, Colombia, and analyzed for chemical and isotopic composition show the effects of long-term degassing of the magma body and a gradual decline in sulfur content of the gases. In contrast, short-term (weeks), sharp variations are the precursors to explosive eruptions. Selective absorption of magmatic SO{sub 2} and HCl due to interaction with low-temperature geothermal waters allows the gas emissions to become dominated by CO{sub 2}. Absorption appears to precede an eruption because magmatic volatiles are slowed or retained by a sealing carapace, reducing the total flux of volatiles and allowing the hydrothermal volatiles to dominate gas emissions. Temporal changes in gas compositions were correlated with eruptive activity and provide new evidence bearing on the mechanism of this type of `pneumatic` explosive eruptions. 18 refs., 5 figs.

  13. Development of an automatic volcanic ash sampling apparatus for active volcanoes

    NASA Astrophysics Data System (ADS)

    Shimano, Taketo; Nishimura, Takeshi; Chiga, Nobuyuki; Shibasaki, Yoshinobu; Iguchi, Masato; Miki, Daisuke; Yokoo, Akihiko

    2013-12-01

    We develop an automatic system for the sampling of ash fall particles, to be used for continuous monitoring of magma ascent and eruptive dynamics at active volcanoes. The system consists of a sampling apparatus and cameras to monitor surface phenomena during eruptions. The Sampling Apparatus for Time Series Unmanned Monitoring of Ash (SATSUMA-I and SATSUMA-II) is less than 10 kg in weight and works automatically for more than a month with a 10-kg lead battery to obtain a total of 30 to 36 samples in one cycle of operation. The time range covered in one cycle varies from less than an hour to several months, depending on the aims of observation, allowing researchers to target minute-scale fluctuations in a single eruptive event, as well as daily to weekly trends in persistent volcanic activity. The latest version, SATSUMA-II, also enables control of sampling parameters remotely by e-mail commands. Durability of the apparatus is high: our prototypes worked for several months, in rainy and typhoon seasons, at windy and humid locations, and under strong sunlight. We have been successful in collecting ash samples emitted from Showa crater almost everyday for more than 4 years (2008-2012) at Sakurajima volcano in southwest Japan.

  14. Seismic image of a CO2 reservoir beneath a seismically active volcano

    USGS Publications Warehouse

    Julian, B.R.; Pitt, A.M.; Foulger, G.R.

    1998-01-01

    Mammoth Mountain is a seismically active volcano 200 000 to 50 000 years old, situated on the southwestern rim of Long Valley caldera, California. Since 1989 it has shown evidence of unrest in the form of earthquake swarms (Hill et al. 1990), volcanic 'long-period' earthquakes (Pitt and Hill 1994), increased output of magmatic 3He (Sorey et al. 1993) and the emission of about 500 tonnes day-1 of CO2 (Farrar et al. 1995; Hill 1996; M. Sorey, personal communication, 1997) which has killed trees and poses a threat to human safety. Local-earthquake tomography shows that in mid-1989 areas of subsequent tree-kill were underlain by extensive regions where the ratio of the compressional and shear elastic-wave speeds Vp/VS was about 9% lower than in the surrounding rocks. Theory (Mavko and Mukerji 1995), experiment (Ito, DeVilbiss and Nur 1979) and experience at other geothermal/volcanic areas (Julian et al. 1996) and at petroleum reservoirs (Harris et al. 1996) indicate that Vp/VS is sensitive to pore-fluid compressibility, through its effect on Vp. The observed Vp/VS anomaly is probably caused directly by CO2, and seismic Vp/VS tomography is thus a promising tool for monitoring gas concentration and movement in volcanoes, which may in turn be related to volcanic activity.

  15. How caldera collapse shapes the shallow emplacement and transfer of magma in active volcanoes

    NASA Astrophysics Data System (ADS)

    Corbi, F.; Rivalta, E.; Pinel, V.; Maccaferri, F.; Bagnardi, M.; Acocella, V.

    2015-12-01

    Calderas are topographic depressions formed by the collapse of a partly drained magma reservoir. At volcanic edifices with calderas, eruptive fissures can circumscribe the outer caldera rim, be oriented radially and/or align with the regional tectonic stress field. Constraining the mechanisms that govern this spatial arrangement is fundamental to understand the dynamics of shallow magma storage and transport and evaluate volcanic hazard. Here we show with numerical models that the previously unappreciated unloading effect of caldera formation may contribute significantly to the stress budget of a volcano. We first test this hypothesis against the ideal case of Fernandina, Galápagos, where previous models only partly explained the peculiar pattern of circumferential and radial eruptive fissures and the geometry of the intrusions determined by inverting the deformation data. We show that by taking into account the decompression due to the caldera formation, the modeled edifice stress field is consistent with all the observations. We then develop a general model for the stress state at volcanic edifices with calderas based on the competition of caldera decompression, magma buoyancy forces and tectonic stresses. These factors control: 1) the shallow accumulation of magma in stacked sills, consistently with observations; 2) the conditions for the development of circumferential and/or radial eruptive fissures, as observed on active volcanoes. This top-down control exerted by changes in the distribution of mass at the surface allows better understanding of how shallow magma is transferred at active calderas, contributing to forecasting the location and type of opening fissures.

  16. Origin and Distribution of Thiophenes and Furans in Gas Discharges from Active Volcanoes and Geothermal Systems

    PubMed Central

    Tassi, Franco; Montegrossi, Giordano; Capecchiacci, Francesco; Vaselli, Orlando

    2010-01-01

    The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C2–C20 species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C4H8O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection. PMID:20480029

  17. SO2 Emissions at Semeru Volcano, Indonesia: Characterization and Quantification of Persistent and Periodic Explosive Activity.

    NASA Astrophysics Data System (ADS)

    Smekens, J. F.; Clarke, A. B.; Burton, M. R.; Harijoko, A.; Wibowo, H.

    2014-12-01

    We present the first measurements of SO2 emissions at Semeru volcano, Indonesia, using an SO2 camera. Activity at Semeru is characterized by quiescent degassing interspersed with short-lived explosive events with low ash burden. The interval between explosions was measured at 32.1±15.7 minutes in a webcam survey of the volcano between the months of June and December 2013. We distinguish between two types of events: shorter events (type I: ~5 mins duration) with emissions returning quickly to baseline levels, and longer events (type II: ~15 mins duration) often showing multiple pulses and a longer period of increased emissions before a return to quiescent levels. Type I events represent >90% of the activity and release an average of 200-450 kg of SO2 per event. The single type II event we documented with the SO2 camera released a total of 1300 kg of SO2. We estimate the daily average emissions of Semeru to be 21-60 t d-1 of SO2, amounting to a yearly output of 7.5-22 Gg (7,500 - 22,000 metric tons), with 35-60% released during explosive events. The time series patterns of degassing are consistent with the existence of a viscous plug at the top of the conduit, causing accumulation and pressurization of the magma to produce the explosive events.

  18. SO2 emissions at Semeru volcano, Indonesia: Characterization and quantification of persistent and periodic explosive activity

    NASA Astrophysics Data System (ADS)

    Smekens, Jean-François; Clarke, Amanda B.; Burton, Michael R.; Harijoko, Agung; Wibowo, Haryo E.

    2015-07-01

    We present the first measurements of SO2 emissions at Semeru volcano, Indonesia, using an SO2 camera. Activity at Semeru is characterized by quiescent degassing interspersed with short-lived explosive events with low ash burden. The interval between explosions was measured at 32.1 ± 15.7 min in a webcam survey of the volcano between the months of June and December 2013. We distinguish between two types of events: shorter events (type I: ~ 5 min duration) with emissions returning quickly to baseline levels, and longer events (type II: ~ 15 min duration) often showing multiple pulses and a longer period of increased emissions before a return to quiescent levels. Type I events represent > 90% of the activity and release an average of 200-500 kg of SO2 per event. The single type II event we documented with the SO2 camera released a total of 1460 kg of SO2. We estimate the daily average emissions of Semeru to be 21-71 t d- 1 of SO2, amounting to a yearly output of 8-26 Gg (8000-26,000 metric tons), with 35-65% released during explosive events. The time series patterns of degassing are consistent with the existence of a viscous plug at the top of the conduit, which seals the conduit immediately prior to explosive events, causing pressurization of the underlying magma followed by a sudden release of gas and fragmented magma.

  19. Origin and distribution of thiophenes and furans in gas discharges from active volcanoes and geothermal systems.

    PubMed

    Tassi, Franco; Montegrossi, Giordano; Capecchiacci, Francesco; Vaselli, Orlando

    2010-03-31

    The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C(2)-C(20) species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C(4)H(8)O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection.

  20. Mercury speciation in the Mt. Amiata mining district (Italy): interplay between urban activities and mercury contamination

    USGS Publications Warehouse

    Rimondi, Valentina; Bardelli, Fabrizio; Benvenuti, Marco; Costagliola, Pilario; Gray, John E.; Lattanzi, Pierfranco

    2014-01-01

    A fundamental step to evaluate the biogeochemical and eco-toxicological significance of Hg dispersion in the environment is to determine speciation of Hg in solid matrices. In this study, several analytical techniques such as scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), sequential chemical extractions (SCEs), and X-ray absorption spectroscopy (XANES) were used to identify Hg compounds and Hg speciation in samples collected from the Mt. Amiata Hg mining district, southern Tuscany, Italy. Different geological materials, such as mine waste calcine (retorted ore), soil, stream sediment, and stream water suspended particulate matter were analyzed. Results show that the samples were generally composed of highly insoluble Hg compounds such as sulphides (HgS, cinnabar and metacinnabar), and more soluble Hg halides such as those associated with the mosesite group. Other moderately soluble Hg compounds, HgCl2, HgO and Hg0, were also identified in stream sediments draining the mining area. The presence of these minerals suggests active and continuous runoff of soluble Hg compounds from calcines, where such Hg compounds form during retorting, or later in secondary processes. Specifically, we suggest that, due to the proximity of Hg mines to the urban center of Abbadia San Salvatore, the influence of other anthropogenic activities was a key factor for Hg speciation, resulting in the formation of unusual Hg-minerals such as mosesite.

  1. Mt. St. Helens: Influence of Magmatic Activity on the Biogeochemistry of Thermal Springs

    NASA Astrophysics Data System (ADS)

    Montross, S. N.; Skidmore, M.; Abrahamson, I. S.

    2005-12-01

    Mt St. Helens erupted explosively in 1980, and the intense heat of this event effectively sterilized the crater. The crater is filled with significant ash and volcanic debris and the crater environment has limited vegetation despite relatively abundant water, from rainfall and snowmelt. However, microorganisms thrive in the hot springs that have developed in the crater since the 1980 eruption in this otherwise biologically hostile environment. Channelized drainages exiting the crater contain numerous hot spring sources which result from thermal heating of meteoric water and gain solutes from water-rock interactions. These solutes are important inputs for the microbial communities found within the crater thermal systems. Water samples collected in August 2004 and August 2005 from thermal springs in Step Canyon allow the opportunity to assess the effects of recent magmatic activity in the crater since September 2004, on the aqueous chemistry and microbiology of thermal spring water. We have investigated the composition of microbial communities in crater hot spring ecosystems by identifying small subunit ribosomal RNA sequences amplified directly from extracted genomic DNA. Initial screening of cloned DNA (16S rRNA gene sequence) by restriction fragment length polymorphism and sequencing indicates moderate microbial diversity in this environment with representatives from the domains Bacteria and Archaea. The presentation will examine relationships between the aqueous geochemistry and the microbial communities and temporal changes in these related to the recent magmatic activity.

  2. Stable and unstable phases of elevated seismic activity at the persistently restless Telica Volcano, Nicaragua

    NASA Astrophysics Data System (ADS)

    Rodgers, Mel; Roman, Diana C.; Geirsson, Halldor; LaFemina, Peter; McNutt, Stephen R.; Muñoz, Angelica; Tenorio, Virginia

    2015-01-01

    Telica Volcano, Nicaragua, is a persistently restless volcano with daily seismicity rates that can vary by orders of magnitude without apparent connection to eruptive activity. Low-frequency (LF) events are dominant and peaks in seismicity rate show little correlation with eruptive episodes, presenting a challenge for seismic monitoring and eruption forecasting. A short period seismic station (TELN) has been operated on Telica's summit since 1993, and in 2010 the installation of a six-station broadband seismic and eleven-station continuous GPS network (the TESAND network) was completed to document in detail the seismic characteristics of a persistently restless volcano. Between our study period of November 2009 and May 2013, over 400,000 events were detected at the TESAND summit station (TBTN), with daily event rates ranging from 5 to 1400. We present spectral analyses and classifications of ~ 200,000 events recorded by the TESAND network between April 2010 and March 2013, and earthquake locations for a sub-set of events between July 2010 and February 2012. In 2011 Telica erupted in a series of phreatic vulcanian explosions. Six months before the 2011 eruption, we observe a sudden decrease in LF events concurrent with a swarm of high-frequency (HF) events, followed by a decline in overall event rates, which reached a minimum at the eruption onset. We observe repeated periods of high and low seismicity rates and suggest these changes in seismicity represent repeated transitions between open-system and closed-system degassing. We suggest that these short- and long-term transitions between open to closed-system degassing form part of a long-term pattern of stable vs. unstable phases at Telica. Stable phases are characterised by steady high-rate seismicity and represent stable open-system degassing, whereas unstable phases are characterised by highly variable seismicity rates and represent repeated transitions from open to closed-system degassing, where the system is

  3. Santorini Volcano

    USGS Publications Warehouse

    Druitt, T.H.; Edwards, L.; Mellors, R.M.; Pyle, D.M.; Sparks, R.S.J.; Lanphere, M.; Davies, M.; Barreirio, B.

    1999-01-01

    Santorini is one of the most spectacular caldera volcanoes in the world. It has been the focus of significant scientific and scholastic interest because of the great Bronze Age explosive eruption that buried the Minoan town of Akrotiri. Santorini is still active. It has been dormant since 1950, but there have been several substantial historic eruptions. Because of this potential risk to life, both for the indigenous population and for the large number of tourists who visit it, Santorini has been designated one of five European Laboratory Volcanoes by the European Commission. Santorini has long fascinated geologists, with some important early work on volcanoes being conducted there. Since 1980, research groups at Cambridge University, and later at the University of Bristol and Blaise Pascal University in Clermont-Ferrand, have collected a large amount of data on the stratigraphy, geochemistry, geochronology and petrology of the volcanics. The volcanic field has been remapped at a scale of 1:10 000. A remarkable picture of cyclic volcanic activity and magmatic evolution has emerged from this work. Much of this work has remained unpublished until now. This Memoir synthesizes for the first time all the data from the Cambridge/Bristol/Clermont groups, and integrates published data from other research groups. It provides the latest interpretation of the tectonic and magmatic evolution of Santorini. It is accompanied by the new 1:10 000 full-colour geological map of the island.

  4. Prokaryotic diversity and metabolically active microbial populations in sediments from an active mud volcano in the Gulf of Mexico.

    PubMed

    Martinez, Robert J; Mills, Heath J; Story, Sandra; Sobecky, Patricia A

    2006-10-01

    In this study, ribosomes and genomic DNA were extracted from three sediment depths (0-2, 6-8 and 10-12 cm) to determine the vertical changes in the microbial community composition and identify metabolically active microbial populations in sediments obtained from an active seafloor mud volcano site in the northern Gulf of Mexico. Domain-specific Bacteria and Archaea 16S polymerase chain reaction primers were used to amplify 16S rDNA gene sequences from extracted DNA. Complementary 16S ribosomal DNA (crDNA) was obtained from rRNA extracted from each sediment depth that had been subjected to reverse transcription polymerase chain reaction amplification. Twelve different 16S clone libraries, representing the three sediment depths, were constructed and a total of 154 rDNA (DNA-derived) and 142 crDNA (RNA-derived) Bacteria clones and 134 rDNA and 146 crDNA Archaea clones obtained. Analyses of the 576 clones revealed distinct differences in the composition and patterns of metabolically active microbial phylotypes relative to sediment depth. For example, epsilon-Proteobacteria rDNA clones dominated the 0-2 cm clone library whereas gamma-Proteobacteria dominated the 0-2 cm crDNA library suggesting gamma to be among the most active in situ populations detected at 0-2 cm. Some microbial lineages, although detected at a frequency as high as 9% or greater in the total DNA library (i.e. Actinobacteria, alpha-Proteobacteria), were markedly absent from the RNA-derived libraries suggesting a lack of in situ activity at any depth in the mud volcano sediments. This study is one of the first to report the composition of the microbial assemblages and physiologically active members of archaeal and bacterial populations extant in a Gulf of Mexico submarine mud volcano. PMID:16958759

  5. Some insights about the activity of the Ceboruco Volcano (Nayarit, Mexico) from recent seismic low-frequency activity

    NASA Astrophysics Data System (ADS)

    Rodríguez Uribe, María Carolina; Núñez-Cornú, Francisco Javier; Nava Pichardo, Fidencio Alejandro; Suárez-Plascencia, Carlos

    2013-10-01

    The Ceboruco stratovolcano (2,280 m.a.s.l.) is located in Nayarit, Mexico, at the western end of the Mexican volcanic belt, near several population centers and by the side of a strategic highway. During the last 1,000 years it has had, on the average, one eruption every 125 years. It last eruptive activity began in 1870, and during the following 5 years it presented superficial activity including vapor emissions, ash falls, and rhyodacitic lava flows along the southeast side. A data set consisting of 139 low-frequency volcanic-type earthquakes, recorded from March 2003 to July 2008 at the CEBN triaxial short period digital station on the southwestern side of the volcano, was classified according to waveform and spectral characteristics into four families: short duration, extended coda, bobbin, and modulated amplitude. Approximate hypocentral locations indicate that there is no particular location for events of any family, but rather that all events occur at different points within the volcano. The presence of ongoing volcanic-earthquake activity together with the ongoing vapor emissions indicate that the Ceboruco volcano continues to be active, and the higher occurrence rates of short-duration events, as compared with those for the other families, could indicate an increase in the stress in the volcanic edifice. This apparent stress increase, together with the fact that the last eruption occurred 143 years ago, tell us that the Ceboruco may be approaching a critical state, and may represent a hazard to the surrounding communities and economic activities.

  6. Recent uplift and hydrothermal activity at Tangkuban Parahu volcano, west Java, Indonesia

    USGS Publications Warehouse

    Dvorak, J.; Matahelumual, J.; Okamura, A.T.; Said, H.; Casadevall, T.J.; Mulyadi, D.

    1990-01-01

    Tangkuban Parahu is an active stratovolcano located 17 km north of the city of Bandung in the province west Java, Indonesia. All historical eruptive activity at this volcano has been confined to a complex of explosive summit craters. About a dozen eruptions-mostly phreatic events- and 15 other periods of unrest, indicated by earthquakes or increased thermal activity, have been noted since 1829. The last magmatic eruption occurred in 1910. In late 1983, several small phreatic explosions originated from one of the summit craters. More recently, increased hydrothermal and earthquake activity occurred from late 1985 through 1986. Tilt measurements, using a spirit-level technique, have been made every few months since February 1981 in the summit region and along the south and east flanks of the volcano. Measurements made in the summit region indicated uplift since the start of these measurements through at least 1986. From 1981 to 1983, the average tilt rate at the edges of the summit craters was 40-50 microradians per year. After the 1983 phreatic activity, the tilt rate decreased by about a factor of five. Trilateration surveys across the summit craters and on the east flank of the volcano were conducted in 1983 and 1986. Most line length changes measured during this three-year period did not exceed the expected uncertainty of the technique (4 ppm). The lack of measurable horizontal strain across the summit craters seems to contradict the several years of tilt measurements. Using a point source of dilation in an elastic half-space to model tilt measurements, the pressure center at Tangkuban Parahu is located about 1.5 km beneath the southern part of the summit craters. This is beneath the epicentral area of an earthquake swarm that occurred in late 1983. The average rate in the volume of uplift from 1981 to 1983 was 3 million m3 per year; from 1983 to 1986 it averaged about 0.4 million m3 per year. Possible causes for this uplift are increased pressure within a very

  7. Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system.

    PubMed

    Rizzo, Andrea Luca; Caracausi, Antonio; Chavagnac, Valèrie; Nomikou, Paraskevi; Polymenakou, Paraskevi N; Mandalakis, Manolis; Kotoulas, Georgios; Magoulas, Antonios; Castillo, Alain; Lampridou, Danai

    2016-01-01

    Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report (3)He/(4)He measurements in CO2-dominated gases discharged at 500 m below sea level from the high-temperature (~220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a (3)He/(4)He signature of at least 7.0 Ra (being Ra the (3)He/(4)He ratio of atmospheric He equal to 1.39×10(-6)), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like (3)He/(4)He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano. PMID:27311383

  8. Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system.

    PubMed

    Rizzo, Andrea Luca; Caracausi, Antonio; Chavagnac, Valèrie; Nomikou, Paraskevi; Polymenakou, Paraskevi N; Mandalakis, Manolis; Kotoulas, Georgios; Magoulas, Antonios; Castillo, Alain; Lampridou, Danai

    2016-06-17

    Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report (3)He/(4)He measurements in CO2-dominated gases discharged at 500 m below sea level from the high-temperature (~220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a (3)He/(4)He signature of at least 7.0 Ra (being Ra the (3)He/(4)He ratio of atmospheric He equal to 1.39×10(-6)), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like (3)He/(4)He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano.

  9. High-resolution seismic structure analysis of an active submarine mud volcano area off SW Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Hsiao-Shan; Hsu, Shu-Kun; Tsai, Wan-Lin; Tsai, Ching-Hui; Lin, Shin-Yi; Chen, Song-Chuen

    2015-04-01

    In order to better understand the subsurface structure related to an active mud volcano MV1 and to understand their relationship with gas hydrate/cold seep formation, we conducted deep-towed side-scan sonar (SSS), sub-bottom profiler (SBP), multibeam echo sounding (MBES), and multi-channel reflection seismic (MCS) surveys off SW Taiwan from 2009 to 2011. As shown in the high-resolution sub-bottom profiler and EK500 sonar data, the detailed structures reveal more gas seeps and gas flares in the study area. In addition, the survey profiles show several submarine landslides occurred near the thrust faults. Based on the MCS results, we can find that the MV1 is located on top of a mud diapiric structure. It indicates that the MV1 has the same source as the associated mud diapir. The blanking of the seismic signal may indicate the conduit for the upward migration of the gas (methane or CO2). Therefore, we suggest that the submarine mud volcano could be due to a deep source of mud compressed by the tectonic convergence. Fluids and argillaceous materials have thus migrated upward along structural faults and reach the seafloor. The gas-charged sediments or gas seeps in sediments thus make the seafloor instable and may trigger submarine landslides.

  10. Social studies of volcanology: knowledge generation and expert advice on active volcanoes

    NASA Astrophysics Data System (ADS)

    Donovan, Amy; Oppenheimer, Clive; Bravo, Michael

    2012-04-01

    This paper examines the philosophy and evolution of volcanological science in recent years, particularly in relation to the growth of volcanic hazard and risk science. It uses the lens of Science and Technology Studies to examine the ways in which knowledge generation is controlled and directed by social forces, particularly during eruptions, which constitute landmarks in the development of new technologies and models. It also presents data from a survey of volcanologists carried out during late 2008 and early 2009. These data concern the felt purpose of the science according to the volcanologists who participated and their impressions of the most important eruptions in historical time. It demonstrates that volcanologists are motivated both by the academic science environment and by a social concern for managing the impact of volcanic hazards on populations. Also discussed are the eruptions that have most influenced the discipline and the role of scientists in policymaking on active volcanoes. Expertise in volcanology can become the primary driver of public policy very suddenly when a volcano erupts, placing immense pressure on volcanologists. In response, the epistemological foundations of volcanology are on the move, with an increasing volume of research into risk assessment and management. This requires new, integrated methodologies for knowledge collection that transcend scientific disciplinary boundaries.

  11. Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system

    PubMed Central

    Rizzo, Andrea Luca; Caracausi, Antonio; Chavagnac, Valèrie; Nomikou, Paraskevi; Polymenakou, Paraskevi N.; Mandalakis, Manolis; Kotoulas, Georgios; Magoulas, Antonios; Castillo, Alain; Lampridou, Danai

    2016-01-01

    Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report 3He/4He measurements in CO2–dominated gases discharged at 500 m below sea level from the high-temperature (~220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a 3He/4He signature of at least 7.0 Ra (being Ra the 3He/4He ratio of atmospheric He equal to 1.39×10−6), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like 3He/4He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano. PMID:27311383

  12. Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system

    NASA Astrophysics Data System (ADS)

    Rizzo, Andrea Luca; Caracausi, Antonio; Chavagnac, Valèrie; Nomikou, Paraskevi; Polymenakou, Paraskevi N.; Mandalakis, Manolis; Kotoulas, Georgios; Magoulas, Antonios; Castillo, Alain; Lampridou, Danai

    2016-06-01

    Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report 3He/4He measurements in CO2–dominated gases discharged at 500 m below sea level from the high-temperature (~220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a 3He/4He signature of at least 7.0 Ra (being Ra the 3He/4He ratio of atmospheric He equal to 1.39×10‑6), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like 3He/4He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano.

  13. Active Volcanic and Hydrothermal Processes at NW Rota-1 Submarine Volcano: Mariana Volcanic Arc

    NASA Astrophysics Data System (ADS)

    Embley, R. W.; Baker, E. T.; Butterfield, D. A.; Chadwick, W. W.; de Ronde, C.; Dower, J.; Evans, L.; Hein, J.; Juniper, K.; Lebon, G.; Lupton, J. E.; Merle, S.; Metaxas, A.; Nakamura, K.; Resing, J. E.; Roe, K.; Stern, R.; Tunnicliffe, V.

    2004-12-01

    Dives with the remotely operated vehicle ROPOS in March/April 2004 documented a volcanic eruption at NW Rota-1, a submarine volcano of basaltic composition located at 14\\deg 36.0'N, 144\\deg 46.5'E lying 65 km northwest of Rota Island in the Commonwealth of the Northern Mariana Islands. The site was chosen as a dive target because of the of the high concentrations of H2S and alunite in the hydrothermal plume overlying its summit in February 2003. The summit of the volcano is composed of curvilinear volcanic ridge oriented NW-SE bounded by NE-SW trending normal faults. Lavas collected on the upper part of the edifice are primitive to moderately fractionated basalts (Mg# = 51-66). The eruptive activity is occurring within a small crater (Brimstone Pit) located on the upper south flank of the volcano at 550 m, about 30 m below the summit. The crater is approximately 15 m wide and at least 20 meters deep. The ROPOS's cameras observed billowing clouds of sulfur-rich fluid rising out of the crater, punctuated by frequent bursts of several minutes duration that entrained glassy volcanic ejecta up to at least 2 cm in diameter. ROPOS recorded a temperature of 38\\degC within the plume. The volcanic activity had substantial temporal variability on the scale of minutes. ROPOS was sometimes completely enveloped by the plume while on the rim of the crater, and its surfaces were coated with large sulfur droplets. Black glassy fragments were entrained in the plume up to least 50 m above the crater and deposits of this material were on ledges and tops of outcrops up to several hundred meters from Brimstone Pit. The pit crater fluids have an extremely high content of particulate sulfur and extremely acidic, with pH around 2.0. This strongly implicates magmatic degassing of SO2 and disproportionation into elemental S and sulfuric acid. Diffuse venting of clear fluids was also present on the summit of the volcano, with temperatures exceeding 100\\degC in volcaniclastic sands

  14. Measuring volcanic gases at Taal Volcano Main Crater for monitoring volcanic activity and possible gas hazard

    NASA Astrophysics Data System (ADS)

    Arpa, M.; Hernandez Perez, P. A.; Reniva, P.; Bariso, E.; Padilla, G.; Melian Rodriguez, G.; Barrancos, J.; Calvo, D.; Nolasco, D.; Padron, E.; Garduque, R.; Villacorte, E.; Fajiculay, E.; Perez, N.; Solidum, R.

    2012-12-01

    Taal is an active volcano located in southwest Luzon, Philippines. It consists of mainly tuff cones which have formed an island at the center of a 30 km wide Taal Caldera. Most historical eruptions, since 1572 on Taal Volcano Island, have been characterized as hydromagmatic eruptions. Taal Main Crater, produced during the 1911 eruption, is the largest crater in the island currently filled by a 1.2 km wide, 85 m deep acidic lake. The latest historical eruption occurred in 1965-1977. Monitoring of CO2 emissions from the Main Crater Lake (MCL) and fumarolic areas within the Main Crater started in 2008 with a collaborative project between ITER and PHIVOLCS. Measurements were done by accumulation chamber method using a Westsystem portable diffuse fluxmeter. Baseline total diffuse CO2 emissions of less than 1000 t/d were established for the MCL from 3 campaign-type surveys between April, 2008 to March, 2010 when seismicity was within background levels. In May, 2010, anomalous seismic activity from the volcano started and the total CO2 emission from the MCL increased to 2716±54 t/d as measured in August, 2010. The CO2 emission from the lake was highest last March, 2011 at 4670±159 t/d when the volcano was still showing signs of unrest. Because CO2 emissions increased significantly (more than 3 times the baseline value) at this time, this activity may be interpreted as magmatic and not purely hydrothermal. Most likely deep magma intrusions occurred but did not progress further to shallower depths and no eruption occurred. No large increase in lake water temperature near the surface (average for the whole lake area) during the period when CO2 was above background, it remained at 30-34°C and a few degrees lower than average ambient temperature. Total CO2 emissions from the MCL have decreased to within baseline values since October, 2011. Concentrations of CO2, SO2 and H2S in air in the fumarolic area within the Main Crater also increased in March, 2011. The measurements

  15. MT-Stabilizer, Dictyostatin, Exhibits Prolonged Brain Retention and Activity: Potential Therapeutic Implications.

    PubMed

    Brunden, Kurt R; Gardner, Nicola M; James, Michael J; Yao, Yuemang; Trojanowski, John Q; Lee, Virginia M-Y; Paterson, Ian; Ballatore, Carlo; Smith, Amos B

    2013-09-12

    Inclusions comprising the microtubule (MT)-stabilizing protein, tau, are found within neurons in the brains of patients with Alzheimer's disease and related neurodegenerative disorders that are broadly referred to as tauopathies. The sequestration of tau into inclusions is believed to cause a loss of tau function, such that MT structure and function are compromised, leading to neuronal damage. Recent data reveal that the brain-penetrant MT-stabilizing agent, epothilone D (EpoD), improves cognitive function and decreases both neuron loss and tau pathology in transgenic mouse models of tauopathy. There is thus a need to identify additional MT-stabilizing compounds with blood-brain barrier (BBB) permeability and slow brain clearance, as observed with EpoD. We report here that the MT-stabilizing natural product, dictyostatin, crosses the BBB in mice and has extended brain retention. Moreover, a single administration of dictyostatin to mice causes prolonged stabilization of MTs in the brain. In contrast, the structurally related MT-stabilizer, discodermolide, shows significantly less brain exposure. Thus, dictyostatin merits further investigation as a potential tauopathy therapeutic.

  16. MT-Stabilizer, Dictyostatin, Exhibits Prolonged Brain Retention and Activity: Potential Therapeutic Implications

    PubMed Central

    2013-01-01

    Inclusions comprising the microtubule (MT)-stabilizing protein, tau, are found within neurons in the brains of patients with Alzheimer’s disease and related neurodegenerative disorders that are broadly referred to as tauopathies. The sequestration of tau into inclusions is believed to cause a loss of tau function, such that MT structure and function are compromised, leading to neuronal damage. Recent data reveal that the brain-penetrant MT-stabilizing agent, epothilone D (EpoD), improves cognitive function and decreases both neuron loss and tau pathology in transgenic mouse models of tauopathy. There is thus a need to identify additional MT-stabilizing compounds with blood–brain barrier (BBB) permeability and slow brain clearance, as observed with EpoD. We report here that the MT-stabilizing natural product, dictyostatin, crosses the BBB in mice and has extended brain retention. Moreover, a single administration of dictyostatin to mice causes prolonged stabilization of MTs in the brain. In contrast, the structurally related MT-stabilizer, discodermolide, shows significantly less brain exposure. Thus, dictyostatin merits further investigation as a potential tauopathy therapeutic. PMID:24900764

  17. Infrasound of basaltic effusive activity at Piton de la Fournaise Volcano

    NASA Astrophysics Data System (ADS)

    Genco, Riccardo; Valade, Sebastien; Villeneuve, Nicolas; Peltier, Aline; Ferrazzini, Valérie; Di Muro, Andrea; Ripepe, Maurizio

    2016-04-01

    On August 24th 2015, a 67 days long eruptive activity started at Piton de la Fournaise Volcano. During the last phases of the eruption we deployed a portable, small aperture, infrasonic array which allowed us to record unprecedented data from effusive volcanic activity. The array consisted on four, few tens of meters spaced, infrasound pressure sensors and was installed on the outer rim of the Enclos Foqué, roughly 2.5 km far from the active vent, sited on the southern flank of the central cone. The system was almost continuously operating from October, 15th to December, 7th 2015, thus recording the end of the first eruptive phase (Autust 24th - October 17th) as well as the two short-living following phases (from 22 to 24 and from 29 to 31 October, 2015). The infrasound records have been coupled with discrete high-rate (30 Hz) thermal and visible imagery acquisitions located at a short distance from the vent (100-200 m) providing detailed information on the eruptive source dynamics. The comparison with seismic and ground tilt data recorded by the permanent network operated by the Observatoire Volcanologique du Piton de la Fournaise (OVPF), shows that infrasound can be succesfully used to locate the source, detect the onset, and the end, of the effusive phases as well as accurately track the time evolution of the effusive process. We present results which allows a detailed analysis of the shallow magma dynamics during the effusive activity at Piton de la Fournaise Volcano. As far as we know these are amongst the few rare infrasound dataset reported for this style of basaltic volcanic activity.

  18. MT1-MMP promotes cell growth and ERK activation through c-Src and paxillin in three-dimensional collagen matrix

    SciTech Connect

    Takino, Takahisa; Tsuge, Hisashi; Ozawa, Terumasa; Sato, Hiroshi

    2010-06-11

    Membrane-type 1 matrix metalloproteinase (MT1-MMP) is essential for tumor invasion and growth. We show here that MT1-MMP induces extracellular signal-regulated kinase (ERK) activation in cancer cells cultured in collagen gel, which is indispensable for their proliferation. Inhibition of MT1-MMP by MMP inhibitor or small interfering RNA suppressed activation of focal adhesion kinase (FAK) and ERK in MT1-MMP-expressing cancer cells, which resulted in up-regulation of p21{sup WAF1} and suppression of cell growth in collagen gel. Cell proliferation was also abrogated by the inhibitor against ERK pathway without affecting FAK phosphorylation. MT1-MMP and integrin {alpha}{sub v}{beta}{sub 3} were shown to be involved in c-Src activation, which induced FAK and ERK activation in collagen gel. These MT1-MMP-mediated signal transductions were paxillin dependent, as knockdown of paxillin reduced cell growth and ERK activation, and co-expression of MT1-MMP with paxillin induced ERK activation. The results suggest that MT1-MMP contributes to proliferation of cancer cells in the extracellular matrix by activating ERK through c-Src and paxillin.

  19. Motif Discovery on Seismic Amplitude Time Series: The Case Study of Mt Etna 2011 Eruptive Activity

    NASA Astrophysics Data System (ADS)

    Cassisi, Carmelo; Aliotta, Marco; Cannata, Andrea; Montalto, Placido; Patanè, Domenico; Pulvirenti, Alfredo; Spampinato, Letizia

    2013-04-01

    Algorithms searching for similar patterns are widely used in seismology both when the waveforms of the events of interest are known and when there is no a priori-knowledge. Such methods usually make use of the cross-correlation coefficient as a measure of similarity; if there is no a-priori knowledge, they behave as brute-force searching algorithms. The disadvantage of these methods, preventing or limiting their application to very large datasets, is computational complexity. The Mueen-Keogh (MK) algorithm overcomes this limitation by means of two optimization techniques—the early abandoning concept and space indexing. Here, we apply the MK algorithm to amplitude time series retrieved from seismic signals recorded during episodic eruptive activity of Mt Etna in 2011. By adequately tuning the input to the MK algorithm we found eight motif groups characterized by distinct seismic amplitude trends, each related to a different phenomenon. In particular, we observed that earthquakes are accompanied by sharp increases and decreases in seismic amplitude whereas lava fountains are accompanied by slower changes. These results demonstrate that the MK algorithm, because of its particular features, may have wide applicability in seismology.

  20. Subglacial melting associated with activity at Bárdarbunga volcano, Iceland, explored using numerical reservoir simulations

    NASA Astrophysics Data System (ADS)

    Reynolds, Hannah I.; Gudmundsson, Magnús T.; Högnadóttir, Thórdís

    2015-04-01

    Increased seismic activity was observed within the caldera of Bárdarbunga, a central volcano beneath Vatnajökull glacier, on 16 August 2014. The seismicity traced the path of a lateral dyke, initially propagating to the south east of the volcano, before changing course and continuing beyond the northern extent of the glacier. A short fissure eruption occurred at the site of the Holuhraun lavas on 29 August, lasting for approximately 5 hours and producing less than 1 million cubic meters of lava, before recommencing in earnest on 31 August with the large effusive eruption, which is still ongoing at the time of writing. The glacier surface has been monitored aerially since the onset of heightened seismic activity, and the caldera and dyke propagation path surveyed using radar profiling. Ice cauldrons are shallow depressions which form on the glacier surface due to basal melting, as a manifestation of heat flux from below; the melting ice acts as a calorimeter, allowing estimations of heat flux magnitude to be made. Several cauldrons were observed outside the caldera, two to the south east of Bárdarbunga, and three located above the path of the dyke under the Dyngjujökull outlet glacier. The cauldrons range in volume from approximately 0.001 km3 to 0.02 km3. We present time series data of the development and evolution of these cauldrons, with estimates of the heat flux magnitudes involved. The nature of the heat source required to generate the aforementioned cauldrons is not obvious and two scenarios are explored: 1) small subglacial eruptions; or 2) increased geothermal activity induced by the dyke intrusion. We investigate these scenarios using analytical and finite element modelling, considering the surface heat flux produced, and timescales and spatial extent of associated surface anomalies. A range of permeabilities has been explored. It is found that an intrusion of a dyke or sill into rocks where the groundwater is near or at the boiling point curve can

  1. Plume indications from hydrothermal activity on Kawio Barat Submarine Volcano, Sangihe Talaud Sea, North Sulawesi, Indonesia

    NASA Astrophysics Data System (ADS)

    Makarim, S.; Baker, E. T.; Walker, S. L.; Wirasantosa, S.; Permana, H.; Sulistiyo, B.; Shank, T. M.; Holden, J. F.; Butterfield, D.; Ramdhan, M.; Adi, R.; Marzuki, M. I.

    2010-12-01

    Kawio Barat submarine volcano has formed in response to the active tectonic conditions in Sangihe Talaud, an area that lies in the subduction zone between the Molucca Sea Plate and Celebes Sea Plate. Submarine volcanic activity in the western Sangihe volcanic arc is controlled by the west-dipping Molucca Sea Plate as it subducts beneath the Sangihe Arc. A secondary faulting system on Kawio Barat is in a northwest - southeast direction, and creates a network of deep cracks that facilitate hydrothermal discharge in this area. Hydrothermal activity on Kawio Barat was first discovered by joint Indonesia/Australian cruises in 2003. In 2010, as part of the joint US/Indonesian INDEX-SATAL expedition, we conducted CTD casts that confirmed continuing activity. Hydrothermal plumes were detected by light -scattering (LSS) and oxidation-reduction potential (ORP) sensors on the CTD package. LSS anomalies were found between 1600-1900 m, with delta NTU levels of 0.020-0.040. ORP anomalies coincident with the LSS anomalies indicate strong concentrations of reduced species such as H2S and Fe, confirming the hydrothermal origin of the plumes. Images of hydrothermal vents on Kawio Barat Submarine volcano, recorded by high- definition underwater cameras on the ROV “Little Hercules” operated from the NOAA ship Okeanos Explorer, confirmed the presence and sources of the detected vent plumes in the northern and southwest part of the summit in 1800-1900 m depth. In southwest part of this summit chimney, drips of molten sulfur were observed in the proximity of microbal staining.

  2. 2005 Volcanic Activity in Alaska, Kamchatka, and the Kurile Islands: Summary of Events and Response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, R.G.; Neal, C.A.; Dixon, J.P.; Ushakov, Sergey

    2008-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptive activity or suspected volcanic activity at or near 16 volcanoes in Alaska during 2005, including the high profile precursory activity associated with the 2005?06 eruption of Augustine Volcano. AVO continues to participate in distributing information about eruptive activity on the Kamchatka Peninsula, Russia, and in the Kurile Islands of the Russian Far East, in conjunction with the Kamchatkan Volcanic Eruption Response Team (KVERT) and the Sakhalin Volcanic Eruption Response Team (SVERT), respectively. In 2005, AVO helped broadcast alerts about activity at 8 Russian volcanoes. The most serious hazard posed from volcanic eruptions in Alaska, Kamchatka, or the Kurile Islands is the placement of ash into the atmosphere at altitudes traversed by jet aircraft along the North Pacific and Russian Trans East air routes. AVO, KVERT, and SVERT work collaboratively with the National Weather Service, Federal Aviation Administration, and the Volcanic Ash Advisory Centers to provide timely warnings of volcanic eruptions and the production and movement of ash clouds.

  3. San Cristobal Volcano, Nicaragua

    NASA Technical Reports Server (NTRS)

    1990-01-01

    A white plume of smoke, from San Cristobal Volcano (13.0N, 87.5W) on the western coast of Nicaragua, blows westward along the Nicaraguan coast just south of the Gulf of Fonseca and the Honduran border. San Csistobal is a strato volcano some 1,745 meters high and is frequently active.

  4. Analysis of the activity pattern of volcanoes through self-organized crack networks: The effect of density barriers—An application to Vesuvius activity in the period 1631-1944

    NASA Astrophysics Data System (ADS)

    Piegari, E.; Di Maio, R.; Scandone, R.

    2013-06-01

    We simulated the pattern of activity of a strato-volcano by using a cellular automaton model where magma is allowed to ascend to the surface through self-organized crack networks. Magma rises toward the surface by filling connected paths of fractures until the magma's density is less than that of surrounding rocks. If magma enters a region with negative or neutral buoyancy, it cools and solidifies; as a result, the local density profile is modified, and magmatic dikes are formed. We simulated the temporal evolution of high-density pathways of dikes that magma may eventually utilize to reach the surface. We showed that if a shallow neutral-negative buoyancy zone is restored after eruptions, due to, for example, piecemeal or chaotic collapses, a characteristic timescale appears in the inter-event repose time distribution. Such characteristic repose time represents the average time that magma takes to form a high-density pathway through the less dense rock layer, and it may give a hint to predict possible eruptive scenarios. Even if the model includes many simplifying assumptions in the definition of magma-rock interaction, the results obtained from simulations are consistent with the eruptive behavior of the Mt. Somma-Vesuvius volcano for the 1631-1944 period.

  5. Chlorine isotopes of thermal springs in arc volcanoes for tracing shallow magmatic activity

    NASA Astrophysics Data System (ADS)

    Li, Long; Bonifacie, Magali; Aubaud, Cyril; Crispi, Olivier; Dessert, Céline; Agrinier, Pierre

    2015-03-01

    The evaluation of the status of shallow magma body (i.e., from the final intrusion stage, to quiescence, and back to activity), one of the key parameters that trigger and sustain volcanic eruptions, has been challenging in modern volcanology. Among volatile tracers, chlorine (Cl) uniquely exsolves at shallow depths and is highly hydrophilic. Consequently, Cl enrichment in volcanic gases and thermal springs has been proposed as a sign for shallow magmatic activities. However, such enrichment could also result from numerous other processes (e.g., water evaporation, dissolution of old chloride mineral deposits, seawater contamination) that are unrelated to magmatic activity. Here, based on stable isotope compositions of chloride and dissolved inorganic carbon, as well as previous published 3He/4He data obtained in thermal springs from two recently erupted volcanoes (La Soufrière in Guadeloupe and Montagne Pelée in Martinique) in the Lesser Antilles Arc, we show that the magmatic Cl efficiently trapped in thermal springs displays negative δ37Cl values (≤ - 0.65 ‰), consistent with a slab-derived origin but distinct from the isotope compositions of chloride in surface reservoirs (e.g. seawater, local meteoric waters, rivers and cold springs) displaying common δ37Cl values of around 0‰. Using this δ37Cl difference as an index of magmatic Cl, we further examined thermal spring samples including a 30-year archive from two thermal springs in Guadeloupe covering samples from its last eruption in 1976-1977 to 2008 and an island-wide sampling event in Martinique in 2008 to trace the evolution of magmatic Cl in the volcanic hydrothermal systems over time. The results show that magmatic Cl can be rapidly flushed out of the hydrothermal systems within <30 to 80 years after the eruption, much quicker than other volatile tracers such as CO2 and noble gases, which can exsolve at greater depths and constantly migrate to the surface. Because arc volcanoes often have well

  6. Potentiating the cellular targeting and anti-tumor activity of Dp44mT via binding to human serum albumin: two saturable mechanisms of Dp44mT uptake by cells

    PubMed Central

    Merlot, Angelica M.; Sahni, Sumit; Lane, Darius J.R.; Fordham, Ashleigh M.; Pantarat, Namfon; Hibbs, David E.; Richardson, Vera; Doddareddy, Munikumar R.; Ong, Jennifer A.; Huang, Michael L.H.

    2015-01-01

    Di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT) demonstrates potent anti-cancer activity. We previously demonstrated that 14C-Dp44mT enters and targets cells through a carrier/receptor-mediated uptake process. Despite structural similarity, 2-benzoylpyridine 4-ethyl-3-thiosemicarbazone (Bp4eT) and pyridoxal isonicotinoyl hydrazone (PIH) enter cells via passive diffusion. Considering albumin alters the uptake of many drugs, we examined the effect of human serum albumin (HSA) on the cellular uptake of Dp44mT, Bp4eT and PIH. Chelator-HSA binding studies demonstrated the following order of relative affinity: Bp4eT≈PIH>Dp44mT. Interestingly, HSA decreased Bp4eT and PIH uptake, potentially due to its high affinity for the ligands. In contrast, HSA markedly stimulated Dp44mT uptake by cells, with two saturable uptake mechanisms identified. The first mechanism saturated at 5-10 μM (Bmax:1.20±0.04 × 107 molecules/cell; Kd:33±3 μM) and was consistent with a previously identified Dp44mT receptor/carrier. The second mechanism was of lower affinity, but higher capacity (Bmax:2.90±0.12 × 107 molecules/cell; Kd:65±6 μM), becoming saturated at 100 μM and was only evident in the presence of HSA. This second saturable Dp44mT uptake process was inhibited by excess HSA and had characteristics suggesting it was mediated by a specific binding site. Significantly, the HSA-mediated increase in the targeting of Dp44mT to cancer cells potentiated apoptosis and could be important for enhancing efficacy. PMID:25848850

  7. The Pulse of the Volcano: Discovery of Episodic Activity at Prometheus on Io

    NASA Technical Reports Server (NTRS)

    Davies, A. G.

    2003-01-01

    The temporal behaviour of thermal output from a volcano yields valuable clues to the processes taking place at and beneath the surface. Galileo Near Infrared Mapping Spectrometer (NIMS) data show that the ionian volcanoes Prometheus and Amirani have significant thermal emission in excess of nonvolcanic background emission in every geometrically appropriate NIMS observation. The 5 micron brightness of these volcanoes shows considerable variation from orbit to orbit. Prometheus in particular exhibits an episodicity that yields valuable constraints to the mechanisms of magma supply and eruption. This work is part of an on-going study to chart and quantify the thermal emission of Io's volcanoes, determine mass eruption rates, and note eruption style.

  8. Dopamine Activation Preserves Visual Motion Perception Despite Noise Interference of Human V5/MT

    PubMed Central

    Yousif, Nada; Fu, Richard Z.; Abou-El-Ela Bourquin, Bilal; Bhrugubanda, Vamsee; Schultz, Simon R.

    2016-01-01

    When processing sensory signals, the brain must account for noise, both noise in the stimulus and that arising from within its own neuronal circuitry. Dopamine receptor activation is known to enhance both visual cortical signal-to-noise-ratio (SNR) and visual perceptual performance; however, it is unknown whether these two dopamine-mediated phenomena are linked. To assess this, we used single-pulse transcranial magnetic stimulation (TMS) applied to visual cortical area V5/MT to reduce the SNR focally and thus disrupt visual motion discrimination performance to visual targets located in the same retinotopic space. The hypothesis that dopamine receptor activation enhances perceptual performance by improving cortical SNR predicts that dopamine activation should antagonize TMS disruption of visual perception. We assessed this hypothesis via a double-blinded, placebo-controlled study with the dopamine receptor agonists cabergoline (a D2 agonist) and pergolide (a D1/D2 agonist) administered in separate sessions (separated by 2 weeks) in 12 healthy volunteers in a William's balance-order design. TMS degraded visual motion perception when the evoked phosphene and the visual stimulus overlapped in time and space in the placebo and cabergoline conditions, but not in the pergolide condition. This suggests that dopamine D1 or combined D1 and D2 receptor activation enhances cortical SNR to boost perceptual performance. That local visual cortical excitability was unchanged across drug conditions suggests the involvement of long-range intracortical interactions in this D1 effect. Because increased internal noise (and thus lower SNR) can impair visual perceptual learning, improving visual cortical SNR via D1/D2 agonist therapy may be useful in boosting rehabilitation programs involving visual perceptual training. SIGNIFICANCE STATEMENT In this study, we address the issue of whether dopamine activation improves visual perception despite increasing sensory noise in the visual cortex

  9. Broadband seismic monitoring of active volcanoes using deterministic and stochastic approaches

    NASA Astrophysics Data System (ADS)

    Kumagai, H.; Nakano, M.; Maeda, T.; Yepes, H.; Palacios, P.; Ruiz, M. C.; Arrais, S.; Vaca, M.; Molina, I.; Yamashina, T.

    2009-12-01

    We systematically used two approaches to analyze broadband seismic signals observed at active volcanoes: one is waveform inversion of very-long-period (VLP) signals in the frequency domain assuming possible source mechanisms; the other is a source location method of long-period (LP) and tremor using their amplitudes. The deterministic approach of the waveform inversion is useful to constrain the source mechanism and location, but is basically only applicable to VLP signals with periods longer than a few seconds. The source location method uses seismic amplitudes corrected for site amplifications and assumes isotropic radiation of S waves. This assumption of isotropic radiation is apparently inconsistent with the hypothesis of crack geometry at the LP source. Using the source location method, we estimated the best-fit source location of a VLP/LP event at Cotopaxi using a frequency band of 7-12 Hz and Q = 60. This location was close to the best-fit source location determined by waveform inversion of the VLP/LP event using a VLP band of 5-12.5 s. The waveform inversion indicated that a crack mechanism better explained the VLP signals than an isotropic mechanism. These results indicated that isotropic radiation is not inherent to the source and only appears at high frequencies. We also obtained a best-fit location of an explosion event at Tungurahua when using a frequency band of 5-10 Hz and Q = 60. This frequency band and Q value also yielded reasonable locations for the sources of tremor signals associated with lahars and pyroclastic flows at Tungurahua. The isotropic radiation assumption may be valid in a high frequency range in which the path effect caused by the scattering of seismic waves results in an isotropic radiation pattern of S waves. The source location method may be categorized as a stochastic approach based on the nature of scattering waves. We further applied the waveform inversion to VLP signals observed at only two stations during a volcanic crisis

  10. Active mud volcanoes on the continental slope of the Canadian Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Paull, C. K.; Dallimore, S. R.; Caress, D. W.; Gwiazda, R.; Melling, H.; Riedel, M.; Jin, Y. K.; Hong, J. K.; Kim, Y.-G.; Graves, D.; Sherman, A.; Lundsten, E.; Anderson, K.; Lundsten, L.; Villinger, H.; Kopf, A.; Johnson, S. B.; Hughes Clarke, J.; Blasco, S.; Conway, K.; Neelands, P.; Thomas, H.; Côté, M.

    2015-09-01

    Morphologic features, 600-1100 m across and elevated up to 30 m above the surrounding seafloor, interpreted to be mud volcanoes were investigated on the continental slope in the Beaufort Sea in the Canadian Arctic. Sediment cores, detailed mapping with an autonomous underwater vehicle, and exploration with a remotely operated vehicle show that these are young and actively forming features experiencing ongoing eruptions. Biogenic methane and low-chloride, sodium-bicarbonate-rich waters are extruded with warm sediment that accumulates to form cones and low-relief circular plateaus. The chemical and isotopic compositions of the ascending water indicate that a mixture of meteoric water, seawater, and water from clay dehydration has played a significant role in the evolution of these fluids. The venting methane supports extensive siboglinid tubeworms communities and forms some gas hydrates within the near seafloor. We believe that these are the first documented living chemosynthetic biological communities in the continental slope of the western Arctic Ocean.

  11. Lightning and electrical activity during the Shiveluch volcano eruption on 16 November 2014

    NASA Astrophysics Data System (ADS)

    Shevtsov, Boris M.; Firstov, Pavel P.; Cherneva, Nina V.; Holzworth, Robert H.; Akbashev, Renat R.

    2016-03-01

    According to World Wide Lightning Location Network (WWLLN) data, a sequence of lightning discharges was detected which occurred in the area of the explosive eruption of Shiveluch volcano on 16 November 2014 in Kamchatka. Information on the ash cloud motion was confirmed by the measurements of atmospheric electricity, satellite observations and meteorological and seismic data. It was concluded that WWLLN resolution is enough to detect the earlier stage of volcanic explosive eruption when electrification processes develop the most intensively. The lightning method has the undeniable advantage for the fast remote sensing of volcanic electric activity anywhere in the world. There is a good opportunity for the development of WWLLN technology to observe explosive volcanic eruptions.

  12. A novel polymer based on MtCu2+/cellulose acetate with antimicrobial activity.

    PubMed

    Bruna, J E; Galotto, M J; Guarda, A; Rodríguez, F

    2014-02-15

    Cellulose acetate (CA)/copper montmorillonite modified (MtCu(2+)) antimicrobial nanocomposites for food packaging containing 1, 3 and 5 wt.% nanoparticles were prepared by solution casting technique. X-ray diffraction (XRD) and transmission electron microscopy revealed the existence of intercalated and no intercalated clay form in the CA matrix. The thermal stability of the MtCu(2+)/CA nanocomposites was measured by TGA and DSC, which indicated that the nanocomposites were less thermally stable in comparison to CA pure. Mechanical testing of material did not show differences when MtCu(2+) was added in CA. On the other hand, antimicrobial effect was observed for nanocomposites films, obtaining a 98% reduction against Escherichia coli. PMID:24507287

  13. A novel polymer based on MtCu2+/cellulose acetate with antimicrobial activity.

    PubMed

    Bruna, J E; Galotto, M J; Guarda, A; Rodríguez, F

    2014-02-15

    Cellulose acetate (CA)/copper montmorillonite modified (MtCu(2+)) antimicrobial nanocomposites for food packaging containing 1, 3 and 5 wt.% nanoparticles were prepared by solution casting technique. X-ray diffraction (XRD) and transmission electron microscopy revealed the existence of intercalated and no intercalated clay form in the CA matrix. The thermal stability of the MtCu(2+)/CA nanocomposites was measured by TGA and DSC, which indicated that the nanocomposites were less thermally stable in comparison to CA pure. Mechanical testing of material did not show differences when MtCu(2+) was added in CA. On the other hand, antimicrobial effect was observed for nanocomposites films, obtaining a 98% reduction against Escherichia coli.

  14. How caldera collapse shapes the shallow emplacement and transfer of magma in active volcanoes

    NASA Astrophysics Data System (ADS)

    Corbi, Fabio; Rivalta, Eleonora; Pinel, Virginie; Maccaferri, Francesco; Bagnardi, Marco; Acocella, Valerio

    2016-04-01

    Calderas are topographic depressions formed by the collapse of a partly drained magma reservoir. At volcanic edifices with calderas, eruptive fissures can circumscribe the outer caldera rim, be oriented radially and/or align with the regional tectonic stress field. Constraining the mechanisms that govern this spatial arrangement is fundamental to understand the dynamics of shallow magma storage and transport and evaluate volcanic hazard. Here we use numerical models to show that the previously unappreciated unloading effect of caldera formation may contribute significantly to the stress budget of a volcano. We first test this hypothesis against the ideal case of Fernandina, Galápagos, where previous models only partly explained the peculiar pattern of circumferential and radial eruptive fissures and the geometry of the intrusions determined by inverting the deformation data. We show that by taking into account the decompression due to the caldera formation, the modeled edifice stress field is consistent with all the observation. We then develop a general model for the stress state at volcanic edifices with calderas based on the competition of caldera decompression, magma buoyancy forces and tectonic stresses. These factors control the shallow accumulation of magma in stacked sills, consistently with observations as well as the conditions for the development of circumferential and/or radial eruptive fissures, as observed on active volcanoes. This top-down control exerted by changes in the distribution of mass at the surface allows better understanding of how shallow magma is transferred at active calderas, contributing to forecasting the location and type of opening fissures.

  15. Seismicity and eruptive activity at Fuego Volcano, Guatemala: February 1975 -January 1977

    USGS Publications Warehouse

    Yuan, A.T.E.; McNutt, S.R.; Harlow, D.H.

    1984-01-01

    We examine seismic and eruptive activity at Fuego Volcano (14??29???N, 90?? 53???W), a 3800-m-high stratovolcano located in the active volcanic arc of Guatemala. Eruptions at Fuego are typically short-lived vulcanian eruptions producing ash falls and ash flows of high-alumina basalt. From February 1975 to December 1976, five weak ash eruptions occurred, accompanied by small earthquake swarms. Between 0 and 140 (average ??? 10) A-type or high-frequency seismic events per day with M > 0.5 were recorded during this period. Estimated thermal energies for each eruption are greater by a factor of 106 than cumulative seismic energies, a larger ratio than that reported for other volcanoes. Over 4000 A-type events were recorded January 3-7, 1977 (cumulative seismic energy ??? 109 joules), yet no eruption occurred. Five 2-hour-long pulses of intense seismicity separated by 6-hour intervals of quiescence accounted for the majority of events. Maximum likelihood estimates of b-values range from 0.7 ?? 0.2 to 2.1 ?? 0.4 with systematically lower values corresponding to the five intense pulses. The low values suggest higher stress conditions. During the 1977 swarm, a tiltmeter located 6 km southeast of Fuego recorded a 14 ?? 3 microradian tilt event (down to SW). This value is too large to represent a simple change in the elastic strain field due to the earthquake swarm. We speculate that the earthquake swarm and tilt are indicative of subsurface magma movement. ?? 1984.

  16. Volcano infrasound: A review

    NASA Astrophysics Data System (ADS)

    Johnson, Jeffrey Bruce; Ripepe, Maurizio

    2011-09-01

    Exploding volcanoes, which produce intense infrasound, are reminiscent of the veritable explosion of volcano infrasound papers published during the last decade. Volcano infrasound is effective for tracking and quantifying eruptive phenomena because it corresponds to activity occurring near and around the volcanic vent, as opposed to seismic signals, which are generated by both surface and internal volcanic processes. As with seismology, infrasound can be recorded remotely, during inclement weather, or in the dark to provide a continuous record of a volcano's unrest. Moreover, it can also be exploited at regional or global distances, where seismic monitoring has limited efficacy. This paper provides a literature overview of the current state of the field and summarizes applications of infrasound as a tool for better understanding volcanic activity. Many infrasound studies have focused on integration with other geophysical data, including seismic, thermal, electromagnetic radiation, and gas spectroscopy and they have generally improved our understanding of eruption dynamics. Other work has incorporated infrasound into volcano surveillance to enhance capabilities for monitoring hazardous volcanoes and reducing risk. This paper aims to provide an overview of volcano airwave studies (from analog microbarometer to modern pressure transducer) and summarizes how infrasound is currently used to infer eruption dynamics. It also outlines the relative merits of local and regional infrasound surveillance, highlights differences between array and network sensor topologies, and concludes with mention of sensor technologies appropriate for volcano infrasound study.

  17. International Volcanological Field School in Kamchatka and Alaska: Experiencing Language, Culture, Environment, and Active Volcanoes

    NASA Astrophysics Data System (ADS)

    Eichelberger, J. C.; Gordeev, E.; Ivanov, B.; Izbekov, P.; Kasahara, M.; Melnikov, D.; Selyangin, O.; Vesna, Y.

    2003-12-01

    The Kamchatka State University of Education, University of Alaska Fairbanks, and Hokkaido University are developing an international field school focused on explosive volcanism of the North Pacific. An experimental first session was held on Mutnovsky and Gorely Volcanoes in Kamchatka during August 2003. Objectives of the school are to:(1) Acquaint students with the chemical and physical processes of explosive volcanism, through first-hand experience with some of the most spectacular volcanic features on Earth; (2) Expose students to different concepts and approaches to volcanology; (3) Expand students' ability to function in a harsh environment and to bridge barriers in language and culture; (4) Build long-lasting collaborations in research among students and in teaching and research among faculty in the North Pacific region. Both undergraduate and graduate students from Russia, the United States, and Japan participated. The school was based at a mountain hut situated between Gorely and Mutnovsky Volcanoes and accessible by all-terrain truck. Day trips were conducted to summit craters of both volcanoes, flank lava flows, fumarole fields, ignimbrite exposures, and a geothermal area and power plant. During the evenings and on days of bad weather, the school faculty conducted lectures on various topics of volcanology in either Russian or English, with translation. Although subjects were taught at the undergraduate level, lectures led to further discussion with more advanced students. Graduate students participated by describing their research activities to the undergraduates. A final session at a geophysical field station permitted demonstration of instrumentation and presentations requiring sophisticated graphics in more comfortable surroundings. Plans are underway to make this school an annual offering for academic credit in the Valley of Ten Thousand Smokes, Alaska and in Kamchatka. The course will be targeted at undergraduates with a strong interest in and

  18. Hydrodynamic modeling of magmatic-hydrothermal activity at submarine arc volcanoes, with implications for ore formation

    NASA Astrophysics Data System (ADS)

    Gruen, Gillian; Weis, Philipp; Driesner, Thomas; Heinrich, Christoph A.; de Ronde, Cornel E. J.

    2014-10-01

    Subduction-related magmas have higher volatile contents than mid-ocean ridge basalts, which affects the dynamics of associated submarine hydrothermal systems. Interaction of saline magmatic fluids with convecting seawater may enhance ore metal deposition near the seafloor, making active submarine arcs a preferred modern analogue for understanding ancient massive sulfide deposits. We have constructed a quantitative hydrological model for sub-seafloor fluid flow based on observations at Brothers volcano, southern Kermadec arc, New Zealand. Numerical simulations of multi-phase hydrosaline fluid flow were performed on a two-dimensional cross-section cutting through the NW Caldera and the Upper Cone sites, two regions of active venting at the Brothers volcanic edifice, with the former hosting sulfide mineralization. Our aim is to explore the flow paths of saline magmatic fluids released from a crystallizing magma body at depth and their interaction with seawater circulating through the crust. The model includes a 3×2 km sized magma chamber emplaced at ∼2.5 km beneath the seafloor connected to the permeable cone via a ∼200 m wide feeder dike. During the simulation, a magmatic fluid was temporarily injected from the top of the cooling magma chamber into the overlying convection system, assuming hydrostatic conditions and a static permeability distribution. The simulations predict a succession of hydrologic regimes in the subsurface of Brothers volcano, which can explain some of the present-day hydrothermal observations. We find that sub-seafloor phase separation, inferred from observed vent fluid salinities, and the temperatures of venting at Brothers volcano can only be achieved by input of a saline magmatic fluid at depth, consistent with chemical and isotopic data. In general, our simulations show that the transport of heat, water, and salt from magmatic and seawater sources is partly decoupled. Expulsion of magmatic heat and volatiles occurs within the first few

  19. Linking observations at active volcanoes to physical processes through conduit flow modelling

    NASA Astrophysics Data System (ADS)

    Thomas, Mark; Neuberg, Jurgen

    2010-05-01

    Low frequency seismic events observed on volcanoes such as Soufriere hills, Montserrat may offer key indications about the state of a volcanic system. To obtain a better understanding of the source of these events and of the physical processes that take place within a volcano it is necessary to understand the conditions of magma a depth. This can be achieved through conduit flow modelling (Collier & Neuberg, 2006). 2-D compressible Navier-Stokes equations are solved through a Finite Element approach, for differing initial water and crystal contents, magma temperatures, chamber overpressures and geometric shapes of conduit. In the fully interdependent modelled system each of these variables has an effect on the magma density, viscosity, gas content, and also the pressure within the flow. These variables in turn affect the magma ascent velocity and the overall eruption dynamics of an active system. Of particular interest are the changes engendered in the flow by relativity small variations in the conduit geometry. These changes can have a profound local effect of the ascent velocity of the magma. By restricting the width of 15m wide, 5000m long vertical conduit over a 100m distance a significant acceleration of the magma is seen in this area. This has implications for the generation of Low-Frequency (LF) events at volcanic systems. The strain-induced fracture of viscoelastic magma or brittle failure of melt has been previously discussed as a possible source of LF events by several authors (e.g. Tuffen et al., 2003; Neuberg et al., 2006). The location of such brittle failure however has been seen to occur at relativity shallow depths (<1000m), which does not agree with the location of recorded LF events. By varying the geometry of the conduit and causing accelerations in the magma flow, localised increases in the shear strain rate of up to 30% are observed. This provides a mechanism of increasing the depth over witch brittle failure of melt may occur. A key observable

  20. Organic geochemical signatures controlling methane outgassing at active mud volcanoes in the Canadian Beaufort Sea

    NASA Astrophysics Data System (ADS)

    DongHun, Lee; YoungKeun, Jin; JungHyun, Kim; Heldge, Niemann; JongKu, Gal; BoHyung, Choi

    2016-04-01

    Based on the water column acoustic anomalies related to active methane (CH4) venting, numerous active Mud Volcanoes (MVs) were recently identified at ~282, ~420, and ~740 m water depths on the continental slope of the Canadian Beaufort Sea (Paull et al., 2015). While geophysical aspects such as the multibeam bathymetric mapping are thoroughly investigated, biogeochemical processes controlling outgassing CH4 at the active MVs are not well constrained. Here, we investigated three sediment cores from the active MVs and one sediment core from a non-methane influenced reference site recovered during the ARA-05C expedition with the R/V ARAON in 2014. We analyzed lipid biomarkers and their stable carbon isotopic values (δ13C) in order to determine key biogeochemical processes involved in CH4 cycling in the MV sediments. Downcore CH4 and sulphate (SO42-) concentration measurements revealed a distinct sulfate-methane transition zone (SMTZ) at the shallow sections of the cores (15 - 45 cm below seafloor (cm bsf) at 282 m MV, 420 m MV, and 740 m MV). The most abundant diagnostic lipid biomarkers in the SMTZ were sn-2-hydroxyarchaeol (-94‰) and archaeol (-66‰) with the sn-2-hydroxyarchaeol: archaeol ratio of 1.1 to 5, indicating the presence of ANME-2 or -3. However, we also found substantial amounts of monocyclic biphytane-1 (BP-1, -118‰), which is rather indicative for ANME-1. Nevertheless, the concentration of sn-2-hydroxyarchaeol was 2-fold higher than any other archaeal lipids, suggesting a predominant ANME-2 or -3 rather than ANME-1 as a driving force for the anaerobic methane oxidation (AOM) in these systems. We will further investigate the microbial community at the active MVs using nucleic acid (RNA and DNA) sequence analyses in near future. Our study provides first biogeochemical data set of the active MVs in the Canadian Beaufort Sea, which helps to better understand CH4 cycling mediated in these systems. Reference Paull, C.K., et al. (2015), Active mud

  1. 1994 Volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; Doukas, Michael P.; McGimsey, Robert G.

    1995-01-01

    During 1994, the Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, or false alarms at nine volcanic centers-- Mount Sanford, Iliamna, the Katmai group, Kupreanof, Mount Veniaminof, Shishaldin, Makushin, Mount Cleveland and Kanaga (table 1). Of these volcanoes, AVO has a real time, continuously recording seismic network only at Iliamna, which is located in the Cook Inlet area of south-central Alaska (fig. 1). AVO has dial-up access to seismic data from a 5-station network in the general region of the Katmai group of volcanoes. The remaining unmonitored volcanoes are located in sparsely populated areas of the Wrangell Mountains, the Alaska Peninsula, and the Aleutian Islands (fig. 1). For these volcanoes, the AVO monitoring program relies chiefly on receipt of pilot reports, observations of local residents and analysis of satellite imagery.

  2. A Wireless Seismoacoustic Sensor Network for Monitoring Activity at Volcano Reventador, Ecuador

    NASA Astrophysics Data System (ADS)

    Welsh, M.; Werner-Allen, G.; Lorincz, K.; Marcillo, O.; Ruiz, M.; Johnson, J.; Lees, J. M.

    2005-12-01

    We developed a wireless sensor network for monitoring seismoacoustic activity at Volcano Reventador, Ecuador. Wireless sensor networks are a new technology and our group is among the first to apply them to monitoring volcanoes. The small size, low power, and wireless communication capabilities can greatly simplify deployments of large sensor arrays. The network consisted of 16 wireless sensor nodes, each outfitted with an 8 MHz CPU (TI MSP430) and a 2.4 GHz IEEE 802.15.4 radio (Chipcon CC2420) with data rates up to 80 Kbps. Each node acquired acoustic and seismic data at 24-bit resolution, with a microphone and either a single-axis geophone or triaxial short-period seismometer. Each node is powered by two D-cell batteries with a lifetime of about 1 week, and measures 18 x 10 x 8 cm. Nodes were distributed radially from the vent over a 3 km aperture. Control and data messages are relayed via radio to a base station node, with inter-node distances of up to 420 m. The base station transmits data using a FreeWave radio modem, via a repeater, to a laptop located 4 km from the deployment site. Each node samples continuous sensor data and a simple event-detection algorithm is used to trigger data collection. When a sensor detects an event, it relays a short message to the base station via radio. If several nodes report an event within a short time interval, the last 60 seconds of data is downloaded from each node in turn. One of the sensor nodes is programmed to transmit continuous data; due to limited radio bandwidth, it is not possible to collect continuous data from all nodes in the array. A GPS receiver and time synchronization protocol is used to establish a global timebase across all sensor nodes.

  3. Stratigraphy, geochronology and evolution of the Mt. Melbourne volcanic field (North Victoria Land, Antarctica)

    NASA Astrophysics Data System (ADS)

    Giordano, Guido; Lucci, Federico

    2016-04-01

    Mt. Melbourne (2,732 ma.s.l.) is a large quiescent stratovolcano located in Northern Victoria Land (Antarctica) and is one of a handful of volcanoes on the Antarctic plate with the potential for large-scale explosive eruptions. The early, Lower Pleistocene, volcanism was largely alkali basaltic to hawaiitic in composition and monogenetic in style, producing tens of small scoria cones and lava flows scattered over a wide area across the Transantarctic Mountains (Random Hills Period). During the Middle Pleistocene, volcanic activity focused to the area of the Mt. Melbourne stratovolcano, where several monogenetic centres show the transition from early subglacial/ subaqueous conditions to emergent subaerial conditions (Shield Nunatak Period). The oldest exposed deposit associated with the early activity of the Mt. Melbourne stratovolcano (Mt. Melbourne Period) is a trachytic subaerial ignimbrite dated at 123.6±6.0 ka, which reflects the establishment of a crustal magma chamber. Above the ignimbrite a succession of alkali basaltic, hawaiitic, and subordinate benmoreitic lavas and scoria cones is exposed, dated at 90.7±19.0 ka. The most recent deposits are exposed at the top of Mt. Melbourne, where the crater rim is composed of trachytic to rhyolitic pumice fall deposits, which are also extensively dispersed around the volcano, originated from Plinian-scale eruptions. The most recent explosive deposit proved difficult to date accurately because very low quantities of radiogenic 40Ar were released, resulting in imprecise plateau ages of 50±70 and 35±22 ka.

  4. Investigating the active hydrothermal field of Kolumbo Volcano using CTD profiling

    NASA Astrophysics Data System (ADS)

    Eleni Christopoulou, Maria; Mertzimekis, Theo; Nomikou, Paraskevi; Papanikolaou, Dimitrios; Carey, Steve

    2014-05-01

    The submarine Kolumbo volcano NE of Santorini Island and the unique active hydrothermal vent field on its crater field (depth ~ 500 m) have been recently explored in multiple cruises aboard E/V Nautilus. ROV explorations showed the existence of extensive vent activity and almost completely absence of vent-specific macrofauna. Gas discharges have been found to be 99%-rich in CO2, which is sequestered at the bottom of the crater due to a special combination of physicochemical and geomorphological factors. The dynamic conditions existing along the water column in the crater have been studied in detail by means of temperature, salinity and conductivity depth profiles for the first time. CTD sensors aboard the ROV Hercules were employed to record anomalies in those parameters in an attempt to investigate several active and inactive vent locations. Temporal CTD monitoring inside and outside of the crater was carried out over a period of two years. Direct comparison between the vent field and locations outside the main cone, where no hydrothermal activity is known to exist, showed completely different characteristics. CTD profiles above the active vent field (NNE side) are correlated to Kolumbo's cone morphology. The profiles suggest the existence of four distinct zones of physicochemical properties in the water column. The layer directly above the chimneys exhibit gas discharges highly enriched in CO2. Continuous gas motoring is essential to identify the onset of geological hazards in the region.

  5. Nicaraguan Volcanoes

    Atmospheric Science Data Center

    2013-04-18

    article title:  Nicaraguan Volcanoes     View Larger Image Nicaraguan volcanoes, February 26, 2000 . The true-color image at left is a ... February 26, 2000 - Plumes from the San Cristobal and Masaya volcanoes. project:  MISR category:  gallery ...

  6. Cotopaxi volcano's unrest and eruptive activity in 2015: mild awakening after 73 years of quiescence

    NASA Astrophysics Data System (ADS)

    Hidalgo, Silvana; Bernard, Benjamin; Battaglia, Jean; Gaunt, Elizabeth; Barrington, Charlotte; Andrade, Daniel; Ramón, Patricio; Arellano, Santiago; Yepes, Hugo; Proaño, Antonio; Almeida, Stefanie; Sierra, Daniel; Dinger, Florian; Kelly, Peter; Parra, René; Bobrowski, Nicole; Galle, Bo; Almeida, Marco; Mothes, Patricia; Alvarado, Alexandra

    2016-04-01

    Cotopaxi volcano (5,897 m) is located 50 km south of Quito, the capital of Ecuador. The most dangerous hazards of this volcano are the devastating lahars that can be generated by the melting of its ice cap during pyroclastic flow-forming eruptions. The first seismic station was installed in 1976. Cotopaxi has been monitored by the Instituto Geofísico (Escuela Politécnica Nacional) since 1983. Presently the monitoring network is comprised of 11 broadband and 5 short period seismometers, 4 scanning DOAS, 1 infrared and 5 visible cameras, 7 DGPS, 5 tiltmeters, 11 AFM (lahar detectors) and a network of ashmeters. Due to the recent unrest, the monitoring of the volcano has been complemented by campaign airborne Multi-GAS and thermal IR measurements and ground-based mobile DOAS and stationary solar FTIR. After 73 years of quiescence, the first sign of unrest was a progressive increase in the amplitude of transient seismic events in April 2015. Since May 20, an increase in SO2 emissions from ˜500 t/d to ˜3 kt/day was detected followed by the appearance of seismic tremor on June 4. Both SO2 emissions of up to 5 kt/day and seismic tremor were observed until August 14 when a swarm of volcano-tectonic earthquakes preceded the first phreatic explosions. These explosions produced ash and gas columns reaching up to 9 km above the crater. The ash fall produced by the opening phase covered over 500 km2 with a submillimetric deposit corresponding to a mass of 1.65E+8 kg (VEI 1). During this period of explosions, SO2 emission rates up to 24 kt/day were observed, the highest thus far. The ash was dominantly hydrothermally altered and oxidized lithic fragments, hydrothermal minerals (alunite, gypsum), free crystals of plagioclase and pyroxenes, and little juvenile material. Unrest continued after August 14, with three episodes of ash emission. However, the intensity of ash fallout, average seismic amplitude, and SO2 emissions during each successive episode progressively decreased

  7. The activity of the Colima volcano and morphological changes in the summit between 2004 and 2007.

    NASA Astrophysics Data System (ADS)

    Suarez-Plascencia, C.; Nuñez-Cornu, F. J.; Sanchez-Aguilar, J.; Arriaga, F.

    2007-12-01

    Colima Volcano, located in the West of the Volcanic Mexican Belt, has shown a new cycle of explosive activity beginning May 30 1999, and reaching its maximum in March and April of 2005. This year the explosive activity increased gradually, having the largest event on May 23, when a new dome was created. Hours later this dome was destroyed by a strong explosion, forming an ash column 5.6 km high with subsequent pyroclastic flows that reached a distance of 4.2 km flowing along the ravines of the South sector. On May 30 the most intense explosion in 1999 occurred, when the plume reached heights in excess of 4.4 km above the crater, and piroclastic flows were created. On the same year in July two explosive events occurred of characteristics similar to those in May. These constant explosions caused continuos morphological changes in the summit, the most significant being the collapse of the North and South walls of the crater, in the first week of June of 2005, and the creation of a new crater in July. In 2006 the most significant explosive activity took place during April, May and July, when the eruptive columns reached heights of more than 1500 meters above the crater, occasionally forming small pyroclastic flows. In May of 2007 morphological changes were observed in the summit. Among them a crater explosion on the East side, a new dome was formed on the West side, with 20 m in high and 50 m in diameter. The explosive events continue to date, but they have diminished in size and intensity. This activity was similar to the one observed in 1902-1903 and reported by Severo Diaz (1906), but without reaching the maximum levels of activity reported for 1903, where it had levels of three to five maximum explosive events per day. The photographs and the digital mapping have provided detailed information to quantify the dynamic evolution of the volcanic structures that developed on the summit of the volcano in the course of the last for years.

  8. Geothermal energy resource investigations at Mt. Spurr, Alaska

    SciTech Connect

    Turner, D.L.; Wescott, E.M.

    1986-12-01

    Spurr volcano is a composite Quaternary cone of largely andesitic composition located on the west side of Cook Inlet about 80 miles west of Anchorage and about 40 miles from the Beluga electrical transmission line. Geologic mapping (Plate 1-1) shows that the present summit depression was produced by a Mt. St. Helens-type sector collapse, rather than by a caldera collapse. Geochronologic and previous tephrachronologic studies show that there has been an active magmatic system at Spurr volcano during the late Pleistocene-to-Holocene time interval that is of critical interest for geothermal energy resource assessment. Major effort was devoted to geochemical and geophysical surveys of the accessible area south of Mt. Spurr, in addition to geologic mapping and geochronologic studies. Many coincident mercury and helium anomalies were found, suggesting the presence of geothermal systems at depth. Extremely large electrical self-potential anomalies were also found, together with extensive zones of low resistivity discovered by our controlled-source audiomagnetotelluric survey. The juxtaposition of all of these different types of anomalies at certain areas on the south slope of Crater Peak indicates the presence of a geothermal system which should be accessible by drilling to about 2000 ft depth. It is also evident that there is a strong volcanic hazard to be evaluated in considering any development on the south side of Mt. Spurr. This hazardous situation may require angle drilling of production wells from safer areas and placement of power generation facilities at a considerable distance from hazardous areas.

  9. Imaging the magmatic system of Newberry Volcano using Joint active source and teleseismic tomography

    NASA Astrophysics Data System (ADS)

    Heath, Benjamin A.; Hooft, Emilie E. E.; Toomey, Douglas R.; Bezada, Maximiliano J.

    2015-12-01

    In this paper, we combine active and passive source P wave seismic data to tomographically image the magmatic system beneath Newberry Volcano, located east of the Cascade arc. By using both travel times from local active sources and delay times from teleseismic earthquakes recorded on closely spaced seismometers (300-800 m), we significantly improve recovery of upper crustal velocity structure (<10 km depth). The tomographic model reveals a low-velocity feature between 3 and 5 km depth that lies beneath the caldera, consistent with a magma body. In contrast to earlier tomographic studies, where elevated temperatures were sufficient to explain the recovered low velocities, the larger amplitude low-velocity anomalies in our joint tomography model require low degrees of partial melt (˜10%), and a minimum melt volume of ˜2.5 km3. Furthermore, synthetic tests suggest that even greater magnitude low-velocity anomalies, and by inference larger volumes of magma (up to 8 km3), are needed to explain the observed waveform variability. The lateral extent and shape of the inferred magma body indicates that the extensional tectonic regime at Newberry influences the emplacement of magmatic intrusions. Our study shows that jointly inverting active source and passive source seismic data improves tomographic imaging of the shallow crustal seismic structure of volcanic systems and that active source experiments would benefit from longer deployment times to also record teleseismic sources.

  10. Directed evolution of protease beacons that enable sensitive detection of endogenous MT1-MMP activity in tumor cell lines.

    PubMed

    Jabaiah, Abeer; Daugherty, Patrick S

    2011-03-25

    Directed evolution was applied to identify peptide substrates with enhanced hydrolysis rates by MT1-MMP suitable for protease beacon development. Screening of a random pentapeptide library, using two-color CLiPS, yielded several substrates identical to motifs in distinct collagens that shared the consensus sequence P-x-G↓L. To identify substrates with enhanced cleavage rates, a second-generation decapeptide library incorporating the consensus was screened under stringent conditions, which resulted in a MxPLG↓(M)/(L)M(G)/(A)R consensus motif. These substrates are hydrolyzed by human-MT1-MMP up to six times faster than reported peptide substrates and are stable in plasma. Finally, incubation of soluble protease beacons incorporating the optimized substrates, but not previous substrates, enabled direct detection of endogenous MT1-MMP activity of human-fibrosarcoma (HT-1080) cells. Extended substrate libraries coupled with CLiPS should be useful to generate more effective activity probes for a variety of proteolytic enzymes.

  11. AVHotRR version 2.0. Enhanced routine for near-real time monitoring of active volcanoes using IR satellite data.

    NASA Astrophysics Data System (ADS)

    Lombardo, Valerio

    2016-04-01

    The AVHotRR routine operates since 2006 to process satellite data for monitoring active volcanoes in the Mediterranean area. AVHotRR is a continually evolving program. It needs to adapt both to the availability of new incoming data and to the variability of volcanic phenomena. Though originally developed to work with Advanced Very High Resolution Radiometer (AVHRR) data, AVHotRR has been improved over the years to adapt to other sensors. Currently implemented version allows to integrate results from different dataset in order to better constrain the detection of volcanic hot-spots. In particular, the high temporal resolution of the SEVIRI instrument aboard MSG provides a key to reduce false positives in AVHRR and Moderate Resolution Imaging Spectroradiometer MODIS images. A new detection method based on the wavelet transform of SEVIRI data is proposed. Results from the application of AVHotRR to a dataset of AVHRR and SEVIRI images from Mt Etna, Italy, are presented and discussed to advantages and limitations of the algorithm.

  12. Volcano hazards at Newberry Volcano, Oregon

    USGS Publications Warehouse

    Sherrod, David R.; Mastin, Larry G.; Scott, William E.; Schilling, Steven P.

    1997-01-01

    Newberry volcano is a broad shield volcano located in central Oregon. It has been built by thousands of eruptions, beginning about 600,000 years ago. At least 25 vents on the flanks and summit have been active during several eruptive episodes of the past 10,000 years. The most recent eruption 1,300 years ago produced the Big Obsidian Flow. Thus, the volcano's long history and recent activity indicate that Newberry will erupt in the future. The most-visited part of the volcano is Newberry Crater, a volcanic depression or caldera at the summit of the volcano. Seven campgrounds, two resorts, six summer homes, and two major lakes (East and Paulina Lakes) are nestled in the caldera. The caldera has been the focus of Newberry's volcanic activity for at least the past 10,000 years. Other eruptions during this time have occurred along a rift zone on the volcano's northwest flank and, to a lesser extent, the south flank. Many striking volcanic features lie in Newberry National Volcanic Monument, which is managed by the U.S. Forest Service. The monument includes the caldera and extends along the northwest rift zone to the Deschutes River. About 30 percent of the area within the monument is covered by volcanic products erupted during the past 10,000 years from Newberry volcano. Newberry volcano is presently quiet. Local earthquake activity (seismicity) has been trifling throughout historic time. Subterranean heat is still present, as indicated by hot springs in the caldera and high temperatures encountered during exploratory drilling for geothermal energy. This report describes the kinds of hazardous geologic events that might occur in the future at Newberry volcano. A hazard-zonation map is included to show the areas that will most likely be affected by renewed eruptions. In terms of our own lifetimes, volcanic events at Newberry are not of day-to-day concern because they occur so infrequently; however, the consequences of some types of eruptions can be severe. When Newberry

  13. The anticancer drug Dp44mT inhibits T-cell activation and CD25 through a copper-dependent mechanism.

    PubMed

    Gundelach, Justin H; Madhavan, Ajay A; Wettstein, Peter J; Bram, Richard J

    2013-02-01

    The di-2-pyridylketone thiosemicarbazone Dp44mT is a metal-chelating compound that has been demonstrated to have potent activity as an anticancer agent. Here we report that it also has a dramatic inhibitory effect on T-cell activation in vitro. We found that 10 nM Dp44mT (IC(50) 3.2 nM) prevented the up-regulation of surface CD25, and completely suppressed the activation and proliferation of splenic T cells isolated from Mus musculus that were stimulated with either T-cell receptor (TCR) cross-linking antibodies or phorbol ester plus ionomycin. In contrast, Dp44mT had no adverse effects on the survival of resting T cells. In addition, T cells stimulated in the presence of Dp44mT maintained the ability to up-regulate CD69 surface expression and secrete interleukin-2. Consistent with these observations, Dp44mT did not inhibit multiple canonical signals downstream of the TCR, including the nuclear factor of activated T cells. The effects of Dp44mT were easily mitigated by addition of nontoxic copper chelators or N-acetylcysteine, indicating a role for copper and reactive oxygen species in its actions. Together, these findings suggest that Dp44mT may serve as a potent immunosuppressive agent that could complicate its use as a cancer therapeutic agent, but might have utility in the treatment of autoimmunity.

  14. The heartbeat of the volcano: The discovery of episodic activity at Prometheus on Io

    USGS Publications Warehouse

    Davies, A.G.; Wilson, L.; Matson, D.; Leone, G.; Keszthelyi, L.; Jaeger, W.

    2006-01-01

    The temporal signature of thermal emission from a volcano is a valuable clue to the processes taking place both at and beneath the surface. The Galileo Near Infrared Mapping Spectrometer (NIMS) observed the volcano Prometheus, on the jovian moon Io, on multiple occasions between 1996 and 2002. The 5 micron (??m) brightness of this volcano shows considerable variation from orbit to orbit. Prometheus exhibits increases in thermal emission that indicate episodic (though non-periodic) effusive activity in a manner akin to the current Pu'u 'O'o-Kupaianaha (afterwards referred to as the Pu'u 'O'o) eruption of Kilauea, Hawai'i. The volume of material erupted during one Prometheus eruption episode (defined as the interval from minimum thermal emission to peak and back to minimum) from 6 November 1996 to 7 May 1997 is estimated to be ???0.8 km3, with a peak instantaneous volumetric flux (effusion rate) of ???140 m3 s-1, and an averaged volumetric flux (eruption rate) of ???49 m3 s-1. These quantities are used to model subsurface structure, magma storage and magma supply mechanisms, and likely magma chamber depth. Prometheus appears to be supplied by magma from a relatively shallow magma chamber, with a roof at a minimum depth of ???2-3 km and a maximum depth of ???14 km. This is a much shallower depth range than sources of supply proposed for explosive, possibly ultramafic, eruptions at Pillan and Tvashtar. As Prometheus-type effusive activity is widespread on Io, shallow magma chambers containing magma of basaltic or near-basaltic composition and density may be common. This analysis strengthens the analogy between Prometheus and Pu'u 'O'o, at least in terms of eruption style. Even though the style of eruption appears to be similar (effusive emplacement of thin, insulated, compound pahoehoe flows) the scale of activity at Prometheus greatly exceeds current activity at Pu'u 'O'o in terms of volume erupted, area covered, and magma flux. Whereas the estimated magma chamber at

  15. Thermal surveillance of volcanoes of the Cascade Range utilizing ERTS DCP systems and imagery

    NASA Technical Reports Server (NTRS)

    Friedman, J. D. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Successful installation of DCP sets at Mt. Baker volcano and at Mt. St. Helens volcano, Washington, completed the installation phase of experiment SR 251. Aerial IR scanner missions over the Cascade volcanoes were completed with a mission April 29th which provided thermographic IR images of Glacier Peak, Mt. Baker, Mt. St. Helens, Mt. Rainier, and Mt. Adams. Earlier repetitive coverage had obtained IR images depicting thermal anomalies of Lassen Volcanic National Park, Shasta, Crater Lake, and the northern Cascades. The April 29th mission and subsequent ground reconnaissance yielded new information on 48 heretofore unreported pinpoint radiation anomalies, of possible fumarolic origin, on the flanks of Mt. Rainier and several new thermal points on Mt. Baker. Cartographic plots of these anomalies, in conjunction with surface temperature and other data obtained as a result of experiment SR 251 will permit estimation of radiation heat loss during the repose periods of the host volcanoes.

  16. Seismic body wave separation in volcano-tectonic activity inferred by the Convolutive Independent Component Analysis

    NASA Astrophysics Data System (ADS)

    Capuano, Paolo; De Lauro, Enza; De Martino, Salvatore; Falanga, Mariarosaria; Petrosino, Simona

    2015-04-01

    One of the main challenge in volcano-seismological literature is to locate and characterize the source of volcano/tectonic seismic activity. This passes through the identification at least of the onset of the main phases, i.e. the body waves. Many efforts have been made to solve the problem of a clear separation of P and S phases both from a theoretical point of view and developing numerical algorithms suitable for specific cases (see, e.g., Küperkoch et al., 2012). Recently, a robust automatic procedure has been implemented for extracting the prominent seismic waveforms from continuously recorded signals and thus allowing for picking the main phases. The intuitive notion of maximum non-gaussianity is achieved adopting techniques which involve higher-order statistics in frequency domain., i.e, the Convolutive Independent Component Analysis (CICA). This technique is successful in the case of the blind source separation of convolutive mixtures. In seismological framework, indeed, seismic signals are thought as the convolution of a source function with path, site and the instrument response. In addition, time-delayed versions of the same source exist, due to multipath propagation typically caused by reverberations from some obstacle. In this work, we focus on the Volcano Tectonic (VT) activity at Campi Flegrei Caldera (Italy) during the 2006 ground uplift (Ciaramella et al., 2011). The activity was characterized approximately by 300 low-magnitude VT earthquakes (Md < 2; for the definition of duration magnitude, see Petrosino et al. 2008). Most of them were concentrated in distinct seismic sequences with hypocenters mainly clustered beneath the Solfatara-Accademia area, at depths ranging between 1 and 4 km b.s.l.. The obtained results show the clear separation of P and S phases: the technique not only allows the identification of the S-P time delay giving the timing of both phases but also provides the independent waveforms of the P and S phases. This is an enormous

  17. Integrating science and education during an international, multi-parametric investigation of volcanic activity at Santiaguito volcano, Guatemala

    NASA Astrophysics Data System (ADS)

    Lavallée, Yan; Johnson, Jeffrey; Andrews, Benjamin; Wolf, Rudiger; Rose, William; Chigna, Gustavo; Pineda, Armand

    2016-04-01

    In January 2016, we held the first scientific/educational Workshops on Volcanoes (WoV). The workshop took place at Santiaguito volcano - the most active volcano in Guatemala. 69 international scientists of all ages participated in this intensive, multi-parametric investigation of the volcanic activity, which included the deployment of seismometers, tiltmeters, infrasound microphones and mini-DOAS as well as optical, thermographic, UV and FTIR cameras around the active vent. These instruments recorded volcanic activity in concert over a period of 3 to 9 days. Here we review the research activities and present some of the spectacular observations made through this interdisciplinary efforts. Observations range from high-resolution drone and IR footage of explosions, monitoring of rock falls and quantification of the erupted mass of different gases and ash, as well as morphological changes in the dome caused by recurring explosions (amongst many other volcanic processes). We will discuss the success of such integrative ventures in furthering science frontiers and developing the next generation of geoscientists.

  18. Groundwater radon measurements in the Mt. Etna area.

    PubMed

    D'Alessandro, Walter; Vita, Fabio

    2003-01-01

    Radon levels were measured in 119 groundwater samples collected throughout the active volcanic area of Mt. Etna by means of a portable Lucas-type scintillation chamber. The measured activity values range from 1.8 to 52.7 Bq l(-1). About 40% of the samples exceed the maximum contaminant level of 11 Bq l(-1) proposed by the USEPA in 1991. The highest radon levels are measured in the eastern sector of the volcano, which is the seismically most active zone of the volcano. On the contrary the south-western sector, which is both seismically active and a site of intense magmatic degassing, display lower radon levels. This is probably due to the formation of a free gas phase (oversaturation of CO(2)) that strips the radon from the water. Comparison of the data gathered at Mt. Etna with those of other areas indicates that (222)Rn activity in groundwater is positively correlated with both the content of parent elements in the aquifer rocks and the temperature of the geothermal systems that interacts with the sampled aquifers. PMID:12527235

  19. Groundwater radon measurements in the Mt. Etna area.

    PubMed

    D'Alessandro, Walter; Vita, Fabio

    2003-01-01

    Radon levels were measured in 119 groundwater samples collected throughout the active volcanic area of Mt. Etna by means of a portable Lucas-type scintillation chamber. The measured activity values range from 1.8 to 52.7 Bq l(-1). About 40% of the samples exceed the maximum contaminant level of 11 Bq l(-1) proposed by the USEPA in 1991. The highest radon levels are measured in the eastern sector of the volcano, which is the seismically most active zone of the volcano. On the contrary the south-western sector, which is both seismically active and a site of intense magmatic degassing, display lower radon levels. This is probably due to the formation of a free gas phase (oversaturation of CO(2)) that strips the radon from the water. Comparison of the data gathered at Mt. Etna with those of other areas indicates that (222)Rn activity in groundwater is positively correlated with both the content of parent elements in the aquifer rocks and the temperature of the geothermal systems that interacts with the sampled aquifers.

  20. Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system

    NASA Astrophysics Data System (ADS)

    Rizzo, Andrea; Caracausi, Antonio; Chavagnac, Valérie; Nomikou, Paraskevi; Polymenakou, Paraskevi; Mandalakis, Manolis; Kotoulas, Georgios; Magoulas, Antonios; Castillo, Alain

    2016-04-01

    Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important ource of mantle-derived gases. These gases are fundamental for the comprehension of mantle characteristics in key sectors where subaerial volcanism is missing or strongly modified by mixing with crustal and atmospheric components. Though, the study of submarine volcanic areas remains a challenge due to their hazardousness and sea depth. Here, we report 3He/4He measurements in CO2-dominated gases discharged at 500 m below the sea level from the high-temperature (~220°C) hydrothermal system of Kolumbo submarine volcano, located 7 km northeast off Santorini Island in the central part of Hellenic Volcanic Arc (HVA). For the first time, we demonstrate that the mantle below Kolumbo and Santorini has a 3He/4He signature of at least 7.1 Ra (being Ra the 3He/4He ratio of atmospheric He equal to 1.39×10-6), 3 Ra units higher than actually known for Santorini gases-rocks. This isotopic ratio is also the highest measured across HVA and is indicative of the direct degassing of a MORB-like mantle through lithospheric faults or a possible slab tear. We finally highlight that the 3He/4He ratio has been increasing since 2010 (ΔRa=0.3), which implies an enhanced magmatic activity beneath Kolumbo.

  1. Volcanic activity and satellite-detected thermal anomalies at Central American volcanoes

    NASA Technical Reports Server (NTRS)

    Stoiber, R. E. (Principal Investigator); Rose, W. I., Jr.

    1973-01-01

    The author has identified the following significant results. A large nuee ardente eruption occurred at Santiaguito volcano, within the test area on 16 September 1973. Through a system of local observers, the eruption has been described, reported to the international scientific community, extent of affected area mapped, and the new ash sampled. A more extensive report on this event will be prepared. The eruption is an excellent example of the kind of volcanic situation in which satellite thermal imagery might be useful. The Santiaguito dome is a complex mass with a whole series of historically active vents. It's location makes access difficult, yet its activity is of great concern to large agricultural populations who live downslope. Santiaguito has produced a number of large eruptions with little apparent warning. In the earlier ground survey large thermal anomalies were identified at Santiaguito. There is no way of knowing whether satellite monitoring could have detected changes in thermal anomaly patterns related to this recent event, but the position of thermal anomalies on Santiaguito and any changes in their character would be relevant information.

  2. Control of Muscle Mitochondria by Insulin Entails Activation of Akt2-mtNOS Pathway: Implications for the Metabolic Syndrome

    PubMed Central

    Finocchietto, Paola; Barreyro, Fernando; Holod, Silvia; Peralta, Jorge; Franco, María C.; Méndez, Carlos; Converso, Daniela P.; Estévez, Alvaro; Carreras, Maria C.; Poderoso, Juan J.

    2008-01-01

    Background In the metabolic syndrome with hyperinsulinemia, mitochondrial inhibition facilitates muscle fat and glycogen accumulation and accelerates its progression. In the last decade, nitric oxide (NO) emerged as a typical mitochondrial modulator by reversibly inhibiting citochrome oxidase and oxygen utilization. We wondered whether insulin-operated signaling pathways modulate mitochondrial respiration via NO, to alternatively release complete glucose oxidation to CO2 and H2O or to drive glucose storage to glycogen. Methodology/Principal Findings We illustrate here that NO produced by translocated nNOS (mtNOS) is the insulin-signaling molecule that controls mitochondrial oxygen utilization. We evoke a hyperinsulinemic-normoglycemic non-invasive clamp by subcutaneously injecting adult male rats with long-lasting human insulin glargine that remains stable in plasma by several hours. At a precise concentration, insulin increased phospho-Akt2 that translocates to mitochondria and determines in situ phosphorylation and substantial cooperative mtNOS activation (+4–8 fold, P<.05), high NO, and a lowering of mitochondrial oxygen uptake and resting metabolic rate (−25 to −60%, P<.05). Comparing in vivo insulin metabolic effects on gastrocnemius muscles by direct electroporation of siRNA nNOS or empty vector in the two legs of the same animal, confirmed that in the silenced muscles disrupted mtNOS allows higher oxygen uptake and complete (U-14C)-glucose utilization respect to normal mtNOS in the vector-treated ones (respectively 37±3 vs 10±1 µmolO2/h.g tissue and 13±1 vs 7.2±1 µmol 3H2O/h.g tissue, P<.05), which reciprocally restricted glycogen-synthesis by a half. Conclusions/Significance These evidences show that after energy replenishment, insulin depresses mitochondrial respiration in skeletal muscle via NO which permits substrates to be deposited as macromolecules; at discrete hyperinsulinemia, persistent mtNOS activation could contribute to mitochondrial

  3. Active high-resolution seismic tomography of compressional wave velocity and attenuation structure at Medicine Lake Volcano, Northern California Cascade Range

    NASA Astrophysics Data System (ADS)

    Evans, John R.; Zucca, John J.

    1988-12-01

    We determine compressional wave velocity and attenuation structures for the upper crust beneath Medicine Lake volcano in northeast California using a high-resolution active source seismic tomography method. Medicine Lake volcano is a basalt through rhyolite shield volcano of the Cascade Range, lying east of the range axis. The Pg wave from eight explosive sources which has traveled upward through the target volume to a dense array of 140 seismographs provides 1- to 2-km resolution in the upper 5 to 7 km of the crust beneath the volcano. The experiment tests the hypothesis that Cascade Range volcanoes of this type are underlain only by small silicic magma chambers. We image a low-velocity low-Q region not larger than a few tens of cubic kilometers in volume beneath the summit caldera, supporting the hypothesis. A shallower high-velocity high-density feature, previously known to be present, is imaged for the first time in full plan view; it is east-west elongate, paralleling a topographic lineament between Medicine Lake volcano and Mount Shasta. This lineament is interpreted to be the result of an old crustal weakness now affecting the emplacement of magma, both on direct ascent from the lower crust and mantle and in migration from the shallow silicic chamber to summit vents. Differences between this high-velocity feature and the equivalent feature at Newbeny volcano, a volcano in central Oregon resembling Medicine Lake volcano, may partly explain the scarcity of surface hydrothermal features at Medicine Lake volcano. A major low-velocity low-Q feature beneath the southeast flank of the volcano, in an area with no Holocene vents, is interpreted as tephra, flows, and sediments from the volcano deeply ponded on the downthrown side of the Gillem fault, a normal fault mapped at the surface north of the volcano. A high-Q normal-velocity feature beneath the north rim of the summit caldera may be a small, possibly hot, subsolidus intrusion. A high-velocity low-Q region

  4. The magmatic- and hydrothermal-dominated fumarolic system at the Active Crater of Lascar volcano, northern Chile

    NASA Astrophysics Data System (ADS)

    Tassi, F.; Aguilera, F.; Vaselli, O.; Medina, E.; Tedesco, D.; Delgado Huertas, A.; Poreda, R.; Kojima, S.

    2009-03-01

    Low-to-high temperature fumaroles discharging from the Active Crater of Lascar volcano (northern Chile) have been collected in November 2002, May 2005 and October 2006 for chemical and isotopic analysis to provide the first geochemical survey on the magmatic-hydrothermal system of this active volcano. Chemical and isotopic gas composition shows direct addition of high-temperature fluids from magmatic degassing, mainly testified by the very high contents of SO2, HCl and HF (up to 87,800, 29,500 and 2,900 μmol/mol) and the high R/Ra values (up to 7.29). Contributions from a hydrothermal source, mainly in gas discharges of the Active Crater rim, has also been detected. Significant variations in fluid chemistry, mainly consisting of a general decrease of magmatic-related compounds, i.e. SO2, have affected the fumarolic system during the period of observation, indicating an increase of the influence of the hydrothermal system surrounding the ascending deep fluids. The chemical composition of Active Crater fumaroles has been used to build up a geochemical model describing the main processes that regulate the fluid circulation system of Lascar volcano to be utilized in volcanic surveillance.

  5. Electric and magnetic phenomena observed before the volcano-seismic activity in 2000 in the Izu Island Region, Japan

    PubMed Central

    Uyeda, S.; Hayakawa, M.; Nagao, T.; Molchanov, O.; Hattori, K.; Orihara, Y.; Gotoh, K.; Akinaga, Y.; Tanaka, H.

    2002-01-01

    Significant anomalous changes in the ultra low frequency range (≈0.01 Hz) were observed in both geoelectric and geomagnetic fields before the major volcano-seismic activity in the Izu Island region, Japan. The spectral intensity of the geoelectric potential difference between some electrodes on Niijima Island and the third principal component of geomagnetic field variations at an array network in Izu Peninsula started to increase from a few months before the onset of the volcano-seismic activity, culminating immediately before nearby magnitude 6 class earthquakes. Appearance of similar changes in two different measurements conducted at two far apart sites seems to provide information supporting the reality of preseismic electromagnetic signals. PMID:12032286

  6. Identifying different regimes in eruptive activity: An application to Etna volcano

    NASA Astrophysics Data System (ADS)

    Mulargia, F.; Gasperini, P.; Tinti, S.

    1987-12-01

    The objective identification of different regimes in the eruptive time-history of a volcano is crucial to the understanding of its physics. While a problem well-known in statistical literature under the name of change-point or scan-point problem, no method of general applicability exists for the identification of different regimes in a time-series. In particular, the available techniques seem unsuitable to the volcanological case. We developed an original procedure based on two-sample Kolmogorov-Smirnov statistics which offers satisfactory accuracy in a broad range of conditions with a minimum of assumptions and is expressly tailored to the study of geophysical phenomena. Our procedure requires neither the a priori knowledge of the number of regimes nor of the statistical distributions governing the whole process, which can be of different type. The parent distribution of each regime is inferred through a goodness-of-fit test, and this in turn allows the confidence intervals for each of the change-points identified to be estimated by numerical simulation. This procedure is applied to the eruptive history of Mount Etna volcano. Available data allow the analysis of flank eruptions in the period 1600-1980, while the total output (summit and flank activity) can be studied only in the period 1971-1981. Information on eruptive history can be therefore obtained at two different timescales. Since no univocally accepted catalog exists except for the last few decades, we use two different sets of data, which practically exhaust all the available information. The results are interpreted by a stability analysis, and only stable results are retained. Our analysis yields that: - The inter-event times of flank eruptions in the period 1600-1980 follow two regimes before and after year 1865, while the eruptive activity in the period 1971-1981 follows four different regimes. In each regime eruptions occur according to a Poisson process and Etna behaves as a random nonstationary

  7. Nyiragonga Volcano

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image of the Nyiragonga volcano eruption in the Congo was acquired on January 28, 2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters about 50 to 300 feet ), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

    Image: A river of molten rock poured from the Nyiragongo volcano in the Congo on January 18, 2002, a day after it erupted, killing dozens, swallowing buildings and forcing hundreds of thousands to flee the town of Goma. The flow continued into Lake Kivu. The lave flows are depicted in red on the image indicating they are still hot. Two of them flowed south form the volcano's summit and went through the town of Goma. Another flow can be seen at the top of the image, flowing towards the northwest. One of Africa's most notable volcanoes, Nyiragongo contained an active lava lake in its deep summit crater that drained catastrophically through its outer flanks in 1977. Extremely fluid, fast-moving lava flows draining from the summit lava lake in 1977 killed 50 to 100 people, and several villages were destroyed. The image covers an area of 21 x 24 km and combines a thermal band in red, and two infrared bands in green and blue.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the

  8. Numerical Tsunami Hazard Assessment of the Only Active Lesser Antilles Arc Submarine Volcano: Kick 'em Jenny.

    NASA Astrophysics Data System (ADS)

    Dondin, F. J. Y.; Dorville, J. F. M.; Robertson, R. E. A.

    2015-12-01

    The Lesser Antilles Volcanic Arc has potentially been hit by prehistorical regional tsunamis generated by voluminous volcanic landslides (volume > 1 km3) among the 53 events recognized so far. No field evidence of these tsunamis are found in the vincity of the sources. Such a scenario taking place nowadays would trigger hazardous tsunami waves bearing potentially catastrophic consequences for the closest islands and regional offshore oil platforms.Here we applied a complete hazard assessment method on the only active submarine volcano of the arc Kick 'em Jenny (KeJ). KeJ is the southernmost edifice with recognized associated volcanic landslide deposits. From the three identified landslide episodes one is associated with a collapse volume ca. 4.4 km3. Numerical simulations considering a single pulse collapse revealed that this episode would have produced a regional tsunami. An edifice current volume estimate is ca. 1.5 km3.Previous study exists in relationship to assessment of regional tsunami hazard related to shoreline surface elevation (run-up) in the case of a potential flank collapse scenario at KeJ. However this assessment was based on inferred volume of collapse material. We aim to firstly quantify potential initial volumes of collapse material using relative slope instability analysis (RSIA); secondly to assess first order run-ups and maximum inland inundation distance for Barbados and Trinidad and Tobago, i.e. two important economic centers of the Lesser Antilles. In this framework we present for seven geomechanical models tested in the RSIA step maps of critical failure surface associated with factor of stability (Fs) for twelve sectors of 30° each; then we introduce maps of expected potential run-ups (run-up × the probability of failure at a sector) at the shoreline.The RSIA evaluates critical potential failure surface associated with Fs <1 as compared to areas of deficit/surplus of mass/volume identified on the volcanic edifice using (VolcanoFit 2

  9. Spectral Analysis of the Signals Associated with Increased Activity in Popocatepetl Volcano April 2012

    NASA Astrophysics Data System (ADS)

    Cuenca, J.

    2013-05-01

    After several decades of being inactive in 1994 had a strong reactivation. Since then he has had long periods where volcanic activity including increased growth and destruction of a dome. In April 2012 Popocatepetl Volcano activity showed an increase in the emission of gas and ash, and Vulcanian type explosions. As a result the National Center for Disaster Prevention (CENAPRED) raised the yellow phase from 2 to 3. Spectrally analyzes seismic activity characteristic of the types of events (explosions, LP, Type-B and tremors) that provides information of the source processes that cause it, despite sustained change reflected by the complexity of the volcanic apparatus, through of: 1) the spectral content of the process provides the source, 2) the spectral ratio H / V, its associated amplification and dominant frequencies, 3) time frequency analysis showing the variation in frequency, 4) the particle motion to analyze its retrograde or prograde acting in a volcanic complex medium. The calculation of H / V was performed by each hour using windows with duration of 80 seconds in the broadband seismic station "Canario" (PPPB). The predominant frequencies of H / V are around 1.4-1.8 Hz to 2.1-2.6 Hz and amplifications from 2.3 to 6.9 times. Analysis of H / V of 48 hours (days 16 and April 17) for the case of 1.4-1.8 Hz was observed: (1) From 0-9 hours there is no amplification. (2) The seismic amplification increases from 10 to 11 hours. (3) A first crisis reaches a maximum at 13 hours with about 6 times of amplification. (4) From 14 to 15 hours there is a strong relaxation of the activity. (5) The activity begins to increase from 16 to 23 hours where it reaches its maximum amplification of almost 7 times. (6) The following two hours and is kept exceeding 6 times of amplification. (7) Then is followed by a decrease to 4 hours on the day 17, from which is maintained at a level variable. (8) At 18 hours of the day 17 grows the amplification at 6.2 times, which conforms a

  10. Near-bottom water column anomalies associated with active hydrothermal venting at Aeolian arc volcanoes, Tyrrhenian Sea, Italy

    NASA Astrophysics Data System (ADS)

    Walker, S. L.; Carey, S.; Bell, K. L.; Baker, E. T.; Faure, K.; Rosi, M.; Marani, M.; Nomikou, P.

    2012-12-01

    Hydrothermal deposits such as metalliferous sediments, Fe-Mn crusts, and massive sulfides are common on the submarine volcanoes of the Aeolian arc (Tyrrhenian Sea, Italy), but the extent and style of active hydrothermal venting is less well known. A systematic water column survey in 2007 found helium isotope ratios indicative of active venting at 6 of the 9 submarine volcanoes surveyed plus the Marsili back-arc spreading center (Lupton et al., 2011). Other plume indicators, such as turbidity and temperature anomalies were weak or not detected. In September 2011, we conducted five ROV Hercules dives at Eolo, Enarete, and Palinuro volcanoes during an E/V Nautilus expedition. Additionally, two dives explored the Casoni seamount on the southern flank of Stromboli where a dredge returned apparently warm lava in 2002 (Gamberi, 2006). Four PMEL MAPRs, with temperature, optical backscatter (particles), and oxidation-reduction potential (ORP) sensors, were arrayed along the lowermost 50 m of the Hercules/Argus cable during the dives to assess the relationship between seafloor observations and water column anomalies. Active venting was observed at each of the volcanoes visited. Particle anomalies were weak or absent, consistent with the 2007 CTD surveys, but ORP anomalies were common. Venting at Eolo volcano was characterized by small, localized patches of yellow-orange bacteria; living tubeworms were observed at one location. ORP anomalies (-1 to -22 mv) were measured at several locations, primarily along the walls of the crescent-shaped collapse area (or possible caldera) east of the Eolo summit. At Enarete volcano, we found venting fluids with temperatures up to 5°C above ambient as well as small, fragile iron-oxide chimneys. The most intense ORP anomaly (-140 mv) occurred at a depth of about 495 m on the southeast side of the volcano, with smaller anomalies (-10 to -20 mv) more common as the ROV moved upslope to the summit. At Palinuro volcano, multiple dives located

  11. Changes of biogeochemical activities before and after significant mud displacement at the Håkon Mosby Mud Volcano (HMMV)

    NASA Astrophysics Data System (ADS)

    Felden, J.; Wenzhöfer, F.; Yoerger, D.; Camilli, R.; German, C.; Olu, K.; Feseker, T.; de Beer, D.; Boetius, A.

    2012-04-01

    The Håkon Mosby Mud Volcano (72°N, 14° 43' E, 1250 m water depth) was studied for a period of a year by the Long-term Observatory On Mud-volcano Eruptions (LOOME) in 2009-2010, to investigate temporal variations of mud volcanism and consequences for biogeochemical processes. The HMMV is a highly active methane cold seep ecosystem characterized by high rates of methane efflux. It hosts different chemosynthetic communities such as thiotrophic bacterial mats and siboglinid tubeworm assemblages. This study focuses on changes in community composition and biogeochemical activity such as methane emission, total benthic oxygen uptake, microbial methane and sulfate consumption before and after a major mud displacement recorded by LOOME. The sensor-enabled long-term observations of the HMMV habitats were combined with short-term analyses before and after the displacement events by ROVs QUEST (MARUM) and GENESIS (University of Gent), the AUV Sentry (WHOI) equipped with a multibeam and subbottom profiler, CTD and photographic unit as well as with a mass spectrometer. We found shifts in the distribution patterns of chemosynthetic communities and also substantial changes in their activity, consistent with changes in temperature gradients. This study was sponsored by the EU-Projects HERMIONE "Hotspot Ecosystem Research and Man's Impact on European Seas", and ESONET "European Seas Observatory Network" (Demonstration Mission LOOME "Long term observations on mud volcano eruptions").

  12. Monitoring crater-wall collapse at active volcanoes: a study of the 12 January 2013 event at Stromboli

    NASA Astrophysics Data System (ADS)

    Calvari, Sonia; Intrieri, Emanuele; Di Traglia, Federico; Bonaccorso, Alessandro; Casagli, Nicola; Cristaldi, Antonio

    2016-05-01

    Crater-wall collapses are fairly frequent at active volcanoes and they are normally studied through the analysis of their deposits. In this paper, we present an analysis of the 12 January 2013 crater-wall collapse occurring at Stromboli volcano, investigated by means of a monitoring network comprising visible and infrared webcams and a Ground-Based Interferometric Synthetic Aperture Radar. The network revealed the triggering mechanisms of the collapse, which are comparable to the events that heralded the previous effusive eruptions in 1985, 2002, 2007 and 2014. The collapse occurred during a period of inflation of the summit cone and was preceded by increasing explosive activity and the enlargement of the crater. Weakness of the crater wall, increasing magmastatic pressure within the upper conduit induced by ascending magma and mechanical erosion caused by vent opening at the base of the crater wall and by lava fingering, are considered responsible for triggering the collapse on 12 January 2013 at Stromboli. We suggest that the combination of these factors might be a general mechanism to generate crater-wall collapse at active volcanoes.

  13. Coupling of Activity at Neighbouring Volcanoes in Iceland: Ground Deformation and Activity at the Bárðarbunga-Tungnafellsjökull and Eyjafjallajökull-Katla Volcano Pairs

    NASA Astrophysics Data System (ADS)

    Parks, M.; Heimisson, E. R.; Sigmundsson, F.; Hooper, A. J.; Ofeigsson, B.; Vogfjord, K. S.; Arnadottir, T.; Dumont, S.; Drouin, V.; Bagnardi, M.; Spaans, K.; Hreinsdottir, S.; Friðriksdóttir, H. M.; Jonsdottir, K.; Guðmundsson, G.; Hensch, M.; Hjaltadottir, S.; Hjartardottir, A. R.; Einarsson, P.; Gudmundsson, M. T.; Hognadottir, T.; Lafemina, P.; Geirsson, H.; Sturkell, E.; Magnússon, E.

    2015-12-01

    Interferometric Synthetic Aperture Radar (InSAR) techniques are used to generate a time series of high-resolution deformation measurements, in the vicinity of two pairs of closely spaced volcanoes in Iceland: Bárðarbunga and Tungnafellsjökull, as well as Eyjafjallajökull and Katla. Following the declaration of Icelandic Volcanoes as a Permanent Geohazard Supersite in 2013, a considerable amount of SAR data was made available for both past and future satellite acquisitions, including new X-band images and historic C-band images. InSAR time series have been formed using these data and compared to other geodetic and microseismic measurements to determine the most likely processes responsible for recently observed deformation and/or seismicity. A comprehensive network of seismometers and continuous GPS stations are already deployed at these volcanoes and a series of campaign GPS measurements have been undertaken since 2010. We present an overview of the temporal variation in InSAR observations and these complementary field based measurements at Bárðarbunga and Tungnafellsjökull from 2014-2015 (covering the recent eruption at Holuhraun and contemporaneous slow collapse of the Bárðarbunga caldera), and Eyjafjallajökull and Katla volcanoes from 2010 onwards, after the 2010 explosive eruption of Eyjafjallajökull. We undertake a joint InSAR-GPS inversion using a Markov-chain Monte Carlo approach. The best-fit source geometries responsible for both the inflation of a 50 km long dyke and simultaneous deflation of the Bárðarbunga central volcano during the 2014-2015 unrest and eruption are found. Using these we calculate the stress changes associated with the Bárðarbunga deformation events and compare our results to the location of earthquake swarms in the vicinity of neighbouring Tungnafellsjökull, where seismic activity increased significantly following the onset of unrest at Bárðarbunga in August 2014. We also determine the optimal source parameters for

  14. Volcanic history of El Chichón Volcano (Chiapas, Mexico) during the Holocene, and its impact on human activity

    NASA Astrophysics Data System (ADS)

    Espíndola, J. M.; Macías, J. L.; Tilling, R. I.; Sheridan, M. F.

    Before its devastating eruption in 1982, El Chichón Volcano was little known and did not appear on any listings of hazardous volcanoes. Subsequent geologic studies, based on stratigraphic and radiocarbon investigations, showed that at least three explosive eruptions had occurred previously at this volcano. In this paper, we present the result of recent studies on the stratigraphy of the volcano and new radiocarbon ages which show that at least 11 eruptions have taken place at El Chichón in the past 8000years. Explosive events, most of them producing block-and-ash flow and surge deposits, occurred around 550, 900, 1250, 1500, 1600, 1900, 2000, 2500, 3100, 3700 and 7700years BP. The juvenile products of these eruptions have a trachyandesitic composition with similar degree of evolution, as evidenced from their SiO2 abundance and depletion in MgO, CaO, TiO2, as well as trace and rare earth elements. This suggests segregation of olivine and orthopyroxene from the melt. Since human settlements in southeast Mexico and Central America can be traced as far back as approximately 2500years BP, most of these events probably affected human activity. In fact, there are reports of pottery shards and other artifacts in deposits from the eruption of 1250 BP. Pottery fragments in deposits of an eruption that took place 2500 BP are also reported in this paper. Thus, the impact of the volcano on human activities has been frequent, with most of the repose intervals lasting between 100 to 600years. The impact of the eruptions was probably of greater than local extent, because airfall tephra could reach distant sites and possibly even affect weather. The eruptive history of El Chichón also offers clues in the investigation of the Maya civilization. Several researchers have considered the volcano as an important factor in the answer to some intriguing questions such as the extensive use of volcanic ash in Late Classic Maya ceramics or, of greater importance, the causes of the collapse

  15. Volcanic history of El Chichon Volcano (Chiapas, Mexico) during the Holocene, and its impact on human activity

    USGS Publications Warehouse

    Espindola, J.M.; Macias, J.L.; Tilling, R.I.; Sheridan, M.F.

    2000-01-01

    Before its devastating eruption in 1982, El Chichon Volcano was little known and did not appear on any listings of hazardous volcanoes. Subsequent geologic studies, based on stratigraphic and radiocarbon investigations, showed that at least three explosive eruptions had occurred previously at this volcano. In this paper, we present the result of recent studies on the stratigraphy of the volcano and new radiocarbon ages which show that at least 11 eruptions have taken place at El Chichon in the past 8000 years. Explosive events, most of them producing block-and-ash flow and surge deposits, occurred around 550, 900, 1250, 1500, 1600, 1900, 2000, 2500, 3100, 3700 and 7700 years BP. The juvenile products of these eruptions have a trachyandesitic composition with similar degree of evolution, as evidenced from their SiO2 abundance and depletion in MgO, CaO, TiO2, as well as trace and rare earth elements. This suggests segregation of olivine and orthopyroxene from the melt. Since human settlements in southeast Mexico and Central America can be traced as far back as approximately 2500 years BP, most of these events probably affected human activity. In fact, there are reports of pottery shards and other artifacts in deposits from the eruption of 1250 BP. Pottery fragments in deposits of an eruption that took place 2500 BP are also reported in this paper. Thus, the impact of the volcano on human activities has been frequent, with most of the repose intervals lasting between 100 to 600 years. The impact of the eruptions was probably of greater than local extent, because airfall tephra could reach distant sites and possibly even affect weather. The eruptive history of El Chichon also offers clues in the investigation of the Maya civilization. Several researchers have considered the volcano as an important factor in the answer to some intriguing questions such as the extensive use of volcanic ash in Late Classic Maya ceramics or, of greater importance, the causes of the

  16. Active faults on the eastern flank of Etna volcano (Italy) monitored through soil radon measurements

    NASA Astrophysics Data System (ADS)

    Neri, M.; Giammanco, S.; Ferrera, E.; Patanè, G.; Zanon, V.

    2012-04-01

    This study concerns measurements of radon and thoron emissions from soil carried out in 2004 on the unstable eastern flank of Mt. Etna, in a zone characterized by the presence of numerous seismogenic and aseismic faults. The statistical treatment of the geochemical data allowed recognizing anomaly thresholds for both parameters and producing distribution maps that highlighted a significant spatial correlation between soil gas anomalies and tectonic lineaments. In particular, the highest anomalies were found at the intersection between WNW-ESE and NW-SE -running faults. The seismic activity occurring in and around the study area during 2004 was analyzed, producing maps of hypocentral depth and released seismic energy. These maps revealed a progressive deepening of hypocenters from NW to SE, with the exception of a narrow zone in the central part of the area, with a roughly WNW-ESE direction. Also, the highest values of seismic energy were released during events in the southern and northwestern sectors of the area. Both radon and thoron anomalies were located in areas affected by relatively deep (5-10 km depth) seismic activity, while less evident correlation was found between soil gas anomalies and the released seismic energy. This study confirms that mapping the distribution of radon and thoron in soil gas can reveal hidden faults buried by recent soil cover or faults that are not clearly visible at the surface. The correlation between soil gas data and earthquake depth and intensity can give some hints on the source of gas and/or on fault dynamics. Lastly, an important spin-off of this study is the recognition of some areas where radon activity was so high (>50000 Bq/m3) that it may represent a potential hazard to the local population. In fact, radon is the leading cause of lung cancer after cigarette smoke for long exposures and, due to its molecular weight, it accumulates in underground rooms or in low ground, particularly where air circulation is low or absent

  17. Volcanic Environments Monitoring by Drones Mud Volcano Case Study

    NASA Astrophysics Data System (ADS)

    Amici, S.; Turci, M.; Giulietti, F.; Giammanco, S.; Buongiorno, M. F.; La Spina, A.; Spampinato, L.

    2013-08-01

    Volcanic activity has often affected human life both at large and at small scale. For example, the 2010 Eyjafjallajokull eruption caused severe economic damage at continental scale due to its strong effect on air traffic. At a local scale, ash fall and lava flow emission can cause harm and disruption. Understanding precursory signals to volcanic eruptions is still an open and tricky challenge: seismic tremor and gas emissions, for example, are related to upcoming eruptive activity but the mechanisms are not yet completely understood. Furthermore, information related to gases emission mostly comes from the summit crater area of a volcano, which is usually hard to investigate with required accuracy. Although many regulation problems are still on the discussion table, an increasing interest in the application of cutting-edge technology like unmanned flying systems is growing up. In this sense, INGV (Istituto Nazionale di Geofisica e Vulcanologia) started to investigate the possibility to use unmanned air vehicles for volcanic environment application already in 2004. A flight both in visual- and radio-controlled mode was carried out on Stromboli volcano as feasibility test. In this work we present the preliminary results of a test performed by INGV in collaboration with the University of Bologna (aerospace division) by using a multi-rotor aircraft in a hexacopter configuration. Thermal camera observations and flying tests have been realised over a mud volcano located on its SW flank of Mt. Etna and whose activity proved to be related to early stages of magma accumulation within the volcano.

  18. [Membrane type 1 matrix metalloproteinase (MT1-MMP) and the regulators of its activity as invasive factors in squamous cell cervical carcinomas].

    PubMed

    Timoshenko, O S; Gureeva, T A; Kugaevskaia, E V; Solov'eva, N I

    2014-01-01

    Membrane type 1 matrix metalloproteinase (MT1MMP) is one of matrix metalloproteinases (MMP), which play а key role in tumor invasion and metastasis. The aim of this study was to elucidate the peculiarities of expression of MT1MMP and endogenous regulators of its activity: the activator - furin and the inhibitor - TIMP-2, as invasive factors of squamous cell cervical carcinomas (SCC). The study was carried out using 11 specimens of SCC and 11 specimens of morphologically normal tissue adjacent to the tumor. It was shown that the increase of MT1-MMP and furin expression and low of TIMP-2 expression makes the main contribution to the destructive (invasive) potential of SCC. Moreover, substantial expression of MT1-MMP was registered in the specimens of morphologically normal adjoining to tumor tissue. This expression was found to make an additional contribution to the destructive potential of the cervical tumor.

  19. Active sulfur cycling by diverse mesophilic and thermophilic microorganisms in terrestrial mud volcanoes of Azerbaijan.

    PubMed

    Green-Saxena, A; Feyzullayev, A; Hubert, C R J; Kallmeyer, J; Krueger, M; Sauer, P; Schulz, H-M; Orphan, V J

    2012-12-01

    Terrestrial mud volcanoes (TMVs) represent geochemically diverse habitats with varying sulfur sources and yet sulfur cycling in these environments remains largely unexplored. Here we characterized the sulfur-metabolizing microorganisms and activity in four TMVs in Azerbaijan. A combination of geochemical analyses, biological rate measurements and molecular diversity surveys (targeting metabolic genes aprA and dsrA and SSU ribosomal RNA) supported the presence of active sulfur-oxidizing and sulfate-reducing guilds in all four TMVs across a range of physiochemical conditions, with diversity of these guilds being unique to each TMV. The TMVs varied in potential sulfate reduction rates (SRR) by up to four orders of magnitude with highest SRR observed in sediments where in situ sulfate concentrations were highest. Maximum temperatures at which SRR were measured was 60°C in two TMVs. Corresponding with these trends in SRR, members of the potentially thermophilic, spore-forming, Desulfotomaculum were detected in these TMVs by targeted 16S rRNA analysis. Additional sulfate-reducing bacterial lineages included members of the Desulfobacteraceae and Desulfobulbaceae detected by aprA and dsrA analyses and likely contributing to the mesophilic SRR measured. Phylotypes affiliated with sulfide-oxidizing Gamma- and Betaproteobacteria were abundant in aprA libraries from low sulfate TMVs, while the highest sulfate TMV harboured 16S rRNA phylotypes associated with sulfur-oxidizing Epsilonproteobacteria. Altogether, the biogeochemical and microbiological data indicate these unique terrestrial habitats support diverse active sulfur-cycling microorganisms reflecting the in situ geochemical environment.

  20. Active sulfur cycling by diverse mesophilic and thermophilic microorganisms in terrestrial mud volcanoes of Azerbaijan.

    PubMed

    Green-Saxena, A; Feyzullayev, A; Hubert, C R J; Kallmeyer, J; Krueger, M; Sauer, P; Schulz, H-M; Orphan, V J

    2012-12-01

    Terrestrial mud volcanoes (TMVs) represent geochemically diverse habitats with varying sulfur sources and yet sulfur cycling in these environments remains largely unexplored. Here we characterized the sulfur-metabolizing microorganisms and activity in four TMVs in Azerbaijan. A combination of geochemical analyses, biological rate measurements and molecular diversity surveys (targeting metabolic genes aprA and dsrA and SSU ribosomal RNA) supported the presence of active sulfur-oxidizing and sulfate-reducing guilds in all four TMVs across a range of physiochemical conditions, with diversity of these guilds being unique to each TMV. The TMVs varied in potential sulfate reduction rates (SRR) by up to four orders of magnitude with highest SRR observed in sediments where in situ sulfate concentrations were highest. Maximum temperatures at which SRR were measured was 60°C in two TMVs. Corresponding with these trends in SRR, members of the potentially thermophilic, spore-forming, Desulfotomaculum were detected in these TMVs by targeted 16S rRNA analysis. Additional sulfate-reducing bacterial lineages included members of the Desulfobacteraceae and Desulfobulbaceae detected by aprA and dsrA analyses and likely contributing to the mesophilic SRR measured. Phylotypes affiliated with sulfide-oxidizing Gamma- and Betaproteobacteria were abundant in aprA libraries from low sulfate TMVs, while the highest sulfate TMV harboured 16S rRNA phylotypes associated with sulfur-oxidizing Epsilonproteobacteria. Altogether, the biogeochemical and microbiological data indicate these unique terrestrial habitats support diverse active sulfur-cycling microorganisms reflecting the in situ geochemical environment. PMID:23116231

  1. A real-time framework for classifying, indexing and querying image database volcano activity

    NASA Astrophysics Data System (ADS)

    Aliotta, M. A.; Cannata, A.; Cassisi, C.; Montalto, P.; Prestifilippo, M.

    2013-12-01

    INGV-OE monitors explosive activity at Stromboli Volcano in order to analyze its eruptive dynamics. Since strombolian activity can be monitored using thermal camera frames, an efficient system able to require information from a huge amount of frames is needed. Aim of this work is the development of a novel system capable of fast data retrieval, based on similarity concepts. In the light of it, an indexing algorithm was developed. The concept is finding elements of a set that are close respect to a query element, according to a similarity criterion. To accomplish this task each video frame is processed using morphological image processing techniques to extract the image area of the explosion. Each closed curve, representing the explosion contour, is processed in order to extract useful features that constitute the metric space in which similarity between objects can be evaluated calculating the distances using an appropriate distance function. This approach suffers from an intrinsic problem related to the number of distances to be computed on a huge amount of data. To overcome this drawback, an indexing algorithm was applied. The idea behind this concept is a tree data structure that minimizes the number of distances to be computed among objects. Proposed method allows us to perform a fast query execution. The proposed system is able to find similar objects using distance among their features. Thus, we can group together explosions related to different kinds of activities using reference items. For instance, if we have a known image sequence, showing a given explosion, we can easily and quickly find all sequences containing explosions similar to it. The developed framework is able to both classifying each new explosion and dynamically insert the corresponding object into the tree structure. Therefore, by our approach, we can cluster the entire data space grouping objects having similar characteristics and classify them.

  2. A large hydrothermal reservoir beneath Taal Volcano (Philippines) revealed by magnetotelluric observations and its implications to the volcanic activity.

    PubMed

    Alanis, Paul K B; Yamaya, Yusuke; Takeuchi, Akihiro; Sasai, Yoichi; Okada, Yoshihiro; Nagao, Toshiyasu

    2013-01-01

    Taal Volcano is one of the most active volcanoes in the Philippines. The magnetotelluric 3D forward analyses indicate the existence of a large high resistivity anomaly (∼100 Ω·m) with a volume of at least 3 km×3 km×3 km, which is capped by a conductive layer (∼10 Ω·m), beneath the Main Crater. This high resistivity anomaly is hypothesized to be a large hydrothermal reservoir, consisting of the aggregate of interconnected cracks in rigid and dense host rocks, which are filled with hydrothermal fluids coming from a magma batch below the reservoir. The hydrothermal fluids are considered partly in gas phase and liquid phase. The presence of such a large hydrothermal reservoir and the stagnant magma below may have influences on the volcano's activity. Two possibilities are presented. First, the 30 January 1911 explosion event was a magmatic hydrothermal eruption rather than a base-surge associated with a phreato-magmatic eruption. Second, the earlier proposed four eruption series may be better interpreted by two cycles, each consisting of series of summit and flank eruptions. PMID:24126286

  3. A large hydrothermal reservoir beneath Taal Volcano (Philippines) revealed by magnetotelluric observations and its implications to the volcanic activity.

    PubMed

    Alanis, Paul K B; Yamaya, Yusuke; Takeuchi, Akihiro; Sasai, Yoichi; Okada, Yoshihiro; Nagao, Toshiyasu

    2013-01-01

    Taal Volcano is one of the most active volcanoes in the Philippines. The magnetotelluric 3D forward analyses indicate the existence of a large high resistivity anomaly (∼100 Ω·m) with a volume of at least 3 km×3 km×3 km, which is capped by a conductive layer (∼10 Ω·m), beneath the Main Crater. This high resistivity anomaly is hypothesized to be a large hydrothermal reservoir, consisting of the aggregate of interconnected cracks in rigid and dense host rocks, which are filled with hydrothermal fluids coming from a magma batch below the reservoir. The hydrothermal fluids are considered partly in gas phase and liquid phase. The presence of such a large hydrothermal reservoir and the stagnant magma below may have influences on the volcano's activity. Two possibilities are presented. First, the 30 January 1911 explosion event was a magmatic hydrothermal eruption rather than a base-surge associated with a phreato-magmatic eruption. Second, the earlier proposed four eruption series may be better interpreted by two cycles, each consisting of series of summit and flank eruptions.

  4. The Alaska Volcano Observatory - Expanded Monitoring of Volcanoes Yields Results

    USGS Publications Warehouse

    Brantley, Steven R.; McGimsey, Robert G.; Neal, Christina A.

    2004-01-01

    Recent explosive eruptions at some of Alaska's 52 historically active volcanoes have significantly affected air traffic over the North Pacific, as well as Alaska's oil, power, and fishing industries and local communities. Since its founding in the late 1980s, the Alaska Volcano Observatory (AVO) has installed new monitoring networks and used satellite data to track activity at Alaska's volcanoes, providing timely warnings and monitoring of frequent eruptions to the aviation industry and the general public. To minimize impacts from future eruptions, scientists at AVO continue to assess volcano hazards and to expand monitoring networks.

  5. Observed inflation-deflation cycles at Popocatepetl volcano using tiltmeters and its possible correlation with regional seismic activity in Mexico

    NASA Astrophysics Data System (ADS)

    Contreras Ruiz Esparza, M. G., Sr.; Jimenez Velazquez, J. C., Sr.; Valdes Gonzalez, C. M., Sr.; Reyes Pimentel, T. A.; Galaviz Alonso, S. A.

    2014-12-01

    Popocatepetl, the smoking mountain, is a stratovolcano located in central Mexico with an elevation of 5450 masl. The active volcano, close to some of the largest urban centers in Mexico - 60 km and 30 km far from Mexico City and Puebla, respectively - poses a high hazard to an estimated population of 500 thousand people living in the vicinity of the edifice. Accordingly, in July 1994 the Popocatepetl Volcanological Observatory (POVO) was established. The observatory is operated and supported by the National Center for Disaster Prevention of Mexico (CENAPRED), and is equipped to fully monitor different aspects of the volcanic activity. Among the instruments deployed, we use in this investigation two tiltmometers and broad-band seismometers at two sites (Chipiquixtle and Encinos), which send the information gathered continuously to Mexico City.In this research, we study the characteristics of the tiltmeters signals minutes after the occurrence of certain earthquakes. The Popocatepetl volcano starts inflation-deflation cycles due to the ground motion generated by events located at certain regions. We present the analysis of the tiltmeters and seismic signals of all the earthquakes (Mw>5) occurred from January 2013 to June 2014, recorded at Chipiquixtle and Encinos stations. First, we measured the maximum tilt variation after each earthquake. Next, we apply a band-pass filter for different frequency ranges to the seismic signals of the two seismic stations, and estimated the total energy of the strong motion phase of the seismic record. Finally, we compared both measurements and observed that the maximum tilt variations were occurring when the maximum total energy of the seismic signals were in a specific frequency range. We also observed that the earthquake records that have the maximum total energy in that frequency range were the ones with a epicentral location south-east of the volcano. We conclude that our observations can be used set the ground for an early

  6. Northern Arizona Volcanoes

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Northern Arizona is best known for the Grand Canyon. Less widely known are the hundreds of geologically young volcanoes, at least one of which buried the homes of local residents. San Francisco Mtn., a truncated stratovolcano at 3887 meters, was once a much taller structure (about 4900 meters) before it exploded some 400,000 years ago a la Mt. St. Helens. The young cinder cone field to its east includes Sunset Crater, that erupted in 1064 and buried Native American homes. This ASTER perspective was created by draping ASTER image data over topographic data from the U.S. Geological Survey National Elevation Data.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 20.4 by 24.6 kilometers (12.6 by 15.2 miles) Location: 35.3 degrees North latitude, 111

  7. A fluorescein tracer release experiment in the hydrothermally active crater of Vailulu'u volcano, Samoa

    NASA Astrophysics Data System (ADS)

    Hart, S. R.; Staudigel, H.; Workman, R.; Koppers, A. A. P.; Girard, A. P.

    2003-08-01

    On 3 April 2001, a 20 kg point source of fluorescein dye was released 30 m above the bottom of the active summit caldera of Vailulu'u submarine volcano, Samoa. Vailulu'u crater is 2000 m wide and at water depths of 600-1000 m, with the bottom 200 m completely enclosed; it thus provides an ideal site to study the hydrodynamics of an active hydrothermal system. The magmatically driven hydrothermal system in the crater is currently exporting massive amounts of particulates, manganese, and helium. The dispersal of the dye was tracked for 4 days with a fluorimeter in tow-yo mode from the U.S. Coast Guard icebreaker Polar Sea. Lateral dispersion of the dye ranged from 80 to 500 m d-1; vertical dispersion had two components: a diapycnal diffusivity component averaging 21 cm2 s-1, and an advective component averaging 0.025 cm s-1. These measurements constrain the mass export of water from the crater during this period to be 8-1.3+4.6 × 107 m3 d-1, which leads to a "turnover" time for water in the crater of ˜3.2 days. Coupled with temperature data from CTD profiles and Mn analyses of water samples, the power output from the crater is 610-100+350 MW, and the manganese export flux is ˜240 kg d-1. The Mn/Heat ratio of 4.7 ng J-1 is significantly lower than ratios characteristic of hot smokers and diffuse hydrothermal flows on mid-ocean ridges and points to phase separation processes in this relatively shallow hydrothermal system.

  8. The study of active submarine volcanoes and hydrothermal vents in the Southernmost Part of Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Lee, Y.; Tsai, C.; Lee, C.

    2004-12-01

    The study area is located in the Southernmost Part of Okinawa Trough (SPOT), which is a back-arc basin formed by extension of Eurasian plate. Previous research indicated two extensional stages in SPOT area. Many normal-fault structures were come into existence during both extensional processes. The SPOT is presently in an activity tectonic episode. Therefore, the area becomes a frequent earthquake and abundant magmatism. The purpose of this study is to discuss which relationship between tectonics, submarine volcanoes and hydrothermal vents in SPOT area. The investigations are continued from 1998 to 2004, we have found at least twelve active hydrothermal vents in study area. Compare the locations hydrothermal vents with fault systems, we find both of them have highly correlated. We can distinguish them into two shapes, pyramidal shape and non-pyramidal shape. According to plumes height, we are able to divide these vents into two groups near east longitude 122.5° . East of this longitude, the hydrothermal plumes are more powerful and west of it are the weaker. This is closely related to the present extensional axis (N80° E) of the southern part of the Okinawa Trough. This can be explained the reason of why the more powerful vents coming out of the east group. The east group is associated with the present back-arc spreading system. West of 122.5° , the spreading system are in a primary stage. The andesitic volcanic island, the Turtle Island, is a result of N60° E extensional tectonism with a lot of faults. Besides the pyramidal shape, this can be proved indirectly. The vents located in the west side were occurred from previous extensional faults and are weaker than the eastern. Therefore, we suggest that if last the extension keeps going on, the hydrothermal vents located at the west side of the longitude 122.5° will be intensified.

  9. Fundamental changes in the activity of the natrocarbonatite volcano Oldoinyo Lengai, Tanzania

    USGS Publications Warehouse

    Kervyn, M.; Ernst, G.G.J.; Keller, J.; Vaughan, R. Greg; Klaudius, J.; Pradal, E.; Belton, F.; Mattsson, H.B.; Mbede, E.; Jacobs, P.M.

    2010-01-01

    On September 4, 2007, after 25 years of effusive natrocarbonatite eruptions, the eruptive activity of Oldoinyo Lengai (OL), N Tanzania, changed abruptly to episodic explosive eruptions. This transition was preceded by a voluminous lava eruption in March 2006, a year of quiescence, resumption of natrocarbonatite eruptions in June 2007, and a volcano-tectonic earthquake swarm in July 2007. Despite the lack of ground-based monitoring, the evolution in OL eruption dynamics is documented based on the available field observations, ASTER and MODIS satellite images, and almost-daily photos provided by local pilots. Satellite data enabled identification of a phase of voluminous lava effusion in the 2 weeks prior to the onset of explosive eruptions. After the onset, the activity varied from 100 m high ash jets to 2–15 km high violent, steady or unsteady, eruption columns dispersing ash to 100 km distance. The explosive eruptions built up a ∼400 m wide, ∼75 m high intra-crater pyroclastic cone. Time series data for eruption column height show distinct peaks at the end of September 2007 and February 2008, the latter being associated with the first pyroclastic flows to be documented at OL. Chemical analyses of the erupted products, presented in a companion paper (Keller et al.2010), show that the 2007–2008 explosive eruptions are associated with an undersaturated carbonated silicate melt. This new phase of explosive eruptions provides constraints on the factors causing the transition from natrocarbonatite effusive eruptions to explosive eruptions of carbonated nephelinite magma, observed repetitively in the last 100 years at OL.

  10. A Sinuous Tumulus over an Active Lava Tube at Klauea Volcano: Evolution, Analogs, and Hazard Forecasts

    NASA Technical Reports Server (NTRS)

    Orr, Tim R.; Bleacher, Jacob E.; Patrick, Matthew R.; Wooten, Kelly M.

    2015-01-01

    Inflation of narrow tube-fed basaltic lava flows (tens of meters across), such as those confined by topography, can be focused predominantly along the roof of a lava tube. This can lead to the development of an unusually long tumulus, its shape matching the sinuosity of the underlying lava tube. Such a situation occurred during Klauea Volcanos (Hawaii, USA) ongoing East Rift Zone eruption on a lava tube active from July through November 2010. Short-lived breakouts from the tube buried the flanks of the sinuous, ridge-like tumulus, while the tumulus crest, its surface composed of lava formed very early in the flows emplacement history, remained poised above the surrounding younger flows. At least several of these breakouts resulted in irrecoverable uplift of the tube roof. Confined sections of the prehistoric Carrizozo and McCartys flows (New Mexico, USA) display similar sinuous, ridge-like features with comparable surface age relationships. We contend that these distinct features formed in a fashion equivalent to that of the sinuous tumulus that formed at Kilauea in 2010. Moreover, these sinuous tumuli may be analogs for some sinuous ridges evident in orbital images of the Tharsis volcanic province on Mars. The short-lived breakouts from the sinuous tumulus at Kilauea were caused by surges in discharge through the lava tube, in response to cycles of deflation and inflation (DI events) at Kilauea's summit. The correlation between DI events and subsequent breakouts aided in lava flow forecasting. Breakouts from the sinuous tumulus advanced repeatedly toward the sparsely populated Kalapana Gardens subdivision, destroying two homes and threatening others. Hazard assessments, including flow occurrence and advance forecasts, were relayed regularly to the Hawai?i County Civil Defense to aid their lava flow hazard mitigation efforts while this lava tube was active.

  11. 2012 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Herrick, Julie A.; Neal, Christina A.; Cameron, Cheryl E.; Dixon, James P.; McGimsey, Robert G.

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest, or suspected unrest at 11 volcanic centers in Alaska during 2012. Of the two verified eruptions, one (Cleveland) was clearly magmatic and the other (Kanaga) was most likely a single phreatic explosion. Two other volcanoes had notable seismic swarms that probably were caused by magmatic intrusions (Iliamna and Little Sitkin). For each period of clear volcanic unrest, AVO staff increased monitoring vigilance as needed, reviewed eruptive histories of the volcanoes in question to help evaluate likely outcomes, and shared observations and interpretations with the public. 2012 also was the 100th anniversary of Alaska’s Katmai-Novarupta eruption of 1912, the largest eruption on Earth in the 20th century and one of the most important volcanic eruptions in modern times. AVO marked this occasion with several public events.

  12. Cost effective aero-photogrammetry toys at active volcanoes: On the use of drones, balloons and kites

    NASA Astrophysics Data System (ADS)

    Walter, Thomas R.

    2014-05-01

    The availability of aerial photographs allows spatial mapping of flows and fractures, generation of digital elevation models and other change detection. Therefore aerial photographs significantly improve our understanding of volcanic processes. The common problem is the lack of available data for most volcanoes, and the lack of systematic and chronologic repeat surveys. This work summarizes the current state of knowledge and technical implementations that currently revolutionize the field of aero-photogrammetry. By the use of unmanned vehicles, such as octocopters, helicopters and small airplanes, photo data can be acquired from almost any place at distances up to kilometres from the operator. Moreover, by the use of helium balloons, kites or their hybrid helikites, near field aero-photographs are obtained. In combination with modern stitching procedures and computer vision algorithms, the positioning of the camera and the digital elevation model of the ground can be extracted, and the active volcano and its eruption cloud be imaged from almost any perspective. This field is increasingly gaining flexibility, as lightweight cameras are available from visible, infrared and other spectral bands. Here example data are provided from volcanoes that are difficult to access by regular airplanes, showing the strengths and the limits of these new aero-photogrammetry toys.

  13. Muon dynamic radiography of density changes induced by hydrothermal activity at the La Soufrière of Guadeloupe volcano

    PubMed Central

    Jourde, Kevin; Gibert, Dominique; Marteau, Jacques; de Bremond d’Ars, Jean; Komorowski, Jean-Christophe

    2016-01-01

    Imaging geological structures through cosmic muon radiography is a newly developed technique which shows a great potential in volcanology. Here we demonstrate that muon radiography permits to detect and characterize mass movements in shallow hydrothermal systems of low-energy active volcanoes like the La Soufrière lava dome. We present an experiment conducted on this volcano during the Summer 2014 and bring evidence that very important density changes occurred in three domains of the lava dome. Depending on their position and on the medium porosity the volumes of these domains vary from 1 × 106 m3 to 7 × 106 m3. However, the total mass budget remains approximately constant : two domains show a mass loss (Δm∈ [−0.8;−0.4] × 109 kg) and the third one a mass gain (Δm∈ [1.5; 2.5] × 109 kg). We attribute the negative mass changes to the formation of steam in shallow hydrothermal reservoir previously partly filled with liquid water. This coincides with the emergence of new fumaroles on top of the volcano. The positive mass change is synchronized with the negative mass changes indicating that liquid water probably flowed from the two reservoirs invaded by steam toward the third reservoir. PMID:27629497

  14. Muon dynamic radiography of density changes induced by hydrothermal activity at the La Soufrière of Guadeloupe volcano.

    PubMed

    Jourde, Kevin; Gibert, Dominique; Marteau, Jacques; de Bremond d'Ars, Jean; Komorowski, Jean-Christophe

    2016-01-01

    Imaging geological structures through cosmic muon radiography is a newly developed technique which shows a great potential in volcanology. Here we demonstrate that muon radiography permits to detect and characterize mass movements in shallow hydrothermal systems of low-energy active volcanoes like the La Soufrière lava dome. We present an experiment conducted on this volcano during the Summer 2014 and bring evidence that very important density changes occurred in three domains of the lava dome. Depending on their position and on the medium porosity the volumes of these domains vary from 1 × 10(6) m(3) to 7 × 10(6) m(3). However, the total mass budget remains approximately constant : two domains show a mass loss (Δm∈ [-0.8;-0.4] × 10(9) kg) and the third one a mass gain (Δm∈ [1.5; 2.5] × 10(9) kg). We attribute the negative mass changes to the formation of steam in shallow hydrothermal reservoir previously partly filled with liquid water. This coincides with the emergence of new fumaroles on top of the volcano. The positive mass change is synchronized with the negative mass changes indicating that liquid water probably flowed from the two reservoirs invaded by steam toward the third reservoir. PMID:27629497

  15. Muon dynamic radiography of density changes induced by hydrothermal activity at the La Soufrière of Guadeloupe volcano.

    PubMed

    Jourde, Kevin; Gibert, Dominique; Marteau, Jacques; de Bremond d'Ars, Jean; Komorowski, Jean-Christophe

    2016-09-15

    Imaging geological structures through cosmic muon radiography is a newly developed technique which shows a great potential in volcanology. Here we demonstrate that muon radiography permits to detect and characterize mass movements in shallow hydrothermal systems of low-energy active volcanoes like the La Soufrière lava dome. We present an experiment conducted on this volcano during the Summer 2014 and bring evidence that very important density changes occurred in three domains of the lava dome. Depending on their position and on the medium porosity the volumes of these domains vary from 1 × 10(6) m(3) to 7 × 10(6) m(3). However, the total mass budget remains approximately constant : two domains show a mass loss (Δm∈ [-0.8;-0.4] × 10(9) kg) and the third one a mass gain (Δm∈ [1.5; 2.5] × 10(9) kg). We attribute the negative mass changes to the formation of steam in shallow hydrothermal reservoir previously partly filled with liquid water. This coincides with the emergence of new fumaroles on top of the volcano. The positive mass change is synchronized with the negative mass changes indicating that liquid water probably flowed from the two reservoirs invaded by steam toward the third reservoir.

  16. Muon dynamic radiography of density changes induced by hydrothermal activity at the La Soufrière of Guadeloupe volcano

    NASA Astrophysics Data System (ADS)

    Jourde, Kevin; Gibert, Dominique; Marteau, Jacques; de Bremond D’Ars, Jean; Komorowski, Jean-Christophe

    2016-09-01

    Imaging geological structures through cosmic muon radiography is a newly developed technique which shows a great potential in volcanology. Here we demonstrate that muon radiography permits to detect and characterize mass movements in shallow hydrothermal systems of low-energy active volcanoes like the La Soufrière lava dome. We present an experiment conducted on this volcano during the Summer 2014 and bring evidence that very important density changes occurred in three domains of the lava dome. Depending on their position and on the medium porosity the volumes of these domains vary from 1 × 106 m3 to 7 × 106 m3. However, the total mass budget remains approximately constant : two domains show a mass loss (Δm∈ [‑0.8‑0.4] × 109 kg) and the third one a mass gain (Δm∈ [1.5; 2.5] × 109 kg). We attribute the negative mass changes to the formation of steam in shallow hydrothermal reservoir previously partly filled with liquid water. This coincides with the emergence of new fumaroles on top of the volcano. The positive mass change is synchronized with the negative mass changes indicating that liquid water probably flowed from the two reservoirs invaded by steam toward the third reservoir.

  17. Application of emulsion imaging system for cosmic-ray muon radiography to explore the internal structure of Teide and Cumbre Vieja volcanoes in the Canary Islands, Spain

    NASA Astrophysics Data System (ADS)

    Hernandez Perez, P. A.; Tanaka, H.; Miyamoto, S.; Perez, N.; Barrancos, J.; Padron, E.; Hernandez, I.

    2012-12-01

    The internal structure of volcanoes, especially in their up per part, is product of past eruptions. Therefore, the knowledge of the internal structure of a volcano is of great importance for understanding its behaviour and to forecast the nature and style of the next eruptions. For these reasons, during past years scientists have made a big effort to investigate the internal structure of the volcanoes with different geophysical techniques, including deep drilling, passive and active seismic tomography, geoelectrics and magnetotellurics and gravimetry. One of the limits of conventional geophysical methods is the spatial resolution, which typically ranges between some tens of meters up to 1 km. In this sense, the radiography of active volcanoes based on natural muons, even if limited to the external part of the volcano, represents an important tool for investigating the internal structure of a volcano at higher spatial resolution (Macedonio and Martini, 2009). Moreover, muon radiography is able to resolve density contrasts of the order of 1-3%, significantly greater than the resolution obtained with conventional methods. As example, the experiment of muon radiography carried out at Mt. Asama volcano by Tanaka et al., 2007, allowed the reconstruction of the density map of the cone and detection of a dense region that corresponds to the position and shape of a lava deposit created during the last eruption in 2004. In the framework of a research project financed by the Canary Agency of Research, Innovation and Information Society, we will implement muon measurements at Teide volcano in Tenerife Island and Cumbre Vieja volcano in La Palma Island, Canary Islands, to radiographically image the subsurface structure of these two volcanic edifices. The data analysis will involve the study both of the shallow structure of both volcanoes and of the requirements for the implementation of the muon detectors. Both Cumbre Vieja and Teide are two active volcanoes that arouse great

  18. Application of emulsion imaging system for cosmic-ray muon radiography to explore the internal structure of Teide and Cumbre Vieja volcanoes in the Canary Islands, Spain

    NASA Astrophysics Data System (ADS)

    Hernández, Iñigo; Hernández, Pedro; Pérez, Nemesio; Tanaka, Hiroyuki; Miyamoto, Seygo; Barrancos, José; Padrón, Eleazar

    2013-04-01

    The internal structure of volcanoes, especially in their up per part, is product of past eruptions. Therefore, the knowledge of the internal structure of a volcano is of great importance for understanding its behaviour and to forecast the nature and style of the next eruptions. For these reasons, during past years scientists have made a big effort to investigate the internal structure of the volcanoes with different geophysical techniques, including deep drilling, passive and active seismic tomography, geoelectrics and magnetotellurics and gravimetry. One of the limits of conventional geophysical methods is the spatial resolution, which typically ranges between some tens of meters up to 1 km. In this sense, the radiography of active volcanoes based on natural muons, even if limited to the external part of the volcano, represents an important tool for investigating the internal structure of a volcano at higher spatial resolution (Macedonio and Martini, 2009). Moreover, muon radiography is able to resolve density contrasts of the order of 1-3%, significantly greater than the resolution obtained with conventional methods. As example, the experiment of muon radiography carried out at Mt. Asama volcano by Tanaka et al., 2007, allowed the reconstruction of the density map of the cone and detection of a dense region that corresponds to the position and shape of a lava deposit created during the last eruption in 2004. In the framework of a research project financed by the Canary Agency of Research, Innovation and Information Society, we will implement muon measurements at Teide volcano in Tenerife Island and Cumbre Vieja volcano in La Palma Island, Canary Islands, to radiographically image the subsurface structure of these two volcanic edifices. The data analysis will involve the study both of the shallow structure of both volcanoes and of the requirements for the implementation of the muon detectors. Both Cumbre Vieja and Teide are two active volcanoes that arouse great

  19. Direct Observations of Explosive Eruptive Activity at a Submarine Volcano, NW Rota-1, Mariana Arc

    NASA Astrophysics Data System (ADS)

    Chadwick, W. W.; Embley, R. W.; de Ronde, C. E.; Deardorff, N.; Matsumoto, H.; Cashman, K. V.; Dziak, R. P.; Merle, S. G.

    2006-12-01

    In April 2006, a series of extraordinary observations of a deep-sea volcanic eruption were made at NW Rota-1, located at 14^{circ}36'N in the Mariana arc, western Pacific. This is a conical, basaltic-andesite submarine volcano with a summit depth of 517 m. Explosive eruptive activity at NW Rota-1 was discovered in 2004 and was witnessed again in 2005, but the activity in 2006 was especially vigorous and well documented. During six dives with the remotely operated vehicle Jason II over a period of 7 days, video observations made at close range documented a diverse and increasingly energetic range of volcanic activity that culminated in explosive bursts with flashes of glowing red lava propelled by violently expanding gases. Other notable activity included discreet degassing events, extrusion of sluggish lava flows, explosions that formed dilute density currents and/or expelled rocks and ash tens of meters from the vent, and rapid pressure oscillations apparently caused by the repeated formation and condensation of steam. During the last dive when the highest extrusion rates were observed, quasi-periodic bursts from the vent, each lasting 1-10 minutes, were separated by pauses lasting 10 seconds to a few minutes. Each burst started as a plug of crusted-over lava rose in the vent and was blown apart by expanding gases, producing large lava bombs with distinctly flat, disc-like shapes. A remarkable aspect of these observations was how close Jason II could be to the vent during the eruptions. This was because the pressure of the overlying seawater dampened the energy of the explosions and slowed the velocity of volcanic ejecta. Also, lava degassing could be visualized with great clarity underwater as either clear bubbles (CO2) or opaque yellow clouds (dominated by SO2 and H2S). A portable hydrophone with a 30-hour recording capacity was deployed twice by Jason II at the summit of NW Rota-1 during the 2006 dive series. The hydrophone data extends the visual observations

  20. Waters associated with an active basaltic volcano, Kilauea, Hawaii: Variation in solute sources, 1973-1991

    USGS Publications Warehouse

    Tilling, R.I.; Jones, B.F.

    1996-01-01

    Chemical and isotopic analyses of samples collected from a 1262-m-deep research borehole at the summit of Kilauea Volcano provide unique time-series data for composition of waters in the uppermost part of its hydrothermal system. These waters have a distinctive geochemical signature: a very low proportion of chloride relative to other anions compared with other Hawaiian wa-ters - thermal (???30 ??C) or nonthermal (<30 ??C) - and with most thermal waters of the world. Isotope data demonstrate that the borehole waters are of essentially meteoric origin, with minimal magmatic input. The water chemistry exhibits marked temporal variations, including pronounced short-term (days to weeks) effects of rainfall dilution and longer term (months to years) decline of total solutes. The 1973-1974 samples are Na-sulfate-dominant, but samples collected after July 1975 are (Mg + Ca)-bicarbonate-dominant. This compositional shift, probably abrupt, was associated with an increase in the partial pressure of CO2 (PCO2) related to volcanic degassing of CO2 accompanying a large eruption (December 31, 1974) and associated intense seismicity. Following the initial sharp increase, the PCO2 then decreased, approaching preemption values in April 1976. Beginning in mid-1975, solute concentrations of the borehole waters decreased substantially, from ???45 meq/L to <25 meq/L in only eight months; by 1991, total solute concentrations were <17 meq/L. This decline in solutes cannot be attributed to rainfall dilution and is inferred to reflect the decreasing availability with time of the easily leachable salts of alkali metals and sulfate, which originated in sublimates and fumarolic encrustations in fractures and cavities of rocks along the hydrologic flow paths. The overall chemistry of the summit-borehole waters is largely determined by hydrolysis reactions associated with normal weathering of host tholeiitic basalts on a geologic time scale, despite short-term perturbations in composition

  1. Observations of Io's Active Volcanoes from IRTF: Imaging and Occultation Lightcurves

    NASA Astrophysics Data System (ADS)

    Rathbun, J. A.; Spencer, J. R.

    2014-12-01

    We have been observing Ionian volcanism from NASA's Infrared Telescope Facility (IRTF) for more than two decades. The frequency of our observations increases dramatically when spacecraft are observing Io in order to complement the data returned by the spacecraft. The Japanese Space Agency's (JAXA) Hisaki (Sprint-A) mission recently observd the Jupiter system from earth orbit, monitoring the Io Plasma Torus and Jovian aurora. In order to investigate the possible influence of Io volcanism on the torus, we observed Io's volcanoes from the IRTF in Hawaii between September 2013 and May 2014. We imaged Io at 2.2, 3.5, and 4.8 microns in eclipse and reflected sunlight. We also observed Io during occultation by Jupiter, which allows us to locate and characterize individual volcanic eruptions, with greater spatial accuracy, on the Jupiter-facing hemisphere. The 2013 3.5 micron images of a sunlit Io showed no obvious bright volcanic features. However, further increases in spatial resolution is possible with shift-and-add processing of short exposure images. Preliminary occultation lightcurves from 2013 show moderate levels of activity at Kaneheliki/Janus and Loki, the two volcanic centers most often observed in occultation lightcurves. Loki was much brighter in 2013 than during the New Horizons flyby in 2007, but not as bright as during the Galileo era (see figure). From February 2014 through May 2014, due to a planned upgrade on the SPEX instrument and an unplanned required repair on the NSFCam2 instrument (both of which we have used previously), we exclusively used the CSHELL instrument as an imager. Unfortunately, CSHELL was not designed for imaging and has limited spatial resolution and photometric precision, complicating image analysis.

  2. Acoustic measurements of the 1999 basaltic eruption of Shishaldin volcano, Alaska 1. Origin of Strombolian activity

    USGS Publications Warehouse

    Vergniolle, S.; Boichu, M.; Caplan-Auerbach, J.

    2004-01-01

    The 1999 basaltic eruption of Shishaldin volcano (Alaska, USA) displayed both classical Strombolian activity and an explosive Subplinian plume. Strombolian activity at Shishaldin occurred in two major phases following the Subplinian activity. In this paper, we use acoustic measurements to interpret the Strombolian activity. Acoustic measurements of the two Strombolian phases show a series of explosions that are modeled by the vibration of a large overpressurised cylindrical bubble at the top of the magma column. Results show that the bubble does not burst at its maximum radius, as expected if the liquid film is stretched beyond its elasticity. But bursting occurs after one cycle of vibration, as a consequence of an instability of the air-magma interface close to the bubble minimum radius. During each Strombolian period, estimates of bubble length and overpressure are calculated. Using an alternate method based on acoustic power, we estimate gas velocity to be 30-60 m/s, in very good agreement with synthetic waveforms. Although there is some variation within these parameters, bubble length and overpressure for the first Strombolian phase are found to be ??? 82 ?? 11 m and 0.083 MPa. For the second Strombolian phase, bubble length and overpressure are estimated at 24 ?? 12 m and 0.15 MPa for the first 17 h after which bubble overpressure shows a constant increase, reaching a peak of 1.4 MPa, just prior to the end of the second Strombolian phase. This peak suggests that, at the time, the magma in the conduit may contain a relatively large concentration of small bubbles. Maximum total gas volume and gas fluxes at the surface are estimated to be 3.3 ?? 107 and 2.9 ?? 103 m3/s for the first phase and 1.0 ?? 108 and 2.2 ?? 103 m3/s for the second phase. This gives a mass flux of 1.2 ?? 103 and 8.7 ?? 102 kg/s, respectively, for the first and the second Strombolian phases. ?? 2004 Elsevier B.V. All rights reserved.

  3. Geochemical surveillance of magmatic volatiles at Popocatepetl volcano, Mexico

    USGS Publications Warehouse

    Goff, F.; Janik, C.J.; Delgado, H.; Werner, C.; Counce, D.; Stimac, J.A.; Siebe, C.; Love, S.P.; Williams, S.N.; Fischer, T.; Johnson, L.

    1998-01-01

    Surveillance of Popocatepetl volcanic plume geochemistry and SO2 flux began in early 1994 after fumarolic and seismic activity increased significantly during 1993. Volatile traps placed around the summit were collected at near-monthly intervals until the volcano erupted on December 21, 1994. Additional trap samples were obtained in early 1996 before the volcano erupted again, emplacing a small dacite dome in the summit crater. Abundances of volatile constituents (ppm/day of Cl, Stotal, F, CO2, Hg, and As) vaaried, but most constituents were relatively high in earl\\y and late 1994. However, ratios of these constituents to Cl were highest in mid-1994. ??34S-Stotal in trap solutions ranged from 1.5??? to 6.4???; lowest values generally occurred during late 1994. ??13C-CO2 of trap solutions were greatly contaminated with atmospheric CO2 and affected by absorption kinetics. When trap data are combined with SO2 flux measurements made through November 1996, Popocatepetl released about 3.9 Mt SO2, 16 Mt CO2, 0.75 Mt HCl, 0.075 Mt HF, 260 t As, 2.6 t Hg, and roughly 200 Mt H2O. Near-vent gas concentrations in the volcanic plume measured by correlation spectrometer (COSPEC) and Fourier transform infrared (FTIR) commonly exceed human recommended exposure limits and may constitute a potential health hazard. Volatile geochemistry combined with petrologic observations and melt-inclusion studies show that mafic magma injection into a preexisting silicic chamber has accompanied renewed volcanism at Popocatepetl. Minor assimilation of Cretaceous wall rocks probably occurred in mid-1994.

  4. Discovery of an active shallow submarine silicic volcano in the northern Izu-Bonin Arc: volcanic structure and potential hazards of Oomurodashi Volcano (Invited)

    NASA Astrophysics Data System (ADS)

    Tani, K.; Ishizuka, O.; Nichols, A. R.; Hirahara, Y.; Carey, R.; McIntosh, I. M.; Masaki, Y.; Kondo, R.; Miyairi, Y.

    2013-12-01

    Oomurodashi is a bathymetric high located ~20 km south of Izu-Oshima, an active volcanic island of the northern Izu-Bonin Arc. Using the 200 m bathymetric contour to define its summit dimensions, the diameter of Oomurodashi is ~20 km. Oomurodashi has been regarded as inactive, largely because it has a vast flat-topped summit at 100 - 150 meters below sea level (mbsl). During cruise NT07-15 of R/V Natsushima in 2007, we conducted a dive survey in a small crater, Oomuro Hole, located in the center of the flat-topped summit, using the remotely-operated vehicle (ROV) Hyper-Dolphin. The only heat flow measurement conducted on the floor of Oomuro Hole during the dive recorded an extremely high value of 4,200 mW/m2. Furthermore, ROV observations revealed that the southwestern wall of Oomuro Hole consists of fresh rhyolitic lavas. These findings suggest that Oomurodashi is in fact an active silicic submarine volcano. To confirm this hypothesis, we conducted detailed geological and geophysical ROV Hyper-Dolphin (cruise NT12-19). In addition to further ROV surveys, we carried out single-channel seismic (SCS) surveys across Oomurodashi in order to examine the shallow structures beneath the current edifice. The ROV surveys revealed numerous active hydrothermal vents on the floor of Oomuro Hole, at ~200 mbsl, with maximum water temperature measured at the hydrothermal vents reaching 194°C. We also conducted a much more detailed set of heat flow measurements across the floor of Oomuro Hole, detecting very high heat flows of up to 29,000 mW/m2. ROV observations revealed that the area surrounding Oomuro Hole on the flat-topped summit of Oomurodashi is covered by extensive fresh rhyolitic lava and pumice clasts with minimum biogenetic or manganese cover, suggesting recent eruption(s). These findings strongly indicate that Oomurodashi is an active silicic submarine volcano, with recent eruption(s) occurring from Oomuro Hole. Since the summit of Oomurodashi is in shallow water, it

  5. Dynamics of active magmatic and hydrothermal systems at Taal Volcano, Philippines, from continuous GPS measurements

    NASA Astrophysics Data System (ADS)

    Bartel, Beth A.; Hamburger, Michael W.; Meertens, Chuck M.; Lowry, Anthony R.; Corpuz, Ernesto

    2003-10-01

    A dense network of continuous single- and dual-frequency GPS receivers at Taal Volcano, Philippines, reveals four major stages of volcanogenic deformation: deflation, from installation in June 1998 to December 1998; inflation, from January to March 1999; deflation, from April 1999 to February 2000; and inflation, from February to November 2000. The largest displacements occurred during the February-November 2000 period of inflation, which was characterized by ˜120 mm of uplift of the center of Volcano Island relative to the northern caldera rim at average rates up to 216 mm/yr. Deformation sources were modeled using a constrained least squares inversion algorithm. The source of 1999 deflation and inflation in 2000 were modeled as contractional and dilatational Mogi point sources centered at 4.2 and 5.2 km depth, respectively, beneath Volcano Island. The locations of the inflationary and deflationary sources are indistinguishable within the 95% confidence estimates. Modeling using a running 4-month time window from June 1999 to March 2001 reveals little evidence for source migration. We suggest that the two periods of inflation observed at Taal result from episodic intrusions of magma into a shallow reservoir centered beneath Volcano Island. Subsequent deflation may result from exsolution of magmatic fluids and/or gases into an overlying, unconfined hydrothermal system.

  6. Seismic structure and origin of active intraplate volcanoes in Northeast Asia

    NASA Astrophysics Data System (ADS)

    Duan, Yonghong; Zhao, Dapeng; Zhang, Xiankang; Xia, Shaohong; Liu, Zhi; Wang, Fuyun; Li, Li

    2009-05-01

    Three-dimensional P-wave velocity structure beneath the Changbai and other intraplate volcanic areas in Northeast Asia is determined by inverting 1378 high-quality P-wave arrival times from 186 teleseismic events recorded by 61 broadband seismic stations. Low-velocity (low-V) anomalies are revealed beneath the Changbai, Longgan, Xianjindao volcanoes. High-velocity (high-V) anomalies are found in the mantle transition zone, where deep-focus earthquakes under Hunchun occur at depths of 500-600 km. The high-V anomaly reflects the deep subduction of the Pacific slab under NE Asia which may have contributed to the formation of the Changbai, Longgang, Xianjindao and Jingpohu intraplate volcanoes. A low-V anomaly is also revealed in the mantle transition zone, which may have a close relationship with the occurrence of deep earthquakes under the Hunchun area. Our results support the Big Mantle Wedge (BMW) model by Zhao et al. [Zhao, D., Lei, J., Tang, Y., 2004. Origin of the Changbai volcano in northeast China: evidence from seismic tomography, Chin. Sci. Bull. 49, 1401-1408; Zhao, D., Maruyama, S., Omori, S., 2007. Mantle dynamics of western Pacific and East Asia: insight from seismic tomography and mineral physics. Gondwana Res. 11, 120-131.] who proposed that the intraplate volcanoes in NE Asia are caused by the back-arc magmatism associated with the deep dehydration process of the subducting slab and convective circulation process in the BMW above the stagnant Pacific slab.

  7. Mg(++) requirement for MtHK binding, and Mg(++) stabilization of mitochondrial membranes via activation of MtHK & MtCK and promotion of mitochondrial permeability transition pore closure: A hypothesis on mechanisms underlying Mg(++)'s antioxidant and cytoprotective effects.

    PubMed

    Golshani-Hebroni, Shiva

    2016-04-25

    Evidence points to magnesium's antioxidant, anti-necrotic, and anti-apoptotic effects in cardio- and neuroprotection. With magnesium being involved in over 300 biochemical reactions, the mechanisms underlying its cytoprotective and antioxidant effects have remained elusive. The profound anti-apoptotic, anabolic, and antioxidant effects of mitochondrion bound hexokinase (MtHk), and the anti-apoptotic, anti-necrotic, and antioxidant functions of mitochondrial creatine kinase (MtCK) have been established over the past few decades. As powerful regulators of the mitochondrial permeability transition pore (PTP), MtHK and MtCK promote anti-apoptosis and anti-necrosis by stabilizing mitochondrial outer and inner membranes. In this article, it is proposed that magnesium is essentially and directly involved in mitochondrial membrane stabilization via (i) Mg(++) ion requirement for the binding of mitochondrial hexokinase (ii) Mg(++)'s allosteric activation of mitochondrial bound hexokinase, and stimulation of mitochondrial bound creatine kinase activities, and (iii) Mg(++) inhibition of PTP opening by Ca(++) ions. These effects of Mg(++) ions are indirectly supplanted by the stimulatory effect of magnesium on the Akt kinase survival pathway. The "Magnesium/Calcium Yin Yang Hypothesis" proposes here that because of the antagonistic effects of Ca(++) and Mg(++) ions in the presence of high Ca(++) ion concentration at MtHK, MtCK, and PTP, magnesium supplementation may provide cytoprotective effects in the treatment of some degenerative diseases and cytopathies with high intracellular [Ca(++)]/ [Mg(++)] ratio at these sites, whether of genetic, developmental, drug induced, ischemic, immune based, toxic, or infectious etiology. PMID:26732303

  8. Mount St. Helens Volcano Reawakens: An Overview of the First Month of Activity

    NASA Astrophysics Data System (ADS)

    Gardner, C. A.; Sisson, T.; Scott, W. E.

    2004-12-01

    Late in the evening of 22 September 2004, a shallow (< 2 km), high-frequency earthquake swarm began beneath Mount St. Helens volcano in southwest Washington. Seismicity declined and then, on the afternoon of 25 September and the following day, rapidly increased both in rate and magnitude. This prompted the U.S. Geological Survey's Cascades Volcano Observatory to issue an alert above background level for the first time since the 1980s. Over the following week, maximum earthquake magnitudes increased to M3.5 and the first steam-and-ash emission occurred on 1 October. Four additional steam-and-ash emissions occurred through 5 October; the last and largest sent an ash plume to 15,000 feet. Seismicity then dropped to low levels and changed character to more low-frequency events where it remains as of 24 October. Throughout, earthquake locations have remained shallow. By 30 September, field observers noted localized deformation on the south side of the 1980-86 lava dome and adjacent glacier, but in retrospect the deformation probably began earlier. The volume of the deforming area, or welt, grew to 5.4 million cubic meters by 4 October, grew to 11.7 million cubic meters by 13 October, and continues growing. Gas-sensing flights began on 27 September and detected only a few point sources of magmatic gas over the next several days. By 4 October, however, emission rates for carbon dioxide were large enough to be detected in the plume and by 7 October emissions rates for carbon dioxide, hydrogen sulfide and sulfur dioxide were readily measured. Since 7 October, sulfur dioxide has remained the principal sulfur gas. Forward-Looking InfraRed (FLIR) images from 1 to 10 October recorded increasing, but well below magmatic, temperatures on the northwest flank of the welt. On 11 October, temperature measurements of 500 to 600 degrees C coincided with the appearance of a lava spine on the northwest side of the welt that heralded the beginning of exogenous dome growth. Microbeam

  9. Using a combined population-based and kinetic modelling approach to assess timescales and durations of magma migration activities prior to the 1669 flank eruption of Mt. Etna

    NASA Astrophysics Data System (ADS)

    Kahl, M.; Morgan, D. J.; Viccaro, M.; Dingwell, D. B.

    2015-12-01

    The March-July eruption of Mt. Etna in 1669 is ranked as one of the most destructive and voluminous eruptions of Etna volcano in historical times. To assess threats from future eruptions, a better understanding of how and over what timescales magma moved underground prior to and during the 1669 eruption is required. We present a combined population based and kinetic modelling approach [1-2] applied to 185 olivine crystals that erupted during the 1669 eruption. By means of this approach we provide, for the first time, a dynamic picture of magma mixing and magma migration activity prior to and during the 1669 flank eruption of Etna volcano. Following the work of [3] we have studied 10 basaltic lava samples (five SET1 and five SET2 samples) that were erupted from different fissures that opened between 950 and 700 m a.s.l. Following previous work [1-2] we were able to classify different populations of olivine based on their overall core and rim compositional record and the prevalent zoning type (i.e. normal vs. reverse). The core plateau compositions of the SET1 and SET2 olivines range from Fo70 up to Fo83 with a single peak at Fo75-76. The rims differ significantly and can be distinguished into two different groups. Olivine rims from the SET1 samples are generally more evolved and range from Fo50 to Fo64 with a maximum at Fo55-57. SET2 olivine rims vary between Fo65-75 with a peak at Fo69. SET1 and SET2 olivines display normal zonation with cores at Fo75-76 and diverging rim records (Fo55-57 and Fo65-75). The diverging core and rim compositions recorded in the SET1 and SET2 olivines can be attributed to magma evolution possibly in three different magmatic environments (MEs): M1 (=Fo75-76), M2 (=Fo69) and M3 (=Fo55-57) with magma transfer and mixing amongst them. The MEs established in this study differ slightly from those identified in previous works [1-2]. We note the relative lack of olivines with Fo-rich core and rim compositions indicating a major mafic magma

  10. Expert Systems for Real-Time Volcano Monitoring

    NASA Astrophysics Data System (ADS)

    Cassisi, C.; Cannavo, F.; Montalto, P.; Motta, P.; Schembra, G.; Aliotta, M. A.; Cannata, A.; Patanè, D.; Prestifilippo, M.

    2014-12-01

    In the last decade, the capability to monitor and quickly respond to remote detection of volcanic activity has been greatly improved through use of advanced techniques and semi-automatic software applications installed in most of the 24h control rooms devoted to volcanic surveillance. Ability to monitor volcanoes is being advanced by new technology, such as broad-band seismology, microphone networks mainly recording in the infrasonic frequency band, satellite observations of ground deformation, high quality video surveillance systems, also in infrared band, improved sensors for volcanic gas measurements, and advances in computer power and speed, leading to improvements in data transmission, data analysis and modeling techniques. One of the most critical point in the real-time monitoring chain is the evaluation of the volcano state from all the measurements. At the present, most of this task is delegated to one or more human experts in volcanology. Unfortunately, the volcano state assessment becomes harder if we observe that, due to the coupling of highly non-linear and complex volcanic dynamic processes, the measurable effects can show a rich range of different behaviors. Moreover, due to intrinsic uncertainties and possible failures in some recorded data, precise state assessment is usually not achievable. Hence, the volcano state needs to be expressed in probabilistic terms that take account of uncertainties. In the framework of the project PON SIGMA (Integrated Cloud-Sensor System for Advanced Multirisk Management) work, we have developed an expert system approach to estimate the ongoing volcano state from all the available measurements and with minimal human interaction. The approach is based on hidden markov model and deals with uncertainties and probabilities. We tested the proposed approach on data coming from the Mt. Etna (Italy) continuous monitoring networks for the period 2011-2013. Results show that this approach can be a valuable tool to aid the

  11. Multi-temporal behaviour of a persistently active volcano - Masaya, Nicaragua

    NASA Astrophysics Data System (ADS)

    Williams-Jones, G.; Mauri, G.

    2007-05-01

    An in depth understanding of the processes responsible for persistent volcanism can only be achieved through the integration of multi-temporal geophysical and geochemical techniques. Gravity changes combined with ground deformation and gas flux have provided important information on magma reservoir mass changes and rates of magma emplacement or recharge. While the long-term micro-gravity, ground deformation and SO2 flux data collected at Masaya volcano (Nicaragua) since 1993 has identified significant multi-year cycles of activity, recent continuous micro-gravity surveys have shown significant short-term signals. Current activity is characterised by repeated periods of significant passive degassing (>2000 t/d SO2) with infrequent vent-clearing eruptions of negligible amounts of juvenile material. The multi-year gravity and gas flux variations are most likely due to gas accumulation in the shallow substructure controlled by the convective overturn of shallow degassed, cooled and dense magma replaced periodically by lower density, hot, gas-rich magma from depth. However, the presence of a small hydrothermal system can act as a physical and chemical buffer to the volcanic system while the essentially 'open' nature of Masaya's substructure can obscure short-term variations. In order to investigate the origin and importance of these short-term variations, continuous gravity and deformation surveys were made in March 2006 and 2007 in the summit craters of Masaya. During this period, residual gravity variations of ~60 µGal were measured with wavelengths of ~20 hours. These variations may be due in part to rapid changes in the hydrothermal system, occilations in height of the magma column or changes in vesiculation due to varying rates of gas flux. Concurrent detailed self-potential (SP) mapping, with soil CO2 and temperature measurements, delineated the shape and position of a small hydrothermal system centered on the main Nindiri crater. Processing of the SP data by

  12. Stratigraphy, geochronology and evolution of the Mt. Melbourne volcanic field (North Victoria Land, Antarctica)

    NASA Astrophysics Data System (ADS)

    Giordano, Guido; Lucci, Federico; Phillips, David; Cozzupoli, Domenico; Runci, Valentina

    2012-11-01

    Mt. Melbourne (2,732 m a.s.l.) is a large quiescent stratovolcano located in Northern Victoria Land (Antarctica) and is one of a handful of volcanoes on the Antarctic plate with the potential for large-scale explosive eruptions. During the XVIII Italian Expedition in 2002-2003, the Mt. Melbourne volcanic succession was studied in terms of stratigraphy and sampled for 40Ar/39Ar age determinations and geochemistry. The early, Lower Pleistocene, volcanism was largely alkali basaltic to hawaiitic in composition and monogenetic in style, producing tens of small scoria cones and lava flows scattered over a wide area across the Transantarctic Mountains (Random Hills Period). During the Middle Pleistocene, volcanic activity focused to the area of the Mt. Melbourne stratovolcano, where several monogenetic centres show the transition from early sub-glacial/subaqueous conditions to emergent subaerial conditions (Shield Nunatak Period). The oldest exposed deposit associated with the early activity of the Mt. Melbourne stratovolcano (Mt. Melbourne Period) is a trachytic subaerial ignimbrite dated at 123.6 ± 6.0 ka, which reflects the establishment of a crustal magma chamber. Above the ignimbrite a succession of alkali basaltic, hawaiitic, and subordinate benmoreitic lavas and scoria cones is exposed, dated at 90.7 ± 19.0 ka. The Holocene deposits are exposed at the top of Mt. Melbourne, where the crater rim is composed of trachytic to rhyolitic pumice fall deposits, which are also extensively dispersed around the volcano, likely originated from Plinian-scale eruptions. The most recent explosive deposit proved difficult to date accurately because very low quantities of radiogenic 40Ar were released, resulting in imprecise plateau ages of 50 ± 70 and 35 ± 22 ka.

  13. A Preliminary Study of Hazus-MH Volcano for Korea

    NASA Astrophysics Data System (ADS)

    Yu, S.; An, H.; Oh, J.

    2013-12-01

    This presentation will introduce our design to develop a volcano risk modeling capacity within the Hazus-MH loss estimation framework. In particular, we will present how to build fragility curves within the Hazus-MH framework for loss estimation from volcanoes. This capability is designed to analyze the risk from volcanic hazards in Korea. The Korean peninsula has Mt. Baekdu in North Korea, which will soon enter an active phase, according to some volcanologists. The anticipated eruption will be explosive given the viscous and grassy silica-rich magma, and is expected to be one of the largest in recent millennia. We aim to assess the impacts of this eruption, in particular to South Korea. There are several types of hazards related to volcanic eruption, including ash, pyroclastic flows, volcanic floods and earthquakes. However, our initial efforts focus on modeling losses from volcanic ash. The proposed volcanic ash model is anticipated to be used to estimate losses caused by yellow dust in East Asia as well. Also, many countries, which are exposed to potentially dangerous volcanoes, can benefit from the proposed Hazus-MH Volcano risk model. Acknowledgement: this research was supported by a grant [NEMA-BAEKDUSAN-2012-1-3] from the Volcanic Disaster Preparedness Research Center sponsored by National Emergency Management Agency of Korea. We would like to thank Federal Emergency Management Agency which develops Hazus-MH and allows the international use of Hazus-MH.

  14. Volcano-hazard zonation for San Vicente volcano, El Salvador

    USGS Publications Warehouse

    Major, J.J.; Schilling, S.P.; Pullinger, C.R.; Escobar, C.D.; Howell, M.M.

    2001-01-01

    San Vicente volcano, also known as Chichontepec, is one of many volcanoes along the volcanic arc in El Salvador. This composite volcano, located about 50 kilometers east of the capital city San Salvador, has a volume of about 130 cubic kilometers, rises to an altitude of about 2180 meters, and towers above major communities such as San Vicente, Tepetitan, Guadalupe, Zacatecoluca, and Tecoluca. In addition to the larger communities that surround the volcano, several smaller communities and coffee plantations are located on or around the flanks of the volcano, and major transportation routes are located near the lowermost southern and eastern flanks of the volcano. The population density and proximity around San Vicente volcano, as well as the proximity of major transportation routes, increase the risk that even small landslides or eruptions, likely to occur again, can have serious societal consequences. The eruptive history of San Vicente volcano is not well known, and there is no definitive record of historical eruptive activity. The last significant eruption occurred more than 1700 years ago, and perhaps long before permanent human habitation of the area. Nevertheless, this volcano has a very long history of repeated, and sometimes violent, eruptions, and at least once a large section of the volcano collapsed in a massive landslide. The oldest rocks associated with a volcanic center at San Vicente are more than 2 million years old. The volcano is composed of remnants of multiple eruptive centers that have migrated roughly eastward with time. Future eruptions of this volcano will pose substantial risk to surrounding communities.

  15. Explosive eruptive activity and temporal magmatic changes at Yotei Volcano during the last 50,000 years, southwest Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Uesawa, Shimpei; Nakagawa, Mitsuhiro; Umetsu, Akane

    2016-10-01

    To understand the eruptive history, structure, and magmatic evolution of Yotei Volcano, southwest Hokkaido, Japan, we investigated the geology and petrology of tephras located around the base of the volcano. We identified 43 tephra units interbedded with soils (in descending stratigraphic order, tephras Y1-Y43), and four widespread regional tephras. Ten radiocarbon ages were obtained from soils beneath the Yotei tephras. On the basis of petrologic differences and, the stratigraphic positions of thick layers of volcanic ash soil, indicative of volcanic stratigraphic gaps, the Yotei tephras are divided into four groups (in ascending stratigraphic order): Yotei tephra groups I, II-1, II-2, and II-3. We calculated the age of each eruptive deposit based on the soil accumulation rate, and estimated the volume of each eruption using isopach maps or the correlation between eruption volume and the maximum thickness at ~ 10 km from the summit crater. The results regarding eruptive activity and the rate of explosive eruptions indicate four eruptive stages at Yotei Volcano over the last 50,000 years. Stage I eruptions produced Yotei tephra group I between ca. 54 cal. ka BP and up to at least ca. 46 cal. ka BP, at relatively high average eruption rates of 0.07 km3 dense-rock equivalent (DRE)/ky. After a pause in activity of ca. 8000 years, Stage II-1 to II-2 eruptions produced Yotei tephra groups II-1 and II-2 from ca. 38 to ca. 21 cal. ka BP at high average eruption rates (0.10 km3 DRE/ky), after a pause in activity of 2000-3000 years. Finally, after another pause in activity of 4000-5000 years, Stage II-3 eruptions produced Yotei tephra group II-3 from ca. 16.5 cal. ka BP until the present day, at low average eruption rates (0.009 km3 DRE/ky). Whole-rock geochemical compositions vary within each tephra group over the entire eruption history. For example, group I and II-3 tephras contain the lowest and highest abundances, respectively, of K2O, P2O5, and Zr. Group II-1 has the

  16. Increased mtPDH Activity Through Antisense Inhibition of Mitochondrial Pyruvate Dehydrogenase Kinase Enhances Inflorescence Initiation, and Inflorescence Growth and Harvest Index at Elevated CO2 in Arabidopsis thaliana.

    PubMed

    Weraduwage, Sarathi M; Micallef, Malgre C; Marillia, Elizabeth-France; Taylor, David C; Grodzinski, Bernard; Micallef, Barry J

    2016-01-01

    Mitochondrial pyruvate dehydrogenase (mtPDH) is a key respiratory enzyme that links glycolysis and the tricarboxylic acid cycle, and it is negatively regulated by mtPDH kinase (mtPDHK). Arabidopsis lines carrying either a constitutive or seed-specific antisense construct for mtPDHK were used to test the hypothesis that alteration of mtPDH activity in a tissue- and dosage-dependent manner will enhance reproductive growth particularly at elevated CO2 (EC) through a combined enhancement of source and sink activities. Constitutive transgenic lines showed increased mtPDH activity in rosette leaves at ambient CO2 (AC) and EC, and in immature seeds at EC. Seed-specific transgenic lines showed enhanced mtPDH activity in immature seeds. A strong relationship existed between seed mtPDH activity and inflorescence initiation at AC, and at EC inflorescence stem growth, silique number and seed harvest index were strongly related to seed mtPDH activity. Leaf photosynthetic rates showed an increase in rosette leaves of transgenic lines at AC and EC that correlated with enhanced inflorescence initiation. Collectively, the data show that mtPDHK plays a key role in regulating sink and source activities in Arabidopsis particularly during the reproductive phase. PMID:26904065

  17. Increased mtPDH Activity Through Antisense Inhibition of Mitochondrial Pyruvate Dehydrogenase Kinase Enhances Inflorescence Initiation, and Inflorescence Growth and Harvest Index at Elevated CO2 in Arabidopsis thaliana

    PubMed Central

    Weraduwage, Sarathi M.; Micallef, Malgre C.; Marillia, Elizabeth-France; Taylor, David C.; Grodzinski, Bernard; Micallef, Barry J.

    2016-01-01

    Mitochondrial pyruvate dehydrogenase (mtPDH) is a key respiratory enzyme that links glycolysis and the tricarboxylic acid cycle, and it is negatively regulated by mtPDH kinase (mtPDHK). Arabidopsis lines carrying either a constitutive or seed-specific antisense construct for mtPDHK were used to test the hypothesis that alteration of mtPDH activity in a tissue- and dosage-dependent manner will enhance reproductive growth particularly at elevated CO2 (EC) through a combined enhancement of source and sink activities. Constitutive transgenic lines showed increased mtPDH activity in rosette leaves at ambient CO2 (AC) and EC, and in immature seeds at EC. Seed-specific transgenic lines showed enhanced mtPDH activity in immature seeds. A strong relationship existed between seed mtPDH activity and inflorescence initiation at AC, and at EC inflorescence stem growth, silique number and seed harvest index were strongly related to seed mtPDH activity. Leaf photosynthetic rates showed an increase in rosette leaves of transgenic lines at AC and EC that correlated with enhanced inflorescence initiation. Collectively, the data show that mtPDHK plays a key role in regulating sink and source activities in Arabidopsis particularly during the reproductive phase. PMID:26904065

  18. Increased mtPDH Activity Through Antisense Inhibition of Mitochondrial Pyruvate Dehydrogenase Kinase Enhances Inflorescence Initiation, and Inflorescence Growth and Harvest Index at Elevated CO2 in Arabidopsis thaliana.

    PubMed

    Weraduwage, Sarathi M; Micallef, Malgre C; Marillia, Elizabeth-France; Taylor, David C; Grodzinski, Bernard; Micallef, Barry J

    2016-01-01

    Mitochondrial pyruvate dehydrogenase (mtPDH) is a key respiratory enzyme that links glycolysis and the tricarboxylic acid cycle, and it is negatively regulated by mtPDH kinase (mtPDHK). Arabidopsis lines carrying either a constitutive or seed-specific antisense construct for mtPDHK were used to test the hypothesis that alteration of mtPDH activity in a tissue- and dosage-dependent manner will enhance reproductive growth particularly at elevated CO2 (EC) through a combined enhancement of source and sink activities. Constitutive transgenic lines showed increased mtPDH activity in rosette leaves at ambient CO2 (AC) and EC, and in immature seeds at EC. Seed-specific transgenic lines showed enhanced mtPDH activity in immature seeds. A strong relationship existed between seed mtPDH activity and inflorescence initiation at AC, and at EC inflorescence stem growth, silique number and seed harvest index were strongly related to seed mtPDH activity. Leaf photosynthetic rates showed an increase in rosette leaves of transgenic lines at AC and EC that correlated with enhanced inflorescence initiation. Collectively, the data show that mtPDHK plays a key role in regulating sink and source activities in Arabidopsis particularly during the reproductive phase.

  19. Characterization of volcanic activity using observations of infrasound, volcanic emissions, and thermal imagery at Karymsky Volcano, Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Lopez, T.; Fee, D.; Prata, F.

    2012-04-01

    Karymsky Volcano is one of the most active and dynamic volcanoes in Kamchatka, with activity ranging from vigorous degassing, frequent ash emissions, and apparent vent sealing, all punctuated by daily to weekly explosive magmatic eruptions. Recent studies have highlighted the strengths in using complementary infrasound measurements and remote volcanic emission measurements to characterize volcanic activity, with the potential to discriminate emission-type, approximate ash-cloud height, and estimate SO2 emission mass. Here we use coincident measurements of infrasound, SO2, ash, and thermal radiation collected over a ten day period at Karymsky Volcano in August 2011 to characterize the observed activity and elucidate vent processes. The ultimate goal of this project is to enable different types of volcanic activity to be identified using only infrasound data, which would significantly improve our ability to continuously monitor remote volcanoes. Four types of activity were observed. Type 1 activity is characterized by discrete ash emissions occurring every 1 - 5 minutes that either jet or roil out of the vent, by plumes from 500 - 1500 m (above vent) altitudes, and by impulsive infrasonic onsets. Type 2 activity is characterized by periodic pulses of gas emission, little or no ash, low altitude (100 - 200 m) plumes, and strong audible jetting or roaring. Type 3 activity is characterized by sustained emissions of ash and gas, with multiple pulses lasting from ~1 - 3 minutes, and by plumes from 300 - 1500 m. Type 4 activity is characterized by periods of relatively long duration (~30 minutes to >1 hour) quiescence, no visible plume and weak SO2 emissions at or near the detection limit, followed by an explosive, magmatic eruption, producing ash-rich plumes to >2000 m, and centimeter to meter (or greater) sized pyroclastic bombs that roll down the flanks of the edifice. Eruption onset is accompanied by high-amplitude infrasound and occasionally visible shock

  20. Intense Seismic Activity at Chiles and Cerro Negro Volcanoes on the Colombia-Ecuador Border

    NASA Astrophysics Data System (ADS)

    Torres, R. A.; Cadena, O.; Gomez, D.; Ruiz, M. C.; Prejean, S. G.; Lyons, J. J.; White, R. A.

    2015-12-01

    The region of Chiles and Cerro Negro volcanoes, located on the Colombian-Ecuadorian border, has experienced an ongoing seismic swarm beginning in Aug. 2013. Based on concern for local residents and authorities, a cooperative broadband monitoring network was installed by the Servicio Geológico Colombiano in Colombia and the Instituto Geofísico of the Escuela Politécnica Nacional in Ecuador. Since November 2013 more than 538,000 earthquakes were recorded; although since May 2015 the seismicity has decreased significantly to an average of 70 events per day. Three large earthquake swarms with increasing energy occurred in Aug.-Oct. 2013, March-May 2014, and Sept.-Dec. 2014. By the end of 2014, roughly 400 earthquakes greater than M 3 had occurred with a maximum rate of 8000 earthquakes per day. The largest earthquake was a 5.6 ML on Oct. 20, 2014. This event produced an InSAR coseismic deformation of ~23 cm (S. Ebmeier, personal communication). Most events are typical brittle failure volcano-tectonic (VT) earthquakes that are located in a cluster beneath the southern flank of Chiles volcano, with depths between 1.5 and 10 km. Although the great majority of earthquakes are VT, some low-frequency (LF, ~0.5 Hz) and very-low-frequency (VLF) events have occurred. Particle motion analysis suggests that the VLF source migrated with time. While a VLF on Oct. 15, 2014 was located south of Chiles volcano, near the InSAR source, the VLF registered on Feb. 14, 2015 was likely located very close to Chiles Volcano. We infer that magma intrusion and resulting fluid exsolution at depths greater than 5 km are driving seismicity in the Chiles-Cerro Negro region. However earthquakes are failing in a manner consistent with regional tectonics. Relative relocations reveal a structure consistent with mapped regional faults. Thus seismicity is likely controlled by an interaction of magmatic and tectonic processes. Because the regional stress field is highly compressional and the volcanoes

  1. Time-lapse Imaging of Active Lava Flows at Mt. Etna, Sicily

    NASA Astrophysics Data System (ADS)

    James, M. R.; Pinkerton, H.; Applegarth, L. J.; Hancock, A.; Slatcher, N.; Owen, J.; Calvari, S.; Ganci, G.

    2014-12-01

    Over the last ~6 years, remote time-lapse cameras have been deployed on Mt. Etna, Sicily, with a view to capturing the emplacement of a substantial lava flow field. Initial deployment of wildlife trail-style cameras in 2008 acquired data on lava channel processes during the 2008-9 eruption. In 2009, just in time to capture the dying phases of the eruption, an upgraded network of dSLRs was installed. The network has subsequently captured the steady growth of the New South East crater and the rapid emplacement of short-lived sheet flows that have accompanied the recent paroxysmal fire fountaining events. Most of the imagery has been acquired over distances of multiple kilometres, but the portability of the time-lapse setup has also allowed several opportunistic close range (hundreds of metres or less) deployments, to observe near-vent processes or effusion inside the Bocca Nuova crater. Here, we provide an overview of the equipment, and the approaches used to georeference the monoscopic time-lapse imagery through integrating with 3D data (e.g. existing DEMs, or data simultaneously collected by terrestrial laser scanner or photogrammetric techniques). The acquired observations of flow front emplacement, flow inflation, channel breaching and effusion rate variations that provide insight into the processes involved in long lived flow fields will be presented. Significant opportunities remain, for example, in the near real-time derivation of bulk rheological parameters, and integration with numerical flow models, and the challenges involved in using such imagery will be discussed.

  2. Characterising volcanic activity of Piton de la Fournaise volcano by the spatial distribution of seismic velocity changes

    NASA Astrophysics Data System (ADS)

    Sens-Schoenfelder, C.; Pomponi, E.

    2013-12-01

    We apply Passive Image Interferometry to investigate the seismic noise recorded from October 2009 until December 2011 by 21 stations of the IPGP/OVPF seismic network installed on Piton de la Fournaise volcano within the UnderVolc project. The analyzed period contains three eruptions in 2009 and January 2010, two eruptions plus one dyke intrusion in late 2010, and a seismic crises in 2011. Seismic noise of vertical and horizontal components is cross-correlated to measure velocity changes as apparent stretching of the coda. For some station pairs the apparent velocity changes exceed 1% and a decorrelation of waveforms is observed at the time of volcanic activity. This distorts monitoring results if changes are measured with respect to a global reference. To overcome this we present a method to estimate changes using multiple references that stabilizes the quality of estimated velocity changes. We observe abrupt changes that occur coincident with volcanic events as well as long term transient signals. Using a simple assumption about the spatial sensitivity of our measurements we can map the spatial distribution of velocity changes for selected periods. Comparing these signals with volcanic activity and GPS derived surface deformation we can identify patterns of the velocity changes that appear characteristic for the type of volcanic activity. We can differentiate intrusive processes associated with inflation and increased seismic activity, periods of relaxation without seismicity and eruptions solely based on the velocity signal. This information can help to assess the processes acting in the volcano.

  3. State of the hydrothermal activity of Soufrière of Guadeloupe volcano inferred by VLF surveys

    NASA Astrophysics Data System (ADS)

    Zlotnicki, J.; Vargemezis, G.; Mille, A.; Bruère, F.; Hammouya, G.

    2006-04-01

    La Soufrière (1467 m) is the active island arc volcano of Guadeloupe Island in the Lesser Antilles arc. Its historical eruptions are more or less violent phreatic outbursts the last of which, in 1976-1977, led to the evacuation of nearly 70 000 persons. The subsurface structure of the volcano consists of calderas, craters, and avalanche amphitheatres nested within the composite pile of eruptive products. Since the last magmatic eruption, dated ca. 1440 AD, the four phreatic eruptions have developed radial fractures on Soufrière dome favouring the development of a huge active hydrothermal system emphasized by a tropical environment. After the eruptions, the thermal state and the stable ground water flow are completely disorganised during several years during which the slow mineralization of rocks is becoming again preponderant. Sealing of fractures and decay of rocks permeability act as a cap for upward thermal transfers. Therefore Soufrière dome operates as a valve, resealing the hydrothermal system underlying the volcano thus providing over pressurization that could lead to the next phreatic eruption. In 1992 new small seismic swarms have appeared. Several of them are recorded every year while the emission of acid gas slowly increases. In order to recognise the superficial electrical resistive and conductive zones (less than 100 m depth) as well as the cavities on Soufrière volcano, we have made Very Low Frequency (VLF) surveys in 2000. Electrical conductive zones are clearly associated with major radial faults starting from the summit in which the hydrothermal activity takes place. In the continuation of these active hydrothermal fractures hot springs are located down slope. Conversely some of the resistive zones are associated with inactive clayed and sealed or opened faults. The distribution of the conductive zones allows detailing the state of the superficial part of the hydrothermal system of La Soufrière. The distribution of vertical clayed zones

  4. The limits of seaward spreading and slope instability at the continental margin offshore Mt Etna, imaged by high-resolution 2D seismic data

    NASA Astrophysics Data System (ADS)

    Gross, Felix; Krastel, Sebastian; Geersen, Jacob; Behrmann, Jan Hinrich; Ridente, Domenico; Chiocci, Francesco Latino; Bialas, Jörg; Papenberg, Cord; Cukur, Deniz; Urlaub, Morelia; Micallef, Aaron

    2016-01-01

    Mount Etna is the largest active volcano in Europe. Instability of its eastern flank is well documented onshore, and continuously monitored by geodetic and InSAR measurements. Little is known, however, about the offshore extension of the eastern volcano flank, defining a serious shortcoming in stability models. In order to better constrain the active tectonics of the continental margin offshore the eastern flank of the volcano, we acquired a new high-resolution 2D reflection seismic dataset. The data provide new insights into the heterogeneous geology and tectonics at the continental margin offshore Mt Etna. The submarine realm is characterized by different blocks, which are controlled by local- and regional tectonics. A compressional regime is found at the toe of the continental margin, which is bound to a complex basin system. Both, the clear link between on- and offshore tectonic structures as well as the compressional regime at the easternmost flank edge, indicate a continental margin gravitational collapse as well as spreading to be present at Mt Etna. Moreover, we find evidence for the offshore southern boundary of the moving flank, which is identified as a right lateral oblique fault north of Catania Canyon. Our findings suggest a coupled volcano edifice/continental margin instability at Mt Etna, demonstrating first order linkage between on- and offshore tectonic processes.

  5. Respiratory and TCA cycle activities affect S. cerevisiae lifespan, response to caloric restriction and mtDNA stability.

    PubMed

    Tahara, Erich B; Cezário, Kizzy; Souza-Pinto, Nadja C; Barros, Mario H; Kowaltowski, Alicia J

    2011-10-01

    We studied the importance of respiratory fitness in S. cerevisiae lifespan, response to caloric restriction (CR) and mtDNA stability. Mutants harboring mtDNA instability and electron transport defects do not respond to CR, while tricarboxylic acid cycle mutants presented extended lifespans due to CR. Interestingly, mtDNA is unstable in cells lacking dihydrolipoyl dehydrogenase under CR conditions, and cells lacking aconitase under standard conditions (both enzymes are components of the TCA and mitochondrial nucleoid). Altogether, our data indicate that respiratory integrity is required for lifespan extension by CR and that mtDNA stability is regulated by nucleoid proteins in a glucose-sensitive manner.

  6. TIMP-2 (tissue inhibitor of metalloproteinase-2) regulates MMP-2 (matrix metalloproteinase-2) activity in the extracellular environment after pro-MMP-2 activation by MT1 (membrane type 1)-MMP.

    PubMed Central

    Bernardo, M Margarida; Fridman, Rafael

    2003-01-01

    The matrix metalloproteinase (MMP)-2 has a crucial role in extracellular matrix degradation associated with cancer metastasis and angiogenesis. The latent form, pro-MMP-2, is activated on the cell surface by the membrane-tethered membrane type 1 (MT1)-MMP, in a process regulated by the tissue inhibitor of metalloproteinase (TIMP)-2. A complex of active MT1-MMP and TIMP-2 binds pro-MMP-2 forming a ternary complex, which permits pro-MMP-2 activation by a TIMP-2-free neighbouring MT1-MMP. It remains unclear how MMP-2 activity in the pericellular space is regulated in the presence of TIMP-2. To address this question, the effect of TIMP-2 on MMP-2 activity in the extracellular space was investigated in live cells, and their isolated plasma membrane fractions, engineered to control the relative levels of MT1-MMP and TIMP-2 expression. We show that both free and inhibited MMP-2 is detected in the medium, and that the net MMP-2 activity correlates with the level of TIMP-2 expression. Studies to displace MT1-MMP-bound TIMP-2 in a purified system with active MMP-2 show minimal displacement of inhibitor, under the experimental conditions, due to the high affinity interaction between TIMP-2 and MT1-MMP. Thus inhibition of MMP-2 activity in the extracellular space is unlikely to result solely as a result of TIMP-2 dissociation from its complex with MT1-MMP. Consistently, immunoblot analyses of plasma membranes, and surface biotinylation experiments show that the level of surface association of TIMP-2 is independent of MT1-MMP expression. Thus low-affinity binding of TIMP-2 to sites distinct to MT1-MMP may have a role in regulating MMP-2 activity in the extracellular space generated by the ternary complex. PMID:12755684

  7. Chronology of Postglacial Eruptive Activity and Calculation of Eruption Probabilities for Medicine Lake Volcano, Northern California

    USGS Publications Warehouse

    Nathenson, Manuel; Donnelly-Nolan, Julie M.; Champion, Duane E.; Lowenstern, Jacob B.

    2007-01-01

    Medicine Lake volcano has had 4 eruptive episodes in its postglacial history (since 13,000 years ago) comprising 16 eruptions. Time intervals between events within the episodes are relatively short, whereas time intervals between the episodes are much longer. An updated radiocarbon chronology for these eruptions is presented that uses paleomagnetic data to constrain the choice of calibrated ages. This chronology is used with exponential, Weibull, and mixed-exponential probability distributions to model the data for time intervals between eruptions. The mixed exponential distribution is the best match to the data and provides estimates for the conditional probability of a future eruption given the time since the last eruption. The probability of an eruption at Medicine Lake volcano in the next year from today is 0.00028.

  8. Subaqueous cryptodome eruption, hydrothermal activity and related seafloor morphologies on the andesitic North Su volcano

    NASA Astrophysics Data System (ADS)

    Thal, Janis; Tivey, Maurice; Yoerger, Dana R.; Bach, Wolfgang

    2016-09-01

    North Su is a double-peaked active andesite submarine volcano located in the eastern Manus Basin of the Bismarck Sea that reaches a depth of 1154 m. It hosts a vigorous and varied hydrothermal system with black and white smoker vents along with several areas of diffuse venting and deposits of native sulfur. Geologic mapping based on ROV observations from 2006 and 2011 combined with morphologic features identified from repeated bathymetric surveys in 2002 and 2011 documents the emplacement of a volcanic cryptodome between 2006 and 2011. We use our observations and rock analyses to interpret an eruption scenario where highly viscous, crystal-rich andesitic magma erupted slowly into the water-saturated, gravel-dominated slope of North Su. An intense fragmentation process produced abundant blocky clasts of a heterogeneous magma (olivine crystals within a rhyolitic groundmass) that only rarely breached through the clastic cover onto the seafloor. Phreatic and phreatomagmatic explosions beneath the seafloor cause mixing of juvenile and pre-existing lithic clasts and produce a volcaniclastic deposit. This volcaniclastic deposit consists of blocky, non-altered clasts next, variably (1-100%) altered clasts, hydrothermal precipitates and crystal fragments. The usually applied parameters to identify juvenile subaqueous lava fragments, i.e. fluidal shape or chilled margin, were not applicable to distinguish between pre-existing non-altered clasts and juvenile clasts. This deposit is updomed during further injection of magma and mechanical disruption. Gas-propelled turbulent clast-recycling causes clasts to develop variably rounded shapes. An abundance of blocky clasts and the lack of clasts typical for the contact of liquid lava with water is interpreted to be the result of a cooled, high-viscosity, crystal-rich magma that failed as a brittle solid upon stress. The high viscosity allows the lava to form blocky and short lobes. The pervasive volcaniclastic cover on North Su is

  9. Remote sensing of volcanos and volcanic terrains

    NASA Technical Reports Server (NTRS)

    Mouginis-Mark, Peter J.; Francis, Peter W.; Wilson, Lionel; Pieri, David C.; Self, Stephen; Rose, William I.; Wood, Charles A.

    1989-01-01

    The possibility of using remote sensing to monitor potentially dangerous volcanoes is discussed. Thermal studies of active volcanoes are considered along with using weather satellites to track eruption plumes and radar measurements to study lava flow morphology and topography. The planned use of orbiting platforms to study emissions from volcanoes and the rate of change of volcanic landforms is considered.

  10. Digital Data for Volcano Hazards at Newberry Volcano, Oregon

    USGS Publications Warehouse

    Schilling, S.P.; Doelger, S.; Sherrod, D.R.; Mastin, L.G.; Scott, W.E.

    2008-01-01

    Newberry volcano is a broad shield volcano located in central Oregon, the product of thousands of eruptions, beginning about 600,000 years ago. At least 25 vents on the flanks and summit have been active during the past 10,000 years. The most recent eruption 1,300 years ago produced the Big Obsidian Flow. Thus, the volcano's long history and recent activity indicate that Newberry will erupt in the future. Newberry Crater, a volcanic depression or caldera has been the focus of Newberry's volcanic activity for at least the past 10,000 years. Newberry National Volcanic Monument, which is managed by the U.S. Forest Service, includes the caldera and extends to the Deschutes River. Newberry volcano is quiet. Local earthquake activity (seismicity) has been trifling throughout historic time. Subterranean heat is still present, as indicated by hot springs in the caldera and high temperatures encountered during exploratory drilling for geothermal energy. The report USGS Open-File Report 97-513 (Sherrod and others, 1997) describes the kinds of hazardous geologic events that might occur in the future at Newberry volcano. A hazard-zonation map is included to show the areas that will most likely be affected by renewed eruptions. When Newberry volcano becomes restless, the eruptive scenarios described herein can inform planners, emergency response personnel, and citizens about the kinds and sizes of events to expect. The geographic information system (GIS) volcano hazard data layers used to produce the Newberry volcano hazard map in USGS Open-File Report 97-513 are included in this data set. Scientists at the USGS Cascades Volcano Observatory created a GIS data layer to depict zones subject to the effects of an explosive pyroclastic eruption (tephra fallout, pyroclastic flows, and ballistics), lava flows, volcanic gasses, and lahars/floods in Paulina Creek. A separate GIS data layer depicts drill holes on the flanks of Newberry Volcano that were used to estimate the probability

  11. Magmatic inflation at a dormant stratovolcano: 1996-1998 activity at Mount Peulik volcano, Alaska, revealed by satellite radar interferometry

    USGS Publications Warehouse

    Lu, Zhiming; Wicks, C.; Dzurisin, D.; Power, J.A.; Moran, S.C.; Thatcher, W.

    2002-01-01

    A series of ERS radar interferograms that collectively span the time interval from July 1992 to August 2000 reveal that a presumed magma body located 6.6 ??? 0.5 km beneath the southwest flank of the Mount Peulik volcano inflated 0.051 ??? 0.005 km3 between October 1996 and September 1998. Peulik has been active only twice during historical time, in 1814 and 1852, and the volcano was otherwise quiescent during the 1990s. The inflation episode spanned at least several months because separate interferograms show that the associated ground deformation was progressive. The average inflation rate of the magma body was ???0.003 km3/month from October 1996 to September 1997, peaked at 0.005 km3/month from 26 June to 9 October 1997, and dropped to ???0.001 km3/month from October 1997 to September 1998. An intense earthquake swarm, including three ML 4.8 - 5.2 events, began on 8 May 1998 near Becharof Lake, ???30 km northwest of Peulik. More than 400 earthquakes with a cumulative moment of 7.15 ?? 1017 N m were recorded in the area through 19 October 1998. Although the inflation and earthquake swarm occured at about the same time, the static stress changes that we calculated in the epicentral area due to inflation beneath Peulik appear too small to provide a causal link. The 1996-1998 inflation episode at Peulik confirms that satellite radar interferometry can be used to detect magma accumulation beneath dormant volcanoes at least several months before other signs of unrest are apparent. This application represents a first step toward understanding the eruption cycle at Peulik and other stratovolcanoes with characteristically long repose periods.

  12. A large hydrothermal reservoir beneath Taal Volcano (Philippines) revealed by magnetotelluric observations and its implications to the volcanic activity

    PubMed Central

    ALANIS, Paul K. B.; YAMAYA, Yusuke; TAKEUCHI, Akihiro; SASAI, Yoichi; OKADA, Yoshihiro; NAGAO, Toshiyasu

    2013-01-01

    Taal Volcano is one of the most active volcanoes in the Philippines. The magnetotelluric 3D forward analyses indicate the existence of a large high resistivity anomaly (∼100 Ω·m) with a volume of at least 3 km × 3 km × 3 km, which is capped by a conductive layer (∼10 Ω·m), beneath the Main Crater. This high resistivity anomaly is hypothesized to be a large hydrothermal reservoir, consisting of the aggregate of interconnected cracks in rigid and dense host rocks, which are filled with hydrothermal fluids coming from a magma batch below the reservoir. The hydrothermal fluids are considered partly in gas phase and liquid phase. The presence of such a large hydrothermal reservoir and the stagnant magma below may have influences on the volcano’s activity. Two possibilities are presented. First, the 30 January 1911 explosion event was a magmatic hydrothermal eruption rather than a base-surge associated with a phreato-magmatic eruption. Second, the earlier proposed four eruption series may be better interpreted by two cycles, each consisting of series of summit and flank eruptions. PMID:24126286

  13. Frequency based detection and monitoring of small scale explosive activity by comparing satellite and ground based infrared observations at Stromboli Volcano, Italy

    NASA Astrophysics Data System (ADS)

    Worden, Anna; Dehn, Jonathan; Ripepe, Maurizio; Donne, Dario Delle

    2014-08-01

    Thermal activity is a common precursor to explosive volcanic activity. The ability to use these thermal precursors to monitor the volcano and obtain early warning about upcoming activity is beneficial for both human safety and infrastructure security. By using a very reliably active volcano, Stromboli Volcano in Italy, a method has been developed and tested to look at changes in the frequency of small scale explosive activity and how this activity changes prior to larger, ash producing explosive events. Thermal camera footage was used to designate parameters for typical explosions at Stromboli (size of spatter field, cooling rate, frequency of explosions) and this information was applied to characterize explosions in satellite imagery. Satellite data from The National Aeronautics and Space Administration's Moderate Resolution Imaging Spectroradiometer (MODIS) and US/Japan designed Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) for numerous periods in 2002 to 2009 were analyzed for thermal features which were used to calculate an estimate of the level of activity during the given time period. The results at Stromboli showed a high level of small scale explosions which stop completely prior to large paroxysmal eruptive episodes. This activity also corresponds well to seismic and infrasonic records at Stromboli, indicating that this thermal infrared monitoring method may be used in conjunction with other detection methods where available, and also indicates that it may be a useful method for volcano monitoring when other methods (e.g. seismic instrumentation, infrasound arrays, etc.) are not available.

  14. Abnormally activated one-carbon metabolic pathway is associated with mtDNA hypermethylation and mitochondrial malfunction in the oocytes of polycystic gilt ovaries.

    PubMed

    Jia, Longfei; Li, Juan; He, Bin; Jia, Yimin; Niu, Yingjie; Wang, Chenfei; Zhao, Ruqian

    2016-01-01

    Polycystic ovarian syndrome (PCOS) is associated with hyperhomocysteinemia and polycystic ovaries (PCO) usually produce oocytes of poor quality. However, the intracellular mechanism linking hyperhomocysteinemia and oocyte quality remains elusive. In this study, the quality of the oocytes isolated from healthy and polycystic gilt ovaries was evaluated in vitro in association with one-carbon metabolism, mitochondrial DNA (mtDNA) methylation, and mitochondrial function. PCO oocytes demonstrated impaired polar body extrusion, and significantly decreased cleavage and blastocyst rates. The mitochondrial distribution was disrupted in PCO oocytes, together with decreased mitochondrial membrane potential and deformed mitochondrial structure. The mtDNA copy number and the expression of mtDNA-encoded genes were significantly lower in PCO oocytes. Homocysteine concentration in follicular fluid was significantly higher in PCO group, which was associated with significantly up-regulated one-carbon metabolic enzymes betaine homocysteine methyltransferase (BHMT), glycine N-methyltransferase (GNMT) and the DNA methyltransferase DNMT1. Moreover, mtDNA sequences coding for 12S, 16S rRNA and ND4, as well as the D-loop region were significantly hypermethylated in PCO oocytes. These results indicate that an abnormal activation of one-carbon metabolism and hypermethylation of mtDNA may contribute, largely, to the mitochondrial malfunction and decreased quality of PCO-derived oocytes in gilts. PMID:26758245

  15. Abnormally activated one-carbon metabolic pathway is associated with mtDNA hypermethylation and mitochondrial malfunction in the oocytes of polycystic gilt ovaries

    PubMed Central

    Jia, Longfei; Li, Juan; He, Bin; Jia, Yimin; Niu, Yingjie; Wang, Chenfei; Zhao, Ruqian

    2016-01-01

    Polycystic ovarian syndrome (PCOS) is associated with hyperhomocysteinemia and polycystic ovaries (PCO) usually produce oocytes of poor quality. However, the intracellular mechanism linking hyperhomocysteinemia and oocyte quality remains elusive. In this study, the quality of the oocytes isolated from healthy and polycystic gilt ovaries was evaluated in vitro in association with one-carbon metabolism, mitochondrial DNA (mtDNA) methylation, and mitochondrial function. PCO oocytes demonstrated impaired polar body extrusion, and significantly decreased cleavage and blastocyst rates. The mitochondrial distribution was disrupted in PCO oocytes, together with decreased mitochondrial membrane potential and deformed mitochondrial structure. The mtDNA copy number and the expression of mtDNA-encoded genes were significantly lower in PCO oocytes. Homocysteine concentration in follicular fluid was significantly higher in PCO group, which was associated with significantly up-regulated one-carbon metabolic enzymes betaine homocysteine methyltransferase (BHMT), glycine N-methyltransferase (GNMT) and the DNA methyltransferase DNMT1. Moreover, mtDNA sequences coding for 12S, 16S rRNA and ND4, as well as the D-loop region were significantly hypermethylated in PCO oocytes. These results indicate that an abnormal activation of one-carbon metabolism and hypermethylation of mtDNA may contribute, largely, to the mitochondrial malfunction and decreased quality of PCO-derived oocytes in gilts. PMID:26758245

  16. Not one extrastriate body area: Using anatomical landmarks, hMT+, and visual field maps to parcellate limb-selective activations in human lateral occipitotemporal cortex

    PubMed Central

    Weiner, Kevin S.; Grill-Spector, Kalanit

    2011-01-01

    The prevailing view of human lateral occipitotemporal cortex (LOTC) organization suggests a single area selective for images of the human body (extrastriate body area, EBA) that highly overlaps with the human motion-selective complex (hMT+). Using functional magnetic resonance imaging with higher resolution (1.5mm voxels) than past studies (3–4mm voxels), we examined the fine-scale spatial organization of these activations relative to each other, as well as to visual field maps in LOTC. Rather than one contiguous EBA highly overlapping hMT+, results indicate three limb-selective activations organized in a crescent surrounding hMT+: (1) an activation posterior to hMT+ on the lateral occipital sulcus/middle occipital gyrus (LOS/MOG) overlapping the lower vertical meridian shared between visual field maps LO-2 and TO-1, (2) an activation anterior to hMT+ on the middle temporal gyrus (MTG) consistently overlapping the lower vertical meridian of TO-2 and extending outside presently defined visual field maps, and (3) an activation inferior to hMT+ on the inferotemporal gyrus (ITG) overlapping the parafoveal representation of the TO cluster. This crescent organization of limb-selective activations surrounding hMT+ is reproducible over a span of three years and is consistent across different image types used for localization. Further, these regions exhibit differential position properties: preference for contralateral image presentation decreases and preference for foveal presentation increases from the limb-selective LOS to the MTG. Finally, the relationship between limb-selective activations and visual field maps extends to the dorsal stream where a posterior IPS activation overlaps V7. Overall, our measurements demonstrate a series of LOTC limb-selective activations that 1) have separate anatomical and functional boundaries, 2) overlap distinct visual field maps, and 3) illustrate differential position properties. These findings indicate that category selectivity

  17. Multiparametric approach to unravel the mechanism of Strombolian activity at a multivent system: Mt. Etna case study

    NASA Astrophysics Data System (ADS)

    Cannata, Andrea; Del Bello, Elisabetta; Kueppers, Ulrich; Privitera, Eugenio; Ricci, Tullio; Scarlato, Piergiorgio; Sciotto, Mariangela; Spina, Laura; Taddeucci, Jacopo; Pena Fernandez, Juan Jose; Sesterhenn, Joern

    2016-04-01

    On 5th July 2014 an eruptive fissure (hereafter referred to as EF) opened at the base of North-East Crater (NEC) of Mt. Etna. EF produced both Strombolian explosions and lava effusion. Thanks to the multiparametric experiment planned in the framework of MEDSUV project, we had the chance to acquire geophysical and volcanological data, in order to investigate the ongoing volcanic activity at EF. Temporary instruments (2 broadband seismometers, 2 microphones, 3-microphone arrays, a high-speed video camera and a thermal-camera) were deployed near the active vents during 15-16 July 2014 and were integrated with the data recorded by the permanent networks. Several kinds of studies are currently in progress, such as: frequency analysis by Fourier Transform and Short Time Fourier Transform to evaluate the spectral content of both seismic and acoustic signals; partitioning of seismic and acoustic energies, whose time variations could reflect changes in the volcanic dynamics; investigation on the intertimes between explosions to investigate their recurrence behaviour; classification of the waveforms of infrasound events. Furthermore, joint analysis of video signals and seismic-acoustic wavefields outlined relationships between pyroclasts ejection velocity, total erupted mass, peak explosion pressure, and air-ground motion coupling. This multiparametric approach allowed distinguishing and characterizing individually the behavior of the two vents active along the eruptive fissure via their thermal, visible and infrasonic signatures and shed light in the eruptive dynamics.

  18. NeMO-Net: A System for Near Real-Time Remote Sensing of Hydrothermal and Biological Activity in the Caldera of an Active Submarine Volcano

    NASA Astrophysics Data System (ADS)

    Hammond, S. R.; Butterfield, D.; Embley, R. W.; Meinig, C.; Stalin, S.

    2001-12-01

    In July of 2000, a camera and three temperature sensors were placed on the seafloor near a hydrothermal vent located in the caldera of an active submarine volcano. The volcano's summit lies at a depth of about 1500 m and is located at 46° N, 130° W, approximately 250 nautical miles off the Oregon coast. The volcano is the site of a long-term interdisciplinary study focused in part on discovering relationships between submarine volcanic and hydrothermal activity and a microbial biosphere which exists beneath the sea floor within the volcano's summit caldera. NeMO-Net utilizes an acoustic modem to communicate with a surface mooring anchored nearby. The mooring, in turn, is linked from the ocean surface to the Pacific Marine Environmental Laboratory by means of satellite systems. A unique feature of NeMO-Net is that it enables shore-based investigators to interrogate and command the system to perform specific tasks, the results of which are then reported back typically within several minutes . In the initial year-long deployment, photographic images, along with hourly readings from the three temperature probes, were available on a website which was updated every 24 hours. During the year, the camera documented a dynamic vent biological community as well as water temperature variations due to the influence of tides, and possibly with changing vent fluid temperatures The NeMO-Net system is under continuing development with particular emphasis on linking it to multiple sea floor instruments including near-real-time chemical and water samplers. Near-future plans also call for NeMO Net to be linked to a resident sea floor AUV.

  19. Dynamical parameter analysis of continuous seismic signals of Popocatépetl volcano (Central Mexico): A case of tectonic earthquakes influencing volcanic activity

    NASA Astrophysics Data System (ADS)

    Tárraga, Marta; Cruz-Reyna, Servando; Mendoza-Rosas, Ana; Carniel, Roberto; Martínez-Bringas, Alicia; García, Alicia; Ortiz, Ramon

    2012-06-01

    The continuous background seismic activity contains information on the internal state of a volcanic system. Here, we report the influence of major regional tectonic earthquakes (M > 5 in most cases) on such state, reflected as changes in the spectral and dynamical parameters of the volcano continuous seismic data. Although changes do not always occur, analysis of five cases of earthquake-induced variations in the signals recorded at Popocatépetl volcano in central México reveal significant fluctuations following the tectonic earthquakes. External visible volcanic activity, such as small to moderate explosions and ash emissions, were related to those fluctuations. We briefly discuss possible causes of the variations. We conclude that recognition of fluctuations in the dynamical parameters in volcano monitoring seismic signals after tectonic earthquakes, even those located in the far field, hundreds of kilometers away, may provide an additional criterion for eruption forecasting, and for decision making in the definition of volcanic alert levels.

  20. Lightning and electrical activity during the Shiveluch volcano eruption on 16 November 2014

    NASA Astrophysics Data System (ADS)

    Shevtsov, B. M.; Firstov, P. P.; Cherneva, N. V.; Holzworth, R. H.; Akbashev, R. R.

    2015-11-01

    According to WWLLN data, a sequence of lightning discharges was detected. It occurred on the path of propagation of eruptive ash cloud formed in the result of the explosive eruption of Shiveluch volcano on 16 November 2014 in Kamchatka. Information on the cloud motion was confirmed by the measurements of atmospheric electricity, satellite observations, meteorological and seismic data. It was concluded that WWLLN resolution is enough to trace ash clouds at the stage of their fragmentation when electrification processes develop the most intensively. The undeniable advantage of WWLLN method is its efficiency and the possibility to apply in the conditions of poor visibility.