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Sample records for lavas las pataguas

  1. Lava

    NASA Image and Video Library

    2012-01-17

    The volcanic flow in this image from NASA 2001 Mars Odyssey spacecraft appears to have flowed in one layer. The surface texture is blocks of lava which cooled and still moved on molten lava below, producing the plate-like texture.

  2. Inverse steptoes in Las Bombas volcano, as an evidence of explosive volcanism in a solidified lava flow field. Southern Mendoza-Argentina

    NASA Astrophysics Data System (ADS)

    Risso, Corina; Prezzi, Claudia; Orgeira, María Julia; Nullo, Francisco; Margonari, Liliana; Németh, Karoly

    2015-11-01

    Here we describe the unusual genesis of steptoes in Las Bombas volcano- Llancanelo Volcanic Field (LVF) (Pliocene - Quaternary), Mendoza, Argentina. Typically, a steptoe forms when a lava flow envelops a hill, creating a well-defined stratigraphic relationship between the older hill and the younger lava flow. In the Llancanelo Volcanic Field, we find steptoes formed with an apparent normal stratigraphic relationship but an inverse age-relationship. Eroded remnants of scoria cones occur in "circular depressions" in the lava field. To express the inverse age-relationship between flow fields and depression-filled cones here we define this landforms as inverse steptoes. Magnetometric analysis supports this inverse age relationship, indicating reverse dipolar magnetic anomalies in the lava field and normal dipolar magnetization in the scoria cones (e.g. La Bombas). Negative Bouguer anomalies calculated for Las Bombas further support the interpretation that the scoria cones formed by secondary fracturing on already solidified basaltic lava flows. Advanced erosion and mass movements in the inner edge of the depressions created a perfectly excavated circular depression enhancing the "crater-like" architecture of the preserved landforms. Given the unusual genesis of the steptoes in LVF, we prefer the term inverse steptoe for these landforms. The term steptoe is a geomorphological name that has genetic implications, indicating an older hill and a younger lava flow. Here the relationship is reversed.

  3. Lava Channels

    NASA Image and Video Library

    2013-12-03

    The channels and linear depression in this image captured by NASA 2001 Mars Odyssey spacecraft are located on the western margin of the Elysium Volcanic complex. The channels were created by lava flow.

  4. Lava Lamp

    ERIC Educational Resources Information Center

    Leif, Todd R.

    2008-01-01

    This past semester I brought a Lava Lite[R] Lamp into my classroom. Why bring such a thing into class? Many of today's students are part of the "retro" movement. They buy clothes from the '60s, they wear their hair like people did in the '60s, and they look for the ideals and themes related to living in the 1960s. Physics education reform is also…

  5. Lava Lamp

    ERIC Educational Resources Information Center

    Leif, Todd R.

    2008-01-01

    This past semester I brought a Lava Lite[R] Lamp into my classroom. Why bring such a thing into class? Many of today's students are part of the "retro" movement. They buy clothes from the '60s, they wear their hair like people did in the '60s, and they look for the ideals and themes related to living in the 1960s. Physics education reform is also…

  6. Lava Flows

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03054 Lava Flows

    The lava flows in this image are only a very small part of the voluminous lava erupted from the Arsia Mons volcano.

    Image information: VIS instrument. Latitude 19.1S, Longitude 244.5E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  7. Lava Flows

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03658 Lava Flows

    These relatively young lava flows are part of Arsia Mons.

    Image information: VIS instrument. Latitude -22.5N, Longitude 242.3E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  8. Lava Lamp

    NASA Astrophysics Data System (ADS)

    Leif, Todd R.

    2008-04-01

    This past semester I brought a Lava Lite® Lamp into my classroom. Why bring such a thing into class? Many of today's students are part of the "retro" movement. They buy clothes from the '60s, they wear their hair like people did in the '60s, and they look for the ideals and themes related to living in the 1960s. Physics education reform is also examining ideas from the "retro" world of science. This was the post-Sputnik era, a time when science was done by actually doing it and not necessarily by lecturing about it. Cliff Swartz, former TPT editor, once mentioned during a presentation at a Texas AAPT meeting, "The world of physics teaching is cyclic, like a swinging pendulum. We as physics teachers jump from `new ideas' back to our old ones, each generation testing what works best for them."

  9. Lunar Lava Tube Sensing

    NASA Technical Reports Server (NTRS)

    York, Cheryl Lynn; Walden, Bryce; Billings, Thomas L.; Reeder, P. Douglas

    1992-01-01

    Large (greater than 300 m diameter) lava tube caverns appear to exist on the Moon and could provide substantial safety and cost benefits for lunar bases. Over 40 m of basalt and regolith constitute the lava tube roof and would protect both construction and operations. Constant temperatures of -20 C reduce thermal stress on structures and machines. Base designs need not incorporate heavy shielding, so lightweight materials can be used and construction can be expedited. Identification and characterization of lava tube caverns can be incorporated into current precursor lunar mission plans. Some searches can even be done from Earth. Specific recommendations for lunar lava tube search and exploration are (1) an Earth-based radar interferometer, (2) an Earth-penetrating radar (EPR) orbiter, (3) kinetic penetrators for lunar lava tube confirmation, (4) a 'Moon Bat' hovering rocket vehicle, and (5) the use of other proposed landers and orbiters to help find lunar lava tubes.

  10. Kaumana lava tube

    NASA Technical Reports Server (NTRS)

    Greeley, R.

    1974-01-01

    The entrance to Kaumana Lava Tube is in a picnic ground next to Highway 20 (Kaumana Drive) about 6.5 km southwest of Hilo. The area is passed on the way to the Kona Coast via the Saddle Road and is identified by a Hawaii Visitors Bureau sign. Although it is not the largest lava tube in the islands, Kaumana Lava Tube is an interesting geological formation, displaying many of the features typical of lava tube interiors. It is accessible, relatively easy to walk through, and is in an excellent state of preservation. The tube developed in a historic lava flow (1881, from Mauna Loa), and many aspects of lava tube activity are observed.

  11. Introducing Kansas Lava

    NASA Astrophysics Data System (ADS)

    Gill, Andy; Bull, Tristan; Kimmell, Garrin; Perrins, Erik; Komp, Ed; Werling, Brett

    Kansas Lava is a domain specific language for hardware description. Though there have been a number of previous implementations of Lava, we have found the design space rich, with unexplored choices. We use a direct (Chalmers style) specification of circuits, and make significant use of Haskell overloading of standard classes, leading to concise circuit descriptions. Kansas Lava supports both simulation (inside GHCi), and execution via VHDL, by having a dual shallow and deep embedding inside our Signal type. We also have a lightweight sized-type mechanism, allowing for MATLAB style matrix based specifications to be directly expressed in Kansas Lava.

  12. Wind and Lava

    NASA Image and Video Library

    2006-11-27

    In this image wind seems to be the dominant process, but lava flows are still recognizable from the surface texture. It appears that the lava flow top left is relatively thin, and the material below is easily eroded by the wind

  13. Lava That Once Flowed

    NASA Image and Video Library

    2016-10-19

    This image shows some beautiful lava flows in Amazonis Planitia. Lava isn't moving around on Mars today, but it certainly once did, and images like this one are evidence of that. A thick lava flow came in from the west, and you can see the cooled flow lobes and wrinkled upper surface. East of the flow margin, this most recent flow also coursed over an older lava surface which shows some long, north-south breaks, and in the southeast corner, an arrowhead-shaped set of ridges. These textures are most likely from rafted slabs of lava. Under certain conditions, a large piece of lava can cool, but then detach and move like an iceberg over a cushion of still-molten lava. The long, narrow north-south smooth areas are probably where two of these plates rafted away from one another exposing the lava below. The arrowhead-shaped ridges are probably from when one of these plates pushed up against another one and caused a pile-up before cooling. http://photojournal.jpl.nasa.gov/catalog/PIA21113

  14. Olympus Mons Lava Flows

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 05 April 2002) Olympus Mons stands 26 km above the surrounding plains, which is three times taller than Mt. Everest, and is the tallest volcano in the solar system. Olympus Mons is also wider (585 km) than the state of Arizona. Although these are impressive dimensions an astronaut would find walking these slopes easy, as they are typically only 2 to 5 degrees. This image contains numerous lava flows, leveed lava channels, a discontinuous sinuous rille (thought to be a collapsed lava tube) and lava plains. Close examination of the sinuous rille reveals that portions of the roof of the lava tube have not completely collapsed. All of these features can be seen in basaltic (iron and magnesium rich black rock) volcanic regions on Earth like Hawaii and Iceland. Impact craters are scarce, indicating a relatively young age (several hundred million years old) for these surfaces.

  15. Martian Lava Flows

    NASA Technical Reports Server (NTRS)

    2005-01-01

    19 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows lava flows at the southeast base of the giant volcano, Olympus Mons. The flat plain in the south-southeast (bottom/lower right) portion of the image is younger than and cuts off the ends of many of the lava flows that came from the northwest (upper left). Many of the lava flows in this image exhibit channels with levees bounding their margins. As each lava flow was advancing, its outer margins cooled and hardened, forming a channel or tube through which the molten rock continued to advance.

    Location near: 17.2oN, 129.0oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  16. Extra Terrestrial Lava Flows

    NASA Technical Reports Server (NTRS)

    Lopes-Gautier, R.

    1993-01-01

    Volcanism has been one of the major processes shaping the surfaces of the terrestrial planets. Lava flows have been identified on the Moon, Mars, Venus, and on Juptier's moon Io. The study of extra-terrestrial lavas has largely relied on the interpretation of remotely acquired imaging, topographic and spectroscopic data. Models relating the final flow morpohology to eruption characteristics and magma chemistry have been important tools in the interpretation of these data.

  17. Lava flows and domes

    SciTech Connect

    Fink, J. )

    1989-01-01

    This book discusses emplacement of silicic domes and mafic lava flows. The authors have utilized the combination of field, experimental and theoretical methods to constrain various characteristics of recently-emplaced lavas, including dimensions, growth rates, surface morphology, deformation styles, rheology, and volatile contents. Filed measurements from numerous volcanoes are presented. Focus is on data from Mount St. Helens. The value of such investigations is addressed.

  18. Lava Flow Dynamics

    NASA Technical Reports Server (NTRS)

    Taylor, G. Jeffrey

    1996-01-01

    This grant originally had four major tasks, all of which were addressed to varying extents during the course of the research: (1) Measure the fractal dimensions of lava flows as a function of topography, substrate, and rheology; (2) The nature of lava tube systems and their relation to flow fields; (3) A quantitative assessment of lava flow dynamics in light of the fractal nature of lava flow margins; and (4) Development and application of a new remote sensing tool based on fractal properties. During the course of the research, the project expanded to include the following projects: (1) A comparison of what we can-learn from remote sensing studies of lava flow morphology and from studies of samples of lava flows; (2) Study of a terrestrial analog of the nakhlites, one of the groups of meteorites from Mars; and (3) Study of the textures of Hawaiian basalts as an aid in understanding the dynamics (flow rates, inflation rates, thermal history) of flow interiors. In addition, during the first year an educational task (development and writing of a teacher's guide and activity set to accompany the lunar sample disk when it is sent to schools) was included.

  19. Basaltic Lava Channels

    NASA Astrophysics Data System (ADS)

    Cashman, K. V.; Griffiths, R. W.; Kerr, R. C.

    2004-12-01

    In Hawaii, the mode of lava transport - through open channels or through insulating lava tubes - determines the thermal, rheological, and emplacement history of a lava flow. Most Hawaiian lavas are erupted at near-liquidus temperatures and are therefore crystal-poor; lava transport through open channels allows rapid cooling and consequent rapid increases in lava crystallinity. Solidified aa flows resulting from channelized flow are typically fine-grained throughout their thickness, indicating cooling of the entire flow thickness during transport. In contrast, transport of lava through insulating tubes permits flow over long distances with little cooling. Flows emerging from such tubes typically have pahoehoe flow surfaces with glassy crusts. Groundmass textures that coarsen from the flow rind to the interior reflect rates of post-emplacement, rather than syn-emplacement, cooling. To distinguish eruption conditions that result in lava channels from those that allow formation of lava tubes, we have performed a series of laboratory experiments involving injection of PEG 600 (a wax with a Newtonian rheology and freezing temperature of 19ºC) into cold water through both uniform and non-uniform sloping channels. In uniform channels, tube formation can be distinguished from open channel flow using a dimensionless parameter based on a solidification time scale, an advection time scale, and a Rayleigh number that describes convection by heat loss from crust-free shear zones. Theoretical analysis predicts that in the open channel regime, the width of the crust (dc) will vary with the channel width (W) as dc = W5/3. Crustal coverage of non-uniform channels in both laboratory experiments and field examples from Kilauea Volcano, Hawaii, is consistent with this prediction. However, experiments in non-uniform channels illustrate additional controls on the surface coverage of lava channels. Most important is crustal extension resulting from flow acceleration through constrictions

  20. The foaming of lavas

    NASA Technical Reports Server (NTRS)

    Okeefe, J. A.; Walton, W.

    1976-01-01

    Foaming is of great practical and theoretical significance for volcanic processes on the earth, the moon, and perhaps the meteorite parent bodies. The theory of foams agrees with steelmaking experience to indicate that their presence depends on the existence of solutes in the lavas which reduce the surface tension, and are not saturated. These solutes concentrate at the surface, and are called surfactants. The surfactant responsible for the formation of volcanic ash was not identified; it appears to be related to the oxygen partial pressure above the lava. This fact may explain why lunar and meteoritic melts are not observed to foam. Experimental studies are needed to clarify the process.

  1. LAVA Applications to Open Rotors

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin C.; Housman, Jeff; Barad, Mike; Brehm, Christoph

    2015-01-01

    Outline: LAVA (Launch Ascent Vehicle Aerodynamics); Introduction; Acoustics Related Applications; LAVA Applications to Open Rotor; Structured Overset Grids; Cartesian Grid with Immersed Boundary; High Speed Case; High Speed Case with Plate Low Speed Case.

  2. Lava Flows of Daedalia Planum

    NASA Image and Video Library

    2002-12-19

    This NASA Mars Odyssey image captures a portion of several lava flows in Daedalia Planum southwest of the Arsia Mons shield volcano. Textures characteristic of the variable surface roughness associated with different lava flows in this region are easily s

  3. Lava Flows around Olympus Mons

    NASA Image and Video Library

    2002-12-16

    This image from NASA Mars Odyssey of lava flows around the large scarp of Olympus Mons reveals textures characteristic of the variable surface roughness associated with different lava flows in this region.

  4. Lava Tube Collapse Pits

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form.

    These collapse pits are found in the southern hemisphere of Mars. They are likely lava tube collapse pits related to flows from Hadriaca Patera.

    Image information: VIS instrument. Latitude -36.8, Longitude 89.6 East (270.4 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space

  5. Lava Tube Collapse Pits

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form.

    These collapse pits are found in the southern hemisphere of Mars. They are likely lava tube collapse pits related to flows from Hadriaca Patera.

    Image information: VIS instrument. Latitude -36.8, Longitude 89.6 East (270.4 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space

  6. Lava Lakes on Io?

    NASA Astrophysics Data System (ADS)

    Lopes, R. M. C.; Kamp, L. W.; Smythe, W. D.; Howell, R.; Mouginis-Mark, P.; Kargel, J. S.; Radebaugh, J.; Turtle, E. P.; Perry, J.; Williams, D. A.; Carlson, R. W.; Doute, S.; Galileo NIMS Team

    2003-05-01

    At least 152 active volcanic centers have been identified on Jupiter's moon Io [Lopes et al., 2003, submitted to Icarus]. Eruptions at these centers include lava flows (``Promethean" type eruptions), explosive ``Pillanian" eruptions [Keszthelyi et al., 2001, JGR 106, 33,025-52] and volcanism confined within patera walls (``Lokian", Lopes et al., 2003). Understanding the Lokian eruption mechanism is particularly important because paterae are the most ubiquitous volcanic constructs on Io's surface [Radebaugh et al. 2001, JGR, 106, 33,005-33,020] and patera volcanism is the most common eruption type on Io. We use observations from Galileo's Near-Infrared Mapping Spectrometer (NIMS) and compare them with images from Galileo's Solid State Imaging system (SSI) to map the distribution of thermal emission at several Ionian paterae. This allows us to examine how thermal emission correlates with visible features, and to investigate how thermal emission varies with time. Galileo's close fly-bys of Io from 1999 to 2001 allowed NIMS to observe the volcanoes at relatively high spatial resolution (1-30 km pixel). At these scales, observations of the several paterae reveal that the greatest thermal emission occurs at the edges. This can be explained as the crust of a lava lake breaking up against the base of the patera (caldera) walls, similar to what has been observed at lava lakes on Earth. Comparison with terrestrial analogs shows that several Ionian active paterae, such as Loki, Tupan, and Emakong, have thermal properties consistent with relatively inactive lava lakes on Earth. We discuss these results and their implications for eruption styles and resurfacing on Io. This work was supported in part by NASA's Planetary Geology and Geophysics Program.

  7. Lava-Filled Craters

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 12 June 2003

    Craters and hills form high standing streamlined plateaus or islands in a channeled area. The plateaus are rounded in the upstream direction and taper to a point in the downstream direction, indicating that the direction of flow in this area was roughly south to north, or bottom to top. The channels appear to be filled with lava flow deposits that are raised above the channel in some areas. A lava flow diverges around a small streamlined hill near the bottom of the image and then merges again around the northern end of it. Near the top of the image is a crater with a breach on the east (right) side that allowed the lava to flow in, leaving a lobate, high standing deposit. The channels may have been formed by the lava flows that currently fill them or there may have been flow of liquid water that created them before the lava was emplaced.

    Image information: VIS instrument. Latitude 16, Longitude 183 East (177 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built

  8. Lava-Filled Craters

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 12 June 2003

    Craters and hills form high standing streamlined plateaus or islands in a channeled area. The plateaus are rounded in the upstream direction and taper to a point in the downstream direction, indicating that the direction of flow in this area was roughly south to north, or bottom to top. The channels appear to be filled with lava flow deposits that are raised above the channel in some areas. A lava flow diverges around a small streamlined hill near the bottom of the image and then merges again around the northern end of it. Near the top of the image is a crater with a breach on the east (right) side that allowed the lava to flow in, leaving a lobate, high standing deposit. The channels may have been formed by the lava flows that currently fill them or there may have been flow of liquid water that created them before the lava was emplaced.

    Image information: VIS instrument. Latitude 16, Longitude 183 East (177 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built

  9. Phenocryst fragments in rhyolitic lavas and lava domes

    NASA Astrophysics Data System (ADS)

    Allen, S. R.; McPhie, J.

    2003-08-01

    Although rhyolitic lavas and lava domes are characterised by evenly porphyritic textures, not all the phenocrysts are whole euhedra. We undertook image analysis of 46 rhyolitic lava and lava dome samples to determine the abundance and shape of quartz and feldspar phenocryst fragments. Phenocryst fragments were identified in nearly all samples. On average, fragments amount to ˜5% of the total phenocryst population, or ˜0.5 modal%. The abundance of fragments in lavas and lava domes is not related to the groundmass texture (whether vesicular, flow banded, massive, glassy or crystalline), nor to distance from source. Fragments are, however, more abundant in samples with higher phenocryst contents. The phenocryst fragments in rhyolitic lavas and lava domes are mainly medium to large (0.5-3.5 mm), almost euhedral crystals with only a small portion removed, or chunky, equant, subhedral fragments, and occur in near-jigsaw-fit or clast-rotated pairs or groups. The fragments probably formed in response to decompression of large melt inclusions. Shear during laminar flow then dismembered the phenocrysts; continued laminar shear separated and rotated the fragments. Fractures probably formed preferentially along weaknesses in the phenocrysts, such as zones of melt inclusions, cleavage planes and twin composition planes. Rare splintery fragments are also present, especially within devitrified domains. Splinters are attributed to comminution of solid lava adjacent to fractures that were later healed. For comparison, we measured crystal abundance in a further 12 rhyolite samples that include block and ash flow deposits and ignimbrite. Phenocryst fragments within clasts in the block and ash flow samples showed similar shapes and abundances to those fragments within the lava and lava domes. Crystal fragments are much more abundant in ignimbrite (exceeding 67% of the crystal population) however, and dominated by small, equant, anhedral chunks or splinters. The larger crystals in

  10. Lava Flow at Kilauea, Hawaii

    NASA Image and Video Library

    2007-08-31

    On July 21, 2007, the world most active volcano, Kilauea on Hawaii Big Island, produced a fissure eruption from the Puu Oo vent, which fed an open lava channel and lava flows toward the east. This image is from NASA Terra satellite.

  11. Hawaii Lava Flows

    NASA Image and Video Library

    2001-10-22

    This sequence of ASTER nighttime thermal images shows the Pu'u O'o lava flows entering the sea at Kamokuna on the southeast side of the Island of Hawaii. Each image covers an area of 9 x 12 km. The acquisition dates are April 4 2000, May 13 2000, May 22 2000 (upper row) and June 30 2000, August 1 2000 and January 1 2001 (lower row). Thermal band 14 has been color coded from black (coldest) through blue, red, yellow and white (hottest). The first 5 images show a time sequence of a single eruptive phase; the last image shows flows from a later eruptive phase. The images are located at 19.3 degrees north latitude, 155 degrees west longitude. http://photojournal.jpl.nasa.gov/catalog/PIA11093

  12. Eroding Lava Flows

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Today's image illustrates how radically the wind can affect the surface of Mars. The lava flows in this region have been covered by fine materials, and eroded by the sand blasting action of the wind. In this region the winds are blowing to the west, eroding the lava surface to form small east/west ridges and bumps. Given enough time the winds will change the appearance of the surface to such a large extent that all flow features will be erased.

    Image information: VIS instrument. Latitude -11.7, Longitude 220 East (140 West). 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  13. Nighttime Lava Flows

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    This nighttime IR image is of lava flows from Arsia Mons, the southernmost of the three Tharsis Montes. Lava flow surfaces are generally rough, and trap sand and dust with time. The addition of sand/dust will affect the nighttime IR appearance of the surface [dust cools quickly and is darker than slow cooling rocks in the nighttime IR]. The rough, rockier surface of young flows are brighter than the older dust covered flows.

    Image information: IR instrument. Latitude -14, Longitude 247.4 East (112.6 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  14. Lava lamp optics.

    PubMed

    Clark, Thomas Alan

    2011-10-01

    An interesting optical focusing effect occurred in the early heating phases of a simple model of a lava lamp that was constructed to demonstrate convection effects. During this early heating phase, the interface between the two immiscible liquids was found to form a surface of rotation with a conic cross section that acted as a mirror to produce an excellent image of the filament of the bulb within the lower liquid. The relevant features of the lamp construction are discussed briefly, and photographs of this focusing effect are shown. A simple analysis is presented that transforms the photographed cross section of the liquid interface into the true cross section by removing the effect of the cylindrical lens formed by the fluid-filled bottle, and the resulting cross section is then fitted to the shape of an ellipse. The possible cause for the shape of this liquid interface is discussed and compared and contrasted with the somewhat analogous situation of a stretched circular membrane that is subjected to different gas pressures on either side of the membrane.

  15. Lava crusts and flow dynamics

    NASA Technical Reports Server (NTRS)

    Kilburn, C. R. J.

    1993-01-01

    Lava flows can be considered as hot viscous cores within thinner, solidified crusts. Interaction between crust and core determines a flow's morphological and dynamical evolution. When the lava core dominates, flow advance approaches a steady state. When crusts are the limiting factor, advance is more irregular. These two conditions can be distinguished by a timescale ratio comparing rates of core deformation and crustal formation. Aa and budding pahoehoe lavas are used as examples of core- and crustal-dominated flows, respectively. A simple model describes the transition between pahoehoe and aa flow in terms of lava discharge rate, underlying slope, and either the thickness or velocity of the flow front. The model shows that aa morphologies are characterized by higher discharge rates and frontal velocities and yields good quantitative agreement with empirical relations distinguishing pahoehoe and aa emplacement on Hawaii.

  16. Lava flows and volcanic landforms

    NASA Astrophysics Data System (ADS)

    Tarquini, Simone

    2016-04-01

    Lava flows constitute a large portion of the edifice of basaltic volcanoes. The substantial difference existing between the emplacement dynamics of different basaltic lava flows suggests a relation between the dominant flow dynamic and the overall shape of the ensuing volcano. Starting from the seminal works of Walker (1971, 1973) it is proposed that the rate of heat dissipation per unit volume of lava can be the founding principium at the roots of the emplacement dynamics of lava flows. Within the general framework of the thermodynamics of irreversible processes, a conceptual model is presented, in which the dynamic of lava flows can evolve in a linear or in a nonlinear regime on the basis of the constraint active on the system: a low constraint promotes a linear dynamic (i.e. fluctuations are damped), a high constraint a nonlinear one (i.e. fluctuations are enhanced). Two cases are considered as end-members for a linear and a nonlinear dynamic in lava flows: the typical "Hawaiian" sheet flow and the classic "Etnean" channelized flow (respectively). In lava flows, the active constraint is directly proportional to the slope of the topography and to the thermal conductivity and thermal capacity of the surrounding environment, and is inversely proportional to the lava viscosity and to the supply rate. The constraint indicates the distance from the equilibrium conditions of the system, and determines the rate of heat dissipation per unit volume. In subaerial flows, the heat dissipated during the emplacement is well approximated by the heat lost through radiation, which can be retrieved through remote-sensing techniques and can be used to correlate dynamic and dissipation. The model presented recombines previously unrelated concepts regarding the dynamics and the thermal regimes observed in different lava flows, providing a global consistent picture. References Walker GPL (1971) Compound and simple lava flows and flood basalts. Bull Volcanol 35:579-590 Walker GPL (1973

  17. Wind, Water, and Lava

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 18 June 2003

    The three main geological agents acting on the Martian surface are visible in this image, within an outflow channel to the east of the Tharsis volcanos and north of Valles Marineris. In a wide channel previously eroded by water, linear features have been eroded into the rock by the wind. Later, lava flows embayed the streamlined rocks. A second, younger flow lobe is visible at the bottom of the image.

    Image information: VIS instrument. Latitude 17, Longitude 283.6 East (76.4 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  18. Obstacles and Wakes in Lava

    NASA Image and Video Library

    2017-02-21

    Amazonis Planitia is a broad plain on Mars, covered with ancient lava. This image shows an interesting feature of an old lava flow. When it was mostly liquid, the lava had a crust of cooled debris floating on the surface. Here, the crust just barely scraped over some hills. The flow was able to make it past the hills, but the rubble crust was caught and piled up, forming thick masses of debris. Downstream from the hills, there was no crust left and the lava formed a smoother, fresh surface. Observations like this tell us about the scale of the lava flow (which must have been a huge sheet) and also which direction it was moving at the time when the crust interacted with the hills. The map is projected here at a scale of 50 centimeters (19.7 inches) per pixel. [The original image scale is 59.0 centimeters (23.2 inches) per pixel (with 2 x 2 binning); objects on the order of 177 centimeters (69.7 inches) across are resolved.] North is up. http://photojournal.jpl.nasa.gov/catalog/PIA21460

  19. LAVA Pressure Transducer Trade Study

    NASA Technical Reports Server (NTRS)

    Oltman, Samuel B.

    2016-01-01

    The Regolith and Environment Science and Oxygen and Lunar Volatile Extraction (RESOLVE) payload will transport the (LAVA) subsystem to hydrogen-rich locations on the moon supporting NASA's in-situ resource utilization (ISRU) programs. There, the LAVA subsystem will analyze volatiles that evolve from heated regolith samples in order to quantify how much water is present. To do this, the system needs resilient pressure transducers (PTs) to calculate the moles in the gas samples. The PT trade study includes a comparison of newly-procured models to a baseline unit with prior flight history in order to determine the PT model with the best survivability in flight-forward conditions.

  20. Leveed Channel in Lava Flow

    NASA Technical Reports Server (NTRS)

    2004-01-01

    14 December 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a leveed channel running down the middle of a lava flow in Daedalia Planum, the southern plains of the Tharsis volcanic region. Transport of fluid lava through a channel such as this helps insulate the molten rock, keeping it hot longer, and thus permits the flow to extend to greater distances than it otherwise might. This example is located near 23.6oS, 123.2oW, and covers an area approximately 3 km (1.9 mi) wide. The scene is illuminated by sunlight from the upper left.

  1. Compositionally Constraining Elysium Lava Fields

    NASA Astrophysics Data System (ADS)

    Karunatillake, S.; Button, N. E.; Skok, J. R.

    2013-12-01

    Chemical provinces of Mars defined recently [1-3] became possible with the maps of elemental mass fractions generated with Mars Odyssey Gamma and Neutron Spectrometer (GS) data [4,5]. These provide a unique perspective by representing compositional signatures distinctive of the regolith vertically at decimeter depths and laterally at hundreds of kilometer scale. Some provinces overlap compellingly with regions highlighted by other remote sensing observations, such as the Mars Radar Stealth area [3]. The spatial convergence of mutually independent data with the consequent highlight of a region provides a unique opportunity of insight not possible with a single type of remote sensing observation. Among such provinces, previous work [3] highlighted Elysium lava flows as a promising candidate on the basis of convergence with mapped geologic units identifying Elysium's lava fields generally, and Amazonian-aged lava flows specifically. The South Eastern lava flows of Elysium Mons, dating to the recent Amazonian epoch, overlap compellingly with a chemical province of K and Th depletion relative to the Martian midlatitudes. We characterize the composition, geology, and geomorphology of the SE Elysium province to constrain the confluence of geologic and alteration processes that may have contributed to its evolution. We compare this with the North Western lava fields, extending the discussion on chemical products from the thermal evolution of Martian volcanism as discussed by Baratoux et al. [6]. The chemical province, by regional proximity to Cerberus Fossae, may also reflect the influence of recently identified buried flood channels [7] in the vicinity of Orcus Patera. Despite the compelling chemical signature from γ spectra, fine grained unconsolidated sediment hampers regional VNTIR (Visible, Near, and Thermal Infrared) spectral analysis. But some observations near scarps and fresh craters allow a view of small scale mineral content. The judicious synthesis of

  2. An Enigmatic Feature in Athabasca Lava Flows

    NASA Image and Video Library

    2014-12-03

    The Athabasca region contains some of the youngest lava flows on Mars. This looks like a circular island surrounded by a ea of smooth-looking lava flows. This image was observed by NASA Mars Reconnaissance Orbiter.

  3. Newberry Volcano's youngest lava flows

    USGS Publications Warehouse

    Robinson, Joel E.; Donnelly-Nolan, Julie M.; Jensen, Robert A.

    2015-01-01

    The central caldera is visible in the lower right corner of the center map, outlined by the black dashed line. The caldera collapsed about 75,000 years ago when massive explosions sent volcanic ash as far as the San Francisco Bay area and created a 3,000-ft-deep hole in the center of the volcano. The caldera is now partly refilled by Paulina and East Lakes, and the byproducts from younger eruptions, including Newberry Volcano’s youngest rhyolitic lavas, shown in red and orange. The majority of Newberry Volcano’s many lava flows and cinder cones are blanketed by as much as 5 feet of volcanic ash from the catastrophic eruption of Mount Mazama that created Crater Lake caldera approximately 7,700 years ago. This ash supports abundant tree growth and obscures the youthful appearance of Newberry Volcano. Only the youngest volcanic vents and lava flows are well exposed and unmantled by volcanic ash. More than one hundred of these young volcanic vents and lava flows erupted 7,000 years ago during Newberry Volcano’s northwest rift zone eruption.

  4. Lava Flow at Kilauea, Hawaii

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On July 21, 2007, the world's most active volcano, Kilauea on Hawaii's Big Island, produced a new fissure eruption from the Pu'u O'o vent, which fed an open lava channel and lava flows toward the east. Access to the Kahauale'a Natural Area Reserve was closed due to fire and gas hazards. The two Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) nighttime thermal infrared images were acquired on August 21 and August 30, 2007. The brightest areas are the hottest lava flows from the recent fissure eruption. The large lava field extending down to the ocean is part of the Kupaianaha field. The most recent activity there ceased on June 20, but the lava is still hot and appears bright on the images. Magenta areas are cold lava flows from eruptions that occurred between 1969 and 2006. Clouds are cold (black) and the ocean is a uniform warm temperature, and light gray in color. These images are being used by volcanologists at the U.S. Geological Survey Hawaii Volcano Observatory to help monitor the progress of the lava flows.

    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 spacecraft. 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

  5. Introduction to special section: Long lava flows

    NASA Astrophysics Data System (ADS)

    Cashman, Katharine; Pinkerton, Harry; Stephenson, Jon

    1998-11-01

    Long lava flows are traditionally considered to form when low-viscosity lava is erupted at high effusion rates. However, this view has recently been challenged. Detailed field measurements on active lava flows on Kilauea have shown that inflation of lava flows after emplacement can result in reactivation and continued lengthening of flows. Inflated sheets can thus act a insulated conduits (lava tubes) that permit the transport of lava over great distances at near isothermal conditions. Detailed observations of long lava flows in the Columbia River Basalt Group and in the Cenozoic Volcanic Provinces in northern Queensland confirm that this mechanism is not restricted to recent flows on Hawaii. These findings have led to a search for evidence of inflation in flows in other parts of the world and have stimulated theoretical and laboratory research on the emplacement and cooling of lava in flows and in tubes. Understanding the formation of long submarine and planetary lava flows presents an additional challenge. Current evidence supports high effusion rates for some, possibly all, long planetary lava flows, and improved resolution from the Mars Global Surveyor will undoubtedly lead to either a confirmation or a rejection of this view. In this review, we discuss the geological importance and distribution of long lava flows, we investigate diametrically opposed views on the formation of long lava flows, and we stress the need for an interdisciplinary approach to improve our understanding of these enigmatic geological features.

  6. Selected caves and lava-tube systems in and near Lava Beds National Monument, California

    USGS Publications Warehouse

    Waters, Aaron Clement; Donnelly-Nolan, Julie M.; Rogers, Bruce W.

    1990-01-01

    Much of the north and south flanks of the Medicine Lake shield were built from molten lava transmitted through lava tubes. These tubes formed beneath the congealing surface of basalt flows in somewhat the same way that a brook may continue to flow beneath a cover of its own winter ice. As molten lava emerges from a vent and flows downslope, congealing lava from the top and sides of the central channel often forms a bridge over the lava stream. The sticking together of bits of lava spatter and fragile lava crusts strengthens the bridge in the manner that thin crusts of floating ice raft together to cover a brook during early stages of a winter freeze. Eruption of basalt lava, however, is a much more violent and spasmodic process than the steady gathering of water that feeds a brook. If liquid lava stops rising from its source deep within the earth, the still-molten lava moving beneath the crusted-over top of a lava flow will continue to drain downhill and may ultimately leave an open lavatube cave-often large enough for people to walk through. It is rare, however, to find such a simple scenario recorded intact among the hundreds of lava-tube caves in the monument. Even before the top and walls of a lava flow have time to cool during a pause in lava supply, a new and violent eruption of lava may refill the open tube, overflow its upper end, and spread a new lava flow beside or on top of the first flow. Even if the original tube is large enough to contain the renewed supply of lava, this tube must deliver the new lava beyond the end of its original flow and thus the lava field extends farther and farther downslope. If the gradient of flow flattens, the tube may subdivide into a number of smaller distributaries, which spread laterally over the more gently sloping ground. 

  7. LavaSIM: the effect of heat transfer in 3D on lava flow characteristics (Invited)

    NASA Astrophysics Data System (ADS)

    Fujita, E.

    2013-12-01

    Characteristics of lava flow are governed by many parameters like lava viscosity, effusion rate, ground topography, etc. The accuracy and applicability of lava flow simulation code is evaluated whether the numerical simulation can reproduce these features quantitatively, which is important from both strategic and scientific points of views. Many lava flow simulation codes are so far proposed, and they are classified into two categories, i.e., the deterministic and the probabilistic models. LavaSIM is one of the former category models, and has a disadvantage of time consuming. But LavaSIM can solves the equations of continuity, motion, energy by step and has an advantage in the calculation of three-dimensional analysis with solid-liquid two phase flow, including the heat transfer between lava, solidified crust, air, water and ground, and three-dimensional convection in liquid lava. In other word, we can check the detailed structure of lava flow by LavaSIM. Therefore, this code can produce both channeled and fan-dispersive flows. The margin of the flow is solidified by cooling and these solidified crusts control the behavior of successive lava flow. In case of a channel flow, the solidified margin supports the stable central main flow and elongates the lava flow distance. The cross section of lava flow shows that the liquid lava flows between solidified crusts. As for the lava extrusion flow rate, LavaSIM can include the time function as well as the location of the vents. In some cases, some parts of the solidified wall may be broken by the pressure of successive flow and/or re-melting. These mechanisms could characterize complex features of the observed lava flows at many volcanoes in the world. To apply LavaSIM to the benchmark tests organized by V-hub is important to improve the lava flow evaluation technique.

  8. Lava Flows in Eastern Tharsis

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 31 May 2002) This image may at first appear somewhat bland -- there is little contrast in the surface materials due to dust cover, and there are few impact craters -- but there are some very interesting geologic features here. The great Tharsis volcanoes have produced vast fields of lava flows, such as those shown in this image, to the east of Tharsis Tholus. The flows in this image have moved from west to east, down the regional topographic slope. The lobate edges of the flows are distinctive, and permit the discrimination of many overlapping individual flows that may represent tens, hundreds, thousands, or even millions of years worth of volcanic activity (overlapping relationships are especially evident at the bottom of the image). Viewed at full resolution, the image reveals interesting patterns and textures on the top surfaces of these flows. In particular, at the top of the image, there are numerous parallel curved ridges visible on the upper surfaces of the lava flows. These ridges make the flow surface look somewhat ropy, and at smaller scales this flow might be referred to as pahoehoe, indicative of a relatively fluid type of lava flow. At the scales observed here, however, these features are probably better referred to as pressure ridges. Pressure ridges form on the surface of a lava flow when the upper part of the flow is exposed to air, freezing it, but the insulated unfrozen interior of the flow continues to move down slope (and more material is pushed forward from behind), causing the surface to compress and pile up like a rug. Rough-looking flows with less distinct (more random) patterns on their surfaces may be flows that are more like terrestrial a'a flows, which are distinguished from pahoehoe flows by their higher viscosities and effusion rates. Near the center of the image there is an east-west trending, smooth-floored depression. The somewhat continuous width of this depression suggests that it is not simply formed by the edges of two

  9. Emplacement of Long Lava Flows: Detailed Topography of the Carrizozo Basalt Lava Flow, New Mexico

    NASA Technical Reports Server (NTRS)

    Zimbelman, J. R; Johnston, A. K.

    2000-01-01

    The Carrizozo flow in south-central New Mexico was examined to obtain detailed topography for a long basaltic lava flow. This information will be helpful in evaluating emplacement models for long lava flows.

  10. Emplacement of Long Lava Flows: Detailed Topography of the Carrizozo Basalt Lava Flow, New Mexico

    NASA Technical Reports Server (NTRS)

    Zimbelman, J. R; Johnston, A. K.

    2000-01-01

    The Carrizozo flow in south-central New Mexico was examined to obtain detailed topography for a long basaltic lava flow. This information will be helpful in evaluating emplacement models for long lava flows.

  11. Silica activity in lunar lavas

    NASA Technical Reports Server (NTRS)

    Nash, W. P.; Haselton, J. D.

    1975-01-01

    Calculated values of log alpha SiO2 in lunar magmas range from approximately -0.8 to unity in the temperature range of 1100-1300 C. High-titanium mare basalts begin crystallizing at silica activities insufficient for orthopyroxene saturation; in contrast to terrestrial lavas, silica activities rise substantially with crystallization and cause silica saturation in the residuum. Igneous rocks of the highland regions have relatively higher initial silica activities than mare basalts. Thermodynamic calculations indicate that high-titanium mare basalts could be derived from a 90 to 240-km deep source region containing olivine and orthopyroxene in addition to other phases.

  12. What factors control superficial lava dome explosivity?

    PubMed Central

    Boudon, Georges; Balcone-Boissard, Hélène; Villemant, Benoît; Morgan, Daniel J.

    2015-01-01

    Dome-forming eruption is a frequent eruptive style and a major hazard on numerous volcanoes worldwide. Lava domes are built by slow extrusion of degassed, viscous magma and may be destroyed by gravitational collapse or explosion. The triggering of lava dome explosions is poorly understood: here we propose a new model of superficial lava-dome explosivity based upon a textural and geochemical study (vesicularity, microcrystallinity, cristobalite distribution, residual water contents, crystal transit times) of clasts produced by key eruptions. Superficial explosion of a growing lava dome may be promoted through porosity reduction caused by both vesicle flattening due to gas escape and syn-eruptive cristobalite precipitation. Both processes generate an impermeable and rigid carapace allowing overpressurisation of the inner parts of the lava dome by the rapid input of vesiculated magma batches. The relative thickness of the cristobalite-rich carapace is an inverse function of the external lava dome surface area. Explosive activity is thus more likely to occur at the onset of lava dome extrusion, in agreement with observations, as the likelihood of superficial lava dome explosions depends inversely on lava dome volume. This new result is of interest for the whole volcanological community and for risk management. PMID:26420069

  13. Characterizing Lava Flows With LiDAR

    NASA Astrophysics Data System (ADS)

    Deligne, N. I.; Cashman, K. V.; Deardorff, N.; Dietterich, H. R.; House, P. K.; Soule, S.

    2009-12-01

    Digital elevation models (DEMs) have been used in volcanology in predictive modeling of lava flow paths, both for assessment of potential hazards and specific predictions of lava flow paths. Topographic analysis of a lava flow is potentially useful for mapping and quantifying flow surface morphologies, which in turn can be used to determine flow emplacement conditions, such as effusion rate, steadiness of flow, and interactions with pre-existing topography and surface water. However, this has been limited in application because of the coarse resolution of most DEMs. In recent years, use of Light Detection and Ranging (LiDAR) airborne laser altimetry, capable of producing high resolution (≤ 1 meter) DEMs, has become increasingly common in the geomorphic and mapping community. However, volcanologists have made little use of airborne LiDAR. Here we compare information obtained using field observations and standard (10 meter) DEMs against LiDAR high resolution DEMs to assess the usefulness, capabilities, and limitations of LiDAR as applicable to lava flows. We compare morphologic characteristics of five lava flows of different compositions, tectonic settings, flow extents, slopes, and eruption duration: (1) 1984 Mauna Loa lava flow, Hawaii; (2) December 1974 Kilauea lava flow, Hawaii; (3) c. 1600 ybp Collier Cone lava flow, central Oregon Cascades; (4) Holocene lava flows from the Sand Mountain volcanic chain, central Oregon Cascades; and (5) Pleistocene lava flows along the Owyhee River, eastern Oregon basin and range. These lava flows range in composition from basalt to andesite, and have eruption durations ranging from 6 hours (observed) to years (inferred). We measure channel width, levee and flow front heights, compression ridge amplitude, wavelength and tumuli dimensions, and surface roughness. For all but the smallest scale features, LiDAR is easily used to quantify these features, which often is impossible or technically challenging to do in the field, while

  14. Utility of Lava Tubes on Other Worlds

    NASA Technical Reports Server (NTRS)

    Walden, Bryce E.; Billings, T. L.; York, Cheryl Lynn; Gillett, S. L.; Herbert, M. V.

    1998-01-01

    On Mars, as on Earth, lava tubes are found in the extensive lava fields associated with shield volcanism. Lunar lava-tube traces are located near mare-highland boundaries, giving access to a variety of minerals and other resources, including steep slopes, prominent heights for local area communications and observation, large-surface areas in shade, and abundant basalt plains suitable for landing sites, mass-drivers, surface transportation, regolith harvesting, and other uses. Methods for detecting lava tubes include visual observations of collapse trenches and skylights, ground-penetrating radar, gravimetry, magnetometry, seismography, atmospheric effects, laser, lidar, infrared, and human or robotic exploration.

  15. What factors control superficial lava dome explosivity?

    NASA Astrophysics Data System (ADS)

    Boudon, Georges; Balcone-Boissard, Hélène; Villemant, Benoît; Morgan, Daniel J.

    2015-09-01

    Dome-forming eruption is a frequent eruptive style and a major hazard on numerous volcanoes worldwide. Lava domes are built by slow extrusion of degassed, viscous magma and may be destroyed by gravitational collapse or explosion. The triggering of lava dome explosions is poorly understood: here we propose a new model of superficial lava-dome explosivity based upon a textural and geochemical study (vesicularity, microcrystallinity, cristobalite distribution, residual water contents, crystal transit times) of clasts produced by key eruptions. Superficial explosion of a growing lava dome may be promoted through porosity reduction caused by both vesicle flattening due to gas escape and syn-eruptive cristobalite precipitation. Both processes generate an impermeable and rigid carapace allowing overpressurisation of the inner parts of the lava dome by the rapid input of vesiculated magma batches. The relative thickness of the cristobalite-rich carapace is an inverse function of the external lava dome surface area. Explosive activity is thus more likely to occur at the onset of lava dome extrusion, in agreement with observations, as the likelihood of superficial lava dome explosions depends inversely on lava dome volume. This new result is of interest for the whole volcanological community and for risk management.

  16. Propagation style controls lava-snow interactions.

    PubMed

    Edwards, B R; Belousov, A; Belousova, M

    2014-12-16

    Understanding interactions between volcanic eruptions and the cryosphere (a.k.a. glaciovolcanism) is important for climate reconstructions as well as for hazard mitigation at ice-clad volcanoes. Here we present unique field observations of interactions between snowpack and advancing basaltic lava flows during the 2012-13 eruption at Tolbachik volcano, Kamchatka, Russia. Our observations show that lava-snow heat transfer is slow, and that styles of lava propagation control snowpack responses. 'A'a and sheet lava flows advance in a rolling caterpillar-track motion on top of the rigid, snowpack substrate with minor lava-snow interaction. In contrast, pahoehoe lava propagates by inflation of lobes beneath/inside the snowpack, producing rigorous lava-snow interaction via meltwater percolation down into the incandescent lava causing production of voluminous steam, rapid surface cooling and thermal shock fragmentation. The textures produced by pahoehoe-snowpack interactions are distinctive and, where observed at other sites, can be used to infer syn-eruption seasonality and climatic conditions.

  17. Tephra on Lava Flows Promotes Vegetation Development: Case Studies From Recent Holocene Lava Flows

    NASA Astrophysics Data System (ADS)

    Deligne, N. I.; Cashman, K. V.

    2011-12-01

    Volcanic eruptions re-surface landscapes rapidly with lava flows, pyroclastic deposits, or a combination of both. Whereas explosive deposits are generally fine grained and share many characteristics with fertile soil, lava does not - it is massive, fractured, and sterile rock. As such, barren lava presents a formidable challenge for plant colonization. However, most lava-forming eruptions have an explosive component, albeit often in the early stages of activity prior to lava emplacement when the magma still has a considerable gas fraction. Tephra from the explosive stage of an eruption blankets local and downwind areas, and tephra thickness decreases exponentially with distance from the vent. We examine several sites of Holocene volcanism in the United States, Mexico, and Italy and find that in the absence of tephra or external sources of soil, vegetation establishment and growth on lava flows is exceptionally slow. Conversely, lava flows with late stage syn-eruptive explosive activity or lava flows in areas with subsequent repeat volcanism have considerable vegetation development. Although thick tephra blankets hinder plant establishment, it appears that tephra deposits on lava flows provide a growth medium and enhances water retention, promoting plant colonization and vegetation development. Our results caution against the common practice of mapping lava flows based on vegetation, and provide new insights on key factors in plant establishment and growth on lava flows.

  18. Three long lava flows in north Queensland

    NASA Astrophysics Data System (ADS)

    Stephenson, P. J.; Burch-Johnston, A. T.; Stanton, D.; Whitehead, P. W.

    1998-11-01

    The Kinrara, Toomba, and Undara basaltic lava flows are from 55 to 160 km long and range in age from 13 to 190 ka. The lavas were emplaced down low gradients (0.2° to 0.4°) with volumes ranging up to 30 km3. They were not unusually hot at eruption (1130°-1160°) nor unusually fluid. Gentle topography controlled the flows, and shallow drainage lines captured them. Lava tubes operated in places, and some drained to form caves. Injection under surface crust was widespread, producing inflation features ranging from tumuli and low plateaus to extensive ridges. Sustained eruption was essential for the development of the long flows, but each is composite, with pauses between successive pulses that partially covered the earlier, longer flows. The lava structures are mainly pahoehoe but some 'a'a lavas are present. Of the three volcanoes involved, Undara is a simple low-angle lava cone with a 200-m-wide crater, Toomba is a low-angled cone with several eruption centers, and Kinrara has a deep crater with evidence of strong fountaining. Effusion rates are not known but may have been relatively low, similar to those observed in Hawaiian volcanoes. Lava tubes, most of which remained undrained, are believed to have been of major importance in flow emplacement. Given the evidence of successive flows and the time needed to develop widespread inflation, it is suggested that the two long flows over 100 km involved many decades of eruption.

  19. Dynamics of the Mount Nyiragongo lava lake

    NASA Astrophysics Data System (ADS)

    Burgi, P.-Y.; Darrah, T. H.; Tedesco, D.; Eymold, W. K.

    2014-05-01

    The permanent and presently rising lava lake at Mount Nyiragongo constitutes a major potential geological hazard to the inhabitants of the Virunga volcanic region in the Democratic Republic of Congo (DRC) and Rwanda. Based on two field campaigns in June 2010 and 2011, we estimate the lava lake level from the southeastern crater rim (~400 m diameter) and lava lake area (~46,550 m2), which constrains, respectively, the lava lake volume (~9 × 106 m3) and volume flow rate needed to keep the magma in a molten state (0.6 to 3.5 m3 s-1). A bidirectional magma flow model, which includes the characterization of the conduit diameter and funnel-shaped lava lake geometry, is developed to constrain the amount of magma intruded/emplaced within the magmatic chamber and rift-related structures that extend between Mount Nyiragongo's volcanic center and the city of Goma, DRC, since Mount Nyiragongo's last eruption (17 January 2002). Besides matching field data of the lava lake level covering the period 1977 to 2002, numerical solutions of the model indicate that by 2022, 20 years after the January 2002 eruption, between 300 and 1700 × 106 m3 (0.3 to 1.7 km3) of magma could have intruded/emplaced underneath the edifice, and the lava lake volume could exceed 15 × 106 m3.

  20. Ultrathin lava layers exposed near San Luis Obispo Bay, California

    NASA Astrophysics Data System (ADS)

    Moore, James G.; Charlton, Douglas W.

    1984-09-01

    Sequences of extraordinarily thin (1 5 cm thick) lava layers, resembling individual lava flows, are interbedded with Jurassic and Cretaceous pillowed lava flows near San Luis Obispo Bay on the California coast. Such layers are formed inside submarine pillowed lava pipes or flow lobes. As the lava surface in a pillow pipe falls to a lower level owing to diminished supply entering the pipe, water enters the upper compartment through cracks in the outer crust and chills a new crust on top of the lava stream. Repeated lowerings of the lava level in the pipe create a series of discrete lava shelves, each of which represents the upper crust of the lava stream flowing within the pipe. These crusts are supported at different levels on their edges at the side of the pipe. The weight of subsequent overlying lava flows collapses the partly hollow tube, creating a stacked sequence of ultrathin lava layers progressively younger downward.

  1. Early life recorded in archean pillow lavas.

    PubMed

    Furnes, Harald; Banerjee, Neil R; Muehlenbachs, Karlis; Staudigel, Hubert; de Wit, Maarten

    2004-04-23

    Pillow lava rims from the Mesoarchean Barberton Greenstone Belt in South Africa contain micrometer-scale mineralized tubes that provide evidence of submarine microbial activity during the early history of Earth. The tubes formed during microbial etching of glass along fractures, as seen in pillow lavas from recent oceanic crust. The margins of the tubes contain organic carbon, and many of the pillow rims exhibit isotopically light bulk-rock carbonate delta13C values, supporting their biogenic origin. Overlapping metamorphic and magmatic dates from the pillow lavas suggest that microbial life colonized these subaqueous volcanic rocks soon after their eruption almost 3.5 billion years ago.

  2. Mysterious Lava Mineral on Mars

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This graph or spectrum captured by the Moessbauer spectrometer onboard the Mars Exploration Rover Spirit shows the presence of three different iron-bearing minerals in the soil at the rover's landing site. One of these minerals has been identified as olivine, a shiny green rock commonly found in lava on Earth. The other two have yet to be pinned down. Scientists were puzzled by the discovery of olivine because it implies the soil consists at least partially of ground up rocks that have not been weathered or chemically altered. The black line in this graph represents the original data; the three colored regions denote individual minerals and add up to equal the black line.

    The Moessbauer spectrometer uses two pieces of radioactive cobalt-57, each about the size of pencil erasers, to determine with a high degree of accuracy the composition and abundance of iron-bearing minerals in martian rocks and soil. It is located on the rover's instrument deployment device, or 'arm.'

  3. Mysterious Lava Mineral on Mars

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This graph or spectrum captured by the Moessbauer spectrometer onboard the Mars Exploration Rover Spirit shows the presence of three different iron-bearing minerals in the soil at the rover's landing site. One of these minerals has been identified as olivine, a shiny green rock commonly found in lava on Earth. The other two have yet to be pinned down. Scientists were puzzled by the discovery of olivine because it implies the soil consists at least partially of ground up rocks that have not been weathered or chemically altered. The black line in this graph represents the original data; the three colored regions denote individual minerals and add up to equal the black line.

    The Moessbauer spectrometer uses two pieces of radioactive cobalt-57, each about the size of pencil erasers, to determine with a high degree of accuracy the composition and abundance of iron-bearing minerals in martian rocks and soil. It is located on the rover's instrument deployment device, or 'arm.'

  4. Taylor instability in rhyolite lava flows

    NASA Technical Reports Server (NTRS)

    Baum, B. A.; Krantz, W. B.; Fink, J. H.; Dickinson, R. E.

    1989-01-01

    A refined Taylor instability model is developed to describe the surface morphology of rhyolite lava flows. The effect of the downslope flow of the lava on the structures resulting from the Taylor instability mechanism is considered. Squire's (1933) transformation is developed for this flow in order to extend the results to three-dimensional modes. This permits assessing why ridges thought to arise from the Taylor instability mechanism are preferentially oriented transverse to the direction of lava flow. Measured diapir and ridge spacings for the Little and Big Glass Mountain rhyolite flows in northern California are used in conjunction with the model in order to explore the implications of the Taylor instability for flow emplacement. The model suggests additional lava flow features that can be measured in order to test whether the Taylor instability mechanism has influenced the flows surface morphology.

  5. Lunar lava tube radiation safety analysis.

    PubMed

    De Angelis, Giovanni; Wilson, J W; Clowdsley, M S; Nealy, J E; Humes, D H; Clem, J M

    2002-12-01

    For many years it has been suggested that lava tubes on the Moon could provide an ideal location for a manned lunar base, by providing shelter from various natural hazards, such as cosmic radiation, meteorites, micrometeoroids, and impact crater ejecta, and also providing a natural environmental control, with a nearly constant temperature, unlike that of the lunar surface showing extreme variation in its diurnal cycle. An analysis of radiation safety issues on lunar lava tubes has been performed by considering radiation from galactic cosmic rays (GCR) and Solar Particle Events (SPE) interacting with the lunar surface, modeled as a regolith layer and rock. The chemical composition has been chosen as typical of the lunar regions where the largest number of lava tube candidates are found. Particles have been transported all through the regolith and the rock, and received particles flux and doses have been calculated. The radiation safety of lunar lava tubes environments has been demonstrated.

  6. Turbulent Lava Flow in Mars Athabasca Valles

    NASA Image and Video Library

    2010-01-11

    This combination of images, taken by NASA Mars Reconnaissance Orbiter, helped researchers analyze the youngest flood lava on Mars, which is in Athabasca Valles, in the Elysium Planitia region of equatorial Mars.

  7. Lunar lava tube radiation safety analysis

    NASA Technical Reports Server (NTRS)

    De Angelis, Giovanni; Wilson, J. W.; Clowdsley, M. S.; Nealy, J. E.; Humes, D. H.; Clem, J. M.

    2002-01-01

    For many years it has been suggested that lava tubes on the Moon could provide an ideal location for a manned lunar base, by providing shelter from various natural hazards, such as cosmic radiation, meteorites, micrometeoroids, and impact crater ejecta, and also providing a natural environmental control, with a nearly constant temperature, unlike that of the lunar surface showing extreme variation in its diurnal cycle. An analysis of radiation safety issues on lunar lava tubes has been performed by considering radiation from galactic cosmic rays (GCR) and Solar Particle Events (SPE) interacting with the lunar surface, modeled as a regolith layer and rock. The chemical composition has been chosen as typical of the lunar regions where the largest number of lava tube candidates are found. Particles have been transported all through the regolith and the rock, and received particles flux and doses have been calculated. The radiation safety of lunar lava tubes environments has been demonstrated.

  8. Taylor instability in rhyolite lava flows

    NASA Technical Reports Server (NTRS)

    Baum, B. A.; Krantz, W. B.; Fink, J. H.; Dickinson, R. E.

    1989-01-01

    A refined Taylor instability model is developed to describe the surface morphology of rhyolite lava flows. The effect of the downslope flow of the lava on the structures resulting from the Taylor instability mechanism is considered. Squire's (1933) transformation is developed for this flow in order to extend the results to three-dimensional modes. This permits assessing why ridges thought to arise from the Taylor instability mechanism are preferentially oriented transverse to the direction of lava flow. Measured diapir and ridge spacings for the Little and Big Glass Mountain rhyolite flows in northern California are used in conjunction with the model in order to explore the implications of the Taylor instability for flow emplacement. The model suggests additional lava flow features that can be measured in order to test whether the Taylor instability mechanism has influenced the flows surface morphology.

  9. Overlapping Lobate Lava Flows in Daedalia Planum

    NASA Image and Video Library

    2014-09-10

    Lava flows south of Arsia Mons in Daedalia Planum transition from younger flows with elongated, sinuous morphologies to the northeast, to older, broader lobes and sheet flows to the southwest. This image is from NASA Mars Reconnaissance Orbiter.

  10. Lunar Lava Tubes as Prepared Emergency Shelters.

    NASA Astrophysics Data System (ADS)

    Mardon, Austin; Nichol, Kenneth; Mardon, Austin

    If Lunar lava tubes were mapped from orbit and robotically explored their could be supplies for potentially used emergency depots. This occurs in the Antarctic. Lava tubes are hollowed out tubes where ancient lava flowed through and left a tunnel. A major problem of their use is the entering and egress. These might have to be excavated robotically. Lava tubes have been proposed to be used as shelters on the Moon before but supplies could be cached in areas potentially traversed in case of an emergency during a surface traverse. These supplies would be protected from some radiation would be fully protected from micrometeorites and theoretically could be left indefinitely. It has been proposed that they be used as shelters but to the authors knowledge it has not been proposed that they be used as cache and emergency depots.

  11. Lunar lava tube radiation safety analysis

    NASA Technical Reports Server (NTRS)

    De Angelis, Giovanni; Wilson, J. W.; Clowdsley, M. S.; Nealy, J. E.; Humes, D. H.; Clem, J. M.

    2002-01-01

    For many years it has been suggested that lava tubes on the Moon could provide an ideal location for a manned lunar base, by providing shelter from various natural hazards, such as cosmic radiation, meteorites, micrometeoroids, and impact crater ejecta, and also providing a natural environmental control, with a nearly constant temperature, unlike that of the lunar surface showing extreme variation in its diurnal cycle. An analysis of radiation safety issues on lunar lava tubes has been performed by considering radiation from galactic cosmic rays (GCR) and Solar Particle Events (SPE) interacting with the lunar surface, modeled as a regolith layer and rock. The chemical composition has been chosen as typical of the lunar regions where the largest number of lava tube candidates are found. Particles have been transported all through the regolith and the rock, and received particles flux and doses have been calculated. The radiation safety of lunar lava tubes environments has been demonstrated.

  12. Determination of eruption temperature of Io's lavas using lava tube skylights

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    Determining the eruption temperature of Io's dominant silicate lavas would constrain Io's present interior state and composition. We have examined how eruption temperature can be estimated at lava tube skylights through synthesis of thermal emission from the incandescent lava flowing within the lava tube. Lava tube skylights should be present along Io's long-lived lava flow fields, and are attractive targets because of their temporal stability and the narrow range of near-eruption temperatures revealed through them. We conclude that these skylights are suitable and desirable targets (perhaps the very best targets) for the purposes of constraining eruption temperature, with a 0.9:0.7-μm radiant flux ratio ≤6.3 being diagnostic of ultramafic lava temperatures. Because the target skylights may be small - perhaps only a few m or 10 s of m across - such observations will require a future Io-dedicated mission that will obtain high spatial resolution (< 100 m/pixel), unsaturated observations of Io's surface at multiple wavelengths in the visible and near-infrared, ideally at night. In contrast to observations of lava fountains or roiling lava lakes, where accurate determination of surface temperature distribution requires simultaneous or near-simultaneous (< 0.1 s) observations at different wavelengths, skylight thermal emission data are superior for the purposes of temperature derivation, as emission is stable on much longer time scales (minutes, or longer), so long as viewing geometry does not greatly change during that time.

  13. The structural stability of lunar lava tubes

    NASA Astrophysics Data System (ADS)

    Blair, David M.; Chappaz, Loic; Sood, Rohan; Milbury, Colleen; Bobet, Antonio; Melosh, H. Jay; Howell, Kathleen C.; Freed, Andrew M.

    2017-01-01

    Mounting evidence from the SELENE, LRO, and GRAIL spacecraft suggests the presence of vacant lava tubes under the surface of the Moon. GRAIL evidence, in particular, suggests that some may be more than a kilometer in width. Such large sublunarean structures would be of great benefit to future human exploration of the Moon, providing shelter from the harsh environment at the surface-but could empty lava tubes of this size be stable under lunar conditions? And what is the largest size at which they could remain structurally sound? We address these questions by creating elasto-plastic finite element models of lava tubes using the Abaqus modeling software and examining where there is local material failure in the tube's roof. We assess the strength of the rock body using the Geological Strength Index method with values appropriate to the Moon, assign it a basaltic density derived from a modern re-analysis of lunar samples, and assume a 3:1 width-to-height ratio for the lava tube. Our results show that the stability of a lava tube depends on its width, its roof thickness, and whether the rock comprising the structure begins in a lithostatic or Poisson stress state. With a roof 2 m thick, lava tubes a kilometer or more in width can remain stable, supporting inferences from GRAIL observations. The theoretical maximum size of a lunar lava tube depends on a variety of factors, but given sufficient burial depth (500 m) and an initial lithostatic stress state, our results show that lava tubes up to 5 km wide may be able to remain structurally stable.

  14. Geochemical aspects of some Japanese lavas.

    NASA Technical Reports Server (NTRS)

    Philpotts, J. A.; Martin, W.; Schnetzler, C. C.

    1971-01-01

    K, Rb, Sr, Ba and rare-earth concentrations in some Japanese lavas have been determined by mass-spectrometric stable-isotope dilution. The samples fall into three rare-earth groups corresponding to tholeiitic, high alumina and alkali basalts. Japanese tholeiites have trace element characteristics similar to those of oceanic ridge tholeiites except for distinctly higher relative concentrations of Ba. Japanese lavas may result from various degrees of partial fusion of amphibole eclogite.

  15. Non-explosive lava-water interaction in Skaelingar, Iceland and the formation of subaerial lava pillars

    NASA Astrophysics Data System (ADS)

    Gregg, Tracy K. P.; Christle, Kenneth W.

    2013-08-01

    Hollow cylinders of basalt < 2.5 m tall and generally < 1 m in diameter were generated by non-explosive lava-water interactions during the emplacement of the Laki lava flow in Iceland during 1783-1784. We know of only one location within the Laki lava flow where these basalt formations occur: a valley called Skaelingar, located at ~ 64.0°N, 18.5°W, which contains a tributary stream to the Skafta River. Skaelingar was temporarily filled with Laki lava when the main body of the lava flow advancing down the Skafta River valley became blocked, forcing lava to flow upstream into tributary valleys along the north side of the river. After the blockage within the Skafta River valley was removed, the Laki lava mostly drained out of these tributary valleys. We refer to the remaining vertical hollow basalt pipes as lava pillars because they morphologically resemble subaerial lava trees and submarine lava pillars that have been observed at mid-ocean ridges. We propose that the subaerial pillars formed as an inflating lava flow advanced slowly over water-saturated ground, or perhaps into temporarily ponded water, causing heated columns of water to rise between adjacent advancing lava lobes. The subaerial pillars continued to grow in height and diameter as the lava flow inflated. When the lava drained back out of the valley, the lava pillars were left standing. Thus, the Icelandic subaerial pillars represent a non-explosive interaction between lava and water.

  16. Lava Flows On Ascraeus Mons Volcano

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Ascraeus Mons Volcano: Like Earth, Mars has many volcanoes and volcanic features. This high-resolution view shows some of the lava flows near the summit of Ascraeus Mons, one of the three giant shield volcanoes known as the 'Tharsis Montes'. Volcanoes form when magma (molten rock) erupts out onto the surface of a planet. Based on Viking-era observations, Ascraeus Mons is considered to be one of the tallest volcanoes on Mars... its summit is more than 11 km (6.8 miles) above the surrounding plain. The summit is more than 23 km (14 miles) higher in elevation than the place where Mars Pathfinder landed in July 1997.

    Description of MOC Image: This picture shows an area that is about 20 km (12 miles) higher in elevation than the Mars Pathfinder landing site. The picture shows three main features: (1) a crater at the center-right, (2) a sinuous, discontinuous channel across the upper half, and (3) a rough and pitted, elevated surface across the lower half of the image.

    (1) Crater at center right. Distinguishing meteor craters from volcanic craters can sometimes be a challenge on Mars. This particular crater was most likely formed by meteor impact because it has a raised rim and a faint radial ejecta pattern around the outside of it. This crater is 600 m (2000 feet) across, about 3/4 the size of the famous 'Meteor Crater' near Winslow, Arizona.

    (2) Sinuous channel. The type of discontinuous channel running across the upper half of the image is sometimes referred to as a 'sinuous rille'. These are common on the volcanic plains of the Moon and among volcanoes and volcanic plains on Earth. Such a channel was once a lava tube. It is running down the middle of an old lava flow. The 'tube' looks like a 'channel' because its roof has collapsed. The discontinuous nature of this channel is the result of the collapse, or 'cave-in' of what was once the roof of the lava tube. It is common for certain types of relatively fluid lavas to form

  17. Lava Flows On Ascraeus Mons Volcano

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Ascraeus Mons Volcano: Like Earth, Mars has many volcanoes and volcanic features. This high-resolution view shows some of the lava flows near the summit of Ascraeus Mons, one of the three giant shield volcanoes known as the 'Tharsis Montes'. Volcanoes form when magma (molten rock) erupts out onto the surface of a planet. Based on Viking-era observations, Ascraeus Mons is considered to be one of the tallest volcanoes on Mars... its summit is more than 11 km (6.8 miles) above the surrounding plain. The summit is more than 23 km (14 miles) higher in elevation than the place where Mars Pathfinder landed in July 1997.

    Description of MOC Image: This picture shows an area that is about 20 km (12 miles) higher in elevation than the Mars Pathfinder landing site. The picture shows three main features: (1) a crater at the center-right, (2) a sinuous, discontinuous channel across the upper half, and (3) a rough and pitted, elevated surface across the lower half of the image.

    (1) Crater at center right. Distinguishing meteor craters from volcanic craters can sometimes be a challenge on Mars. This particular crater was most likely formed by meteor impact because it has a raised rim and a faint radial ejecta pattern around the outside of it. This crater is 600 m (2000 feet) across, about 3/4 the size of the famous 'Meteor Crater' near Winslow, Arizona.

    (2) Sinuous channel. The type of discontinuous channel running across the upper half of the image is sometimes referred to as a 'sinuous rille'. These are common on the volcanic plains of the Moon and among volcanoes and volcanic plains on Earth. Such a channel was once a lava tube. It is running down the middle of an old lava flow. The 'tube' looks like a 'channel' because its roof has collapsed. The discontinuous nature of this channel is the result of the collapse, or 'cave-in' of what was once the roof of the lava tube. It is common for certain types of relatively fluid lavas to form

  18. Physical volcanology of a voluminous rhyolite lava flow: The Badlands lava, Owyhee Plateau, southwestern Idaho

    NASA Astrophysics Data System (ADS)

    Manley, Curtis R.

    1996-05-01

    This paper describes an extraordinarily well preserved example of a large, high-SiO 2 rhyolite unit that by its exposed physical features can be demonstrated to be an effusive lava flow, not a rheomorphic ignimbrite. The Badlands lava flow of southwestern Idaho shows a multi-lobate form, with flow lobes that advanced along several azimuths from a long fissure vent. The lava flowed around one of its tephra ridges and a bedrock topographic high, creating a kipuka in the middle of the flow; the other tephra ridge was shoved aside by the lava. The lava itself is everywhere flow foliated, with foliation horizontal at the base, steepening toward the top, and convex in the direction of flow advance. The foliation parallels the margins of the flow lobes and reveals the position and orientation of the vent. Many samples of the lava flow's dense upper vitrophyre show one or more fragmental textures that formed by the settling of pumiceous and glassy debris into open fractures and the debris' subsequent welding into a rock that in many respects resembles welded tuff. By this process, the lava flow mimics an ignimbrite at the scale of an outcrop or thin section. Identical textures in other units have been cited as indicative of ash-flow emplacement mechanisms. The Badlands eruption tapped a stratified magma chamber, in which a large volume of phenocryst-rich (30 vol.%) magma underlay a small volume of magma more evolved and nearly aphyric. The lava flow shows mingling relations between the two magmas, with minor volumes of the aphyric magma occurring as early, small lava lobes and as individual layers in the dominant phenocryst-rich lava. Effusion of the 15 km 3 of rhyolite lava may have continued for as short as 6 or as long as 16 years, with effusion rates comparable to those observed at the Mount St. Helens dome. The Badlands lava had a pre-eruptive volatile content of about 2.75 wt.% H 2O or less, and erupted at approximately 830 °C, much lower than the temperatures of

  19. Keck Geology Consortium Lava Project: Undergraduate Research Linking Natural and Experimental Basaltic Lava Flows

    NASA Astrophysics Data System (ADS)

    Karson, J. A.; Hazlett, R. W.; Wysocki, R.; Bromfield, M. E.; Browne, N. C.; Davis, N. C.; Pelland, C. G.; Rowan, W. L.; Warner, K. A.

    2014-12-01

    Undergraduate students in the Keck Geology Consortium Lava Project participated in a month-long investigation of features of basaltic lava flows from two very different perspectives. The first half of the project focused on field relations in basaltic lava flows from the 1984 Krafla Fires eruption in northern Iceland. Students gained valuable experience in the collection of observations and samples in the field leading to hypotheses for the formation of selected features related to lava flow dynamics. Studies focused on a wide range of features including: morphology and heat loss in lava tubes (pyroducts), growth and collapse of lava ponds and overflow deposits, textural changes of lava falls (flow over steep steps), spaced spatter cones from flows over wet ground, and anisotropy of magnetic susceptibility related to flow kinematics. In the second half of the program students designed, helped execute, documented, and analyzed features similar to those they studied in the field with large-scale (50-250 kg) basaltic lava flows created in the Syracuse University Lava Project (http://lavaproject.syr.edu). Data collected included video from multiple perspectives, infrared thermal (FLIR) images, still images, detailed measurements of flow dimensions and rates, and samples for textural and magnetic analyses. Experimental lava flow features provided critical tests of hypotheses generated in the field and a refined understanding of the behavior and final morphology of basaltic lava flows. The linked field and experimental studies formed the basis for year-long independent research projects under the supervision of their faculty mentors, leading to senior theses at the students' respective institutions.

  20. Flood lavas on Earth, Io and Mars

    USGS Publications Warehouse

    Keszthelyi, L.; Self, S.; Thordarson, T.

    2006-01-01

    Flood lavas are major geological features on all the major rocky planetary bodies. They provide important insight into the dynamics and chemistry of the interior of these bodies. On the Earth, they appear to be associated with major and mass extinction events. It is therefore not surprising that there has been significant research on flood lavas in recent years. Initial models suggested eruption durations of days and volumetric fluxes of order 107 m3 s-1 with flows moving as turbulent floods. However, our understanding of how lava flows can be emplaced under an insulating crust was revolutionized by the observations of actively inflating pahoehoe flows in Hawaii. These new ideas led to the hypothesis that flood lavas were emplaced over many years with eruption rates of the order of 104 m3 s-1. The field evidence indicates that flood lava flows in the Columbia River Basalts, Deccan Traps, Etendeka lavas, and the Kerguelen Plateau were emplaced as inflated pahoehoe sheet flows. This was reinforced by the observation of active lava flows of ??? 100 km length on Io being formed as tube-fed flow fed by moderate eruption rates (102-103 m3 s-1). More recently it has been found that some flood lavas are also emplaced in a more rapid manner. New high-resolution images from Mars revealed 'platy-ridged' flood lava flows, named after the large rafted plates and ridges formed by compression of the flow top. A search for appropriate terrestrial analogues found an excellent example in Iceland: the 1783-1784 Laki Flow Field. The brecciated Laki flow top consists of pieces of pahoehoe, not aa clinker, leading us to call this 'rubbly pahoehoe'. Similar flows have been found in the Columbia River Basalts and the Kerguelen Plateau. We hypothesize that these flows form with a thick, insulating, but mobile crust, which is disrupted when surges in the erupted flux are too large to maintain the normal pahoehoe mode of emplacement Flood lavas emplaced in this manner could have

  1. Mapping of Daedalia Planum Lava Field

    NASA Astrophysics Data System (ADS)

    Giacomini, Lorenza; Carli, Cristian; Massironi, Matteo; Pasquarè, Giorgio; Sgavetti, Maria

    2010-05-01

    Daedalia Planum is one of the Tharsis volcanic plains and is located southwest of the Arsia Mons. MOLA, THEMIS, MOC and OMEGA data have been analysed, providing a multi-scale characterisation of this Martian lava field. According to Mars Global Surveyor's MOLA data, the flanks of Arsia have an average slope <5°, while the surrounding regions, including Daedalia Planum, have slopes <0,5° and commonly <0,1°. Mars Odyssey/THEMIS VIS and IR images show a plain covered by a huge number of lava flows. Older and larger lava flows on the field have a length greater than ~1500 km. Moreover most of the Daedalia flows are associated to wrinkly and ropy surfaces, typical of pahoehoe lavas. On the base of the morphology differences among the flows and through stratigraphic relationships we performed a geological map of the area. MEX/OMEGA spectra were collected in different areas of the lava field. Besides the similar absorption bands OMEGA spectra showed also some differences in reflectance and spectral slope. The spectral map created using the SAM classification reveals that these spectral variations are generally in agreement with the lava flows mapped previously on the base of the flows morphology and stratigraphy. This suggested that such variability is related with different surface textures of the lava flow. Moreover in some cases spectral map highlighted the presence of spectral subunits inside the same stratigraphic unit, due likely to a different mineralogy or rock textures. Therefore spectral analysis revealed useful to improve the geological mapping of the Daedalia Planum region.

  2. Nornahraun lava morphology and mode of emplacement

    NASA Astrophysics Data System (ADS)

    Pedersen, Gro B. M.; Höskuldsson, Armann; Riishuus, Morten S.; Jónsdóttir, Ingibjörg; Gudmundsson, Magnús T.; Sigmundsson, Freysteinn; Óskarsson, Birgir V.; Drouin, Vincent; Gallagher, Catherine; Askew, Rob; Moreland, William M.; Dürig, Tobias; Dumont, Stephanie; Þórdarson, Þór

    2015-04-01

    The ongoing Nornahraun eruption is the largest effusive eruption in Iceland since the Laki eruption in 1783-84, with an estimated lava volume of ~1.15 km3 covering an area of ~83.4 km2 (as of 5 JAN 2015). The eruption provides an unprecedented opportunity to study i) lava morphologies and their emplacement styles, ii) the transition from from open to closed lava pathways and iii) lava pond formation. Tracking of the lava advancement and morphology has been performed by GPS and GoPro cameras installed in 4×4 vehicles as well as video footage. Complimentary observations have been provided from aircraft platforms and by satellite data. Of particular importance for lava morphology observations are 1-12 m/pixel airborne SAR images (x-band). The Nornahraun flow field comprises a continuum of morphologies from pāhoehoe to 'a'ā, which have varied tem-porally and spatially. At the onset of the eruption 31 AUG, lava flows advanced rapidly (400-800 m/hr) from the 1.5 km long fissure as large slabby pāhoehoe [1-3] sheet lobes, 100-500 m wide and 0.3-1 m thick at the flow fronts. By 1 SEPT, the flows began channeling towards the NE constrained by the older Holuhraun I lava field and the to-pography of flood plain itself. A central open channel developed, feeding a 1-2 km wide active 'a'ā frontal lobe that advanced 1-2 km/day. In addition to its own caterpillar motion, the frontal lobe advanced in a series of 30-50 m long breakouts, predominantly slabby and rubbly pāhoehoe [4,5]. These breakouts had initial velocities of 10-30 m/hr and reached their full length within tens of minutes and subsequently inflated over hours. With the continuous advancement of the 'a'ā flow front, the breakouts were incorporated into the 'a'ā flow fronts and seldom preserved. At the margins of the frontal lava lobe, the breakouts were more sporadic, but predominantly rubbly pāhoehoe and slabby pāhoehoe, as at the flow front. The lava flow advanced ENE into Jökulsá á Fjöllum on 7 SEPT

  3. Mafic-crystal distributions, viscosities, and lava structures of some Hawaiian lava flows

    NASA Astrophysics Data System (ADS)

    Rowland, Scott K.; Walker, George P. L.

    1988-09-01

    The distribution patterns of mafic phenocrysts in some Hawaiian basalt flows are consistent with simple in situ gravitational settling. We use the patterns to estimate the crystal settling velocity and hence viscosity of the lava, which in turn can be correlated with surface structures. Numerical modeling generates theoretical crystal concentration profiles through lava flow units of different thicknesses for differing settling velocities. By fitting these curves to field data, crystal-settling rates through the lavas can be estimated, from which the viscosities of the flows can be determined using Stokes' Law. Lavas in which the crystal settling velocity was relatively high (on the order of 5 × 10 -4 cm/sec) show great variations in phenocryst content, both from top to bottom of the same flow unit, and from one flow unit to another. Such lava is invariably pahoehoe, flow units of which are usually less than 1 m thick. Lavas in which the crystal-settling velocity was low show a small but measurable variation in phenocryst content. These lavas are part of a progression from a rough pahoehoe to toothpaste lava to a'a. Toothpaste lava is characterized by spiny texture as well as the ability to retain surface grooves during solidification, and flow units are usually thicker than 1 m. In the thickest of Hawaiian a'a flows, those of the distal type, no systematic crystal variations are observed, and high viscosity coupled with a finite yield strength prevented crystal settling. The amount of crystal settling in pahoehoe indicates that the viscosity ranged from 600 to 6000 Pa s. The limited amount of settling in toothpaste lava indicates a viscosity greater than this value, approaching 12,000 Pa s. We infer that distal-type a'a had a higher viscosity still and also possessed a yield strength.

  4. Basics of lava-lamp convection

    NASA Astrophysics Data System (ADS)

    Gyüre, Balázs; Jánosi, Imre M.

    2009-10-01

    Laboratory experiments are reported in an immiscible two-fluid system, where thermal convection is initiated by heating at the bottom and cooling at the top. The lava-lamp regime is characterized by a robust periodic exchange process where warm blobs rise from the bottom, attach to the top surface for a while, then cold blobs sink down again. Immiscibility allows to reach real steady (dynamical equilibrium) states which can be sustained for several days. Two modes of lava-lamp convection could be identified by recording and evaluating temperature time series at the bottom and at the top of the container: a “slow” mode is determined by an effective heat transport speed at a given temperature gradient, while a second mode of constant periodicity is viscosity limited. Contrasting of laboratory and geophysical observations yields the conclusion that the frequently suggested lava-lamp analogy fails for the accepted models of mantle convection.

  5. Basics of lava-lamp convection.

    PubMed

    Gyüre, Balázs; Jánosi, Imre M

    2009-10-01

    Laboratory experiments are reported in an immiscible two-fluid system, where thermal convection is initiated by heating at the bottom and cooling at the top. The lava-lamp regime is characterized by a robust periodic exchange process where warm blobs rise from the bottom, attach to the top surface for a while, then cold blobs sink down again. Immiscibility allows to reach real steady (dynamical equilibrium) states which can be sustained for several days. Two modes of lava-lamp convection could be identified by recording and evaluating temperature time series at the bottom and at the top of the container: a "slow" mode is determined by an effective heat transport speed at a given temperature gradient, while a second mode of constant periodicity is viscosity limited. Contrasting of laboratory and geophysical observations yields the conclusion that the frequently suggested lava-lamp analogy fails for the accepted models of mantle convection.

  6. Studies of fluid instabilities in flows of lava and debris

    NASA Technical Reports Server (NTRS)

    Fink, Jonathan H.

    1987-01-01

    At least two instabilities have been identified and utilized in lava flow studies: surface folding and gravity instability. Both lead to the development of regularly spaced structures on the surfaces of lava flows. The geometry of surface folds have been used to estimate the rheology of lava flows on other planets. One investigation's analysis assumed that lava flows have a temperature-dependent Newtonian rheology, and that the lava's viscosity decreased exponentially inward from the upper surface. The author reviews studies by other investigators on the analysis of surface folding, the analysis of Taylor instability in lava flows, and the effect of surface folding on debris flows.

  7. Fire, Lava Flows, and Human Evolution

    NASA Astrophysics Data System (ADS)

    Medler, M. J.

    2015-12-01

    Richard Wrangham and others argue that cooked food has been obligate for our ancestors since the time of Homo erectus. This hypothesis provides a particularly compelling explanation for the smaller mouths and teeth, shorter intestines, and larger brains that separate us from other hominins. However, natural ignitions are infrequent and it is unclear how earlier hominins may have adapted to cooked food and fire before they developed the necessary intelligence to make or control fire. To address this conundrum, we present cartographical evidence that the massive and long lasting lava flows in the African Rift could have provided our ancestors with episodic access to heat and fire as the front edges of these flows formed ephemeral pockets of heat and ignition and other geothermal features. For the last several million years major lava flows have been infilling the African Rift. After major eruptions there were likely more slowly advancing lava fronts creating small areas with very specific adaptive pressures and opportunities for small isolated groups of hominins. Some of these episodes of isolation may have extended for millennia allowing these groups of early hominins to develop the adaptations Wrangham links to fire and cooked food. To examine the potential veracity of this proposal, we developed a series of maps that overlay the locations of prominent hominin dig sites with contemporaneous lava flows. These maps indicate that many important developments in hominin evolution were occurring in rough spatial and temporal proximity to active lava flows. These maps indicate it is worth considering that over the last several million years small isolated populations of hominins may have experienced unique adaptive conditions while living near the front edges of these slowly advancing lava flows.

  8. The Payun-Matru lava field: a source of analogues for Martian long lava flows

    NASA Astrophysics Data System (ADS)

    Giacomini, L.; Pasquarè, G.; Massironi, M.; Frigeri, A.; Bistacchi, A.; Frederico, C.

    2007-08-01

    The Payun Matru Volcanic complex is a Quaternary fissural structure belonging to the back-arc extensional area of the Andes in the Mendoza Province (Argentina). The eastern portion of the volcanic structure is covered by a basaltic field of pahoehoe lava flows advanced over more than 180 km from the fissural feeding vents that are aligned with a E-W fault system (Carbonilla fault). Thanks to their widespread extension, these flows represent some of the largest lava flows in the world and the Pampas Onduladas flow can be considered the longest sub-aerial individual lava flow on the Earth surface [1,2]. These gigantic flows propagated over the nearly flat surface of the Pampean foreland, moving on a 0.3 degree slope. The very low viscosity of the olivine basalt lavas, coupled with the inflation process and an extensive system of lava tubes are the most probable explanation for their considerable length. The inflation process likely develop under a steady flow rate sustained for a long time [3]. A thin viscoelastic crust, built up at an early stage, is later inflated by the underlying fluid core, which remains hot and fluid thanks to the thermal-shield effect of the crust. The crust is progressively thickened by accretion from below and spreading is due to the continuous creation of new inflated lobes, which develop at the front of the flow. Certain morphological features are considered to be "fingerprints" of inflation [4, 5, 6]; these include tumuli, lava rises, lava lobes and ridges. All these morphologies are present in the more widespread Payun Matru lava flows that, where they form extensive sheetflows, can reach a maximum thickness of more than 20 meters. After the emplacement of the major flows, a second eruptive cycle involved the Payun Matru volcanic structure. During this stage thick and channelized flows of andesitic and dacitic lavas, accompanied the formation of two trachitic and trachiandesitic strato-volcanoes (Payun Matru and Payun Liso) culminated

  9. Experimental Studies of Lava Dome Fracture

    NASA Astrophysics Data System (ADS)

    Smith, R.; Sammonds, P. R.; Kilburn, C. R.

    2005-12-01

    Renewed extrusion at andesitic to dacitic lava domes and collapses of these domes are usually preceded by fracturing and frictional sliding of material in and around the lava dome and magma conduit. This is observed through the occurrence of shallow high frequency earthquakes. Samples of andesite from Mount Shasta in the Cascades, a typical material for both lava domes and shallow underlying country rock, have been deformed in compression and tension, at temperatures of up to 900°C, and under confining pressures of up to 70MPa. During these tests the axial load, sample deformation and acoustic emissions were recorded, in order to compare the results with field observations of deformation and short period seismicity at lava domes. Typical strengths at room temperature and pressure were 6MPa in tension, and 100MPa in compression. Increased temperatures increased the tensile strength, but reduced the compressive strength, whereas both strengths increased with increasing confining pressure. There were ~10 times more acoustic emissions at room temperature than at maximum test temperatures, indicating that increased temperatures favour ductile, rather than brittle, failure. These results suggest that young, hot lava domes may collapse or erupt with little precursory short period seismicity, whilst older, cooler domes are likely to exhibit stronger short period seismic precursors. However, hotter material is likely to exhibit more recognisable deformation precursors. This is consistent with the seismicity observed after the 18 May 1980 climactic eruption at Mount St Helens, where there was ~100 times more seismicity prior to eruptions in 1985 and 1986 than there was prior to eruptions in 1980 and 1981. During these later eruptions, the interior of the dome would still have been ductile due to its temperature and the overburden weight acting as a confining pressure, but the large amount of pre-failure deformation in this zone could drive fracturing of the cooler outer

  10. Geology of selected lava tubes in the Bend Area, Oregon

    NASA Technical Reports Server (NTRS)

    Greely, R.

    1971-01-01

    Longitudinal profiles representing 5872.5 m of mapped lava tubes and a photogeologic map relating lava tubes to surface geology, regional structure and topography are presented. Three sets of lava tubes were examined: (1) Arnold Lava Tube System (7km long) composed of collapsed and uncollapsed tube segments and lava ponds, (2) Horse Lava Tube System (11 km long) composed of parallel and anastomosing lava tube segments, and (3) miscellaneous lava tubes. Results of this study tend to confirm the layered lava hypothesis of Ollier and Brown (1965) for lava tube formation; however, there are probably several modes of formation for lava tubes in general. Arnold System is a single series of tubes apparently formed in a single basalt flow on a relatively steep gradient. The advancing flow in which the tubes formed was apparently temporarily halted, resulting in the formation of lava ponds which were inflated and later drained by the lava tube system. Horse System probably formed in multiple, interconnected flows. Pre-flow gradient appears to have been less than for Arnold System, and resulted in meandrous, multiple tube networks.

  11. 9. CRATER RIM DRIVE NEAR THURSTON LAVA TUBE. VIEW OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. CRATER RIM DRIVE NEAR THURSTON LAVA TUBE. VIEW OF CRENELATED LAVA STONE GUARD WALL AND ROCK CUT OPPOSITE. NOTE CATTLE GUARD ACROSS ROAD PARTIALLY PAVED OVER. - Crater Rim Drive, Volcano, Hawaii County, HI

  12. White Sands, Carrizozo Lava Beds, NM

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A truly remarkable view of White Sands and the nearby Carrizozo Lava Beds in southeast NM (33.5N, 106.5W). White Sands, site of the WW II atomic bomb development and testing facility and later post war nuclear weapons testing that can still be seen in the cleared circular patterns on the ground.

  13. Finding and utilizing lunar lava tubes

    NASA Astrophysics Data System (ADS)

    Kuck, David L.

    Horz describes the evidence for lava tubes associated with rills in lunar photo-imaging. These tubes have terrestrial counterparts as described by Billings, et al., and Gillet. The widths of these tubes range from 10s to 100s of meters. Their roof thickness are at least 0.125 to 0.25 times their widths and stand unsupported on the Moon. To confine one atmosphere of internal pressure, static roof thickness must be at least 16 m. Favorable locations of lava tubes may be surveyed using roving gravity meters on Doodle Bugs, which consist of platforms containing equipment for communication with Earth-based control stations. The stable -20 C temperature of the lava tubes should provide a workable habitat environment. The greater than 16 m of basalt in the roof should give adequate radiation and impact protection. Typically, after clearing entries and grading ramps, habitats might be placed in tubes and inflated. Later, larger habitats might be built by enclosing tube sections with compacted-regolith dams. The interior can then be sealed to hold an atmosphere. The huge lava tubes inferred from the photographs are capable of providing habitats hundreds of meters wide, in lengths of kilometers.

  14. Diverting lava flows in the lab

    USGS Publications Warehouse

    Dietterich, Hannah; Cashman, Katharine V.; Rust, Alison C.; Lev, Einat

    2015-01-01

    Recent volcanic eruptions in Hawai'i, Iceland and Cape Verde highlight the challenges of mitigating hazards when lava flows threaten infrastructure. Diversion barriers are the most common form of intervention, but historical attempts to divert lava flows have met with mixed success and there has been little systematic analysis of optimal barrier design. We examine the interaction of viscous flows of syrup and molten basalt with barriers in the laboratory. We find that flows thicken immediately upslope of an obstacle, forming a localized bow wave that can overtop barriers. Larger bow waves are generated by faster flows and by obstacles oriented at a high angle to the flow direction. The geometry of barriers also influences flow behaviour. Barriers designed to split or dam flows will slow flow advance, but cause the flow to widen, whereas oblique barriers can effectively divert flows, but may also accelerate flow advance. We argue that to be successful, mitigation of lava-flow hazards must incorporate the dynamics of lava flow–obstacle interactions into barrier design. The same generalizations apply to the effect of natural topographic features on flow geometry and advance rates.

  15. Seismogenic lavas and explosive eruption forecasting.

    PubMed

    Lavallée, Y; Meredith, P G; Dingwell, D B; Hess, K-U; Wassermann, J; Cordonnier, B; Gerik, A; Kruhl, J H

    2008-05-22

    Volcanic dome-building episodes commonly exhibit acceleration in both effusive discharge rate and seismicity before explosive eruptions. This should enable the application of material failure forecasting methods to eruption forecasting. To date, such methods have been based exclusively on the seismicity of the country rock. It is clear, however, that the rheology and deformation rate of the lava ultimately dictate eruption style. The highly crystalline lavas involved in these eruptions are pseudoplastic fluids that exhibit a strong component of shear thinning as their deformation accelerates across the ductile to brittle transition. Thus, understanding the nature of the ductile-brittle transition in dome lavas may well hold the key to an accurate description of dome growth and stability. Here we present the results of rheological experiments with continuous microseismic monitoring, which reveal that dome lavas are seismogenic and that the character of the seismicity changes markedly across the ductile-brittle transition until complete brittle failure occurs at high strain rates. We conclude that magma seismicity, combined with failure forecasting methods, could potentially be applied successfully to dome-building eruptions for volcanic forecasting.

  16. White Sands, Carrizozo Lava Beds, NM

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A truly remarkable view of White Sands and the nearby Carrizozo Lava Beds in southeast NM (33.5N, 106.5W). White Sands, site of the WW II atomic bomb development and testing facility and later post war nuclear weapons testing that can still be seen in the cleared circular patterns on the ground.

  17. Early Earth: Lava Floods and Life Opportunity

    NASA Astrophysics Data System (ADS)

    Astafieva, M. M.

    2017-05-01

    At the earliest stages of the Earth development, in Archean, a large part of the Earth was molten due to active volcanism and intense meteorite bombardment that ended about 4.0 GA. Stopping or weakening of the cosmic bombardment has allowed the planet to cool and form a solid crust. It is from this time geologically documented history of the Earth begins. Accordingly, the earliest Earth rocks are igneous, metamorphic and sedimentary rocks were formed later (the oldest metasedimentary rocks - 3.7-3.85 GA). Therefore, the question of microorganism colonization of lava at the earliest stages of life evolution on the Earth is of paramount importance. A few model objects were chosen for investigation of microbial colonization of getting cold lava floods. Among them Early Protherozoic pillow-lavas of Karelia (2.41 and 2.2 GA) and South Africa (2.22 GA). Modern volcanic glasses of pillow lavas of Mid-Atlantic ridge were used as comparative material.

  18. Circulation patterns in active lava lakes

    NASA Astrophysics Data System (ADS)

    Redmond, T. C.; Lev, E.

    2014-12-01

    Active lava lakes provide a unique window into magmatic conduit processes. We investigated circulation patterns of 4 active lava lakes: Kilauea's Halemaumau crater, Mount Erebus, Erta Ale and Nyiragongo, and in an artificial "lava lake" constructed at the Syracuse University Lava Lab. We employed visual and thermal video recordings collected at these volcanoes and use computer vision techniques to extract time-dependent, two-dimensional surface velocity maps. The large amount of data available from Halemaumau enabled us to identify several characteristic circulation patterns. One such pattern is a rapid acceleration followed by rapid deceleration, often to a level lower than the pre-acceleration level, and then a slow recovery. Another pattern is periodic asymmetric peaks of gradual acceleration and rapid deceleration, or vice versa, previously explained by gas pistoning. Using spectral analysis, we find that the dominant period of circulation cycles at approximately 30 minutes, 3 times longer than the dominant period identified previously for Mount Erebus. Measuring a complete surface velocity field allowed us to map and follow locations of divergence and convergence, therefore upwelling and downwelling, thus connecting the surface flow with that at depth. At Nyiragongo, the location of main upwelling shifts gradually, yet is usually at the interior of the lake, for Erebus it is usually along the perimeter yet often there is catastrophic downwelling at the interior; For Halemaumau upwelling/downwelling position is almost always on the perimeter. In addition to velocity fields, we developed an automated tool for counting crustal plates at the surface of the lava lakes, and found a correlation, and a lag time, between changes if circulation vigor and the average size of crustal plates. Circulation in the artificial basaltic lava "lake" was limited by its size and degree of foaming, yet we measured surface velocities and identify patterns. Maximum surface velocity

  19. Lava Flows in the Grand Canyon

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Over vast expanses of time, natural processes like floods and volcanoes deposit layers of rock on the Earth's surface. To delve down through layers of rock is to explore our planet's history. Sometimes rock layers are exposed through human activity, such as drilling or excavation. Other times, rivers carve through the rock. One of the best, and most well-known, examples of a river exposing ancient rocks is Colorado River in Arizona's Grand Canyon. What fewer people know is that the Grand Canyon also has a history of relatively recent (on geologic time scales) volcanism. The evidence--hardened lava--spills down the canyon walls all the way to the river. On June 22, 2003, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of the Grand Canyon, near 36.2 degrees north latitude and 113.2 degrees west longitude. ASTER detects light visible to human eyes as well as 'invisible' infrared light. Because different minerals reflect different portions of the light spectrum, ASTER can see varying mineral compositions of the rocks it observes, as well as detecting vegetation. In this three-dimensional visualization, lava fields appear brownish gray, darker than the layers of limestone, sandstone and other rock in the canyon. Vegetation appears green, and sparsely vegetated areas appear mustard. Water in the Colorado River is blue-purple. Geologists estimate that between 1.8 million and 400,000 years ago, lava flows actually dammed the Colorado River more than a dozen times. Some of the lava dams were as high as 600 meters (about 1,969 feet), forming immense reservoirs. Over time, enough water and sediment built up to push the river flow over the tops of these dams and eventually erode them away. Today, remnants of these lava dams remain throughout the area, along with the much older rock layers they cover. Among the most well known examples of these 'frozen' lava cascades is Lava Falls, which spills down to the

  20. Toothpaste lava: Characteristics and origin of a lava structural type transitional between pahoehoe and aa

    NASA Astrophysics Data System (ADS)

    Rowland, Scott K.; Walker, George P. L.

    1987-08-01

    Toothpaste lava, an important basalt structural type which illustrates the transition from pahoehoe to aa, is particularly well displayed on the 1960 Kapoho lava of Kilauea Volcano. Its transitional features stem from a viscosity higher than that of pahoehoe and a rate of flow slower than that of aa. Viscosity can be quantified by the limited settling of olivine phenocrysts and rate of flow by field observations related to the low-angle slope on which the lava flowed. Much can be learned about the viscosity, rheologic condition, and flow velocity of lavas long after solidification by analyses of their structural characteristics, and it is possible to make at least a semiquantitative assessment of the numerical values of these parameters.

  1. Identifying hazards associated with lava deltas

    NASA Astrophysics Data System (ADS)

    Poland, Michael P.; Orr, Tim R.

    2014-12-01

    Lava deltas, formed where lava enters the ocean and builds a shelf of new land extending from the coastline, represent a significant local hazard, especially on populated ocean island volcanoes. Such structures are unstable and prone to collapse—events that are often accompanied by small explosions that can deposit boulders and cobbles hundreds of meters inland. Explosions that coincide with collapses of the East Lae `Apuki lava delta at Kīlauea Volcano, Hawai`i, during 2005-2007 followed an evolutionary progression mirroring that of the delta itself. A collapse that occurred when the lava-ocean entry was active was associated with a blast of lithic blocks and dispersal of spatter and fine, glassy tephra. Shortly after delta growth ceased, a collapse exposed hot rock to cold ocean water, resulting in an explosion composed entirely of lithic blocks and lapilli. Further collapse of the delta after several months of inactivity, by which time it had cooled significantly, resulted in no recognizable explosion deposit. Seaward displacement and subsidence of the coastline immediately inland of the delta was measured by both satellite and ground-based sensors and occurred at rates of several centimeters per month even after the lava-ocean entry had ceased. The anomalous deformation ended only after complete collapse of the delta. Monitoring of ground deformation may therefore provide an indication of the potential for delta collapse, while the hazard associated with collapse can be inferred from the level of activity, or the time since the last activity, on the delta.

  2. Emplacing a cooling-limited rhyolite lava flow: similarities with basaltic lava flows

    NASA Astrophysics Data System (ADS)

    Magnall, Nathan; James, Mike R.; Tuffen, Hugh; Vye-Brown, Charlotte

    2017-06-01

    Accurate forecasts of lava flow length rely on estimates of eruption and magma properties and, potentially more challengingly, an understanding of the relative influence of characteristics such as the apparent viscosity, the yield strength of the flow core, or the strength of the surface crust. Consequently, even the most straightforward models of lava advance involve sufficient parameters that constraints can be relatively easily fitted within the uncertainties involved, at the expense of gaining insight. Here, for the first time, we incorporate morphological observations from during and after flow field evolution to improve model constraints and reduce uncertainties. After demonstrating the approach on a basaltic lava flow (Mt. Etna, 2001), we apply it to the 2011-12 Cordón Caulle rhyolite flow, where unprecedented observations and syn-emplacement satellite imagery of an advancing silica-rich lava flow have indicated an important crustal influence on flow emplacement. Our results show that an initial phase of viscosity-controlled advance at Cordón Caulle was followed by later crustal control, accompanied by formation of flow surface folds and large-scale crustal fractures. Where the lava was unconstrained by topography, the cooled crust ultimately halted advance of the main flow and led to the formation of breakouts from the flow front and margins, influencing the footprint of the lava, its advance rate, and the duration of flow advance. Highly similar behaviour occurred in the 2001 Etna basaltic lava flow. The processes controlling the advance of crystal-poor rhyolite and basaltic lava flow therefore appear similar, indicating common controlling mechanisms that transcend profound rheological and compositional differences.

  3. Ridge-like lava tube systems in southeast Tharsis, Mars

    NASA Astrophysics Data System (ADS)

    Zhao, Jiannan; Huang, Jun; Kraft, Michael D.; Xiao, Long; Jiang, Yun

    2017-10-01

    Lava tubes are widely distributed in volcanic fields on a planetary surface and they are important means of lava transportation. We have identified 38 sinuous ridges with a lava-tube origin in southeast Tharsis. The lengths vary between 14 and 740 km, and most of them occur in areas with slopes < 0.3°. We analyzed their geomorphology in detail with CTX (Context Camera) and HiRISE (High Resolution Imaging Science Experiment) images and DTM (digital terrain model) derived from them. We identified three cross-sectional shapes of these sinuous ridges: round-crested, double-ridged, and flat-crested and described features associated with the lava tubes, including branches, axial cracks, collapsed pits, breakout lobes, and tube-fed lava deltas. Age determination results showed that most of the lava tubes formed in Late Hesperian and were active until the Hesperian-Amazonian boundary. We proposed that these lava tubes formed at relatively low local flow rate, low lava viscosity, and sustained magma supply during a long period. Besides, lava flow inflation is also important in the formation of the ridge-like lava tubes and some associated features. These lava tubes provide efficient lateral pathways for magma transportation over the relatively low topographic slopes in southeast Tharsis, and they are important for the formation of long lava flows in this region. The findings of this study provide an alternative formation mechanism for sinuous ridges on the martian surface.

  4. Ice-Confined Basaltic Lava Flows: Review and Discussion

    NASA Astrophysics Data System (ADS)

    Skilling, I.; Edwards, B. R.

    2012-12-01

    Basaltic lavas that are interpreted as having been emplaced in subglacial or ice-confined subaerial settings are known from several localities in Iceland, British Columbia and Antarctica. At least four different types of observations have been used to date to identify emplacement of basaltic lavas in an ice-rich environment: i) gross flow morphology, ii) surface structures, iii) evidence for ice-confined water during emplacement, and iv) lava fracture patterns. Five types of ice-confined lava are identified: sheets, lobes, mounds, linear ridges and sinuous ridges. While the appearance of lavas is controlled by the same factors as in the submarine environment, such as the geometry and configuration of vents and lava tubes, flow rheology and rates, and underlying topography, the presence of ice can lead to distinct features that are specific to the ice-confined setting. Other types have very similar or identical equivalents in submarine environment, albeit with some oversteepening/ice contact surfaces. Ice-confined lavas can form as (1) subaerial or subaqueous lavas emplaced against ice open to the air, (2) subaqueous lavas emplaced into pre-existing sub-ice drainage networks, and (3) subaqueous lavas emplaced into ponded water beneath ice. Their surface structures reflect the relationship between rates of lava flow emplacement at the site of ice-water-lava contact, ice melting and water drainage. Variations in local lava flow rates could be due to lava cooling, constriction, inflation, tube development, ice melting, ice collapse, lava collapse, changes in eruption rate etc. Episodes of higher lava flow rate would favour direct ice contact and plastic compression against the ice, generating oversteepened and/or overthickened chilled margins, cavities in the lava formed by melting of enveloped ice blocks (cryolith cavities) and structures such as flattened pillows and lava clasts embedded into the glassy margins. Melting back of the confining ice generates space to

  5. Underwater observations of active lava flows from Kilauea volcano, Hawaii

    USGS Publications Warehouse

    Tribble, G.W.

    1991-01-01

    Underwater observation of active submarine lava flows from Kilauea volcano, Hawaii, in March-June 1989 revealed both pillow lava and highly channelized lava streams flowing down a steep and unconsolidated lava delta. The channelized streams were 0.7-1.5 m across and moved at rates of 1-3 m/s. The estimated flux of a stream was 0.7 m3/s. Jets of hydrothermal water and gas bubbles were associated with the volcanic activity. The rapidly moving channelized lava streams represent a previously undescribed aspect of submarine volcanism. -Author

  6. Modelling the emplacement of compound lava flows

    NASA Astrophysics Data System (ADS)

    Blake, S.; Bruno, B. C.

    2000-12-01

    The physical variables controlling crust-dominated lava flow have been investigated using laboratory experiments in which molten polyglycol wax was extruded from a point source on to a horizontal plane under cold water. The wax initially spread axisymmetrically and a crust of solid wax grew. Eventually wax broke out from the flow's periphery, sending out a flow lobe which in turn cooled and produced another breakout. The process repeated itself many times, building a 'compound lava'. The time for the first breakout to form correlates well with the theoretically predicted time ( tc) required for cooling to form a crust thick enough for its strength to limit the flow's spreading rate. This time is proportional to the product of effusion rate ( Q) and initial magma viscosity ( μ) and inversely proportional to the square of the crust strength at the flow front. The number of flow units and the apparent fractal dimension of the flow perimeter increase with time normalised by tc. Our model illuminates the physical basis for the observation by Walker [G.P.L. Walker, Bull. Volcanol. 35 (1972) 579-590] that compound lava flows form by slow effusion of low viscosity magma, whereas faster effusion and higher viscosity favour lavas with fewer flow units. Because compound flows require t≫ tc, and given that tc∝ Qμ and the relationship between volume and effusion rate is V= Qt, simple and compound lava flows are predicted to fall in separate fields on a graph of μ against V/ Q2, all else being equal. Compound flows plot at small values of μ and large values of V/ Q2, with the position of the simple/compound boundary defined by field data implying a crust strength of order 10 4 Pa for basaltic to intermediate lavas. Whether a flow remains as a simple flow or matures into a compound flow field depends on the combined effect of viscosity, eruption rate and eruption duration (and hence volume) and these parameters need to be taken in to account when using morphology to infer

  7. Lava and Snow on Klyuchevskaya Volcano [detail

    NASA Image and Video Library

    2017-09-27

    This false-color (shortwave infrared, near infrared, green) satellite image reveals an active lava flow on the western slopes of Klyuchevskaya Volcano. Klyuchevskaya is one of several active volcanoes on the Kamchatka Peninsula in far eastern Russia. The lava flow itself is bright red. Snow on Klyuchevskaya and nearby mountains is cyan, while bare ground and volcanic debris is gray or brown. Vegetation is green. The image was collected by Landsat 8 on September 9, 2013. NASA Earth Observatory image by Jesse Allen and Robert Simmon, using Instrument: Landsat 8 - OLI More info: 1.usa.gov/1evspH7 NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  8. Cooling of Kilauea Iki lava lake

    SciTech Connect

    Hills, R.G.

    1982-02-01

    In 1959 Kilauea Iki erupted leaving a 110 to 120 m lake of molten lava in its crater. The resulting lava lake has provided a unique opportunity to study the cooling dynamics of a molten body and its associated hydrothermal system. Field measurements taken at Kilauea Iki indicate that the hydrothermal system above the cooling magma body goes through several stages, some of which are well modeled analytically. Field measurements also indicate that during most of the solidification period of the lake, cooling from above is controlled by 2-phase convection while conduction dominates the cooling of the lake from below. A summary of the field work related to the study of the cooling dynamics of Kilauea Iki is presented. Quantitative and qualitative cooling models for the lake are discussed.

  9. Flow direction determination of lava flows.

    NASA Technical Reports Server (NTRS)

    Smith, E. I.; Rhodes, R. C.

    1972-01-01

    The flow direction technique, previously applied to ash-flow sheets, can be used to determine direction of movement and locate eruptive centers for lava flows. The method provides statistically stronger and more consistent flow direction data for lava than ash-flow tuff. The accuracy and reliability of the technique was established on the porphyritic basaltic andesite of Mount Taylor, New Mexico, which erupted from a known center, the Mount Taylor Amphitheater. The technique was then applied to volcanic units with unknown sources: the John Kerr Peak Quartz Latite and mid-Tertiary andesite flows in the Mogollon Mountains, both in southwestern New Mexico. The flow direction technique indicated flow patterns and suggested source areas for each rock unit. In the Mogollon Mountains flow direction measurements were supported by independent directional criteria such as dips of cross beds, stratigraphic thickening, facies changes, and megascopic textures.-

  10. Support of LAVA Integration and Testing

    NASA Technical Reports Server (NTRS)

    Jackson, Marcus Algernon

    2014-01-01

    The Lunar Advanced Volatile Analysis (LAVA) subsystem is a part of the Regolith and Environment Science & Oxygen and Lunar Volatile Analysis (RESOLVE) Payload that will fly to the lunar pole on the Resource Prospector Mission (RPM) in 2019. The purpose of the mission is to characterize the water on the surface and subsurface of the moon in various locations in order to map the distribution. This characterization of water will help to understand how feasible water is as a resource that can be used for drinking water, breathable air, and propellants in future missions. This paper describes the key support activities performed during a 10 week internship; specifically, troubleshooting the Near Infrared Spectrometer for the Surge Tank (NIRST) instrument count loss, contributing to a clamp to be used in the installation of Resistive Temperature Detectors (RTDs) to tubing, performing a failure analysis of the LAVA Fluid Subsystem (FSS), and finalizing trade studies for release.

  11. Voluminous submarine lava flows from Hawaiian volcanoes

    SciTech Connect

    Holcomb, R.T.; Moore, J.G.; Lipman, P.W.; Belderson, R.H.

    1988-05-01

    The GLORIA long-range sonar imaging system has revealed fields of large lava flows in the Hawaiian Trough east and south of Hawaii in water as deep as 5.5 km. Flows in the most extensive field (110 km long) have erupted from the deep submarine segment of Kilauea's east rift zone. Other flows have been erupted from Loihi and Mauna Loa. This discovery confirms a suspicion, long held from subaerial studies, that voluminous submarine flows are erupted from Hawaiian volcanoes, and it supports an inference that summit calderas repeatedly collapse and fill at intervals of centuries to millenia owing to voluminous eruptions. These extensive flows differ greatly in form from pillow lavas found previously along shallower segments of the rift zones; therefore, revision of concepts of volcano stratigraphy and structure may be required.

  12. Geothermometry of Kilauea Iki lava lake, Hawaii

    USGS Publications Warehouse

    Helz, R.T.; Thornber, C.R.

    1987-01-01

    Data on the variation of temperature with time and in space are essential to a complete understanding of the crystallization history of basaltic magma in Kilauea Iki lava lake. Methods used to determine temperatures in the lake have included direct, downhole thermocouple measurements and Fe-Ti oxide geothermometry. In addition, the temperature variations of MgO and CaO contents of glasses, as determined in melting experiments on appropriate Kilauean samples, have been calibrated for use as purely empirical geothermometers and are directly applicable to interstitial glasses in olivine-bearing core from Kilauea Iki. The uncertainty in inferred quenching temperatures is ??8-10?? C. Comparison of the three methods shows that (1) oxide and glass geothermometry give results that are consistent with each other and consistent with the petrography and relative position of samples, (2) downhole thermo-couple measurements are low in all but the earliest, shallowest holes because the deeper holes never completely recover to predrilling temperatures, (3) glass geothermometry provides the greatest detail on temperature profiles in the partially molten zone, much of which is otherwise inaccessible, and (4) all three methods are necessary to construct a complete temperature profile for any given drill hole. Application of glass-based geothermometry to partially molten drill core recovered in 1975-1981 reveals in great detail the variation of temperature, in both time and space, within the partially molten zone of Kilauea Iki lava lake. The geothermometers developed here are also potentially applicable to glassy samples from other Kilauea lava lakes and to rapidly quenched lava samples from eruptions of Kilauea and Mauna Loa. ?? 1987 Springer-Verlag.

  13. Kilauea Iki lava lake experiment plans

    SciTech Connect

    Dunn, J.C.; Hills, R.G.

    1981-01-01

    Twelve experimental studies are proposed to complete field laboratory work at Kilauea Iki lava lake. Of these twelve experiments, eleven do not require the presence of melt. Some studies are designed to use proven techniques in order to expand our existing knowledge, while others are designed to test new concepts. Experiments are grouped into three main categories: geophysics, energy extraction, and drilling technology. Each experiment is described in terms of its location, purpose, background, configuration, operation, and feasibility.

  14. White Sands, Carrizozo Lava Beds, NM

    NASA Image and Video Library

    1973-06-22

    SL2-04-288 (22 June 1973) --- A truly remarkable view of White Sands and the nearby Carrizozo Lava Beds in southeast New Mexico (33.5N, 106.5W). White Sands, site of the WW II atomic bomb development and testing facility and later post war nuclear weapons testing that can still be seen in the cleared circular patterns on the ground. Photo credit: NASA

  15. Flow and convective cooling in lava tubes

    NASA Astrophysics Data System (ADS)

    Sakimoto, S. E. H.; Zuber, M. T.

    1998-11-01

    Tube-fed basaltic lava flows with lengths ranging from 10 to 200 km are inferred to exhibit similar amounts of cooling. To explain the wide range of implied cooling rates, we consider forced convection as a dominant cooling process in lava tubes and present solutions that express mean temperature versus distance down the tube as a function of flow rate and flow cross section. Our models treat forced convective thermal losses in steady laminar flow through a lava tube with constant temperature walls and constant material properties. We explore the effects of different wall temperature and heat flux rate boundary conditions for circular tube and parallel plate flows over a range of tube sizes, plate spacings, eruption temperatures, and volume flow rates. Results show that nonlinear cooling rates over distance are characteristic of constant wall temperature for a piecewise parallel plate/circular tube model. This provides the best fit to temperature observations for Hawaiian tubes. Such a model may also provide an explanation for the very low (˜10°C) cooling observed in ˜10 km long Hawaii tube flows and inferred in longer ˜50 to 150 km tube-fed flows in Queensland. The forced convective cooling model may also explain similar flow morphologies for long tube-fed basaltic lava flows in a wide variety of locations, since small variations in eruption temperature or flow rate can accommodate the entire range of flow lengths and cooling rates considered. Our results are consistent with previous suggestions that long basaltic flows may be a reflection of low slopes, a particularly steady moderate eruption rate, and well-insulated flow, rather than of high discharge rates.

  16. Modeling steam pressure under martian lava flows

    USGS Publications Warehouse

    Dundas, Colin M.; Keszthelyi, Laszlo P.

    2013-01-01

    Rootless cones on Mars are a valuable indicator of past interactions between lava and water. However, the details of the lava–water interactions are not fully understood, limiting the ability to use these features to infer new information about past water on Mars. We have developed a model for the pressurization of a dry layer of porous regolith by melting and boiling ground ice in the shallow subsurface. This model builds on previous models of lava cooling and melting of subsurface ice. We find that for reasonable regolith properties and ice depths of decimeters, explosive pressures can be reached. However, the energy stored within such lags is insufficient to excavate thick flows unless they draw steam from a broader region than the local eruption site. These results indicate that lag pressurization can drive rootless cone formation under favorable circumstances, but in other instances molten fuel–coolant interactions are probably required. We use the model results to consider a range of scenarios for rootless cone formation in Athabasca Valles. Pressure buildup by melting and boiling ice under a desiccated lag is possible in some locations, consistent with the expected distribution of ice implanted from atmospheric water vapor. However, it is uncertain whether such ice has existed in the vicinity of Athabasca Valles in recent history. Plausible alternative sources include surface snow or an aqueous flood shortly before the emplacement of the lava flow.

  17. Magnetic Mineralogy in Oxidized Lava Flows

    NASA Astrophysics Data System (ADS)

    Kontny, A.; Kletetschka, G.; Wasilewski, P. J.

    2004-12-01

    Oxidized basaltic lava flows are common in terrestrial environment and magnetic mineralogy ranges from rhombohedral to spinel phases contributing to a complex overall magnetic behavior. Similar rock types are responsable for very intense magnetic anomalies on Earth and may be an equivalent to those on Mars. Therefore this research may identify the magnetic techniques that should be employed as part of instrumentation on board of remote control rover on surface of Mars. We obtained a large number of magnetic and mineralogic tests on a basaltic profile across a tree mold from Kilauea volcano, Hawaii, where the oxygen fugacity was presumably modified by the presence of combustible organic material within the lava flow. The lava flow cools down rapidly as it approaches much cooler organic material. This process results in contrasting contents of titanium in magnetic phases and different Fe-Ti oxide textures, which is important for the overall rock magnetic properties. We attempted to identify the contribution of all the magnetic phases within these rocks using different remanence and susceptibility measurement at very low-, low- and high-temperature as well as optical and electron microscope investigations. The phases within these rocks are titanohematite (self reversing composition), ferrian ilmenite and titanomagnetite, which contribute to the induced as well as to the remanent component of the magnetization.

  18. Electromagnetic Monitoring of Lava Tubes: Numerical Modeling and Instrument Testing

    NASA Astrophysics Data System (ADS)

    Sly, Michael K.

    Currently the only method to measure the flow rates of lava in lava tubes is through the use of a skylight. This means that only a fraction of lava tubes can be measured. It is important to know the flow rate throughout a lava tube to know how much lava is being produced by a volcano at a given time. In order to measure the flow rate without using a skylight we can utilize the electromagnetic properties of flowing lava and the Lorentz force. Theoretical as well as numerical methods have been used to model an expected response using this technique. The experimental results will be compared to these models to discern accuracy. The main difficulty involved in this experiment is the high resistivity of the basalt that surrounds the lava tube. In order to obtain measurements in this environment high impedance electrodes are needed. After months of development and testing, multiple high impedance electrodes are available to be used on any surface including basalt. These electrodes are able to measure electric signals through any highly resistive surface including concrete, asphalt, basalt, and ice. Currently no tests have been done or are planned to measure flowing lava. Instead we will measure flowing sea water in pipes on the SIO campus. These pipes provide a good analog to the lava tubes. These tests have provided useful information about the noise floor for this system, telling us that a response from a full size lava tube could most likely be seen.

  19. Geochemistry of the Hawi lavas, Kohala Volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Spengler, Steven R.; Garcia, Michael O.

    1988-05-01

    Hawi lavas form the late stage alkalic cap on Kohala Volcano and range in composition from hawaiite to trachyte. New, detailed field mapping of Kohala and reinterpretation of previously published age data suggest that there was no significant eruption hiatus between the Hawi and underlying Pololu shield lavas as was previously suggested. Mineral and whole-rock chemical data are consistent with a crystal fractionation origin for the hawaiite to trachyte compositional variation observed within the Hawi lavas. Plagioclase, clinopyroxene, Ti-magnetite, olivine and apatite fractionation are needed to explain this variation. The clinopyroxene fractionation may have occurred at moderate pressure because it is virtually absent in these lavas and is not a near liquidus phase at pressures of less than 8 Kb. Plagioclase would be buoyant in the Hawi hawaiite magmas so a mechanism like dynamic flow crystallization is needed for its fractionation and to account for the virtual absence of phenocrysts in the lavas. Hawi lavas are distinct in Sr and Nd isotopic ratios and/or incompatible element ratios from the Pololu lavas. Thus they were derived from compositionally distinct sources. Compared to other suites of Hawaiian alkalic cap lavas, Hawi lavas have anomalously high concentrations of phosphorus and rare earth elements. These differences could be due to greater apatite content in the source for the Hawi lavas.

  20. Using Lava Tube Skylights To Derive Lava Eruption Temperatures on Io

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    The eruption temperature of Io’s silicate lavas constrains Io’s interior state and composition [1]. We have examined the theoretical thermal emission from lava tube skylights above basaltic and ultramafic lava channels. Assuming that tube-fed lava flows are common on Io, skylights could also be common. Skylights present steady thermal emission on a scale of days to months. We find that the thermal emission from such a target, measured at multiple visible and NIR wavelengths, can provide a highly accurate diagnostic of eruption temperature. However, the small size of skylights means that close flybys of Io are necessary, requiring a dedicated Io mission [2]. Observations would ideally be at night or in eclipse. We have modelled the thermal emission spectrum for different skylight sizes, lava flow stream velocities, end-member lava compositions, and skylight radiation shape factors, determining the resulting flow surface cooling rates. We calculate the resulting thermal emission spectrum as a function of viewing geometry. From the resulting 0.7:0.9 μm ratios, we see a clear distinction between basaltic and ultramafic compositions for skylights smaller than 20 m across, even if sub-pixel. Our analysis will be further refined as accurate high-temperature short-wavelength emissivity values become available [3]. This work was performed at the Jet Propulsion Laboratory-California Institute of Technology, under contract to NASA. We thank the NASA OPR Program for support. References: [1] Keszthelyi et al. (2007) Icarus 192, 491-502 [2] McEwen et al. (2015) The Io Volcano Observer (IVO) LPSC-46 abstract 1627 [3] Ramsey and Harris (2015) IAVCEI-2015, Prague, Cz. Rep., abstract IUGG-3519.

  1. Additional Observations of Actively Forming Lava Tubes and Associated Structures, Hawaii

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald

    1972-01-01

    Extensive changes occurred after the initial observations (Greeley, 1971) of lava tube and channel formation associated with the eruption of Mauna Ulu. Individual vents, which apparently acted somewhat independently, merged by collapse of intervening sections to form an elongate trench. Lava erupted from the summit vent flowed down the trench to the lower end and drained through lava tubes into Alae lava lake. Alae lava lake is in turn drained occasionally by other lava tubes and lava tube networks.

  2. Gusev Rocks Solidified from Lava (False Color)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    In recent weeks, as NASA's Mars Exploration Rover Spirit has driven through the basin south of 'Husband Hill,' it has been traversing mainly sand and dune deposits. This week, though, Spirit has been maneuvering along the edge of an arc-shaped feature called 'Lorre Ridge' and has encountered some spectacular examples of basaltic rocks with striking textures. This panoramic camera (Pancam) image shows a group of boulders informally named 'FuYi.' These basaltic rocks were formed by volcanic processes and may be a primary constituent of Lorre Ridge and other interesting landforms in the basin.

    Spirit first encountered basalts at its landing site two years ago, on a vast plain covered with solidified lava that appeared to have flowed across Gusev Crater. Later, basaltic rocks became rare as Spirit climbed Husband Hill. The basaltic rocks that Spirit is now seeing are interesting because they exhibit many small holes or vesicles, similar to some kinds of volcanic rocks on Earth. Vesicular rocks form when gas bubbles are trapped in lava flows and the rock solidifies around the bubbles. When the gas escapes, it leaves holes in the rock. The quantity of gas bubbles in rocks on Husband Hill varies considerably; some rocks have none and some, such as several here at FuYi, are downright frothy.

    The change in textures and the location of the basalts may be signs that Spirit is driving along the edge of a lava flow. This lava may be the same as the basalt blanketing the plains of Spirit's landing site, or it may be different. The large size and frothy nature of the boulders around Lorre Ridge might indicate that eruptions once took place at the edge of the lava flow, where the lava interacted with the rocks of the basin floor. Scientists hope to learn more as Spirit continues to investigate these rocks.

    As Earth approaches the Chinese New Year (The Year of the Dog), the Athena science team decided to use nicknames representing Chinese culture and geography

  3. Gusev Rocks Solidified from Lava (3-D)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    In recent weeks, as NASA's Mars Exploration Rover Spirit has driven through the basin south of 'Husband Hill,' it has been traversing mainly sand and dune deposits. This week, though, Spirit has been maneuvering along the edge of an arc-shaped feature called 'Lorre Ridge' and has encountered some spectacular examples of basaltic rocks with striking textures. This panoramic camera (Pancam) image shows a group of boulders informally named 'FuYi.' These basaltic rocks were formed by volcanic processes and may be a primary constituent of Lorre Ridge and other interesting landforms in the basin.

    Spirit first encountered basalts at its landing site two years ago, on a vast plain covered with solidified lava that appeared to have flowed across Gusev Crater. Later, basaltic rocks became rare as Spirit climbed Husband Hill. The basaltic rocks that Spirit is now seeing are interesting because they exhibit many small holes or vesicles, similar to some kinds of volcanic rocks on Earth. Vesicular rocks form when gas bubbles are trapped in lava flows and the rock solidifies around the bubbles. When the gas escapes, it leaves holes in the rock. The quantity of gas bubbles in rocks on Husband Hill varies considerably; some rocks have none and some, such as several here at FuYi, are downright frothy.

    The change in textures and the location of the basalts may be signs that Spirit is driving along the edge of a lava flow. This lava may be the same as the basalt blanketing the plains of Spirit's landing site, or it may be different. The large size and frothy nature of the boulders around Lorre Ridge might indicate that eruptions once took place at the edge of the lava flow, where the lava interacted with the rocks of the basin floor. Scientists hope to learn more as Spirit continues to investigate these rocks.

    As Earth approaches the Chinese New Year (The Year of the Dog), the Athena science team decided to use nicknames representing Chinese culture and geography

  4. Sampling Elysium lavas (13 deg N, 203 deg W)

    NASA Technical Reports Server (NTRS)

    Allen, Carlton C.

    1994-01-01

    The proposed Pathfinder landing site presents the opportunity to determine chemical and mineralogical compositions of an Elysium lava flow. The flow is part of a geologic unit of planetary significance. The proposed site appears suitable for landing, and lava surfaces should be accessible to the Pathfinder instruments. By analogy to terrestrial flood basalts, any lava analyzed by Pathfinder is likely to be representative of the entire Elysium province.

  5. Observations of actively forming lava tubes and associated structures, Hawaii.

    NASA Technical Reports Server (NTRS)

    Greeley, R.

    1971-01-01

    Fluid basalts were erupted in August, 1970, from a vent near Alae Crater and flowed southeast. Forming exclusively in pahoehoe basalt, tubes in general evolve from lava channels by crustal formation, although some tubes develop directly from the vent. The observation discussed shows that channel crusts and tube roofs form in several ways. Lava channels usually form along the axis of highest velocity within the flow and are often centered along older lava channels, stream beds, rifts, grabens, or fracture zones.

  6. Identifying hazards associated with lava deltas

    USGS Publications Warehouse

    Poland, Michael P.; Orr, Tim R.

    2014-01-01

    Lava deltas, formed where lava enters the ocean and builds a shelf of new land extending from the coastline, represent a significant local hazard, especially on populated ocean island volcanoes. Such structures are unstable and prone to collapse—events that are often accompanied by small explosions that can deposit boulders and cobbles hundreds of meters inland. Explosions that coincide with collapses of the East Lae ‘Apuki lava delta at Kīlauea Volcano, Hawai‘i, during 2005–2007 followed an evolutionary progression mirroring that of the delta itself. A collapse that occurred when the lava–ocean entry was active was associated with a blast of lithic blocks and dispersal of spatter and fine, glassy tephra. Shortly after delta growth ceased, a collapse exposed hot rock to cold ocean water, resulting in an explosion composed entirely of lithic blocks and lapilli. Further collapse of the delta after several months of inactivity, by which time it had cooled significantly, resulted in no recognizable explosion deposit. Seaward displacement and subsidence of the coastline immediately inland of the delta was measured by both satellite and ground-based sensors and occurred at rates of several centimeters per month even after the lava–ocean entry had ceased. The anomalous deformation ended only after complete collapse of the delta. Monitoring of ground deformation may therefore provide an indication of the potential for delta collapse, while the hazard associated with collapse can be inferred from the level of activity, or the time since the last activity, on the delta.

  7. Chips Off an Old Lava Flow

    NASA Astrophysics Data System (ADS)

    Taylor, G. J.

    2007-12-01

    Photogeologic and remote sensing studies of the Moon show that many light-colored, smooth areas in the highlands contain craters surrounded by dark piles of excavated debris. The dark deposits resemble the dark basalts that make up the lunar maria. They contain the same diagnostic minerals (especially high-calcium pyroxene) and chemical compositions (high iron oxide) as do mare basalts. The deposits formed when vast amounts of material ejected during the formation of giant impact basins covered pre-existing lava plains. Since the smooth plains are older than the youngest impact basin (about 3.8 billion years old), the lavas must have erupted before formation of the visible maria. In fact, they were visible maria for a while eons ago, but were buried by ejecta when the basins formed. We have samples of these ancient mare basalts. They reside in breccias collected from the lunar highlands. Age dating indicates that the chips have ages of 3.9 billion years and older. The oldest dated mare basalt in the Apollo collection is 4.23 billion years. Now Kentaro Terada (Hiroshima University, Japan), Mahesh Anand (Open University, UK), Anna Sokol and Addi Bischoff (Institute for Planetology, Muenster, Germany), and Yuji Sano (The University of Tokyo, Japan) have determined the age of pieces of an ancient lava flow in a lunar meteorite, Kalahari 009, found in Botswana in 1999. The team dated this very low-titanium mare basalt by using an ion microprobe to measure the isotopic composition of lead and uranium in phosphate minerals. They found that the basalt fragments in the rock have an age of about 4.35 (plus or minus 0.15) billion years. This overlaps with the ages of chemically-distinct igneous rocks from the highlands, indicating that diverse magmas were being produced early in the history of the Moon.

  8. Geochemical Stratigraphy of Southern Parana' Lava Piles

    NASA Astrophysics Data System (ADS)

    Marzoli, A.; De Min, A.; Marques, L. S.; Nardy, A.; Chiaradia, M.

    2015-12-01

    Basaltic lava flows of the Paranà Large Igneous Province exhibit significant regional and stratigraphic geochemical variations. While the most notable difference concerns the dominance of low-Ti (TiO2 < 2.0 wt.%) and high-Ti types in the southern and northern part of the province, respectively, detailed analyses of lava flow sequences sampled mostly in drill cores allowed definition of six main groups of chemically distinct flow units. The chemical and possible age differences among these units were then used to define the global time-related evolution of Paranà basaltic magmatism and involvement of distinct mantle-source components. Newly sampled outcropping lava flow sequences from the southern Paranà do however only partially support this picture. Our new major and trace element and Sr-Nd-Pb isotopic data show that high- and low-Ti basaltic flows are interlayered. In particular, Pitanga type high-Ti basalts are interlayered with Gramado and Esmeralda low-Ti basalts (these latter being present both towards the base and the top of the sequence) in Paranà State, while in Santa Caterina State Gramado flows are interlayered with Urubici-type high-Ti basalts. The interlayering of distinct basaltic magma type requires near-synchronous eruption of chemically strongly different magma types generated from clearly heterogeneous mantle sources and erupted through separated magma plumbing systems, without apparent interaction (mixing) among the distinct basalts. In conclusion, the relative timing of low- and high-Ti magma types seems to be much more complicated than previously thought, as for example Esmeralda or Pitanga basalts, previously considered as quite late and postdating Gramado basalts, are indeed synchronous with them.

  9. Determining the Compositions of Extraterrestrial Lava Flows

    NASA Technical Reports Server (NTRS)

    Fink, Jonathan H.

    2002-01-01

    The primary purpose of this research project has been to develop techniques that allow the emplacement conditions of volcanic landforms on other planets to be related to attributes that can be remotely detected with available instrumentation. The underlying assumption of our work is that the appearance of a volcano, lava flow, debris avalanche, or exhumed magmatic intrusion can provide clues about the conditions operating when that feature was first emplaced. Magma composition, amount of crustal heat flow, state of tectonic stress, and climatic conditions are among the important variables that can be inferred from the morphology and texture of an igneous body.

  10. White Sands, Carrizozo Lava Beds, NM

    NASA Image and Video Library

    1982-03-30

    STS003-10-613 (22-30 March 1982) --- A truly remarkable view of White Sands and the nearby Carrizozo Lava Beds in southeast NM (33.5N, 106.5W). White Sands, site of the WW II atomic bomb development and testing facility and later post war nuclear weapons testing that can still be seen in the cleared circular patterns on the ground. Space shuttle Columbia (STS-3), this mission, landed at the White Sands alternate landing site because of bad weather at Edwards AFB, CA. Photo credit: NASA

  11. Laboratory Investigations of Lava Flow Heat Transfer

    NASA Astrophysics Data System (ADS)

    Fagents, S. A.; Rumpf, M. E.; Hamilton, C. W.

    2011-12-01

    To investigate the effectiveness with which lava can heat substrates of different types, we conducted a suite of experiments in which molten basalt was poured onto solid or particulate materials, and the downward propagation of the heat pulse was measured. The motivation for this work lies in seeking to understand how lava flows on the Moon would have heated the underlying regolith, and thus to determine the depths at which solar wind particles implanted in the regolith would have been protected from the heat of the overlying flow. Extraction and analysis of ancient solar wind samples would provide a wealth of information on the evolution and fate of the Sun. Our experimental device consists of a box constructed from 1"-thick calcium silicate sheeting with interior dimensions of 20 x 20 x 25 cm. The substrate material (a particulate lunar regolith simulant or solid basalt) occupies the lower 15 cm of the box, which is embedded with an array of 8 thermocouples. Up to 6 kg of crushed basalt collected from the 2010 Kilauea lava flows is heated to supraliquidus temperatures and poured directly onto the substrate. The evolution of the temperature profile within the lava flow and substrate is recorded as the basalt cools, and the surface temperature distribution is recorded using a Forward Looking Infrared Radiometer (FLIR) video camera. We have been using the experimental data sets to validate a numerical model of substrate heating. If the physics is appropriately formulated, the model will accurately predict both surface and internal temperature distribution as a function of time. A key issue has been incorporation of valid temperature-dependent thermophysical properties, because particulate materials are not well characterized at elevated temperatures. Regolith thermal conductivity in particular exerts a strong control over the depth of penetration of the thermal wave, so its accurate description is essential for a robust model. Comparison of experimental vs. modeled

  12. Lava tubes - Potential shelters for habitats. [on moon

    NASA Technical Reports Server (NTRS)

    Horz, F.

    1985-01-01

    Natural caverns occur on the moon in the form of 'lava tubes', which are the drained conduits of underground lava rivers. The inside dimensions of these tubes measure tens to hundreds of meters, and their roofs are expected to be thicker than 10 meters. Consequently, lava tube interiors offer an environment that is naturally protected from the hazards of radiation and meteorite impact. Further, constant, relatively benign temperatures of -20 C prevail. These are extremely favorable environmental conditions for human activities and industrial operations. Significant operational, technological, and economical benefits might result if a lunar base were constructed inside a lava tube.

  13. Lava tubes - Potential shelters for habitats. [on moon

    NASA Technical Reports Server (NTRS)

    Horz, F.

    1985-01-01

    Natural caverns occur on the moon in the form of 'lava tubes', which are the drained conduits of underground lava rivers. The inside dimensions of these tubes measure tens to hundreds of meters, and their roofs are expected to be thicker than 10 meters. Consequently, lava tube interiors offer an environment that is naturally protected from the hazards of radiation and meteorite impact. Further, constant, relatively benign temperatures of -20 C prevail. These are extremely favorable environmental conditions for human activities and industrial operations. Significant operational, technological, and economical benefits might result if a lunar base were constructed inside a lava tube.

  14. Physical characteristics of a lava flow determined from thermal measurements at the lava's surface

    NASA Astrophysics Data System (ADS)

    Ismail-Zadeh, A. T.; Kovtunov, D. A.; Korotkii, A. I.; Melnik, O. E.; Tsepelev, I. A.

    2016-04-01

    We consider the problem about determination of characteristics of a lava flow from the physical parameters measured on its surface. The problem is formulated as an inverse boundary problem for the model simulating the dynamics of a viscous heat-conducting incompressible inhomogeneous fluid, where, on the basis of additional data at one part of the model boundary, the missing conditions at another part of the boundary have to be determined, and then the characteristics of fluid in the entire model domain have to be reconstructed. The considered problem is ill-posed. We develop a numerical approach to the solution of the problem in the case of a steady-state flow. Assuming that the temperature and the heat flow are known at the upper surface of the lava, we determine the flow characteristics inside the lava. We compute model examples and show that the lava temperature and flow velocity can be determined with a high precision when the initial data are smooth or slightly noisy.

  15. Topographic Attributes of Three Hawaiian Lava Flows: Implications for Evaluation of Lava Flow Emplacement on Mars

    NASA Astrophysics Data System (ADS)

    Zimbelman, J. R.

    2004-12-01

    Differential Global Positioning System surveys were carried out recently across portions of three lava flows on the Big Island of Hawaii. Transects crossed an entire flow in several cases, and in other cases provided detailed information about selected flow margins. The 1907 basalt (a'a) flow from the southwestern rift zone of Mauna Loa has easy access at several points via the Ocean View Estates road system; flow thickness ranges from about 1 m near the middle of the eastern flow lobe to more than 10 m toward the distal end of this flow. Several components of a benmoreite (alkali-rich basaltic andesite) flow complex from Mauna Kea were examined near the small community of Mana (with permission of the Parker Ranch management), on the western flank of the volcano. The flows are more than 14,000 years old and completely covered with soil more than a meter thick, but flow morphology at the decameter scale remains very evident in aerial photographs; some benmoreite flows have up to 30 m of relief along their middle reaches. A trachyte flow more than 100,000 years old extends down slope from Puu Waawaa, on the northern flank of Hualalai; Puu Anahulu represents a very advanced stage of magmatic differentiation that resulted in a flow complex with more than 120 m of relief at its southern margin. Width/thickness represents a good discriminator between these three Hawaiian lava flows. Unfortunately, width is often the most difficult parameter to measure remotely for flows on other planets. Recent imaging data from the Thermal Emission Imaging System on the Mars Odyssey spacecraft reveal important new details of lava flows in the Tharsis region of Mars, some of which can be combined with elevation information from the Mars Orbiter Laser Altimeter. The precise topographic characteristics of diverse Hawaiian lava flows provide a new tool for evaluating the potential emplacement conditions for some Martian lava flows, which appear to be more consistent with the basalt to

  16. Eruptive behavior of the Marum/Mbwelesu lava lake, Vanuatu and comparisons with lava lakes on Earth and Io

    NASA Astrophysics Data System (ADS)

    Radebaugh, Jani; Lopes, Rosaly M.; Howell, Robert R.; Lorenz, Ralph D.; Turtle, Elizabeth P.

    2016-08-01

    Observations from field remote sensing of the morphology, kinematics and temperature of the Marum/Mbwelesu lava lake in the Vanuatu archipelago in 2014 reveal a highly active, vigorously erupting lava lake. Active degassing and fountaining observed at the 50 m lava lake led to large areas of fully exposed lavas and rapid ( 5 m/s) movement of lava from the centers of upwelling outwards to the lake margins. These rapid lava speeds precluded the formation of thick crust; there was never more than 30% non-translucent crust. The lava lake was observed with several portable, handheld, low-cost, near-infrared imagers, all of which measured temperatures near 1000 °C and one as high as 1022 °C, consistent with basaltic temperatures. Fine-scale structure in the lava fountains and cooled crust was visible in the near infrared at 5 cm/pixel from 300 m above the lake surface. The temperature distribution across the lake surface is much broader than at more quiescent lava lakes, peaking 850 °C, and is attributed to the highly exposed nature of the rapidly circulating lake. This lava lake has many characteristics in common with other active lava lakes, such as Erta Ale in Ethiopia, being confined, persistent and high-temperature; however it was much more active than is typical for Erta Ale, which often has > 90% crust. Furthermore, it is a good analogue for the persistent, high-temperature lava lakes contained within volcanic depressions on Jupiter's moon Io, such as Pele, also believed from spacecraft and ground-based observations to exhibit similar behavior of gas emission, rapid overturn and fountaining.

  17. Pressure Analysis for LAVA-OVEN

    NASA Technical Reports Server (NTRS)

    Cendana, Donna Q.

    2014-01-01

    The Lunar Advanced Volatiles Analysis (LAVA) and the Oxygen Volatiles Extraction Node (OVEN) are subsystems included in the Regolith Environment Science, and Oxygen Lunar Volatiles Extraction (RESOLVE) payload bound for the Moon in 2019. This Resource Prospector Mission (RPM) has the objective of landing on a shadowed region of the Moons South Pole to collect data and determine whether the resources could be effectively used for space exploration systems. The quantification of the resources will help understand if it can adequately minimize materials carried from Earth by: providing life support, propellants, construction materials or energy supply to the payload or crew. This paper outlines the procedures done for the pressure analysis of the LAVA-OVEN (LOVEN) Integration Testing. The pressure analysis quantifies how much gases and water are present in the sample tested during the Engineering Testing Unit (ETU) phase of instrument development. Ultimately the purpose of these tests is to improve the estimate of the amount of water in each Lunar sample and reduce the time necessary for this estimate. The governing principle that was used for the analysis is the Ideal Gas Law, PV=nRT where P stands for pressure, V for volume, n for number of moles, R being the gas constant and T for temperature. We also estimate the errors involved in these measured and derived quantities since a key objective of the mission is to estimate the quantity of volatiles present in the lunar samples introduced into OVEN.

  18. Lava tube shatter rings and their correlation with lava flux increases at Kīlauea Volcano, Hawai‘i

    USGS Publications Warehouse

    Orr, T.R.

    2011-01-01

    Shatter rings are circular to elliptical volcanic features, typically tens of meters in diameter, which form over active lava tubes. They are typified by an upraised rim of blocky rubble and a central depression. Prior to this study, shatter rings had not been observed forming, and, thus, were interpreted in many ways. This paper describes the process of formation for shatter rings observed at Kīlauea Volcano during November 2005–July 2006. During this period, tilt data, time-lapse images, and field observations showed that episodic tilt changes at the nearby Pu‘u ‘Ō‘ō cone, the shallow magmatic source reservoir, were directly related to fluctuations in the level of lava in the active lava tube, with periods of deflation at Pu‘u ‘Ō‘ō correlating with increases in the level of the lava stream surface. Increases in lava level are interpreted as increases in lava flux, and were coincident with lava breakouts from shatter rings constructed over the lava tube. The repetitive behavior of the lava flux changes, inferred from the nearly continuous tilt oscillations, suggests that shatter rings form from the repeated rise and fall of a portion of a lava tube roof. The locations of shatter rings along the active lava tube suggest that they form where there is an abrupt decrease in flow velocity through the tube, e.g., large increase in tube width, abrupt decrease in tube slope, and (or) sudden change in tube direction. To conserve volume, this necessitates an abrupt increase in lava stream depth and causes over-pressurization of the tube. More than a hundred shatter rings have been identified on volcanoes on Hawai‘i and Maui, and dozens have been reported from basaltic lava fields in Iceland, Australia, Italy, Samoa, and the mainland United States. A quick study of other basaltic lava fields worldwide, using freely available satellite imagery, suggests that they might be even more common than previously thought. If so, this confirms that episodic

  19. Lava tube shatter rings and their correlation with lava flux increases at Kīlauea Volcano, Hawai`i

    NASA Astrophysics Data System (ADS)

    Orr, Tim R.

    2011-04-01

    Shatter rings are circular to elliptical volcanic features, typically tens of meters in diameter, which form over active lava tubes. They are typified by an upraised rim of blocky rubble and a central depression. Prior to this study, shatter rings had not been observed forming, and, thus, were interpreted in many ways. This paper describes the process of formation for shatter rings observed at Kīlauea Volcano during November 2005-July 2006. During this period, tilt data, time-lapse images, and field observations showed that episodic tilt changes at the nearby Pu`u `Ō`ō cone, the shallow magmatic source reservoir, were directly related to fluctuations in the level of lava in the active lava tube, with periods of deflation at Pu`u `Ō`ō correlating with increases in the level of the lava stream surface. Increases in lava level are interpreted as increases in lava flux, and were coincident with lava breakouts from shatter rings constructed over the lava tube. The repetitive behavior of the lava flux changes, inferred from the nearly continuous tilt oscillations, suggests that shatter rings form from the repeated rise and fall of a portion of a lava tube roof. The locations of shatter rings along the active lava tube suggest that they form where there is an abrupt decrease in flow velocity through the tube, e.g., large increase in tube width, abrupt decrease in tube slope, and (or) sudden change in tube direction. To conserve volume, this necessitates an abrupt increase in lava stream depth and causes over-pressurization of the tube. More than a hundred shatter rings have been identified on volcanoes on Hawai`i and Maui, and dozens have been reported from basaltic lava fields in Iceland, Australia, Italy, Samoa, and the mainland United States. A quick study of other basaltic lava fields worldwide, using freely available satellite imagery, suggests that they might be even more common than previously thought. If so, this confirms that episodic fluctuation in lava

  20. Construction dynamics of a lava channel

    NASA Astrophysics Data System (ADS)

    Harris, Andrew J. L.; Favalli, Massimiliano; Mazzarini, Francesco; Hamilton, Christopher W.

    2009-05-01

    We use a kinematic GPS and laser range finder survey of a 200 m-long section of the Muliwai a Pele lava channel (Mauna Ulu, Kilauea) to examine the construction processes and flow dynamics responsible for the channel-levee structure. The levees comprise three packages. The basal package comprises an 80-150 m wide 'a'a flow in which a ˜2 m deep and ˜11 m wide channel became centred. This is capped by a second package of thin (<45 cm thick) sheets of pahoehoe extending no more than 50 m from the channel. The upper-most package comprises localised 'a'a overflows. The channel itself contains two blockages located 130 m apart and composed of levee chunks veneered with overflow lava. The channel was emplaced over 50 h, spanning 30 May-2 June, 1974, with the flow front arriving at our section (4.4 km from the vent) 8 h after the eruption began. The basal 'a'a flow thickness yields effusion rates of 35 m3 s-1 for the opening phase, with the initial flow advancing across the mapped section at ˜10 m/min. Short-lived overflows of fluid pahoehoe then built the levee cap, increasing the apparent channel depth to 4.8 m. There were at least six pulses at 90-420 m3 s-1, causing overflow of limited extent lasting no more than 5 min. Brim-full flow conditions were thus extremely short-lived. During a dominant period of below-bank flow, flow depth was ˜2 m with an effusion rate of ˜35 m3 s-1, consistent with the mean output rate (obtained from the total flow bulk volume) of 23-54 m3 s-1. During pulses, levee chunks were plucked and floated down channel to form blockages. In a final low effusion rate phase, lava ponded behind the lower blockage to form a syn-channel pond that fed 'a'a overflow. After the end of the eruption the roofed-over pond continued to drain through the lower blockage, causing the roof to founder. Drainage emplaced inflated flows on the channel floor below the lower blockage for a further ˜10 h. The complex processes involved in levee-channel construction

  1. The explosive origin of obsidian lava (Invited)

    NASA Astrophysics Data System (ADS)

    Castro, J. M.; Bindeman, I. N.; Tuffen, H.; Schipper, C.

    2013-12-01

    A long-standing challenge in volcanology has been to explain why explosive eruptions of rhyolite magma transition into outpourings of lava. Many studies suggest that lava is the product of non-explosive processes that allow magmatic vapour to escape in an open-system manner without wholesale fragmentation. Recent eruptions at Chaitén and Cordón Caulle volcanoes have shown that effusive rhyolites are anything but 'non-explosive' and may erupt simultaneously with vigourous pyroclastic fountains for months from a common vent. This behaviour implies that pyroclastic processes play a critical if not dominant role in degassing magma sufficiently such that it erupts effusively. Here we use H-isotope and bulk H2O measurements paired with textural evidence from the 2008 Chaitén and 2011 Cordón Caulle eruptions to demonstrate that effusion requires explosion(s)--lavas are the direct product of brittle deformation that fosters batched degassing into transient pyroclastic channels that repetitively and explosively vent from effusing lava. Evidence for cyclical brecciation and collapse of porous and permeable magmatic foams is abundant in the textures and structures of tuffisites--ash and lapilli-filled pyroclastic channels--found in volcanic bombs at both Chaitén and Cordón Caulle. We have used FTIR and a TCEA-MAT 253 system to precisely measure total water and D/H in erupted glass. Bulk H2O measurements on tuffisite and adjacent bomb obsidian indicate significantly lower H2O (~0.2-1.0 wt.%) in the tuffisite veins. These depletions imply effective local degassing and rapid advective transport of exsolved vapour through the veins. The H-isotopic signatures of tuffisites are also different from the hosting material insofar as being enriched in deuterium (up to -20‰). Such deuterium enrichments are inconsistent with isotope fractionation during both closed- and open-system degassing, but can be explained if an abundant and more primitive volatile phase from less degassed

  2. What factors control the superficial lava dome explosivity?

    NASA Astrophysics Data System (ADS)

    Boudon, Georges; Balcone-Boissard, Hélène; Villemant, Benoit; Morgan, Daniel J.

    2015-04-01

    Dome-forming eruption is a frequent eruptive style; lava domes result from intermittent, slow extrusion of viscous lava. Most dome-forming eruptions produce highly microcrystallized and highly- to almost totally-degassed magmas which have a low explosive potential. During lava dome growth, recurrent collapses of unstable parts are the main destructive process of the lava dome, generating concentrated pyroclastic density currents (C-PDC) channelized in valleys. These C-PDC have a high, but localized, damage potential that largely depends on the collapsed volume. Sometimes, a dilute ash cloud surge develops at the top of the concentrated flow with an increased destructive effect because it may overflow ridges and affect larger areas. In some cases, large lava dome collapses can induce a depressurization of the magma within the conduit, leading to vulcanian explosions. By contrast, violent, laterally directed, explosions may occur at the base of a growing lava dome: this activity generates dilute and turbulent, highly-destructive, pyroclastic density currents (D-PDC), with a high velocity and propagation poorly dependent on the topography. Numerous studies on lava dome behaviors exist, but the triggering of lava dome explosions is poorly understood. Here, seven dome-forming eruptions are investigated: in the Lesser Antilles arc: Montagne Pelée, Martinique (1902-1905, 1929-1932 and 650 y. BP eruptions), Soufrière Hills, Montserrat; in Guatemala, Santiaguito (1929 eruption); in La Chaîne des Puys, France (Puy de Dome and Puy Chopine eruptions). We propose a new model of superficial lava-dome explosivity based upon a textural and geochemical study (vesicularity, microcrystallinity, cristobalite distribution, residual water contents, crystal transit times) of clasts produced by these key eruptions. Superficial explosion of a growing lava dome may be promoted through porosity reduction caused by both vesicle flattening due to gas escape and syn-eruptive cristobalite

  3. A flexible open-source toolkit for lava flow simulations

    NASA Astrophysics Data System (ADS)

    Mossoux, Sophie; Feltz, Adelin; Poppe, Sam; Canters, Frank; Kervyn, Matthieu

    2014-05-01

    Lava flow hazard modeling is a useful tool for scientists and stakeholders confronted with imminent or long term hazard from basaltic volcanoes. It can improve their understanding of the spatial distribution of volcanic hazard, influence their land use decisions and improve the city evacuation during a volcanic crisis. Although a range of empirical, stochastic and physically-based lava flow models exists, these models are rarely available or require a large amount of physical constraints. We present a GIS toolkit which models lava flow propagation from one or multiple eruptive vents, defined interactively on a Digital Elevation Model (DEM). It combines existing probabilistic (VORIS) and deterministic (FLOWGO) models in order to improve the simulation of lava flow spatial spread and terminal length. Not only is this toolkit open-source, running in Python, which allows users to adapt the code to their needs, but it also allows users to combine the models included in different ways. The lava flow paths are determined based on the probabilistic steepest slope (VORIS model - Felpeto et al., 2001) which can be constrained in order to favour concentrated or dispersed flow fields. Moreover, the toolkit allows including a corrective factor in order for the lava to overcome small topographical obstacles or pits. The lava flow terminal length can be constrained using a fixed length value, a Gaussian probability density function or can be calculated based on the thermo-rheological properties of the open-channel lava flow (FLOWGO model - Harris and Rowland, 2001). These slope-constrained properties allow estimating the velocity of the flow and its heat losses. The lava flow stops when its velocity is zero or the lava temperature reaches the solidus. Recent lava flows of Karthala volcano (Comoros islands) are here used to demonstrate the quality of lava flow simulations with the toolkit, using a quantitative assessment of the match of the simulation with the real lava flows. The

  4. Lava Flows on Io: Modelling Cooling After Solidification

    NASA Technical Reports Server (NTRS)

    Davies, A. G.; Matson, D. L.; Veeder, G. J.; Johnson, T. V.; Blaney, D. L.

    2003-01-01

    We have modeled the cooling of lava bodies on Io after solidification of the lava, a process that has been little explored since Carr (1986). With recent estimates of lava flow thicknesses on Io ranging from 1 m to 10 m, the modeling of thermal emission from active volcanism must take into account the cooling behaviour after the solidification of the lava, which we model using a finite-element model. Once a lava body is fully solidified, the surface temperature decreases faster, as heat loss is no longer buffered by release of latent heat. This is significant as observed surface temperature is often the only clue available to determine lava surface age. We also find that cooling from the base of the lava is an important process that accelerates the solidification of a flow and therefore subsequent cooling. It is necessary to constrain the cooling process in order to better understand temperature-area relationships on Io's surface and to carry out stochastic modelling of lava flow emplacement.

  5. Lava Flows on Io: Modelling Cooling After Solidification

    NASA Technical Reports Server (NTRS)

    Davies, A. G.; Matson, D. L.; Veeder, G. J.; Johnson, T. V.; Blaney, D. L.

    2003-01-01

    We have modeled the cooling of lava bodies on Io after solidification of the lava, a process that has been little explored since Carr (1986). With recent estimates of lava flow thicknesses on Io ranging from 1 m to 10 m, the modeling of thermal emission from active volcanism must take into account the cooling behaviour after the solidification of the lava, which we model using a finite-element model. Once a lava body is fully solidified, the surface temperature decreases faster, as heat loss is no longer buffered by release of latent heat. This is significant as observed surface temperature is often the only clue available to determine lava surface age. We also find that cooling from the base of the lava is an important process that accelerates the solidification of a flow and therefore subsequent cooling. It is necessary to constrain the cooling process in order to better understand temperature-area relationships on Io's surface and to carry out stochastic modelling of lava flow emplacement.

  6. Field Detection of Chemical Assimilation in A Basaltic Lava Flow

    NASA Technical Reports Server (NTRS)

    Young, K. E.; Bleacher, J. E.; Needham, D. H.; Evans, C. A.; Whelley, P. L.; Scheidt, S. P.; Williams, D. A.; Rogers, A. D.; Glotch, T.

    2017-01-01

    Lava channels are features seen throughout the inner Solar System, including on Earth, the Moon, and Mars. Flow emplacement is therefore a crucial process in the shaping of planetary surfaces. Many studies, including some completed by members of this team at the December 1974 lava flow, have investigated the dynamics of lava flow emplacement, both on Earth and on the Moon and how pre-flow terrain can impact final channel morphology, but far fewer have focused on how the compositional characteristics of the substrate over which a flow was em-placed influenced its final flow morphology. Within the length of one flow, it is common for flows to change in morphology, a quality linked to rheology (a function of multiple factors including viscosi-ty, temperature, composition, etc.). The relationship between rheology and temperature has been well-studied but less is known about the relationship between an older flow's chemistry and how the interaction between this flow and the new flow might affect lava rheology and therefore emplacement dynamics. Lava erosion. Through visual observations of active terrestrial flows, mechanical erosion by flowing lava has been well-documented. Lava erosion by which flow composition is altered as the active lava melts and assimilates the pre-flow terrain over which it moves is also hypothesized to affect channel formation. However, there is only one previous field study that geochemically documents the process in recent basaltic flow systems.

  7. Documenting Chemical Assimilation in a Basaltic Lava Flow

    NASA Technical Reports Server (NTRS)

    Young, K. E.; Bleacher, J. E.; Needham, D. H.; Evans, C.; Whelley, P. L.; Scheidt, S.; Williams, D.; Rogers, A. D.; Glotch, T.

    2017-01-01

    Lava channels are features seen throughout the inner Solar System, including on Earth, the Moon, and Mars. Flow emplacement is therefore a crucial process in the shaping of planetary surfaces. Many studies have investigated the dynamics of lava flow emplacement, both on Earth and on the Moon [1,2,3] but none have focused on how the compositional and structural characteristics of the substrate over which a flow was emplaced influenced its final flow morphology. Within the length of one flow, it is common for flows to change in morphology, a quality linked to lava rheology (a function of multiple factors including viscosity, temperature, composition, etc.). The relationship between rheology and temperature has been well-studied [4,5,6] but less is understood about the relationship between a pre-flow terrain's chemistry and how the interaction between this flow and the new flow might affect lava rheology and therefore emplacement dynamics. Lava erosion. Through visual observations of active terrestrial flows, lava erosion has been well-documented [i.e. 7,8,9,10]. Lava erosion is the process by which flow composition is altered as the active lava melts and assimilates the pre-flow terrain over which it moves. Though this process has been observed, there is only one instance of where it was been geochemically documented.

  8. Olympus Mons, Mars: Constraints on Lava Flow Silica Composition

    NASA Astrophysics Data System (ADS)

    Kirshner, M.; Jurdy, D. M.

    2016-12-01

    Olympus Mons, Mars, the largest known volcano in our solar system, contains numerous enigmatic lava flow features. Lava tubes have received attention as their final morphologies may offer habitable zones for both native life and human exploration. Such tubes were formed through mechanisms involving several volatile species with significant silica content. Olympus Mons, a shield volcano, might be expected to have flows with silica content similar to that of terrestrial basaltic flows. However, past investigations have estimated a slightly more andesitic composition. Data pertaining to lava tubes such as flow width and slope are collected from the Mars Reconnaissance Orbiter's Context Camera, Mars Odyssey's THEMIS instrument, and Mars Express' HRSC instrument. Compiling this data in GIS software allows for extensive mapping and analysis of Olympus Mons' seemingly inactive flow features. A rheological analysis performed on 62 mapped lava tubes utilizes geometric parameters inferred from mapping. Lava was modeled as a Bingham fluid on an inclined plane, allowing for the derivation of lava yield stress. Percent silica content was calculated for each of the 62 mapped flows using a relationship derived from observations of terrestrial lava yield strengths and corresponding silica composition. Results indicate that lava tube flows across Olympus Mons were on average basaltic in nature, occasionally reaching into the andesitic classification: percent silica content is 51% on average and ranges between roughly 40% and 57%.

  9. Small domes on Venus: probable analogs of Icelandic lava shields

    USGS Publications Warehouse

    Garvin, James B.; Williams, Richard S.

    1990-01-01

    On the basis of observed shapes and volumetric estimates, we interpret small, dome-like features on radar images of Venus to be analogs of Icelandic lava-shield volcanoes. Using morphometric data for venusian domes in Aubele and Slyuta (in press), as well as our own measurements of representative dome volumes and areas from Tethus Regio, we demonstrate that the characteristic aspect ratios and flank slopes of these features are consistent with a subclass of low Icelandic lava-shield volcanoes (LILS ). LILS are slightly convex in cross-section with typical flank slopes of ∼3°. Plausible lava-shield-production rates for the venusian plains suggest formation of ∼53 million shields over the past 0.25 Ga. The cumulative global volume of lava that would be associated with this predicted number of lava shields is only a factor of 3–4 times that of a single oceanic composite shield volcano such as Mauna Loa. The global volume of all venusian lava shields in the 0.5–20-km size range would only contribute a meter of resurfacing over geologically significant time scales. Thus, venusian analogs to LILS may represent the most abundant landform on the globally dominant plains of Venus, but would be insignificant with regard to the global volume of lava extruded. As in Iceland, associated lavas from fissure eruptions probably dominate plains volcanism and should be evident on the higher resolution Magellan radar images.

  10. Joint analysis of deformation, gravity, and lava lake elevation reveals temporal variations in lava lake density at Kilauea Volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Carbone, Daniele; Poland, Michael; Patrick, Matthew

    2015-04-01

    We find a tight correlation between (i) changes in lava level within the summit eruptive vent at Kilauea Volcano, Hawaii, observed for at least 2 years since early 2011, and (ii) ground deformation in the vicinity of the vent. The observed correlation indicates that changing pressure within the shallow magma reservoir feeding the lava lake influences both deformation and lava level. However, those two parameters are related to chamber pressure through different properties, namely, the density of the lava filling the vent (for the lava level) and the size/position of the reservoir plus the elastic parameters of the host rock (for the deformation). Joint analyses in the time and frequency domains of lava level (determined from thermal camera imagery of the lava lake) and tilt measured on a borehole instrument (~2 km from the summit vent) reveal a good correlation throughout the studied period. The highest correlation occurs over periods ranging between 1 and 20 days. The ratio between lava level and tilt is not constant over time, however. Using data from a continuously recording gravimeter located near the rim of the summit eruptive vent, we demonstrate that the tilt-lava level ratio is controlled by the fluctuations in the density of the lava inside the vent (i.e., its degree of vesicularity). A second continuous gravimeter was installed near the summit eruptive vent in 2014, providing a new observation point for gravity change associated with summit lava lave activity to test models developed from the previously existing instrument. In addition, a continuous gravimeter was installed on the rim of the Puu Oo eruptive vent on Kilauea's East Rift Zone in 2013. Puu Oo is connected via the subvolcanic magma plumbing system to the summit eruptive vent and often deforms in concert with the summit. This growing network of continuously recording gravimeters at Kilauea can be used to examine correlations in gravity change associated with variations in eruptive activity

  11. Lava inundation zone maps for Mauna Loa, Island of Hawaiʻi, Hawaii

    USGS Publications Warehouse

    Trusdell, Frank A.; Zoeller, Michael H.

    2017-10-12

    Lava flows from Mauna Loa volcano, on the Island of Hawaiʻi, constitute a significant hazard to people and property. This report addresses those lava flow hazards, mapping 18 potential lava inundation zones on the island.

  12. Morphology and dynamics of inflated subaqueous basaltic lava flows

    NASA Astrophysics Data System (ADS)

    Deschamps, Anne; Grigné, Cécile; Le Saout, Morgane; Soule, Samuel Adam; Allemand, Pascal; Van Vliet-Lanoe, Brigitte; Floc'h, France

    2014-06-01

    eruptions onto low slopes, basaltic Pahoehoe lava can form thin lobes that progressively coalesce and inflate to many times their original thickness, due to a steady injection of magma beneath brittle and viscoelastic layers of cooled lava that develop sufficient strength to retain the flow. Inflated lava flows forming tumuli and pressure ridges have been reported in different kinds of environments, such as at contemporary subaerial Hawaiian-type volcanoes in Hawaii, La Réunion and Iceland, in continental environments (states of Oregon, Idaho, Washington), and in the deep sea at Juan de Fuca Ridge, the Galapagos spreading center, and at the East Pacific Rise (this study). These lava have all undergone inflation processes, yet they display highly contrasting morphologies that correlate with their depositional environment, the most striking difference being the presence of water. Lava that have inflated in subaerial environments display inflation structures with morphologies that significantly differ from subaqueous lava emplaced in the deep sea, lakes, and rivers. Their height is 2-3 times smaller and their length being 10-15 times shorter. Based on heat diffusion equation, we demonstrate that more efficient cooling of a lava flow in water leads to the rapid development of thicker (by 25%) cooled layer at the flow surface, which has greater yield strength to counteract its internal hydrostatic pressure than in subaerial environments, thus limiting lava breakouts to form new lobes, hence promoting inflation. Buoyancy also increases the ability of a lava to inflate by 60%. Together, these differences can account for the observed variations in the thickness and extent of subaerial and subaqueous inflated lava flows.

  13. 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.

  14. Rheological analyses of lava flows on Mars

    NASA Technical Reports Server (NTRS)

    Moore, H. J.; Davis, P. A.

    1991-01-01

    Researchers obtained 183 profiles of lava flows on Mars using photoclinometry. These photoclinometric profiles were leveled by adjusting them until the levee crests or bases had the same elevations (depending on the situation). Here, researchers report some of the results of their analysis of 27 flows on the flanks of Alba Patera (3 flows), near the summit of Ascraeus Mons (6 flows), the flanks of Arsia Mons (3 flows), and the flanks of Olympus Mons (15 flows). Results suggest that the flows examined to date are not felsic or ultramafic; rather, they probably range from basalts to basaltic andesites. Thus, the suggestion that flows on Olympus Mons and elsewhere may be more silicic than Hawaiian basalts is supported by the researchers' results. These suggestions are testable with suitable measurements of silica contents of the flows.

  15. Pluto Heart: Like a Cosmic Lava Lamp

    NASA Image and Video Library

    2016-06-01

    Like a cosmic lava lamp, a large section of Pluto's icy surface is being constantly renewed by a process called convection that replaces older surface ices with fresher material. Scientists from NASA's New Horizons mission used state-of-the-art computer simulations to show that the surface of Pluto's informally named Sputnik Planum is covered with churning ice "cells" that are geologically young and turning over due to a process called convection. The scene above, which is about 250 miles (400 kilometers) across, uses data from the New Horizons Ralph/Multispectral Visible Imaging Camera (MVIC), gathered July 14, 2015. Their findings are published in the June 2, 2016, issue of the journal Nature. http://photojournal.jpl.nasa.gov/catalog/PIA20726

  16. Lunar Pit Craters Presumed to be the Entrances of Lava Caves by Analogy to the Earth Lava Tube Pits

    NASA Astrophysics Data System (ADS)

    Hong, Ik-Seon; Yi, Yu; Kim, Eojin

    2014-06-01

    Lava caves could be useful as outposts for the human exploration of the Moon. Lava caves or lava tubes are formed when the external surface of the lava flows cools more quickly to make a hardened crust over subsurface lava flows. The lava flow eventually ceases and drains out of the tube, leaving an empty space. The frail part of the ceiling of lava tube could collapse to expose the entrance to the lava tubes which is called a pit crater. Several pit craters with the diameter of around 100 meters have been found by analyzing the data of SELENE and LRO lunar missions. It is hard to use these pit craters for outposts since these are too large in scale. In this study, small scale pit craters which are fit for outposts have been investigated using the NAC image data of LROC. Several topographic patterns which are believed to be lunar caves have been found and the similar pit craters of the Earth were compared and analyzed to identify caves. For this analysis, the image data of satellites and aerial photographs are collected and classified to construct a database. Several pit craters analogous to lunar pit craters were derived and a morphological pit crater model was generated using the 3D printer based on this database.

  17. The longevity of lava dome eruptions

    NASA Astrophysics Data System (ADS)

    Wolpert, Robert L.; Ogburn, Sarah E.; Calder, Eliza S.

    2016-02-01

    Understanding the duration of past, ongoing, and future volcanic eruptions is an important scientific goal and a key societal need. We present a new methodology for forecasting the duration of ongoing and future lava dome eruptions based on a database (DomeHaz) recently compiled by the authors. The database includes duration and composition for 177 such eruptions, with "eruption" defined as the period encompassing individual episodes of dome growth along with associated quiescent periods during which extrusion pauses but unrest continues. In a key finding, we show that probability distributions for dome eruption durations are both heavy tailed and composition dependent. We construct objective Bayesian statistical models featuring heavy-tailed Generalized Pareto distributions with composition-specific parameters to make forecasts about the durations of new and ongoing eruptions that depend on both eruption duration to date and composition. Our Bayesian predictive distributions reflect both uncertainty about model parameter values (epistemic uncertainty) and the natural variability of the geologic processes (aleatoric uncertainty). The results are illustrated by presenting likely trajectories for 14 dome-building eruptions ongoing in 2015. Full representation of the uncertainty is presented for two key eruptions, Soufriére Hills Volcano in Montserrat (10-139 years, median 35 years) and Sinabung, Indonesia (1-17 years, median 4 years). Uncertainties are high but, importantly, quantifiable. This work provides for the first time a quantitative and transferable method and rationale on which to base long-term planning decisions for lava dome-forming volcanoes, with wide potential use and transferability to forecasts of other types of eruptions and other adverse events across the geohazard spectrum.

  18. Moonshot Laboratories' Lava Relief Google Mapping Project

    NASA Astrophysics Data System (ADS)

    Brennan, B.; Tomita, M.

    2016-12-01

    The Moonshot Laboratories were conceived at the University Laboratory School (ULS) on Oahu, Hawaii as way to develop creative problem solvers able to resourcefully apply 21st century technologies to respond to the problems and needs of their communities. One example of this was involved students from ULS using modern mapping and imaging technologies to assist peers who had been displaced from their own school in Pahoe on the Big Island of Hawaii. During 2015, lava flows from the eruption of Kilauea Volcano were slowly encroaching into the district of Puna in 2015. The lava flow was cutting the main town of Pahoa in half, leaving no safe routes of passage into or out of the town. One elementary school in the path of the flow was closed entirely and a new one was erected north of the flow for students living on that side. Pahoa High School students and teachers living to the north were been forced to leave their school and transfer to Kea'au High School. These students were separated from friends, family and the community they grew up in and were being thrust into a foreign environment that until then had been their local rival. Using Google Mapping technologies, Moonshot Laboratories students created a dynamic map to introduce the incoming Pahoa students to their new school in Kea'au. Elements included a stylized My Maps basemap, YouTube video descriptions of the building, videos recorded by Google Glass showing first person experiences, and immersive images of classrooms were created using 360 cameras. During the first day of orientation at Kea'au for the 200 Pahoa students, each of them were given a tablet to view the map as they toured and got to know their new campus. The methods and technologies, and more importantly innovative thinking, used to create this map have enormous potential for how to educate all students about the world around us, and the issues facing it. http://www.moonshotincubator.com/

  19. Correlation of the Deccan and Rajahmundry Trap lavas: Are these the longest and largest lava flows on Earth?

    USGS Publications Warehouse

    Self, S.; Jay, A.E.; Widdowson, M.; Keszthelyi, L.P.

    2008-01-01

    We propose that the Rajahmundry Trap lavas, found near the east coast of peninsular India, are remnants of the longest lava flows yet recognized on Earth (??? 1000??km long). These outlying Deccan-like lavas are shown to belong to the main Deccan Traps. Several previous studies have already suggested this correlation, but have not demonstrated it categorically. The exposed Rajahmundry lavas are interpreted to be the distal parts of two very-large-volume pa??hoehoe flow fields, one each from the Ambenali and Mahabaleshwar Formations of the Wai Sub-group in the Deccan Basalt Group. Eruptive conditions required to emplace such long flows are met by plausible values for cooling and eruption rates, and this is shown by applying a model for the formation of inflated pa??hoehoe sheet flow lobes. The model predicts flow lobe thicknesses similar to those observed in the Rajahmundry lavas. For the last 400??km of flow, the lava flows were confined to the pre-existing Krishna valley drainage system that existed in the basement beyond the edge of the gradually expanding Deccan lava field, allowing the flows to extend across the subcontinent to the eastern margin where they were emplaced into a littoral and/or shallow marine environment. These lavas and other individual flow fields in the Wai Sub-group may exceed eruptive volumes of 5000??km3, which would place them amongst the largest magnitude effusive eruptive units yet known. We suggest that the length of flood basalt lava flows on Earth is restricted mainly by the size of land masses and topography. In the case of the Rajahmundry lavas, the flows reached estuaries and the sea, where their advance was perhaps effectively terminated by cooling and/or disruption. However, it is only during large igneous province basaltic volcanism that such huge volumes of lava are erupted in single events, and when the magma supply rate is sufficiently high and maintained to allow the formation of very long lava flows. The Rajahmundry lava

  20. Similarities in basalt and rhyolite lava flow emplacement processes

    NASA Astrophysics Data System (ADS)

    Magnall, Nathan; James, Mike; Tuffen, Hugh; Vye-Brown, Charlotte

    2016-04-01

    Here we use field observations of rhyolite and basalt lava flows to show similarities in flow processes that span compositionally diverse lava flows. The eruption, and subsequent emplacement, of rhyolite lava flows is currently poorly understood due to the infrequency with which rhyolite eruptions occur. In contrast, the emplacement of basaltic lava flows are much better understood due to very frequent eruptions at locations such as Mt Etna and Hawaii. The 2011-2012 eruption of Cordón Caulle in Chile enabled the first scientific observations of the emplacement of an extensive rhyolite lava flow. The 30 to 100 m thick flow infilled a topographic depression with a negligible slope angle (0 - 7°). The flow split into two main channels; the southern flow advanced 4 km while the northern flow advanced 3 km before stalling. Once the flow stalled the channels inflated and secondary flows or breakouts formed from the flow front and margins. This cooling rather than volume-limited flow behaviour is common in basaltic lava flows but had never been observed in rhyolite lava flows. We draw on fieldwork conducted at Cordón Caulle and at Mt Etna to compare the emplacement of rhyolite and basaltic flows. The fieldwork identified emplacement features that are present in both lavas, such as inflation, breakouts from the flow font and margins, and squeeze-ups on the flow surfaces. In the case of Cordón Caulle, upon extrusion of a breakout it inflates due to a combination of continued lava supply and vesicle growth. This growth leads to fracturing and breakup of the breakout surface, and in some cases a large central fracture tens of metres deep forms. In contrast, breakouts from basaltic lava flows have a greater range of morphologies depending on the properties of the material in the flows core. In the case of Mt Etna, a range of breakout morphologies are observed including: toothpaste breakouts, flows topped with bladed lava as well as breakouts of pahoehoe or a'a lava. This

  1. Lost Jim Lava Flow, Seward Peninsula, Alaska as an analog for lava-ice interactions on Mars

    NASA Astrophysics Data System (ADS)

    Marcucci, E.; Hamilton, C.; Herrick, R. R.

    2015-12-01

    On Mars, volcanism within Elysium Planitia may have occurred as recently as ~10 million years ago, which associated lava flows being emplaced with ice-bearing permafrost. On Earth, there are few active volcanic regions that are cold enough to support permafrost, but the Seward Peninsula in Alaska is a prime location to study recent volcano-ice interactions. In the early 2000s, J.E. Beget and J.S. Kargel explored two areas in Alaska that exhibit features characteristic of explosive volcanism that may be the result of lava-ice interaction. These locations include the Lost Jim Lava Flow (65°29'N, 163°17'W) and several large maars (66°23'N, 164°29'W). The work presented here focuses on the Lost Jim Lava Flow, emanating from Lost Jim Cone and flowing West and North. The flow was erupted 1000-2000 years ago, covers ~225 km2, and ranges 3-30 m in thickness. Previous fieldwork identified pits along the margins of the flow that were interpreted to be collapse features (i.e., thermokarst) that formed as ground-ice beneath the lava melted due to heat transfer from the overlaying lava flow. This investigation utilizes stereo photogrammetry to generate high-resolution digital terrain models (DTMs) of these flow features to assess if these pits are indeed the products of thermokarstification, or if they are lava-rise pits formed by lava flow inflation. The DTMs were generated from ALOS PRISM data and DigitalGlobe Worldview 1 and 2 panchromatic satellite images taken as stereo-pairs or -triplets. With these new models the extent and morphology of the flow and pits will be categorized across the entire flow. These results are also compared to young lava flows on Mars, which may have experienced lava-ice interactions. Understanding the expression of such interactions on Earth may aid in the identification and interpretation of analogous eruptions on Mars.

  2. Benchmarking computational fluid dynamics models for lava flow simulation

    NASA Astrophysics Data System (ADS)

    Dietterich, Hannah; Lev, Einat; Chen, Jiangzhi

    2016-04-01

    Numerical simulations of lava flow emplacement are valuable for assessing lava flow hazards, forecasting active flows, interpreting past eruptions, and understanding the controls on lava flow behavior. Existing lava flow models vary in simplifying assumptions, physics, dimensionality, and the degree to which they have been validated against analytical solutions, experiments, and natural observations. In order to assess existing models and guide the development of new codes, we conduct a benchmarking study of computational fluid dynamics models for lava flow emplacement, including VolcFlow, OpenFOAM, FLOW-3D, and COMSOL. Using the new benchmark scenarios defined in Cordonnier et al. (Geol Soc SP, 2015) as a guide, we model viscous, cooling, and solidifying flows over horizontal and sloping surfaces, topographic obstacles, and digital elevation models of natural topography. We compare model results to analytical theory, analogue and molten basalt experiments, and measurements from natural lava flows. Overall, the models accurately simulate viscous flow with some variability in flow thickness where flows intersect obstacles. OpenFOAM, COMSOL, and FLOW-3D can each reproduce experimental measurements of cooling viscous flows, and FLOW-3D simulations with temperature-dependent rheology match results from molten basalt experiments. We can apply these models to reconstruct past lava flows in Hawai'i and Saudi Arabia using parameters assembled from morphology, textural analysis, and eruption observations as natural test cases. Our study highlights the strengths and weaknesses of each code, including accuracy and computational costs, and provides insights regarding code selection.

  3. A comparative Study of Circulation Patterns at Active Lava Lakes

    NASA Astrophysics Data System (ADS)

    Lev, Einat; Oppenheimer, Clive; Spampinato, Letizia; Hernandez, Pedro; Unglert, Kathi

    2016-04-01

    Lava lakes present a rare opportunity to study magma dynamics in a large scaled-up "crucible" and provide a unique natural laboratory to ground-truth dynamic models of magma circulation. The persistence of lava lakes allows for long-term observations of flow dynamics and of lava properties, especially compared to surface lava flows. There are currently five persistent lava lakes in the world: Halemaumau in Kilauea (Hawaii, USA), Erta Ale (Ethiopia), Nyiragongo (Congo), Erebus (Antarctica), and Villarica (Chile). Marum and Benbow craters of Ambrym volcano (Vanuatu) and Masaya (Nicaragua) have often hosted lava lakes as well. We use visible-light and thermal infrared time-lapse and video footage collected at all above lakes (except Villarica, where the lake is difficult to observe), and compare the circulation patterns recorded. We calculate lake surface motion from the footage using the optical flow method (Lev et al., 2012) to produce 2D velocity fields. We mined both the surface temperature field and the surface velocity field for patterns using machine learning techniques such as "self-organizing maps (SOMs)" and "principle component analysis (PCA)". We use automatic detection technique to study the configuration of crustal plates at the lakes' surface. We find striking differences among the lakes, in flow direction, flow speed, frequency of changes in flow direction and speed, location and consistency of upwelling and downwelling, and crustal plate configuration. We relate the differences to lake size, shallow conduit geometry, lava viscosity, crystal and gas content, and crust integrity.

  4. Red Hot: Determining the Physical Properties of Lava Lake Skin

    NASA Astrophysics Data System (ADS)

    Ford, C.; Lev, E.

    2015-12-01

    Lava lakes are the surface expression of conduits that bring magma to the mouth of a volcano from deep within the earth. Time-lapse footage from a thermal imaging camera at Halema'uma'u lake at Kilauea volcano, Hawaii was used to investigate the cooling rate of the lava lake's surface. The data was then combined with an analytical model of lava flow cooling to constrain the porosity of the lava lake skin. The data was processed to account for the influence that the camera's position relative to the lake had on the image geometry and the recorded temperature values. We examined lake cooling in two separate scenarios: First, we calculated the cooling rate of the skin immediately after large gas bubbles burst at the lake's surface. Second, the temperature of the skin was measured as a function of distance from molten spreading centers (cracks) on the surface, and then converted to cooling as a function of the skin's age using the local lake surface velocity. The resulting cooling time-series were compared against cooling curves produced by a model that simulates lava flow cooling based on a myriad of physical factors. We performed quantitative data analysis to determine the approximate porosity of the lava lake skin. Preliminary comparisons reveal that the calculated cooling rates most closely correspond to the cooling curves that were produced with a lava porosity value of at least 80%.

  5. Lava flow dynamics driven by temperature-dependent viscosity variations

    NASA Astrophysics Data System (ADS)

    Diniega, S.; Smrekar, S. E.; Anderson, S. W.; Stofan, E. R.

    2011-12-01

    As lava viscosity can change 1-2 orders of magnitude due to small changes in temperature, several studies have predicted the formation of low-viscosity/high-temperature "fingers" (similar to a Saffman-Taylor type instability) within an initially near-uniform flow. We examine the onset and evolution of such fingers within a uniform lava sheet flow due to an influx of lava with slightly-variable temperature. We assume Hele-shaw-type geometry (depth << other dimensions), Newtonian and laminar fluid flow, a simple Nahme's exponential law relating temperature and viscosity, and radiative heat-loss through the flow's upper surface. Through the use of numerical simulation and steady-state analysis of model equations, we identify solutions that provide pahoehoe lava flows with a natural mechanism for the formation of lava channels/tubes within a sheet flow. Preliminary results indicate that flow-focusing occurs rapidly due to the thermo-viscosity relation, but zones of hotter flow commonly settle into a new steady-state and it is difficult to create perpetually-lengthening hot-fingers of lava (which seem more physically similar to developing lava tubes). This suggests that additional and/or discontinuous physical processes (such as decreasing radiative rates due to thickening of the surface crust or crystallization abruptly retarding flow within lower-temperature regions) may play important roles in the continued growth of preferred flow zones. We also derive qualitative and quantitative estimates of environmental controls on finger size, spacing, and location. This work has application to Earth and planetary volcanology studies as pahoehoe flows dominate terrestrial basaltic lavas and the eruption/emplacement mechanics that yield long lava flows on the Earth and Mars are not yet well understood.

  6. Improvement of a 2D numerical model of lava flows

    NASA Astrophysics Data System (ADS)

    Ishimine, Y.

    2013-12-01

    I propose an improved procedure that reduces an improper dependence of lava flow directions on the orientation of Digital Elevation Model (DEM) in two-dimensional simulations based on Ishihara et al. (in Lava Flows and Domes, Fink, JH eds., 1990). The numerical model for lava flow simulations proposed by Ishihara et al. (1990) is based on two-dimensional shallow water model combined with a constitutive equation for a Bingham fluid. It is simple but useful because it properly reproduces distributions of actual lava flows. Thus, it has been regarded as one of pioneer work of numerical simulations of lava flows and it is still now widely used in practical hazard prediction map for civil defense officials in Japan. However, the model include an improper dependence of lava flow directions on the orientation of DEM because the model separately assigns the condition for the lava flow to stop due to yield stress for each of two orthogonal axes of rectangular calculating grid based on DEM. This procedure brings a diamond-shaped distribution as shown in Fig. 1 when calculating a lava flow supplied from a point source on a virtual flat plane although the distribution should be circle-shaped. To improve the drawback, I proposed a modified procedure that uses the absolute value of yield stress derived from both components of two orthogonal directions of the slope steepness to assign the condition for lava flows to stop. This brings a better result as shown in Fig. 2. Fig. 1. (a) Contour plots calculated with the original model of Ishihara et al. (1990). (b) Contour plots calculated with a proposed model.

  7. Numerical simulation of lava flows: Applications to the terrestrial planets

    NASA Technical Reports Server (NTRS)

    Zimbelman, James R.; Campbell, Bruce A.; Kousoum, Juliana; Lampkin, Derrick J.

    1993-01-01

    Lava flows are the visible expression of the extrusion of volcanic materials on a variety of planetary surfaces. A computer program described by Ishihara et al. appears to be well suited for application to different environments, and we have undertaken tests to evaluate their approach. Our results are somewhat mixed; the program does reproduce reasonable lava flow behavior in many situations, but we have encountered some conditions common to planetary environments for which the current program is inadequate. Here we present our initial efforts to identify the 'parameter space' for reasonable numerical simulations of lava flows.

  8. Map Showing Lava Inundation Zones for Mauna Loa, Hawaii

    USGS Publications Warehouse

    Trusdell, F.A.; Graves, P.; Tincher, C.R.

    2002-01-01

    Introduction The Island of Hawaii is composed of five coalesced basaltic volcanoes. Lava flows constitute the greatest volcanic hazard from these volcanoes. This report is concerned with lava flow hazards on Mauna Loa, the largest of the island shield volcanoes. Hilo lies 58 km from the summit of Mauna Loa, the Kona coast 33 km, and the southernmost point of the island 61 km. Hawaiian volcanoes erupt two morphologically distinct types of lava, aa and pahoehoe. The surfaces of pahoehoe flows are rather smooth and undulating. Pahoehoe flows are commonly fed by lava tubes, which are well insulated, lava-filled conduits contained within the flows. The surfaces of aa flows are extremely rough and composed of lava fragments. Aa flows usually form lava channels rather than lava tubes. In Hawaii, lava flows are known to reach distances of 50 km or more. The flows usually advance slowly enough that people can escape from their paths. Anything overwhelmed by a flow will be damaged or destroyed by burial, crushing, or ignition. Mauna Loa makes up 51 percent of the surface area of the Island of Hawaii. Geologic mapping shows that lava flows have covered more than 40 percent of the surface every 1,000 years. Since written descriptions of its activity began in A.D. 1832, Mauna Loa has erupted 33 times. Some eruptions begin with only brief seismic unrest, whereas others start several months to a year following increased seismic activity. Once underway, the eruptions can produce lava flows that reach the sea in less than 24 hours, severing roads and utilities. For example, the 1950 flows from the southwest rift zone reached the ocean in approximately three hours. The two longest flows of Mauna Loa are pahoehoe flows from the 50-kilometer-long 1859 and the 48-kilometer-long 1880-81 eruptions. Mauna Loa will undoubtedly erupt again. When it does, the first critical question that must be answered is: Which areas are threatened with inundation? Once the threatened areas are

  9. Modelling the thermal effects of spherulite growth in rhyolitic lava

    NASA Astrophysics Data System (ADS)

    Tuffen, H.; Cordonnier, B.; Castro, J. M.

    2012-12-01

    Rhyolitic lava flows, sills and dykes commonly comprise a spherulitic interior enveloped by a glassy carapace. Spherulite crystallisation has long been assumed to be a "passive" process that occurs during cooling of the lava around and below its glass transition temperature (~600-700 °C). It has also been suggested to be self-limiting due to diffusion controlled growth, creating only a small proportion of spherulites embedded in glass (snowflake obsidian). However, textures in rhyolitic lava bodies at Hrafntinnuhryggur, Krafla, Iceland indicate that near-complete spherulite crystallisation can occur, and suggest that parts of the lava spatially associated with zones of spherulite and lithophysae growth may be significantly heated. Evidence for heating includes melting of parts of the glassy lava carapace by lower-viscosity, invading melt of identical composition. Additionally, spherulitic crystal morphologies have been grown experimentally at undercoolings of only 100 °C. As the liquidus temperature of dry rhyolite may approach 1200 °C, this means that spherulites could continue to grow in degassed magma at temperatures of >900 °C, well above the initial magma temperature. We use new constraints on spherulite growth rates to model the thermal effects of spherulite growth within rhyolitic lava bodies, using three growth laws (size- and temperature-dependent, diffusion controlled and linear) and a variety of initial temperatures, nucleation densities and seed nuclei sizes. Models consider both latent heat release due to crystallisation and conductive cooling. Model results indicate that, when lava bodies are sufficiently large, spherulite growth can cause considerable heating (possibly >150 °C), enabling parts of lava bodies to heat to above the initial eruption temperature. This heating can lead to a viscosity reduction of orders of magnitude and trigger vesiculation. Model results indicate that cooling rates of between 10-3 to 10-5 °C/s ought to mark the

  10. Comparative analysis between Payen and Daedalia Planum lava fields

    NASA Astrophysics Data System (ADS)

    Giacomini, Lorenza; Massironi, Matteo; Pasquarè, Giorgio; Carli, Cristian; Martellato, Elena; Frigeri, Alessandro; Cremonese, Gabriele; Bistacchi, Andrea; Federico, Costanzo

    The Payen volcanic complex is a large Quaternary fissural structure belonging to the back-arc extensional area of the Andes in the Mendoza Province (Argentina). From the eastern portion of this volcanic structure huge pahoehoe lava flows were emitted, extending more than 180 km from the feeding vents. These huge flows propagated over the nearly flat surface of the Pampean foreland (ca 0.3° slope). The very low viscosity of the olivine basalt lavas, coupled with the inflation process are the most probable explanation for their considerable length. In an inflation process a thin viscoelastic crust, produced at an early stage, is later inflated by the underlying fluid core, which remains hot and fluid thanks to the thermal-shield effect of the crust. The inflation shows some typical morphological fingerprints like tumuli, lava lobes, lava rises and lava ridges. In order to compare the morphology of the Argentinean Payen flows with lava flows on Mars, MOLA, THEMIS, MOC, MRO/HIRISE, and MEX/OMEGA data have been analysed, providing a multi-scale characterisation of Martian flows. Mars Global Surveyor/MOLA data were used to investigate the topographic environment over which flows propagated on Mars in order to detect very low angle slopes where possibly inflation processes could have developed. Then Mars Odyssey/THEMIS and Mars Global Surveyor's MOC data were used to detect Martian lava flows with inflation "fingerprints", whereas OMEGA data were used to obtain some inferences about their composition. Finally the MRO/HIRISE images recently acquired, can provide further details and constraints on surface morphologies and lava fronts. All these data were used to analyze Daedalia Planum lava field, at about 300 km southwest of Arsia Mons, and clear morphological similarities with the longest flows of the Payen lava fields were found. These striking morphological analogies suggest that inflation process is quite common also for the Daedalia field. This is also supported by

  11. Heat transfer measurements of the 1983 kilauea lava flow.

    PubMed

    Hardee, H C

    1983-10-07

    Convective heat flow measurements of a basaltic lava flow were made during the 1983 eruption of Kilauea volcano in Hawaii. Eight field measurements of induced natural convection were made, giving heat flux values that ranged from 1.78 to 8.09 kilowatts per square meter at lava temperatures of 1088 and 1128 degrees Celsius, respectively. These field measurements of convective heat flux at subliquidus temperatures agree with previous laboratory measurements in furnace-melted samples of molten lava, and are useful for predicting heat transfer in magma bodies and for estimating heat extraction rates for magma energy.

  12. Heat-transfer measurements of the 1983 Kilauea lava flow

    SciTech Connect

    Hardee, H.C.

    1983-10-07

    Convective heat flow measurements of a basaltic lava flow were made during the 1983 eruption of Kilauea volcano in Hawaii. Eight field measurements of induced natural convection were made, giving heat flux values that ranged from 1.78 to 8.09 kilowatts per square meter at lava temperatures of 1088 and 1128 degrees Celsius, respectively. These field measurements of convective heat flux at subliquidus temperatures agree with previous laboratory measurements in furnace-melted samples of molten lava, and are useful for predicting heat transfer in magma bodies and for estimating heat extraction rates for magma energy.

  13. Numerical and Experimental Approaches Toward Understanding Lava Flow Heat Transfer

    NASA Astrophysics Data System (ADS)

    Rumpf, M.; Fagents, S. A.; Hamilton, C.; Crawford, I. A.

    2013-12-01

    We have performed numerical modeling and experimental studies to quantify the heat transfer from a lava flow into an underlying particulate substrate. This project was initially motivated by a desire to understand the transfer of heat from a lava flow into the lunar regolith. Ancient regolith deposits that have been protected by a lava flow may contain ancient solar wind, solar flare, and galactic cosmic ray products that can give insight into the history of our solar system, provided the records were not heated and destroyed by the overlying lava flow. In addition, lava-substrate interaction is an important aspect of lava fluid dynamics that requires consideration in lava emplacement models Our numerical model determines the depth to which the heat pulse will penetrate beneath a lava flow into the underlying substrate. Rigorous treatment of the temperature dependence of lava and substrate thermal conductivity and specific heat capacity, density, and latent heat release are imperative to an accurate model. Experiments were conducted to verify the numerical model. Experimental containers with interior dimensions of 20 x 20 x 25 cm were constructed from 1 inch thick calcium silicate sheeting. For initial experiments, boxes were packed with lunar regolith simulant (GSC-1) to a depth of 15 cm with thermocouples embedded at regular intervals. Basalt collected at Kilauea Volcano, HI, was melted in a gas forge and poured directly onto the simulant. Initial lava temperatures ranged from ~1200 to 1300 °C. The system was allowed to cool while internal temperatures were monitored by a thermocouple array and external temperatures were monitored by a Forward Looking Infrared (FLIR) video camera. Numerical simulations of the experiments elucidate the details of lava latent heat release and constrain the temperature-dependence of the thermal conductivity of the particulate substrate. The temperature-dependence of thermal conductivity of particulate material is not well known

  14. Hardened Lava Meets Wind on Mars

    NASA Technical Reports Server (NTRS)

    2006-01-01

    NASA's Mars Exploration Rover Spirit used its microscopic imager to capture this spectacular, jagged mini-landscape on a rock called 'GongGong.' Measuring only 3 centimeters (1.2 inches) across, this surface records two of the most important and violent forces in the history of Mars -- volcanoes and wind.

    GongGong formed billions of years ago in a seething, stirring mass of molten rock. It captured bubbles of gases that were trapped at great depth but had separated from the main body of lava as it rose to the surface. Like taffy being stretched and tumbled, the molten rock was deformed as it moved across an ancient Martian landscape. The tiny bubbles of gas were deformed as well, becoming elongated. When the molten lava solidified, the rock looked like a frozen sponge.

    Far from finished with its life, the rock then withstood billions of years of pelting by small sand grains carried by Martian dust storms that sometimes blanketed the planet. The sand wore away the surface until, little by little, the delicate strands that enclosed the bubbles of gas were breached and the spiny texture we see today emerged.

    Even now, wind continues to deposit sand and dust in the holes and crevices of the rock.

    Similar rocks can be found on Earth where the same complex interplay of volcanoes and weathering occur, whether it be the pelting of rocks by sand grains in the Mojave desert or by ice crystals in the frigid Antarctic.

    GongGong is one of a group of rocks studied by Spirit and informally named by the Athena Science Team to honor the Chinese New Year (the Year of the Dog). In Chinese mythology, GongGong was the god-king of water in the North Land. When he sacrificed his life to knock down Mount BuZhou, he defeated the bad Emperor in Heaven, freed the sun, moon and stars to go from east to west, and caused all the rivers in China to flow from west to east.

    Spirit's microscopic imager took this image during on the rover's 736th day, or sol, of

  15. Hardened Lava Meets Wind on Mars

    NASA Technical Reports Server (NTRS)

    2006-01-01

    NASA's Mars Exploration Rover Spirit used its microscopic imager to capture this spectacular, jagged mini-landscape on a rock called 'GongGong.' Measuring only 3 centimeters (1.2 inches) across, this surface records two of the most important and violent forces in the history of Mars -- volcanoes and wind.

    GongGong formed billions of years ago in a seething, stirring mass of molten rock. It captured bubbles of gases that were trapped at great depth but had separated from the main body of lava as it rose to the surface. Like taffy being stretched and tumbled, the molten rock was deformed as it moved across an ancient Martian landscape. The tiny bubbles of gas were deformed as well, becoming elongated. When the molten lava solidified, the rock looked like a frozen sponge.

    Far from finished with its life, the rock then withstood billions of years of pelting by small sand grains carried by Martian dust storms that sometimes blanketed the planet. The sand wore away the surface until, little by little, the delicate strands that enclosed the bubbles of gas were breached and the spiny texture we see today emerged.

    Even now, wind continues to deposit sand and dust in the holes and crevices of the rock.

    Similar rocks can be found on Earth where the same complex interplay of volcanoes and weathering occur, whether it be the pelting of rocks by sand grains in the Mojave desert or by ice crystals in the frigid Antarctic.

    GongGong is one of a group of rocks studied by Spirit and informally named by the Athena Science Team to honor the Chinese New Year (the Year of the Dog). In Chinese mythology, GongGong was the god-king of water in the North Land. When he sacrificed his life to knock down Mount BuZhou, he defeated the bad Emperor in Heaven, freed the sun, moon and stars to go from east to west, and caused all the rivers in China to flow from west to east.

    Spirit's microscopic imager took this image during on the rover's 736th day, or sol, of

  16. Rhyolite lava fracturing and degassing induced spherulitic growth of Sawajiriwan and Sanukayama lavas in Kozushima Island, Japan

    NASA Astrophysics Data System (ADS)

    Furukawa, K.; Uno, K.; Kanamaru, T.

    2015-12-01

    Sawajiriwan and Sanukayama rhyolite lavas are distributed along west and east coasts of Kozushima Island, Japan, respectively (Taniguchi, 1977). They were erupted in about 40,000-50,000 years ago (Yokoyama et al., 2004). The both lavas are characterized by alignment of spherulites as well as previous works (Seaman et al., 2009; Clay et al., 2013). Seaman et al. (2009) attributed the spherulite alignment to the contrasting water concentration and concluded that the heterogeneity of water contents has already achieved within the magma chamber. In this study, we propose that development of the spherulite alignment is significantly related to the fracturing within the lavas. In Sawajiriwan lava, the distal part is well exposed and shows ramp structure and reverse faults with ductile-deformed fault planes. The both structures were formed within consistent compressional stress deduced from their geometry. Discrepancy of the structure would be attributed to the strain rate variation within the advancing lava. The spherulite alignment is characteristically developed along the planes. This indicates that the fractures acted as degassing pathway, and the part achieved large undercooling. The fault planes would be healed and deformed after decreasing strain rate, and spherulites were eventually grown along the planes. In Sanukayama lava, the ductile-deformed cataclastic faults are often developed as well as Sawajiriwan lava. The cataclasite is composed of porphyroclasts and nano- and micro-scale fine particles such as microlite and crystalline fragments. Microscopic observation clearly showed that the fine particles are released from the fault margin into the surrounding melt and are aligned along the flow line. Spherulites typically nucleated on the aligned fine particles, and consequently spherulite alignment was developed. We concluded from the lavas that development of the spherulite alignment is significantly related to the fracturing within the lavas.

  17. A local heat transfer analysis of lava cooling in the atmosphere: application to thermal diffusion-dominated lava flows

    NASA Astrophysics Data System (ADS)

    Neri, Augusto

    1998-05-01

    The local cooling process of thermal diffusion-dominated lava flows in the atmosphere was studied by a transient, one-dimensional heat transfer model taking into account the most relevant processes governing its behavior. Thermal diffusion-dominated lava flows include any type of flow in which the conductive-diffusive contribution in the energy equation largely overcomes the convective terms. This type of condition is supposed to be satisfied, during more or less extended periods of time, for a wide range of lava flows characterized by very low flow-rates, such as slabby and toothpaste pahoehoe, spongy pahoehoe, flow at the transition pahoehoe-aa, and flows from ephemeral vents. The analysis can be useful for the understanding of the effect of crust formation on the thermal insulation of the lava interior and, if integrated with adequate flow models, for the explanation of local features and morphologies of lava flows. The study is particularly aimed at a better knowledge of the complex non-linear heat transfer mechanisms that control lava cooling in the atmosphere and at the estimation of the most important parameters affecting the global heat transfer coefficient during the solidification process. The three fundamental heat transfer mechanisms with the atmosphere, that is radiation, natural convection, and forced convection by the wind, were modeled, whereas conduction and heat generation due to crystallization were considered within the lava. The magma was represented as a vesiculated binary melt with a given liquidus and solidus temperature and with the possible presence of a eutectic. The effects of different morphological features of the surface were investigated through a simplified description of their geometry. Model results allow both study of the formation in time of the crust and the thermal mushy layer underlying it, and a description of the behavior of the temperature distribution inside the lava as well as radiative and convective fluxes to the

  18. Characteristics of Basaltic Lava Flows on Venus

    NASA Technical Reports Server (NTRS)

    Wilson, L.; Garvin, J. B.; Head, J. W.

    1985-01-01

    Some ideas relating to the formation of lava flows on Venus are reviewed. The surface morphological features seen in the panoramic images made by the Venera 13 and 14 landers are examined in detail. The major element compositions measured by the Soviet probes indicate that the surface rocks at the Venera 13 site resemble a terrestrial tholeite composite whereas the Venera 14 rocks are similar to terrestrial alkali basalts. Few data exist on the rheological properties of such magma types on Earth; these properties are a strong function of magma volatile content, and there are important gaps in our knowledge of the typical volatiles to be associated with the magmas on Venus. However, the suggestion that Venusian magmas may be water poor together with consideration of the fact that the high Venusian surface temperatures may cause magmas to experience up to 50 K less cooling during their rise to the surface than corresponding terrestrial counterparts, leads to the finding that Venusian magmas may typically have plastic viscosities, E, up to a factor of three greater than terrestrial counterparts on eruption. A similar analysis of yield strength variations with temperature, magma composition and volatile content suggests that temperature will exert the main control and that Venusian magma yield strengths, Y, may be a factor of several times smaller than those of terrestrial equivalents.

  19. DETAIL OF LAVA BEDROCK WHICH WILL ACT AS BASE SUPPORT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF LAVA BEDROCK WHICH WILL ACT AS BASE SUPPORT FOR REACTOR. INL NEGATIVE NO. 472. Unknown Photographer, 8/23/1950 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  20. Athabasca Valles, Mars: A lava-draped channel system

    USGS Publications Warehouse

    Jaeger, W.L.; Keszthelyi, L.P.; McEwen, A.S.; Dundas, C.M.; Russell, P.S.

    2007-01-01

    Athabasca Valles is a young outflow channel system on Mars that may have been carved by catastrophic water floods. However, images acquired by the High-Resolution Imaging Science Experiment camera onboard the Mars Reconnaissance Orbiter spacecraft reveal that Athabasca Valles is now entirely draped by a thin layer of solidified lava - the remnant of a once-swollen river of molten rock. The lava erupted from a fissure, inundated the channels, and drained downstream in geologically recent times. Purported ice features in Athabasca Valles and its distal basin, Cerberus Palus, are actually composed of this lava. Similar volcanic processes may have operated in other ostensibly fluvial channels, which could explain in part why the landers sent to investigate sites of ancient flooding on Mars have predominantly found lava at the surface instead.

  1. OBLIQUE VIEW OF THE NORTHWEST SIDE. NOTE THE LAVA ROCK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OBLIQUE VIEW OF THE NORTHWEST SIDE. NOTE THE LAVA ROCK FOUNDATION PIERS AND DETAILING AT THE WINDOWS. VIEW FACING SOUTHWEST. - Hickam Field, Fort Kamehameha Officers' Housing Type Z, 19 Worchester Avenue, Honolulu, Honolulu County, HI

  2. STREET FRONT AND LAVA ROCK RETAINING WALL WITH ENTRY AWNING. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    STREET FRONT AND LAVA ROCK RETAINING WALL WITH ENTRY AWNING. VIEW FACING NORTH-NORTHEAST. - U.S. Naval Base, Pearl Harbor, Naval Housing Area Makalapa, Senior Officers' Quarters Type A, 37 Makalapa Drive, Pearl City, Honolulu County, HI

  3. Detail of redwood tank on lava rock platform. Trestle and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of redwood tank on lava rock platform. Trestle and steel tanks can be see in right background. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  4. Progress of Hawaii Lava Flow Tracked by NASA Spacecraft

    NASA Image and Video Library

    2014-09-24

    On June 27, 2014, a new vent opened on Hawaii Puu Oo vent, on the eastern flank of Kilauea volcano. NASA Terra spacecraft shows the hot lava flow in white, extending about 11 miles 17 kilometers from the vent.

  5. Explore and Study a Martian Lava Tube or Cave

    NASA Astrophysics Data System (ADS)

    Edberg, S. J.

    2012-06-01

    A rover exploring Martian lava tubes would provide crucial data for geology, exobiology, and human exploration disciplines. It would engage the public and provide valuable data on the history of Mars and on potential sites for human habitats.

  6. Lava lakes on Io: New perspectives from modeling

    NASA Astrophysics Data System (ADS)

    Gregg, Tracy K. P.; Lopes, Rosaly M.

    2008-03-01

    Loki Patera (310° W, 12° N) is Io's largest patera at ˜180 km in diameter. Its morphology and distinct thermal behavior have led researchers to hypothesize that Loki Patera may either be an active lava lake that experiences periodic overturn, or a shallow depression whose floor is episodically resurfaced with thin flows. Using results from mathematical models, we suggest that a better model for Loki's behavior is the terrestrial superfast spreading East Pacific Rise (EPR), near 17°30 south. We propose that, like at the southern EPR, Loki Patera is underlain by a thin, persistent magma "lens" that feeds thin, temporary lava lakes within the patera. Also like the southern EPR, overspilling of the volcanic depression is rare, with most of the lava volume being emplaced via a subsurface network of lava tubes.

  7. Athabasca Valles, Mars: a lava-draped channel system.

    PubMed

    Jaeger, W L; Keszthelyi, L P; McEwen, A S; Dundas, C M; Russell, P S

    2007-09-21

    Athabasca Valles is a young outflow channel system on Mars that may have been carved by catastrophic water floods. However, images acquired by the High-Resolution Imaging Science Experiment camera onboard the Mars Reconnaissance Orbiter spacecraft reveal that Athabasca Valles is now entirely draped by a thin layer of solidified lava-the remnant of a once-swollen river of molten rock. The lava erupted from a fissure, inundated the channels, and drained downstream in geologically recent times. Purported ice features in Athabasca Valles and its distal basin, Cerberus Palus, are actually composed of this lava. Similar volcanic processes may have operated in other ostensibly fluvial channels, which could explain in part why the landers sent to investigate sites of ancient flooding on Mars have predominantly found lava at the surface instead.

  8. Automated Search for Lunar Lava Tubes in the Clementine Dataset

    NASA Astrophysics Data System (ADS)

    Taylor, Allen G.; Gibbs, A.

    1998-01-01

    A significant problem in computer science, which has become increasingly acute recently, is the automatic extraction and cataloging of desired features from large sets of complex images. Solution of this problem could potentially have broad applicability. As a prototype of this kind of problem, our group has chosen to attempt the automatic retrieval of lava tubes from the Clementine dataset. Lunar lava tubes have long been recognized as desirable locations for the placement of manned lunar bases. Advantages include that (1) little construction is needed; (2) building materials need not be lifted out of Earth's gravity well; (3) the tubes provide natural environmental control; and (4) the tubes provide natural protection from cosmic rays, meteorites, micrometeorites, and impact crater ejecta. Coombs and Hawke identified about 100 probable lava tubes associated with sinuous rilles in the Lunar Orbiter and Apollo photos, primarily in the nearside maria. The lava tubes that are visible to Earth-based telescopes might be too large to provide good candidates for lunar bases. Such lava tubes of large diameter need a great depth of overlying rock to keep from collapsing. Any intact large tubes would lie inconveniently far underground. Most useful would be lava tubes that are too small to be discerned from Earth. The Clementine spacecraft, which mapped the entire surface of the Moon to an unprecedented level of detail in 1994, gives us a view of these smaller lava tubes. Over 1.9 million images in the visible, near infrared, and mid-infrared portions of the spectrum were captured. Our task is to find and catalog the small lava tubes in the Clementine dataset. Of particular interest are small sinuous rifles that contain interruptions, which represent uncollapsed portions of a tube that has partially collapsed. Once cataloged, the candidate base locations can be examined more closely for suitability. Considerations would be proximity to resources, sites of scientific interest

  9. A review: Quantitative models for lava flows on Mars

    NASA Technical Reports Server (NTRS)

    Baloga, S. M.

    1987-01-01

    The purpose of this abstract is to review and assess the application of quantitative models (Gratz numerical correlation model, radiative loss model, yield stress model, surface structure model, and kinematic wave model) of lava flows on Mars. These theoretical models were applied to Martian flow data to aid in establishing the composition of the lava or to determine other eruption conditions such as eruption rate or duration.

  10. What Is the Emissivity of Active Basaltic Lava Flows?

    NASA Astrophysics Data System (ADS)

    Lee, R.; Ramsey, M. S.

    2016-12-01

    The emissivity of molten lava surfaces has been a topic of study for some time because it directly affects the cooling efficiency of the flow, thermo-rheological models of flow evolution, as well as the accurate interpretation of the bulk composition. Despite past studies, it remains unclear whether the emissivity of molten lava truly is different than that of the cooled surface. Measuring emissivity on flows is complicated with errors arising due to changes in the surface glass content and vesicularity, as well as mixing of multiple temperatures, as the lava cools. We therefore see determination of correct surface emissivity and its change with time to be of great importance to anyone working with thermal infrared (TIR) data or modeling of lava flows. A series of high-resolution melting experiments on basalts has been conducted using a novel micro-furnace and TIR spectrometer, producing high-resolution accurate emissivity measurements at known temperatures transitioning from molten to solid state. These results are compared to data from active analog and natural lava surfaces acquired from a newly-developed field-based multispectral camera system, which is capable of generating lower-resolution emissivity spectra. We present the results of these comparative studies conducted at the Syracuse University Lava Project facility in order to test and calibrate the camera system under controlled conditions. The facility conducts large-scale pours of degassed Palisades Sill basalt, an acceptable analog for natural basalt. In addition, several samples of the analog lava were re-melted in the micro-furnace/spectrometer setup to provide a direct comparison of higher and lower resolution IR spectral data. These results, together with data from the Kilauea lava lake, have allowed us to calibrate and fully test the efficacy of this camera system in a field environment for future deployments as well as provide a means of constraining TIR data from satellite observations.

  11. Small domes on Venus - Probable analogs of Icelandic lava shields

    NASA Technical Reports Server (NTRS)

    Garvin, James B.; Williams, Richard S., Jr.

    1990-01-01

    On the basis of observed shapes and volumetric estimates, small, dome-like features on radar images of Venus are interpreted to be analogs of Icelandic lava-shield volcanoes. Morphometric data for Venusian domes in Aubele and Slyuta as well as measurements of representative dome volumes and areas from Tethus Regio are used to demonstrate that the characteristic aspect ratios and flank slopes of these features are consistent with a subclass of low Icelandic lava-shield volcanoes (LILS).

  12. Lava Flow Fields on Earth and Mars: Scales of Comparison

    NASA Astrophysics Data System (ADS)

    Gregg, T. K.; Bulmer, M. H.; Warner, N. H.

    2001-12-01

    Because an active lava flow has yet to be observed on Mars, and available data on surface composition is of limited scope (e.g., the SNC meteorites, or data collected by Sojourner) or resolution (e.g., the Mars Global Surveyor Thermal Emissions Spectrometer [MGS TES]), Martian eruption and emplacement parameters must be inferred from the resulting volcanic morphologies. A unique set of lava flow lobes to the southwest of Arsia Mons (and possibly genetically associated with that volcano) were initially identified using high-resolution ( ~50 m/pixel) Viking Orbiter (VO) images. These flows are characterized by a ridged surface texture, similar to that observed on folded evolved lava flows (e.g., andesites, dacites and rhyolites) on Earth, and relatively thick ( ~40 to 80 m) flow margins. Additional data collected by the Mars Orbiter Camera (MOC) and the Mars Orbiter Laser Altimeter (MOLA) reveal that these ridged flows are much more widespread than indicated by the VO images. MGS and VO datasets allow us to identify the location of these ridged flows, measure flow thickness and the wavelengths and amplitudes of the surface undulations. A large lava flow field ( ~67.5 km2) surrounding Sabancaya volcano, Peru, displays similar surface textures and flow thicknesses, and we have been investigating these andesitic to trachyandesitic lavas as potential analogs to the Martian flows. Using high-resolution GPS surveys-collected both along-flow and across-flow, we can quantify the surface topography of these flows with +/-1 cm horizontal and +/-2 cm vertical resolution. This resolution is approximately one order of magnitude better than will be obtained using global MOLA coverage of Mars. Quantitative comparison of the Sabancaya lava flows with those adjacent to Arsia Mons, combined with results from analytical and numerical modeling, suggest that the Sabancaya lavas are fundamentally different from the Martian flows. We therefore suggest that the Martian flows are either not

  13. Validating Cellular Automata Lava Flow Emplacement Algorithms with Standard Benchmarks

    NASA Astrophysics Data System (ADS)

    Richardson, J. A.; Connor, L.; Charbonnier, S. J.; Connor, C.; Gallant, E.

    2015-12-01

    A major existing need in assessing lava flow simulators is a common set of validation benchmark tests. We propose three levels of benchmarks which test model output against increasingly complex standards. First, imulated lava flows should be morphologically identical, given changes in parameter space that should be inconsequential, such as slope direction. Second, lava flows simulated in simple parameter spaces can be tested against analytical solutions or empirical relationships seen in Bingham fluids. For instance, a lava flow simulated on a flat surface should produce a circular outline. Third, lava flows simulated over real world topography can be compared to recent real world lava flows, such as those at Tolbachik, Russia, and Fogo, Cape Verde. Success or failure of emplacement algorithms in these validation benchmarks can be determined using a Bayesian approach, which directly tests the ability of an emplacement algorithm to correctly forecast lava inundation. Here we focus on two posterior metrics, P(A|B) and P(¬A|¬B), which describe the positive and negative predictive value of flow algorithms. This is an improvement on less direct statistics such as model sensitivity and the Jaccard fitness coefficient. We have performed these validation benchmarks on a new, modular lava flow emplacement simulator that we have developed. This simulator, which we call MOLASSES, follows a Cellular Automata (CA) method. The code is developed in several interchangeable modules, which enables quick modification of the distribution algorithm from cell locations to their neighbors. By assessing several different distribution schemes with the benchmark tests, we have improved the performance of MOLASSES to correctly match early stages of the 2012-3 Tolbachik Flow, Kamchakta Russia, to 80%. We also can evaluate model performance given uncertain input parameters using a Monte Carlo setup. This illuminates sensitivity to model uncertainty.

  14. Field constraints for modeling the emplacement of the 2010 Gigjökull lava flow, southern Iceland: interplay between subaqueous, ice contact and subaerial lava emplacement

    NASA Astrophysics Data System (ADS)

    Edwards, B.; Oddsson, B.; Gudmundsson, M. T.; Rossi, R.

    2012-04-01

    One of the least accessible products of the 2010 Eyjafjallajokull eruption is the trachyandesite lava that flowed north from the summit eruption site down through Gigjökull glacier. Based on numerous overflights during 2010, syn-eruption satellite imagery and two on-site investigations in 2011, we have developed a preliminary model to illustrate the progressive movement of the complex lava flow down through Gigjökull. Previous workers have documented the events surrounding the explosive summit eruptions, including the flow path for the majority of the water derived from melting ~0.1 cubic km of summit ice, which moved over, through and beneath Gigjökull producing a series of jokulhlaups during April and May 2010. Overflights in 2010 and 2011 show that most of the upper parts of the lava flow are surfaced by oxidized, blocky lava that appears very similar to what would be expected from an entirely subaerial lava flow. However, exposures at the lowest end of the flow preserve a record documenting lava emplacement in water and through ice tunnels. We describe 8 different components visible in this northernmost, lowest part of the lava flow, including: (1) upper subaerial levee-bounded lava flow, (2) subaerial blocky lava bench, (3) subaqueous/ice contact lava mounds, (4) subaqueous/ice contact sheet lava complex, (5) ponded, glaciolacustrine sediments, (6) subaerial slabby lava flow, (7) subaqueous pillow lava lobes, and (8) ice-tunnel confined lava flows. In combination these 8 components are consistent a model for lava emplacement through a valley glacier. We propose that the lava flow, which appears to have started moving down the glacier from a tephra cone immediately north of the main summit craters after the largest of the jokulhlaups, exploited newly formed and/or pre-existing sub-ice drainage systems along the base of Gigjökull. Initial meltwater from the eruption site created/enhanced basal ice drainage systems. Lava flows exploited these drainage systems

  15. Stochastic modeling of a lava-flow aquifer system

    USGS Publications Warehouse

    Cronkite-Ratcliff, Collin; Phelps, Geoffrey A.

    2014-01-01

    This report describes preliminary three-dimensional geostatistical modeling of a lava-flow aquifer system using a multiple-point geostatistical model. The purpose of this study is to provide a proof-of-concept for this modeling approach. An example of the method is demonstrated using a subset of borehole geologic data and aquifer test data from a portion of the Calico Hills Formation, a lava-flow aquifer system that partially underlies Pahute Mesa, Nevada. Groundwater movement in this aquifer system is assumed to be controlled by the spatial distribution of two geologic units—rhyolite lava flows and zeolitized tuffs. The configuration of subsurface lava flows and tuffs is largely unknown because of limited data. The spatial configuration of the lava flows and tuffs is modeled by using a multiple-point geostatistical simulation algorithm that generates a large number of alternative realizations, each honoring the available geologic data and drawn from a geologic conceptual model of the lava-flow aquifer system as represented by a training image. In order to demonstrate how results from the geostatistical model could be analyzed in terms of available hydrologic data, a numerical simulation of part of an aquifer test was applied to the realizations of the geostatistical model.

  16. Studies of vesicle distribution patterns in Hawaiian lavas

    NASA Technical Reports Server (NTRS)

    Walker, George P. L.

    1987-01-01

    Basaltic lava flows are generally vesicular, and the broader facts relating to vesicle distribution have long been established; few studies have yet been made with a view to determining how and when vesicles form in the cooling history of the lava, explaining vesicle shape and size distribution, and gaining enough understanding to employ vesicles as a geological tool. Various avenues of approach exist by which one may seek to gain a better understanding of these ubiquitous structures and make a start towards developing a general theory, and three such avenues have recently been explored. One avenue involves the study of pipe vesicles; these are a well known feature of lava flows and are narrow pipes which occur near the base of many pahoehoe flow units. Another avenue of approach is that presented by the distinctive spongy pahoehoe facies of lava that is common in distal locations on Hawaiian volcanoes. A third avenue of approach is that of the study of gas blisters in lava. Gas blisters are voids, which can be as much as tens of meters wide, where the lava split along a vesicle-rich layer and the roof up-arched by gas pressure. These three avenues are briefly discussed.

  17. Lava-substrate heat transfer: Laboratory experiments and thermodynamic modeling

    NASA Astrophysics Data System (ADS)

    Rumpf, M.; Fagents, S. A.; Hamilton, C. W.; Wright, R.; Crawford, I.

    2012-12-01

    We have performed laboratory experiments and numerical modeling to investigate the heat transfer from a lava flow into various substrate materials, focusing on the effects of the differing thermophysical properties of substrate materials. Initial motivation for this project developed from the desire to understand the loss of solar wind volatiles embedded in lunar regolith deposits that were subsequently covered by a lava flow. The Moon lacks a significant atmosphere and magnetosphere, leaving the surface regolith exposed to bombardment by solar flare and solar wind particles, and by the cosmogenic products of galactic cosmic rays. Preservation of particle-rich regolith deposits may have occurred by the emplacement of an active lava flow on top of the regolith layer, provided the embedded particles survive heating by the lava. During future expeditions to the lunar surface, ancient regolith deposits could be sampled through surface drilling to extract the extra-lunar particles, revealing a history of the solar activity and galactic events not available on the Earth. This project also has important implications for terrestrial lava flows, particularly in the prediction of lava flow hazards. Lava erupted on Earth may be emplaced on various substrates, including solid lava rock, volcanic tephra, sands, soils, etc. The composition, grain size, consolidation, moisture content, etc. of these materials will vary greatly and have different effects on the cooling of the flow. Accounting for specific properties of the substrate could be an important improvement in lava flow models We have performed laboratory experiments in collaboration with the Department of Art and Art History at the University of Hawaii at Manoa in which ~5-6 kg of basalt, collected at Kilauea Volcano, Hawaii, is melted to ~1200 °C. The lava is poured into a device constructed of calcium silicate sheeting that has been filled with a solid or particulate substrate material and embedded with thermocouples

  18. Contamination of basaltic lava by seawater: Evidence found in a lava pillar from Axial Seamount, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Schiffman, Peter; Zierenberg, Robert; Chadwick, William W.; Clague, David A.; Lowenstern, Jacob

    2010-04-01

    A lava pillar formed during the 1998 eruption at Axial Seamount exhibits compositional and textural evidence for contamination by seawater under magmatic conditions. Glass immediately adjacent to anastomosing microfractures within 1 cm of the inner pillar wall is oxidized and significantly enriched in Na and Cl and depleted in Fe and K with respect to that in glassy selvages from the unaffected outer pillar wall. The affected glass contains up to 1 wt % Cl and is enriched by ˜2 wt % Na2O relative to unaffected glass, consistent with a nearly 1:1 (molar) incorporation of NaCl. Glass bordering the Cl-enriched glass in the inner pillar wall is depleted in Na but enriched in K. The presence of tiny (<10 μm) grains of Cu-Fe sulfides and Fe sulfides as well as elemental Ni, Ag, and Au in the Na-depleted, K-enriched glass of the inner pillar wall implies significant reduction of this glass, presumably by hydrogen generated during seawater contamination and oxidation of lava adjacent to microfractures. We interpret the compositional anomalies we see in the glass of the interior pillar wall as caused by rapid incorporation of seawater into the still-molten lava during pillar growth, probably on the time scale of seconds to minutes. Only one of seven examined lava pillars shows this effect, and we interpret that seawater has to be trapped in contact with molten lava (inside the lava pillar, in this case) to produce the effects we see. Thus, under the right conditions, seawater contamination of lavas during submarine eruptions is one means by which the oceanic crust can sequester Cl during its global flux cycle. However, since very few recent lava flows have been examined in similar detail, the global significance of this process in effecting Earth's Cl budget remains uncertain.

  19. Geochemical characteristics of Cocos Plate seamount lavas

    NASA Astrophysics Data System (ADS)

    Allan, James F.; Batiza, Rodey; Sack, Richard O.

    1994-03-01

    A wide compositional continuum of basalts has been erupted from near-ridge seamounts constructed on the Cocos Plate between the Clipperton and Orozco Francture Zones. They range from highly evolved to moderately primitive (3.0 7.8% MgO), LREE-enriched alkali basalts, to moderately evolved to near-primary (5.2 9.5% MgO) tholeiites indistinguishable from N-type MORB. The data set of 159 quench glass analyses exhibits a remarkably consistent variation in both major and trace element composition that is keyed to variations in (La/Sm). Modeling of potential liquid lines of descent at pressures ranging from 1 bar to 8 kbar shows that this covariation is partially due to systematic differences in liquid lines of descent, where the alkaline lavas have undergone substantially more high pressure clinopyroxene fractionation and substantially less low pressure plagioclase fractionation than the tholeiites. In addition, systematic variation in the composition of the more primitive glasses indicates that they were derived from mixing of discrete enriched and depleted melts in the heterogenous seamount mantle source at pressures of 8 10 kbar and greater, and that clinopyroxene may be a residual phase during partial melting. These results show that porous media flow in the seamount mantle source is minor and that melt transport is accomplished primarily through cracking and diking. This study supports suggestions that the general homogeneity of basalt along the EPR is due to mixing in sub-axial magma chambers and mush zones, with additional mixing during partial mantle melting and melt segregation.

  20. Lunar Lava Tubes - The Promise of New Orbital Data

    NASA Technical Reports Server (NTRS)

    Allen, Carlton C.

    2009-01-01

    The basaltic plains of the Moon contain lava channels on scales of tens of meters to hundreds of kilometers. Many of these channels are segmented, strongly suggesting that some portions include covered lava tubes. Lunar lava tubes are expected to provide unique environments below the harsh lunar surface, maintaining near-isothermal conditions and substantial shielding from solar and galactic radiation. A lava tube has often been suggested as natural shelter for a future human outpost. Previous searches for lunar lava tubes have been limited by a combination of image resolution and completeness of coverage. The five robotic Lunar Orbiter spacecraft combined to photograph essentially the entire lunar surface with a resolution of 60 m, and covered selected sites with resolutions as high as 2 m. The highest-resolution Apollo images, from the mapping and panoramic cameras, covered swaths totaling 16% of the lunar surface, at resolutions of approximately 5 m. The Lunar Reconnaissance Orbiter -- launched in June 2009 to a polar orbit -- carries a suite of instruments that will revolutionize lunar remote sensing, including the identification and characterization of lava tubes. The Lunar Reconnaissance Orbiter Camera (LROC) system includes a multi-spectral wide-angle camera with a resolution of 70 m, allowing a comprehensive survey of the entire lunar surface. The LROC narrow-angle camera is providing targeted images at resolutions of 0.5 - 2 m, including stereo coverage, which should allow detection of tube entrances and breakdown structures. The Lunar Orbiter Laser Altimeter is producing a global topographic map with a vertical resolution of 1 m and a horizontal resolution of 50 m. These data will be critical to understanding lava dynamics and tube emplacement.

  1. The Influence of Topographic Obstacles on Basaltic Lava Flow Morphologies

    NASA Astrophysics Data System (ADS)

    von Meerscheidt, H. C.; Brand, B. D.; deWet, A. P.; Bleacher, J. E.; Hamilton, C. W.; Samuels, R.

    2014-12-01

    Smooth pāhoehoe and jagged ´áā represent two end-members of a textural spectrum that reflects the emplacement characteristics of basaltic lava flows. However, many additional textures (e.g., rubbly and slabby pāhoehoe) reflect a range of different process due to lava flow dynamics or interaction with topography. Unfortunately the influence of topography on the distribution of textures in basaltic lava flows is not well-understood. The 18 ± 1.0 ka Twin Craters lava flow in the Zuni-Bandera field (New Mexico, USA) provides an excellent site to study the morphological changes of a lava flow that encountered topographic obstacles. The flow field is 0.2-3.8 km wide with a prominent central tube system that intersects and wraps around a 1000 m long ridge, oriented perpendicular to flow. Upstream of the ridge, the flow has low-relief inflation features extending out and around the ridge. This area includes mildly to heavily disrupted pāhoehoe with interdispersed agglutinated masses, irregularly shaped rubble and lava balls. Breakouts of ´áā and collapse features are also common. These observations suggest crustal disruption due to flow-thickening upstream from the ridge and the movement of lava out and around the obstacle. While the ridge influenced the path of the tube, which wraps around the southern end of the ridge, the series of collapse features and breakouts of ´áā along the tube system are more likely a result of changes in flux throughout the tube system because these features are found both upstream and downstream of the obstacle. This work demonstrates that topography can significantly influence the formation history and surface disruption of a flow field, and in some cases the influence of topography can be separated from the influences of changes in flux along a tube system.

  2. Magma rheology from 3D geometry of martian lava flows

    NASA Astrophysics Data System (ADS)

    Allemand, P.; Deschamps, A.; Lesaout, M.; Delacourt, C.; Quantin, C.; Clenet, H.

    2012-04-01

    Volcanism is an important geologic agent which has been recently active at the surface of Mars. The composition of individual lava flows is difficult to infer from spectroscopic data because of the absence of crystallized minerals and the possible cover of the flows by dust. The 3D geometry of lava flows provides an interesting alternative to infer the chemical composition of lavas and effusion rates. Indeed, chemical composition exerts a strong control on the viscosity and yield strength of the magma and global geometry of lava flow reflects its emplacement rate. Until recently, these studies where realized from 2D data. The third dimension, which is a key parameter, was deduced or supposed from local shadow measurements on MGS Themis IR images with an uncertainty of more than 500%. Recent CTX data (MRO mission) allow to compute Digital Elevation Model at a resolution of 1 or 2 pixels (5 to 10 m) with the help of Isis and the Ames Stereo Pipeline pipe line. The CTX images are first transformed in format readable by Isis. The external geometric parameters of the CTX camera are computed and added to the image header with Isis. During a correlation phase, the homologous pixels are searched on the pair of stereo images. Finally, the DEM is computed from the position of the homologous pixels and the geometrical parameters of the CTX camera. Twenty DEM have been computed from stereo images showing lava flows of various ages on the region of Cerberus, Elyseum, Daedalia and Amazonis planitia. The 3D parameters of the lava flows have been measured on the DEMs and tested against shadows measurement. These 3D parameters have been inverted to estimate the viscosity and the yield strength of the flow. The effusion rate has also been estimated. These parameters have been compared to those of similar lava flows of the East Pacific rise.

  3. Rheology of lava flows on Mercury: An analog experimental study

    NASA Astrophysics Data System (ADS)

    Sehlke, A.; Whittington, A. G.

    2015-11-01

    We experimentally determined the rheological evolution of three basaltic analog compositions appropriate to Mercury's surface, during cooling, and crystallization. Investigated compositions are an enstatite basalt, and two magnesian basalts representing the compositional end-members of the northern volcanic plains with 0.19 wt % (NVP) and 6.26 wt % Na2O (NVP-Na). The viscosity-strain rate dependence of lava was quantified using concentric cylinder viscometry. We measured the viscosities of the crystal-free liquids from 1600°C down to the first detection of crystals. Liquidus temperatures of the three compositions studied are around 1360°C, and all three compositions are more viscous than Hawaiian basalt at the same temperature. The onset of pseudoplastic behavior was observed at crystal fractions ~0.05 to 0.10, which is consistent with previous studies on mafic lavas. We show that all lavas develop detectable yield strengths at crystal fractions around 0.20, beyond which the two-phase suspensions are better described as Herschel-Bulkley fluids. By analogy with the viscosity-strain rate conditions at which the pahoehoe to `a`a transition occurs in Kilauea basalt, this transition is predicted to occur at ~1260 ± 10°C for the enstatite basalt, at ~1285 ± 20°C for the NVP, and at ~1240 ± 40°C for the NVP-Na lavas. Our results indicate that Mercury lavas are broadly similar to terrestrial ones, which suggests that the extensive smooth lava plains of Mercury could be due to large effusion rates (flood basalts) and not to unusually fluid lavas.

  4. Spectral and Morphological Analysis of Daedalia Planum Lava Field

    NASA Astrophysics Data System (ADS)

    Giacomini, L.; Massironi, M.; Carli, C.; Martellato, E.; Pasquarè, G.; Pompilio, L.; Cremonese, G.

    2008-12-01

    Daedalia Planum is one of the Tharsis volcanic plains and is located southwest of the Arsia Mons. According to MOLA data, the flanks of Arsia have an average slope < 5°, while the surrounding regions, including Daedalia Planum, have slopes < 0.5° and commonly < 0.1°. MOC and THEMIS images show a plain covered by a huge number of lava flows. Older and larger lava flows on the field have a length greater than 1500, even if determining their absolute length is difficult as subsequent lava flows have buried the source vents. MEX/OMEGA data reveal that Daedalia Planum lavas have a spectral shapes comparable to those observed in laboratory for rock slabs of Earth's basalts. Moreover most of the Daedalia flows are associated to wrinkly and ropy surfaces, typical of pahoehoe lavas. The Daedalia Planum flow surfaces show several morphological features that remember the inflation fingerprints. This suggests that also Daedalia Planum could have been interested by inflation. However these features appear dissimilar to inflation forms on Elysium Planitia flows. Different degrees of erosion could explain such dissimilarities. In particular Daedalia Planum flow surfaces appear heavily modelled by wind erosion whereas the Elysium Planitia features seem fresher. The different age between the two areas support this hypothesis. Our crater counting dated the most recent Daedalia Planum flows to about 230 Myr , by contrast the Elysium Planitia lava flows range from 100 to 10 My. In conclusion, the inflation process on Martian flows could be more frequent than previously supposed and, consequently, effusion rates and rheological properties of Martian lavas more variable.

  5. Hidden Outgassing Dynamics at Kilauea (Hawaii) Lava Lake

    NASA Astrophysics Data System (ADS)

    Del Bello, E.; Taddeucci, J.; Orr, T. R.; Houghton, B. F.; Scarlato, P.; Patrick, M. R.

    2014-12-01

    Lava lakes offer unique opportunities for understanding how magmatic volatiles physically escape from low-viscosity, vesicular magma in open-vent conditions, a process often referred to as magma outgassing. Large-scale lava convection movements and meter-scale bubble explosions, sometimes triggered by rock falls, are acknowledged outgassing processes but may not be the only ones. In 2013 we used high-frequency (50-500 Hz) thermal and visible imaging to investigate the short-timescale dynamics of the currently active Halema`uma`u lava lake. At that time, besides the dominant release of large bubbles, three types of peculiar outgassing features were observed on the lava lake surface. The first, diffusely observed throughout the observation experiment, consisted of prolonged (up to seconds) gas venting from 'spot vents'. These vents appeared to open and close without the ejection of material or bubble bursting, and were the site of hot gas emission. Spot vents were located both between and inside cooling plates, and followed the general circulation pattern together with the rest of the lava lake surface. The second feature, observed only once, consisted of the transient wobbling of the whole lava lake surface. This wobbling, with a wavelength of meters to tens of meters, was not related to any external trigger, and dampened soon without apparent consequences on the other lake dynamics. Finally, we observed large (meters) doming areas of the lake surface randomly fluctuating over seconds to minutes. These areas were either stationary or moved independently of the general lake surface circulation, and usually were not affected by other lake surface features (e.g., cooling plate boundaries). These three features, though trivial for the overall lake outgassing, testify that the lava lake has a complex shallow subsurface architecture, in which permeable channels and gas pockets act independently of the more common bubble bursts.

  6. A Mechanism for Stratifying Lava Flows

    NASA Astrophysics Data System (ADS)

    Rice, A.

    2005-12-01

    Relict lava flows (e.g., komatiites) are often reported to be zoned in the vertical, each zone separated by a sharp contact. Such stratifications in igneous flows, both intrusive and extrusive, can be treated as analogues of suspended loads of sediments in rivers and streams, and hence amenable to quantitative treatment derived for the hydraulic environment as long as dynamic similitude is assured. Situations typically encountered in the hydraulic environment are streams carrying a bed load at the bottom of the stream, the bed load separated by a sharp horizon from a sediment load carried above it. This sediment load may be topped by others of decreasing density as one moves to the surface of the flow, with perhaps the uppermost layer clear of any suspended matter. Rules exist for estimating the thickness D of these loads: one of them is given by D ~ 4.4V3/rgcvs where V is the shear velocity or average velocity of the flow, r = (ρs - ρl)/ρl where ρs is the density of the suspended solid matter, ρl the density of the fluid, g the acceleration of gravity, c the concentration of the particulate content and vs the settling velocity. The settling velocity is secured through Stoke's Law and the velocity of the flow is given by V = R2/3S1/2/n where R is the hydraulic radius, S the gradient along which the fluid flows and n is the Manning Coefficient. In the igneous case, the bed load would be composed of primocrysts, i.e., of the first crystals to come out of solution as the flow cools along its run. This would leave the upper portions of the flow more evolved except perhaps for a quenched crust riding atop the flow. As the viscosity of the flow is dependent not only on temperature but on composition and crystal content, the mean velocity of each layer will be different from the layer above and below it. This requires shear at the interface of adjoining stratifications, which brings into play another mechanism: dispersive pressure (the Bagnold effect). Dispersive

  7. Analogue experiments as benchmarks for models of lava flow emplacement

    NASA Astrophysics Data System (ADS)

    Garel, F.; Kaminski, E. C.; Tait, S.; Limare, A.

    2013-12-01

    During an effusive volcanic eruption, the crisis management is mainly based on the prediction of lava flow advance and its velocity. The spreading of a lava flow, seen as a gravity current, depends on its "effective rheology" and on the effusion rate. Fast-computing models have arisen in the past decade in order to predict in near real time lava flow path and rate of advance. This type of model, crucial to mitigate volcanic hazards and organize potential evacuation, has been mainly compared a posteriori to real cases of emplaced lava flows. The input parameters of such simulations applied to natural eruptions, especially effusion rate and topography, are often not known precisely, and are difficult to evaluate after the eruption. It is therefore not straightforward to identify the causes of discrepancies between model outputs and observed lava emplacement, whereas the comparison of models with controlled laboratory experiments appears easier. The challenge for numerical simulations of lava flow emplacement is to model the simultaneous advance and thermal structure of viscous lava flows. To provide original constraints later to be used in benchmark numerical simulations, we have performed lab-scale experiments investigating the cooling of isoviscous gravity currents. The simplest experimental set-up is as follows: silicone oil, whose viscosity, around 5 Pa.s, varies less than a factor of 2 in the temperature range studied, is injected from a point source onto a horizontal plate and spreads axisymmetrically. The oil is injected hot, and progressively cools down to ambient temperature away from the source. Once the flow is developed, it presents a stationary radial thermal structure whose characteristics depend on the input flow rate. In addition to the experimental observations, we have developed in Garel et al., JGR, 2012 a theoretical model confirming the relationship between supply rate, flow advance and stationary surface thermal structure. We also provide

  8. Late Holocene lava flow morphotypes of the northern Harrat Rahat, Kingdom of Saudi Arabia: implications for the description of continental lava fields

    NASA Astrophysics Data System (ADS)

    Murcia, H. F.; Nemeth, K.; Moufti, R.; Lindsay, J. M.; El-Masry, N.; Cronin, S. J.; Qaddah, A.; Smith, I. E.

    2013-12-01

    Lava morphotype refers to the surface morphology of a lava flow after solidification. In Saudi Arabia, young and well-preserved mafic lava fields (Harrats) display a wide range of these morphotypes. This study examines those exhibited by four of the post-4500 yrs. BP lava fields in the northern Harrat Rahat (<10 Ma) and describes these lava fields from general characteristics to detailed lava structures. This study also discusses the relationship between rheology and morphotypes, and proposes a preliminary correlation with whole-rock chemical composition. The Harrat Rahat lava fields include one or more lobes that may extend over 20 km from the source, with thicknesses varying between 1-2 m up to 12 m. Each lava flow episode covered areas between ~32 and ~61 km2, with individual volumes estimated between ~0.085 and ~0.29 km3. The whole-rock chemical compositions of these lavas lie between 44.3 to 48.4% SiO2, 9.01-4.28% MgO and 3.13-6.19% NaO+K2O. Seven different morphotypes with several lava structures are documented: Shelly, Slabby, Rubbly-pahoehoe, Platy, Cauliflower, Rubbly-a'a, and Blocky. These may be related to the shear strain and/or apparent viscosity of the lava flows formed from typical pahoehoe (pure or Hawaiian-pahoehoe, or sheet-pahoehoe). The well-preserved lava fields in Harrat Rahat allow the development of a more expanded classification scheme than has been traditionally applied. In addition to the whole-rock composition, these morphotypes may be indicators of other properties such as vesicularity, crystallization, effusion mechanism, as well as significant along-flow variations in topography and lava thickness and temperature that modify the rheology. The linearity of transitions between morphotypes observed in the lava fields suggest that real time forecasting of the evolution of lava flows might be possible.

  9. The Influence of Slope Breaks on Lava Flow Surface Disruption

    NASA Technical Reports Server (NTRS)

    Glaze, Lori S.; Baloga, Stephen M.; Fagents, Sarah A.; Wright, Robert

    2014-01-01

    Changes in the underlying slope of a lava flow impart a significant fraction of rotational energy beyond the slope break. The eddies, circulation and vortices caused by this rotational energy can disrupt the flow surface, having a significant impact on heat loss and thus the distance the flow can travel. A basic mechanics model is used to compute the rotational energy caused by a slope change. The gain in rotational energy is deposited into an eddy of radius R whose energy is dissipated as it travels downstream. A model of eddy friction with the ambient lava is used to compute the time-rate of energy dissipation. The key parameter of the dissipation rate is shown to be rho R(sup 2/)mu, where ? is the lava density and mu is the viscosity, which can vary by orders of magnitude for different flows. The potential spatial disruption of the lava flow surface is investigated by introducing steady-state models for the main flow beyond the steepening slope break. One model applies to slow-moving flows with both gravity and pressure as the driving forces. The other model applies to fast-moving, low-viscosity, turbulent flows. These models provide the flow velocity that establishes the downstream transport distance of disrupting eddies before they dissipate. The potential influence of slope breaks is discussed in connection with field studies of lava flows from the 1801 Hualalai and 1823 Keaiwa Kilauea, Hawaii, and 2004 Etna eruptions.

  10. Substrate mapping and ablation for ventricular tachycardia: the LAVA approach.

    PubMed

    Sacher, Frederic; Lim, Han S; Derval, Nicolas; Denis, Arnaud; Berte, Benjamin; Yamashita, Seigo; Hocini, Mélèze; Haissaguerre, Michel; Jaïs, Pierre

    2015-04-01

    Catheter ablation of ventricular tachycardia (VT) is proven effective therapy particularly in patients with frequent defibrillator shocks. However, the optimal endpoint for VT ablation has been debated and additional endpoints have been proposed. At the same time, ablation strategies aiming at homogenizing the substrate of scar-related VT have been reported. Our method to homogenize the substrate consists of local abnormal ventricular activity (LAVA) elimination. LAVA are high-frequency sharp signals that represent near-field signals of slowly conducting tissue and hence potential VT isthmuses. Pacing maneuvers are sometimes required to differentiate them from far-field signals. Delayed enhancement on cardiac MRI and/or wall thinning on multidetector computed tomography are also extremely helpful to identify the areas of interest during ablation. A strategy aiming at careful LAVA mapping, ablation, and elimination is feasible and can be achieved in about 70% of patients with scar-related VT. Complete LAVA elimination is associated with a better outcome when compared to LAVA persistence even when VT is rendered noninducible. This is a simple approach, with a clear endpoint and the ability to ablate in sinus rhythm. This strategy significantly benefits from high-definition imaging, mapping, and epicardial access. © 2014 Wiley Periodicals, Inc.

  11. High-resolution Digital Mapping of Historical Lava Flows as a Test-bed for Lava Flow Models

    NASA Astrophysics Data System (ADS)

    Pyle, D. M.; Parks, M.; Nomikou, P.; Mather, T. A.; Simou, E.; Kalnins, L. M.; Paulatto, M.; Watts, A. B.

    2013-12-01

    Quantitative analysis of high-resolution lava flow morphology can improve our understanding of past effusive eruptions by providing insight into eruptive processes and the rheological properties of erupted magmas. We report the results of an ongoing investigation into the young dacite lava flows of the Kameni islands, Santorini volcano, Greece, which were emplaced during both subaerial and shallow submarine eruptions over the past 3000 years. Historical eruptions of the Kameni islands since 1866 have been very carefully documented in contemporaneous scientific reports. Eruptions since 1573 appear to be time-predictable, with a close relationship between eruption length, the size of extruded lava domes, and the time elapsed since the previous eruption. A new NERC - Airborne Survey and Research Facility LiDAR survey of the Kameni islands was completed in May 2012, using a Leica ALS50 Airborne Laser Scanner mounted on a Dornier 228 aircraft. The topographic surface was mapped at an average point density of 2.1 points per square metre, and covers the entire extent of the youngest subaerial lava flow fields on Santorini. A 2-m DEM derived from the 2012 LiDAR dataset was merged with a 5-m resolution bathymetric grid, based on multibeam surveys carried out by the Hellenic Centre for Marine Research, during cruises in 2001 and 2006, using a SEABEAM 2120 hull-mounted swath system. The resultant grid provides the first high resolution map of both subaerial and submarine historic lava flows emplaced in the centre of the Santorini caldera, and includes several previously unidentified submarine flows and cones. Attribute maps were used to delineate and identify discrete lava flows both onshore and offshore; and morphometric profiles were used to compute accurate volumetric estimates for each of the historic flows, and to determine bulk rheological properties of the lavas, assuming a Bingham rheology. This ongoing work will improve our analysis of the relationship between

  12. Influence of cooling on lava-flow dynamics

    NASA Astrophysics Data System (ADS)

    Stasiuk, Mark V.; Jaupart, Claude; Stephen, R.; Sparks, J.

    1993-04-01

    Experiments have been carried out to determine the effects of cooling on the flow of fluids with strongly temperature dependent viscosity. Radial viscous-gravity currents of warm glucose syrup were erupted at constant rate into a flat tank filled with a cold aqueous solution. Cold, viscous fluid accumulates at the leading edge, altering the flow shape and thickness and slowing the spreading. The flows attain constant internal temperature distributions and bulk viscosities. The value of the bulk viscosity depends on the Péclet number, which reflects the advective and diffusive heat transport properties of the flow, the flow skin viscosity, which reflects cooling, and the eruption viscosity. Our results explain why most lava flows have bulk viscosities much higher than the lava eruption viscosity. The results can be applied to understanding dynamic lava features such as flow-front thickening, front avalanches, and welded basal breccias.

  13. Lava Flow Near the Base of Olympus Mons

    NASA Image and Video Library

    2015-02-18

    This image from NASA Mars Reconnaissance Orbiter shows a lava channel, which lies just to the east of the largest volcano in the solar system: Olympus Mons. The channel appears to be discontinuous, meaning it disappears several times throughout its length, but in fact, it is likely that the channel continues underground as a lava tube. These are relatively common features at terrestrial volcanic centers, such as the Big Island of Hawai'i. The channel appears to have been infilled with dust and sand, so that the entrance to a lava tube cave is no longer visible at this particular location; fortunately this has been observed elsewhere on Mars. http://photojournal.jpl.nasa.gov/catalog/PIA19299

  14. Biofilter performance of pine nuggets and lava rock as media.

    PubMed

    Akdeniz, Neslihan; Janni, Kevin A; Salnikov, Ilya A

    2011-04-01

    Wood chips and bark mulch are commonly used biofilter media because they are generally locally available and inexpensive. Nevertheless, these organic materials degrade and require replacement every 2-5 years. In this study, airflow characteristics and gas reduction efficiencies of two alternative biofilter media (pine nuggets and lava rock) with high porosity and potentially longer service lives were evaluated at three empty bed contact times (1, 3, and 5s) and two moisture levels (82% and 90% relative humidity). The lava rock had a lower pressure drop across the media and maintained higher media depth. Gas reduction efficiencies were highest for lava rock at 5s empty bed contact time and 90% humidity. The reduction efficiencies at these conditions were 56%, 88%, 87%, 25%, and 0.7% for ammonia, hydrogen sulfide, total reduced sulfur, methane and nitrous oxide, respectively. Odor reduction up to 48% was observed but was not consistent.

  15. Volcanic tremor location during the 2004 Mount Etna lava effusion

    NASA Astrophysics Data System (ADS)

    Di Grazia, G.; Falsaperla, S.; Langer, H.

    2006-02-01

    A lava emission started at Mt. Etna, Italy, on 7 September, 2004. Neither earthquake seismicity heralded or accompanied the opening of the fracture field from which the lava poured out, nor volcanic tremor changed in amplitude and frequency content at the onset of the effusive activity. To highlight long-term changes, we propose a method for the location of the tremor source based on a 3D grid search, using the amplitude decay of the seismic signal, from January to November 2004. We find the centroid of the tremor source within a zone close to and partially overlapped with the summit craters (pre-effusive phase), which extended up to 2 km south of them (effusive phase). The depths are of between 1698 and 2387 m a.s.l. We hypothesize the lava effusion stemmed from a degassed magma body, although we find evidence of temporary magma overpressure conditions, such as those documented on 25 September.

  16. Insights into the dynamics of the Nyiragongo lava lake level

    NASA Astrophysics Data System (ADS)

    Smets, Benoît; d'Oreye, Nicolas; Geirsson, Halldor; Kervyn, Matthieu; Kervyn, François

    2016-04-01

    Nyiragongo volcano, in North Kivu, Democratic Republic of Congo, is among the most active volcanoes in Africa and on Earth. Since the first European observations in the late 19th Century, its eruptive activity mostly concentrated into its main crater, with the presence of a persistent lava lake from at least 1928 to 1977 and since 2002. The size, shape and elevation of this lava lake have evolved through time, modifying the topography of the main crater. In January 1977 and 2002, the uppermost magmatic system of Nyiragongo, including the lava lake, was drained during flank eruptions. These flank events caused major disasters, mostly due to the exceptionally fast-moving lava flows and the presence of a dense population living at foot of this volcano. Despite a large scientific interest and societal concern, the study of the eruptive activity of Nyiragongo remains limited by climate and vegetation conditions that, most of the time, limit use of satellite remote sensing techniques, and recurrent armed conflicts in the Kivu region, which sometimes prevent field access to the main crater. Here we focus on the dynamics of the Nyiragongo lava lake level and its relationship with the volcanic plumbing system by describing the historical and recent lava lake activity and presenting new quantitative observations using close-range photogrammetry, a Stereographic Time-Lapse Camera (STLC) system and high-resolution satellite SAR and InSAR remote sensing. Results highlight that, contrary to the interpretation found in some recent publications, the lava lake drainages appear to be the consequence and not the cause of the 1977 and 2002 flank eruptions. Two types of short-term lava lake level variations are observed. The first one corresponds to cyclic metre-scale variations attributed to gas piston activity. The STLC data recorded in September 2011 show hour-scale gas piston cycles reaching up to 3.8 m, which are interpreted to be related to gas accumulation and release in the

  17. Relative ages of lava flows at Alba Patera, Mars

    NASA Technical Reports Server (NTRS)

    Schneeberger, Dale M.; Pieri, David C.

    1987-01-01

    Many large lava flows on the flanks of Alba Patera are astonishing in their volume and length. As a suite, these flows suggest tremendously voluminous and sustained eruptions, and provide dimensional boundary conditions typically a factor of 100 larger than terrestrial flows. One of the most striking features associated with Alba Patera is the large, radially oriented lava flows that exhibit a variety of flow morphologies. These include sheet flows, tube fed and tube channel flows, and undifferentiated flows. Three groups of flows were studied; flows on the northwest flank, southeast flank, and the intracaldera region. The lava flows discussed probably were erupted as a group during the same major volcanic episode as suggested by the data presented. Absolute ages are poorly constrained for both the individual flows and shield, due in part to disagreement as to which absolute age curve is representative for Mars. A relative age sequence is implied but lacks precision due to the closeness of the size frequency curves.

  18. Bubbled lava from the floor of the Sea of Okhotsk

    NASA Astrophysics Data System (ADS)

    Baturin, G. N.; Dubinchuk, V. T.; Rashidov, V. A.

    2014-05-01

    A sample of bubbled lava raised from a submarine volcano in the Sea of Okhotsk was analyzed by means of electron microscopy and the ICP-MS technique. The outside of the sample is flecked with rounded micro- and macrocavities, and the inner part is characterized by a liquation structure. Along with this, the unstructured mass of the rock contains globular particles of nearly the same diameters as the cavities. The lava is close to andesites and volcanic ashes of Kamchatka Peninsula in the macro- and microelemental composition but different in the somewhat increased content of barium, strontium, lithium, niobium, tungsten, uranium, and thorium. It is suggested that the cavities were formed during the eruption of the submarine volcano owing to contact of the boiling gas-saturated lava with seawater accompanied by the ejection of ash, which was spread by marine currents over long distances.

  19. Neutron Activation Analysis of Trace Elements in Lava

    NASA Astrophysics Data System (ADS)

    Meyer, Ross; Sabella, Jordan; Thomas, Keenan; Norman, Eric; Guillamon, P.; Goldman, I.; Smith, A.

    2012-10-01

    The elemental compositions of lavas vary with the locations of the volcanoes from which they emerged. We have used neutron activa- tion analysis to measure the abundances of approximately 32 different elements in lava samples collected from three different Hawaiian islands and from the summit of Mt. Kilimanjaro. Two different neutron ir- radiations were performed at the McClellan Nuclear Radiation Center to optimize our sensitivities to both short- and long-lived radioisotopes. Gamma-ray counting was done at McClellan, UC Berkeley, and LBNL using large-volume high-purity Ge detectors. Results from the mea- surements will be presented and comparisons will be made between the trace-element compositions of the lavas from these different sites.

  20. Neutron Activation Analysis of Trace Elements in Lava

    NASA Astrophysics Data System (ADS)

    Meyer, R. E.; Sabella, J. L.; Thomas, K. J.; Norman, E. B.; Guillamon, P. V.; Goldman, I. D.; Smith, A. R.

    2012-10-01

    The elemental compositions of lavas vary with the locations of the volcanoes from which they emerged. We have used neutron activation analysis to measure the abundances of approximately 32 different elements in lava samples collected from three different Hawaiian islands and from the summit of Mt. Kilimanjaro. Two different neutron irradiations were performed at the McClellan Nuclear Radiation Center to optimize our sensitivities to both short- and long-lived radioisotopes. Gamma-ray counting was done at McClellan, UC Berkeley, and LBNL using large-volume high-purity Ge detectors. Results from the measurements will be presented and comparisons will be made between the trace-element compositions of the lavas from these different sites.

  1. Chasing lava: a geologist's adventures at the Hawaiian Volcano Observatory

    USGS Publications Warehouse

    Duffield, Wendell A.

    2003-01-01

    A lively account of the three years (1969-1972) spent by geologist Wendell Duffield working at the Hawaiian Volcano Observatory at Kilauea, one of the world's more active volcanoes. Abundantly illustrated in b&w and color, with line drawings and maps, as well. Volcanologists and general readers alike will enjoy author Wendell Duffield's report from Kilauea--home of Pele, the goddess of fire and volcanoes. Duffield's narrative encompasses everything from the scientific (his discovery that the movements of cooled lava on a lava lake mimic the movements of the earth's crust, providing an accessible model for understanding plate tectonics) to the humorous (his dog's discovery of a snake on the supposedly snake-free island) to the life-threatening (a colleague's plunge into molten lava). This charming account of living and working at Kilauea, one of the world's most active volcanoes, is sure to be a delight.

  2. Lava Flow Hazard Assessment for the Idaho National Laboratory: A Probabilistic Approach to Modeling Lava Flow Inundation with MOLASSES

    NASA Astrophysics Data System (ADS)

    Gallant, E.; Connor, C.; Richardson, J. A.; Wetmore, P. H.; Connor, L.

    2015-12-01

    We present the results of a lava flow hazard assessment for the Idaho National Laboratory (INL) using a new lava flow code, MOLASSES (MOdular LAva Simulation Software for Earth Science). INL is a nuclear research and development facility located on the eastern Snake River Plain with the potential for lava flow inundation from both monogenetic and polygenetic basaltic eruptions. Previously published inventories of observed surface vents and vents that are buried by younger lava flows and inferred from interpretation of borehole stratigraphy were used to created spatial density maps of vents within the INL region. Monte carlo simulations were run using the MOLASSES code to compare the difference between events initiated using only surface vents and events initiated using both the surface and the buried vents. We find that the inclusion of the buried vent locations drastically increases the number of site inundations and events initiating within INL boundaries. This highlights the need to seek out a more complete eruption record in an area of heavy prehistoric activity to better assess future hazard and associated risk.

  3. Toothpaste lava from the Barren Island volcano (Andaman Sea)

    NASA Astrophysics Data System (ADS)

    Sheth, Hetu C.; Ray, Jyotiranjan S.; Kumar, Alok; Bhutani, Rajneesh; Awasthi, Neeraj

    2011-04-01

    Toothpaste lava is a basaltic lava flow type transitional between pahoehoe and aa and has been described from Paricutin, Kilauea and Etna volcanoes. Here we describe a spectacular example of toothpaste lava, forming part of a recent (possibly 1994-95) aa flow on the active volcano of Barren Island (Andaman Sea). This flow of subalkalic basalt shows abundant squeeze-ups of viscous toothpasate lava near its entry into the sea. The squeeze-ups are sheets and slabs, up to several meters across and tens of centimeters thick, extruded from boccas. They are often prominently curved, have striated upper surfaces with close-spaced, en echelon linear ridges and grooves, broad wave-like undulations perpendicular to the striations, and sometimes, clefts. Textural, geochemical, and Sr-Nd isotopic data on the squeeze-ups and the exposed aa flow core indicate very crystal-rich, viscous, and isotopically very homogeneous lava. We envisage that a greatly reduced speed of this viscous flow at the coastline, possibly aided by a shallowing of the basal slope, led to lateral spreading of the flow, which caused tension in its upper parts. This, with continued (albeit dwindling) lava supply at the back, led to widespread tearing of the flow surface and extrusion of the squeeze-ups. The larger slabs, while extruding in a plastic condition, curved under their own weight, whereas their surfaces experienced brittle deformation, forming the en echelon grooves. The extruded, detached, and rotated sheets and slabs were carried forward for some distance atop the very slowly advancing aa core, before the flow solidified.

  4. Ultraphyric Lavas of Northern Galapagos Islands: Mineral Scale Compositional Variations

    NASA Astrophysics Data System (ADS)

    Teasdale, R.; Altman, K.; Hiller, J.; Schlom, T.; Harpp, K.; Barr, J.

    2008-12-01

    Volcanoes of northern Galápagos Islands, Wolf, Darwin, Pinta, Marchena, and Genovesa have each erupted subaerial lava flows with abundant coarse plagioclase crystals up to several cm across. These megacrysts make up "ultraphyric lavas" that are largely absent in the rest of the archipelago, revealing unique petrogenetic processes at northern island volcanoes. Wolf and Darwin Islands have high proportions of ultraphyric lavas, making up 25-50% of exposed material. Lavas are generally horizontal (<10 degrees) pahoehoe flows. Similar flows are present but less abundant at Pinta, Marchena, and Genovesa. Plagioclase megacrysts are subhedral to euhedral, heavily fractured, and often have embayed crystal textures. Plagioclase in lavas from Genovesa, Wolf and Darwin volcanoes are indistinguishable from one another compositionally. Electron microprobe analyses of the rims of megacrysts and phenocrysts generally have lower An compositions than cores. Core compositions have highest An compositions (maximum, An96), with rims ranging from An57 to An93. In some cases, cores are as much as 30% An higher than rims. Groundmass plagioclase crystals are typically less anorthite-rich (< An85). High An cores are consistent with crystal growth in a more primitive magma, possibly in a crystal-mush zone. Lower rim (and groundmass) compositions suggest megacrysts were exposed to more evolved magma following initial crystallization, consistent with entrainment into a new magma as xenocrysts. There is no clear correlation between flow thickness and crystal abundance to suggest megacrysts were exclusively entrained into magmas of specific volumes. Rather, crystal compositions and variation in An composition between cores and rims indicate that significant time intervals between eruptions of megacryst-bearing flows likely allowed long periods of crystal growth to occur, followed by disaggregation from crystal mush zones and eruption in host lavas.

  5. Birth of a lava lake: Nyamulagira volcano 2011-2015

    NASA Astrophysics Data System (ADS)

    Coppola, D.; Campion, R.; Laiolo, M.; Cuoco, E.; Balagizi, C.; Ripepe, M.; Cigolini, C.; Tedesco, D.

    2016-03-01

    Since 1938, Nyamulagira volcano (Democratic Republic of Congo) has operated as a classic pressurized basaltic closed system, characterized by frequent dike-fed flank eruptions. However, on June 24, 2014, an active lava lake was observed in its summit, after a period of 76 years. The small lava lake is now exposed at the bottom of a pit-crater and is rising and growing. Based on satellite-derived infrared (IR) data, SO2 fluxes and periodic field surveys, we provide evidence that the development of the lava lake was gradual and occurred more than 2 years before it was first observed in the field. Notably, this process followed the voluminous 2011-2012 distal flank eruption and was coeval with weakening of the central rock column below the summit. Hence, the opening and development of the pit-crater favoured the continuous rise of fresh magma through the central conduit and promoted the gradual "re-birth" of the Nyamulagira lava lake. Budgeted volumes of magma erupted, and magma degassed at depth indicate that the formation of the lava lake is due to the draining and refilling of a shallow plumbing system (1-2 km depth), probably in response to the rift-parallel 2011-2012 distal eruption. We thus suggest that the transition from lateral to central activity did not result from a substantial change in the magma supply rate but, more likely, from the perturbation of the plumbing system (and related stress field) associated with the distal eruption. The processes observed at Nyamulagira are not unique and suggest that rift-fissure eruptions, in addition to triggering caldera collapses or lava lake drainages, may also induce a progressive resumption of central vent activity. Current activity at Nyamulagira represents a tangible and major hazard for the population living at the base of its southern flank.

  6. Crystallization history of the 1984 Mauna Loa lava flow

    NASA Technical Reports Server (NTRS)

    Crisp, Joe; Cashman, Katharine V.; Bonini, Jennifer A.; Hougen, Sarah B.; Pieri, David C.

    1994-01-01

    During a 3-week eruption in 1984, Mauna Loa produced vent lavas that increased in crystallinity from less than 1 to 30%, and 27-km-long flows that increased in crystallinity as they moved downstream. We examined the crystallization history of these lavas using crystal size distribution (CSD) analysis to study the rates of crystallization, viscosity increase, and latent heating. Typical average growth and nucleation rates were 5 x 10(exp -9) cm/s and 5/cu cm/s for microphenocrysts (20- to 500-micron size crystals nucleated in the rift zone) and 5 x 10(exp -8) cm/s and 5 x 10(exp 4)/cu cm/s for microlites (1- to 20-micron size crystals nucleated in the channel). These crystallization rates are high compared with those found in other CSD studies of igneous rocks, probably due to highly nonequilibrium conditions brought on by rapid degassing in the rift zone and cooling in the lava channel. Growth and nucleation rates decreased with time at the vent and with distance downstream. The maximum downstream total crystallinity measured is 39% (25% microlites, 14% microphenocrysts) in a quenched sample 14 km from the vent. Growth and nucleation rates cannot be calculated for postemplacement samples, but they place upper limits of 53-58% on the amount of crystallization in the channel 9-20 km from the vent. Crystallization could have been mostly responsible for the 10(exp 5)-fold downstream increase in apparent viscosity, although degassing and increasing incorporation of solid lava fragments also contributed. Another effect of crystallization on the lava flow was the sizeable latent heating (0.01 J/g/s over the first half of the flow length, if the crystallinity of downstream quench samples is representative of the hot fluid core), which may have been counteracted by entrainment of cooler material. Measurements of crystallization are shown to be crucial in the study of lava flow emplacement dynamics.

  7. Crystallization history of the 1984 Mauna Loa lava flow

    NASA Technical Reports Server (NTRS)

    Crisp, Joe; Cashman, Katharine V.; Bonini, Jennifer A.; Hougen, Sarah B.; Pieri, David C.

    1994-01-01

    During a 3-week eruption in 1984, Mauna Loa produced vent lavas that increased in crystallinity from less than 1 to 30%, and 27-km-long flows that increased in crystallinity as they moved downstream. We examined the crystallization history of these lavas using crystal size distribution (CSD) analysis to study the rates of crystallization, viscosity increase, and latent heating. Typical average growth and nucleation rates were 5 x 10(exp -9) cm/s and 5/cu cm/s for microphenocrysts (20- to 500-micron size crystals nucleated in the rift zone) and 5 x 10(exp -8) cm/s and 5 x 10(exp 4)/cu cm/s for microlites (1- to 20-micron size crystals nucleated in the channel). These crystallization rates are high compared with those found in other CSD studies of igneous rocks, probably due to highly nonequilibrium conditions brought on by rapid degassing in the rift zone and cooling in the lava channel. Growth and nucleation rates decreased with time at the vent and with distance downstream. The maximum downstream total crystallinity measured is 39% (25% microlites, 14% microphenocrysts) in a quenched sample 14 km from the vent. Growth and nucleation rates cannot be calculated for postemplacement samples, but they place upper limits of 53-58% on the amount of crystallization in the channel 9-20 km from the vent. Crystallization could have been mostly responsible for the 10(exp 5)-fold downstream increase in apparent viscosity, although degassing and increasing incorporation of solid lava fragments also contributed. Another effect of crystallization on the lava flow was the sizeable latent heating (0.01 J/g/s over the first half of the flow length, if the crystallinity of downstream quench samples is representative of the hot fluid core), which may have been counteracted by entrainment of cooler material. Measurements of crystallization are shown to be crucial in the study of lava flow emplacement dynamics.

  8. Wing Dike of Hardened Lava in New Mexico

    NASA Image and Video Library

    2017-01-25

    This photograph from northwestern New Mexico shows a ridge roughly 30 feet about 10 meters tall that formed from lava filling an underground fracture then resisting erosion better than the material around it did. The dike extends from a volcanic peak (out of view here) called Shiprock in English and Tsé Bit'a'í, meaning "rock with wings," in the Navajo language. It offers an Earth analog for some larger hardened-lava walls on Mars http://photojournal.jpl.nasa.gov/catalog/PIA21266

  9. Morphometric study of pillow-size spectrum among pillow lavas

    NASA Astrophysics Data System (ADS)

    Walker, George P. L.

    1992-08-01

    Measurements of H and V (dimensions in the horizontal and vertical directions of pillows exposed in vertical cross-section) were made on 19 pillow lavas from the Azores, Cyprus, Iceland, New Zealand, Tasmania, the western USA and Wales. The median values of H and V plot on a straight line that defines a spectrum of pillow sizes, having linear dimensions five times greater at one end than at the other, basaltic toward the small-size end and andesitic toward the large-size end. The pillow median size is interpreted to reflect a control exercised by lava viscosity. Pillows erupted on a steep flow-foot slope in lava deltas can, however, have a significantly smaller size than pillows in tabular pillowed flows (inferred to have been erupted on a small depositonal slope), indicating that the slope angle also exercised a control. Pipe vesicles, generally abundant in the tabular pillowed flows and absent from the flow-foot pillows, have potential as a paleoslope indicator. Pillows toward the small-size end of the spectrum are smooth-surfaced and grew mainly by stretching of their skin, whereas disruption of the skin and spreading were important toward the large-size end. Disruption involved increasing skin thicknesses with increasing pillow size, and pillows toward the large-size end are more analogous with toothpaste lava than with pahoehoe and are inferred from their thick multiple selvages to have taken hours to grow. Pseudo-pillow structure is also locally developed. An example of endogenous pillow-lava growth, that formed intrusive pillows between ‘normal’ pillows, is described from Sicily. Isolated pillow-like bodies in certain andesitic breccias described from Iceland were previously interpreted to be pillows but have anomalously small sizes for their compositions; it is now proposed that they may lack an essential attribute of pillows, namely, the development of bulbous forms by the inflation of a chilled skin, and are hence not true pillows. Para-pillow lava is

  10. Fractal dimension analyses of lava surfaces and flow boundaries

    NASA Technical Reports Server (NTRS)

    Cleghorn, Timothy F.

    1993-01-01

    An improved method of estimating fractal surface dimensions has been developed. The accuracy of this method is illustrated using artificially generated fractal surfaces. A slightly different from usual concept of linear dimension is developed, allowing a direct link between that and the corresponding surface dimension estimate. These methods are applied to a series of images of lava flows, representing a variety of physical and chemical conditions. These include lavas from California, Idaho, and Hawaii, as well as some extraterrestrial flows. The fractal surface dimension estimations are presented, as well as the fractal line dimensions where appropriate.

  11. Conveying Lava Flow Hazards Through Interactive Computer Models

    NASA Astrophysics Data System (ADS)

    Thomas, D.; Edwards, H. K.; Harnish, E. P.

    2007-12-01

    As part of an Information Sciences senior class project, a software package of an interactive version of the FLOWGO model was developed for the Island of Hawaii. The software is intended for use in an ongoing public outreach and hazards awareness program that educates the public about lava flow hazards on the island. The design parameters for the model allow an unsophisticated user to initiate a lava flow anywhere on the island and allow it to flow down-slope to the shoreline while displaying a timer to show the rate of advance of the flow. The user is also able to modify a range of input parameters including eruption rate, the temperature of the lava at the vent, and crystal fraction present in the lava at the source. The flow trajectories are computed using a 30 m digital elevation model for the island and the rate of advance of the flow is estimated using the average slope angle and the computed viscosity of the lava as it cools in either a channel (high heat loss) or lava tube (low heat loss). Even though the FLOWGO model is not intended to, and cannot, accurately predict the rate of advance of a tube- fed or channel-fed flow, the relative rates of flow advance for steep or flat-lying terrain convey critically important hazard information to the public: communities located on the steeply sloping western flanks of Mauna Loa may have no more than a few hours to evacuate in the face of a threatened flow from Mauna Loa's southwest rift whereas communities on the more gently sloping eastern flanks of Mauna Loa and Kilauea may have weeks to months to prepare for evacuation. Further, the model also can show the effects of loss of critical infrastructure with consequent impacts on access into and out of communities, loss of electrical supply, and communications as a result of lava flow implacement. The interactive model has been well received in an outreach setting and typically generates greater involvement by the participants than has been the case with static maps

  12. Field Measurements of the 1983 Royal Gardens Lava Flows, Kilauea Volcano, and 1984 Mauna Loa Lava Flow, Hawaii

    NASA Technical Reports Server (NTRS)

    Fink, J.; Zimbelman, J.

    1985-01-01

    Theoretical models used in the remote determination of lava flow rheology and compositions rely on estimates of such geometric and flow parameters as volume flow rates, levee heights, and channel dimensions, as well as morphologic and structural patterns on the flow surfaces. Quantitative measures of these variables are difficult to obtain, even under optimum conditions. Detailed topographic profiles across several Hawaiian lava flows that were carefully monitored by the U.S. Geological Survey during their emplacement in 1983 were surveyed in order to test various flow emplacement models. Twenty two accurate channel cross sections were constructed by combining these profiles with digitized pre-flow topographic measurements. Levee heights, shear zone widths, and flow depths could then be read directly from the cross sections and input into the models. The profiles were also compared with ones constructed for some Martian lava flows.

  13. Experiments on Natural-Scale Basaltic Lava Flows: Scope and First Results of the Syracuse University Lava Project

    NASA Astrophysics Data System (ADS)

    Karson, J.; Wysocki, R.; Kissane, M. T.; Smith, C.; Spencer, S.

    2012-12-01

    The Syracuse University Lava Project creates natural-scale basaltic lava flows for scientific investigations, educational opportunities and artistic projects. Modified furnaces designed for melting and pouring metals are used to create individual basaltic lava flow lobes of up to 450 kg (10-2m2) with the potential to generate much larger flow fields under controlled conditions. At present, the starting material used in 1.1 Ga Keewenan basalt from the Mid-Continent Rift in NW Wisconsin, a relatively uniform, well-characterized tholeiitic-alkalic basalt. Other compositions (andesite, komatiite, carbonatite) are planned for future experiments. Basaltic gravel is heated to 1100° to 1300°C in a crucible resulting in homogeneous, convecting basaltic magma. Lava is poured over a variety of surfaces including rock slabs, wet or dry sand, H2O or CO2 ice, rough or smooth material, and confined or unconfined channels. Resulting lava flows can be dissected for mapping details of morphological and textural variations. Video from various perspectives is used to document flow behavior and evolution. Infrared images constrain flow temperatures. Textural features of flows such as vesicles and plagioclase microlites have vertical and lateral variations similar to those of natural flows. Differing experimental set-ups provide analogs for a wide range of terrestrial, marine, and extraterrestrial lava flows. In an initial series of experiments, basaltic lava flows (50-200 kg) were poured over dry sand at near constant effusion rates (~10-4m3s-1). Flow temperature and slope were varied to produce a range of different flow morphologies. The results show systematic behavior consistent with observations of natural lava flows and analog experiments. At relatively high T (>1200°C) and steeper slopes (>15°) thin, narrow, leveed flows form. At intermediate T and slope, sheet-like, ropey, pahoehoe forms develop. Flows at the lowest T (1100°C) and gentlest slopes (<10°) investigated

  14. Biogeochemical analysis of hydrogen sulfide removal by a lava-rock packed biofilter.

    PubMed

    Li, Hebi; Lueking, Donald R; Mihelcic, James R; Peterson, Karl

    2005-01-01

    Although lava-rock-based biofilters have demonstrated their efficiencies for hydrogen sulfide (H2S) removal found in odorous air emissions, the biogeochemical basis for this removal is unclear. In this study, samples of lava rock and rinse water from biofilters at Cedar Rapids Water Pollution Control Facilities (Iowa) were used to study the structure and chemical composition of lava rock and to identify the predominant microorganism(s) present in lava-rock-based biofilters. It was found that iron, in the form of Fe2+ and Fe3+, was present in lava rock. Although literature suggests that Acidithiobacillus thiooxidans are primarily responsible for gaseous H2S removal in biofilters, our study showed that Acidithiobacillus ferrooxidans was the dominant microorganism in the lava-rock-based biofilters. A novel mechanism for H2S removal in a lava-rock-based biofilter is proposed based on the biogeochemical analysis of lava rock.

  15. Lava flow materials in the Tharsis region of Mars

    NASA Technical Reports Server (NTRS)

    Schaber, G. G.; Horstman, K. C.; Dial, A. L., Jr.

    1978-01-01

    Lava-flow materials in the Tharsis region of Mars were studied from moderate-resolution (100-280 m/pixel) Viking Orbiter imagery. Individual eruptive sequences were recognized primarily by stratigraphic relations, density of superimposed impact craters, flow morphology, flow trend, and variations in surface albedo. Nine detailed maps of lava flows based on delineation of flow scarps were compiled for a total area of 7.25 million sq km. Two thirds of this area was covered by mappable flows representing at least 14 distinct eruptive sequences. Assuming a rate of crater production twice that of the moon, the observed range of superimposed crater densities (90 to 3200 craters at least 1 km in diameter per sq km) indicates an age range of 100 m.y. to several billion years for these flows. The youngest lavas are associated with flood lavas filling the depression surrounding the Olympus Mons shield. Flow thicknesses range from less than 5 meters to 20 meters on steeper shield slopes (0.5 to 4.5 deg) and from 20 to 65 meters on relatively flat (less than 0.5 deg slope) terrain.

  16. A Radiation Safety Analysis for Lunar Lava Tubes

    NASA Technical Reports Server (NTRS)

    DeAngelis, G.; Wilson, J. W.; Clowdsley, M. S.; Nealy, J. E.; Humes, D. H.; Clem, J. M.

    2002-01-01

    The purpose of this work is an assessment of the lunar lava tubes physical characteristics and an evaluation of the their actual safety features from the point of view of the ionizing radiation environment as potential habitats for future lunar exploration crews. Additional information is contained in the original extended abstract.

  17. Correlated helium and lead isotope variations in Hawaiian lavas

    SciTech Connect

    Eiler, J.M.; Farley, K.A.; Stolper, E.M.

    1998-06-01

    Variations in {sup 3}He/{sup 4}He ratios among Hawaiian shield-building and pre-shield basalts are correlated with variations in {sup 208}Pb/{sup 204}Pb and {sup 206}Pb/{sup 204}Pb ratios. Using this correlation, the {sup 32}He/{sup 4}He ratio of Hawaiian lavas can be predicted to within 2.9 R{sub A} (mean deviation) between 7 and 32 R{sub A} based only upon the lead isotope composition. This level of prediction is as good as can be expected based upon the precision of lead isotope ratio measurements. This correlation demonstrates a coupling of volatile and nonvolatile elements in the sources of Hawaiian basalts and allows the nonvolatile-element characteristics of the high-{sup 3}He/{sup 4}He component of the mantle sources of Hawaiian lavas to be defined. This result confirms and extends previous inferences based upon correlations between helium and strontium isotope ratios in individual suites of Hawaiian lavas. The source of high {sup 3}He/{sup 4}He ratios in Hawaiian lavas has a higher time-integrated Th/U ratio than the sources of Pacific mid-ocean ridge basalts, consistent with it being a mixture containing primitive mantle or having differentiated in two or more stages from primitive mantle.

  18. OVEN & LAVA Subsystems in the RESOLVE Payload for Resource Prospector

    NASA Technical Reports Server (NTRS)

    Captain, Janine E.

    2015-01-01

    A short briefing in Power Point of the status of the OVEN subsystem and the LAVA subsystems of the RESOLVE payload being developed under the Resource Prospector mission. The purpose of the mission is to sample and analyze volatile ices embedded in the lunar soil at the poles of the Moon and is expected to be conducted in the 2020 time frame.

  19. Lava flow materials in the Tharsis region of Mars

    NASA Technical Reports Server (NTRS)

    Schaber, G. G.; Horstman, K. C.; Dial, A. L., Jr.

    1978-01-01

    Lava-flow materials in the Tharsis region of Mars were studied from moderate-resolution (100-280 m/pixel) Viking Orbiter imagery. Individual eruptive sequences were recognized primarily by stratigraphic relations, density of superimposed impact craters, flow morphology, flow trend, and variations in surface albedo. Nine detailed maps of lava flows based on delineation of flow scarps were compiled for a total area of 7.25 million sq km. Two thirds of this area was covered by mappable flows representing at least 14 distinct eruptive sequences. Assuming a rate of crater production twice that of the moon, the observed range of superimposed crater densities (90 to 3200 craters at least 1 km in diameter per sq km) indicates an age range of 100 m.y. to several billion years for these flows. The youngest lavas are associated with flood lavas filling the depression surrounding the Olympus Mons shield. Flow thicknesses range from less than 5 meters to 20 meters on steeper shield slopes (0.5 to 4.5 deg) and from 20 to 65 meters on relatively flat (less than 0.5 deg slope) terrain.

  20. Lava Lakes on Io: New Perspectives from Modeling

    NASA Technical Reports Server (NTRS)

    Gregg, Tracy K. P.; Lopes, Rosaly M.

    2004-01-01

    Ionian paterae are a class of volcanic feature that are characterized by irregular craters with steep walls, flat floors, and arcuate margins that may or may not exhibit nesting. Loki (310 W, 12 N) is Io's largest patera at approx.200 km in diameter (Figure 1), and may account for 15% of Io's total heat flow. Earth-based infrared data, as well as information collected using the Galileo Near-Infrared Mapping Spectrometer (NIMS) and the Photopolarimeter Radiometer (PPR) have been used to interpret Loki s eruption style. Debate continues over whether Loki s occasional (periodic or not) temperature increases are due to an overturning lava lake within the patera, or to an eruption of surface flows on the patera floor. Interpretation of model results and comparisons with active terrestrial lava lakes suggest that Loki behaves quite differently from active lava lakes on Earth, and that surface flows (rather than an overturning lava lake) are a more likely explanation of Loki's thermal brightening.

  1. Where lava meets the sea; Kilauea Volcano, Hawaii

    USGS Publications Warehouse

    Mattox, T.N.

    1993-01-01

    Seaside explosions of the type and magnitude of the event on November 24, 1992, are infrequent. the observation of this event represents a rare opportunity to enhance our understanding of the birth of littoral cones and the nature of explosive activity when lava enters the ocean. 

  2. Removal of methylene blue by lava adsorption and catalysis oxidation.

    PubMed

    Ma, Jianfeng; Zhang, Jinbao; Li, Dinglong

    2010-03-01

    Adsorption has been found to be effective for the removal of dyes from effluent; however, the contaminant will cause secondary pollution if it is not properly treated. In this paper, the ability of lava as a low-cost adsorbent and catalyst for the removal of a commercial dye, Methylene Blue (MB), from aqueous solution has been investigated under various experimental conditions. It was found that lava had a high efficiency (more than 98%) for MB removal by adsorption. The adsorption equilibrium data can be fitted well by the Langmuir adsorption isotherm model. The adsorption kinetics was shown to be pseudo-second-order. After adsorption the contaminant could be catalysis oxidized by lava with the aids of H2O2 and ultrasound. The result showed that 95% of the MB could be decomposed in 100 min with the aid of ultrasound at 85 W/cm2. Overall, this study demonstrates lava as a promising material for wastewater treatment to remove and decompose dyes in a single treatment step.

  3. Oblique view of the northeast side, note the lava rock ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Oblique view of the northeast side, note the lava rock stem wall below the windows of the shed-roof addition, view facing west - U.S. Marine Corps Base Hawaii, Kaneohe Bay, Golf Course Equipment & Repair Shop, Reeves & Moffett Roads, Kaneohe, Honolulu County, HI

  4. Venus - System of Lava Flows and Ridge Belt

    NASA Image and Video Library

    1996-11-14

    This radar image mosaic of Venus from NASA Magellan spacecraft, is in the Lada region. The mosaic shows a system of east-trending radar-bright and dark lava flows encountering and breaching a north-trending ridge belt left of center.

  5. Rheology of lava flows on Mercury: an experimental study

    NASA Astrophysics Data System (ADS)

    Sehlke, A.; Whittington, A. G.

    2014-12-01

    The morphology of lava flows is controlled by the physical properties of the lava and its effusion rates, as well as environmental influences such as surface medium, slope and ambient temperature and pressure conditions. The important rheological properties of lavas include viscosity (η) and yield strength (σy), strongly dependent on temperature (T), composition (X), crystal fraction (φc) and vesicularity (φb). The crystal fraction typically increases as temperature decreases, and also influences the residual liquid composition. The rheological behavior of multi-phase lava flows is expressed as different flow morphologies, for example basalt flows transition from smooth pahoehoe to blocky `a`a at higher viscosities and/or strain rates. We have previously quantified the rheological conditions of this transition for Hawaiian basalts, but lavas on Mercury are very different in composition and expected crystallization history. Here we determine experimentally the temperature and rheological conditions of the pahoehoe-`a`a transition for two likely Mercury lava compositions using concentric cylinder viscometry. We detect first crystals at 1302 ºC for an enstatite basalt and 1317 ºC for a basaltic komatiite composition representative of the northern volcanic plains (NVP). In both cases, we observe a transition from Newtonian to pseudo-plastic response at crystal fractions > 10 vol%. Between 30 to 40 vol%, a yield strength (τ0) around 26±6 and 110±6 Pa develops, classifying the two-phase suspensions as Herschel-Bulkley fluids. The measured increase in apparent viscosity (ηapp) ranges from 10 Pa s to 104 Pa s. This change in rheological properties occurs only in a temperature range up to 100 ºC below the liquidus. By analogy with the rheological conditions of the pahoehoe-`a`a transition for Hawaiian basalts, we can relate the data for Mercury to lava flow surface morphology as shown in Figure 1, where the onset of the transition threshold zone (TTZ) for the

  6. Non-Newtonian and Viscoelastic Properties of Lava Flows

    NASA Astrophysics Data System (ADS)

    Bagdassarov, N. S.

    2004-12-01

    Lava flow models require an in-depth knowledge of the rheological properties of lava. Previous measurements have shown that, at typical eruption temperatures, lavas are non-Newtonian. The reasons for this include the formation and destruction of crystal networks and bubble deformation during shear. The effects of bubbles are investigated experimentally in this contribution using analogue fluids with bubble concentrations <20%. The shear-thinning behaviour of bubbly liquids noted by previous workers is shown to be dependent on the previous shearing history of the fluid. This thixotropic behaviour, which was investigated using a rotational vane viscometer, is caused by delayed bubble deformation and recovery when subjected to changes in shear stress. A rotational vane viscometer and torsional deformation apparatus were used to investigate the rheological properties of bubbly liquids and foams in order to determine a viscoelastic transition. These experiments have shown that the foams tested are viscoelastic power law fluids with a yield strength. Non-Newtonian properties and yield strength of foams are shown to be a probable cause of accelerating flow fragmentation in tube flow experiments on expanding foams. The flow of a bubbly fluid through a narrowing conduit may cause a pulsating regime of a flow due to periodic slip and slip-free boundary conditions near the walls of a conduit. Slip boundary conditions can lead to instability in viscoelastic shear flow causing short wavelength fluctuations at high shear rates. This mechanism may also take place during explosive volcanic eruptions. The frequency and amplitude of oscillation shear affect the structure of lavas which are thixotropic non-Newtonian liquids. The frequency dependent structure of lavas can be identified via frequency hysteresis and time-evolution of internal friction and viscosity. The rheological properties of basaltic lavas from Etna, Hawai'i and Vesuvius have been investigated at temperatures

  7. Eruption constraints on tube-fed planetary lava flows

    NASA Astrophysics Data System (ADS)

    Sakimoto, Susan E. H.; Crisp, Joy; Baloga, Stephen M.

    1997-03-01

    We examine the role of pressure and gravity as driving forces in planetary lava tubes for Newtonian and power law rheologies. The tubes are assumed to have been filled with lava that was emplaced in constant diameter circular tubes in the laminar flow regime and had constant density, heat capacity, thermal conductivity, and viscosity. Our model provides relationships between tube dimensions, driving forces, and effusion rates and rheology parameters. In general, the pressure term in the driving force dominates for very small slopes, but the gravity term eclipses the pressure term as the slope increases. Applying the model to Alba Patera tube flows suggests effusion rates somewhere between 2 and 105m3/s and viscosities between 102 and 106Pas, with tighter constraints (2 to 4 orders of magnitude) for specific tube sizes and travel times. These effusion rate results are lower and the viscosity ranges are higher than those found in previous studies. This allows eruptions that are closer in style to terrestrial basaltic eruptions, although the flows are still considerably larger in scale than the Hawaiian tube flows. We find that very low lava viscosities are not essential for Alba Patera lava tubes and that tube formation may be a better indicator of the steadiness of the eruption and the presence of low slopes than it is of low viscosities (e.g., 102Pas). In addition, this analysis suggests that the tube systems on the steep flanks of Olympus Mons are fundamentally different from those at Alba Patera. The Olympus Mons flows could not have roofed over, been continuously full, or maintained a continuous lava tube transport system in the assumed full, steady, and fully developed conditions.

  8. Transitional lava flows as potential analogues for lunar impact melts

    NASA Astrophysics Data System (ADS)

    Neish, Catherine; Hughes, Scott; Hamilton, Christopher; Kobs Nawotniak, Shannon; Garry, William Brent; Skok, John Roma; Elphic, Richard; Carter, Lynn; Bandfield, Joshua; Osinski, Gordon; Lim, Darlene; Heldmann, Jennifer

    2015-11-01

    Lunar impact melt deposits are among the roughest surface materials on the Moon at the decimeter scale, even though they appear smooth at the meter scale. These characteristics distinguish them from well-studied terrestrial analogues, such as Hawaiian pāhoehoe and ´a´ā lava flows. The morphology of impact melt deposits can be related to their emplacement conditions, so understanding the origin of these unique surface properties will inform us as to the circumstances under which they were formed. Although there is no perfect archetype for lunar impact melts on Earth, certain terrestrial environments lend themselves as functional analogues. Specifically, a variety of transitional lava flow types develop if the surface of a pāhoehoe-like flow is disrupted, producing ‘slabby’ or ‘rubbly’ flows that are extremely rough at the decimeter scale. We investigated the surface roughness of transitional lava flows at Craters of the Moon (COTM) National Monument, comparing radar imagery and high-resolution topographic profiles to similar data sets acquired by the Lunar Reconnaissance Orbiter for impact melt deposits on the Moon. Results suggest that the lava flows at COTM have similar radar properties to lunar impact melt deposits, but the terrestrial flows are considerably rougher at the meter scale. It may be that lunar impact melts represent a unique lava type not observed on Earth, whose surface texture is influenced by their high emplacement temperatures and/or cooling in a vacuum. Information about the surface properties of lunar impact melt deposits will be critical for future landed missions that wish to sample these materials.

  9. Formation of perched lava ponds on basaltic volcanoes: Interaction between cooling rate and flow geometry allows estimation of lava effusion rates

    NASA Technical Reports Server (NTRS)

    Wilson, L.; Parfitt, E. A.

    1993-01-01

    Perched lava ponds are infrequent but distinctive topographic features formed during some basaltic eruptions. Two such ponds, each approximately 150 m in diameter, formed during the 1968 eruption at Napau Crater and the 1974 eruption of Mauna Ulu, both on Kilauea Volcano, Hawaii. Each one formed where a channelized, high volume flux lava flow encountered a sharp reduction of slope: the flow spread out radially and stalled, forming a well-defined terminal levee enclosing a nearly circular lava pond. We describe a model of how cooling limits the motion of lava spreading radially into a pond and compare this with the case of a channelized flow. The difference in geometry has a major effect, such that the size of a pond is a good indicator of the volume flux of the lava forming it. Lateral spreading on distal shallow slopes is a major factor limiting the lengths of lava flows.

  10. Comparison of bacterial communities from lava cave microbial mats to overlying surface soils from Lava Beds National Monument, USA.

    PubMed

    Lavoie, Kathleen H; Winter, Ara S; Read, Kaitlyn J H; Hughes, Evan M; Spilde, Michael N; Northup, Diana E

    2017-01-01

    Subsurface habitats harbor novel diversity that has received little attention until recently. Accessible subsurface habitats include lava caves around the world that often support extensive microbial mats on ceilings and walls in a range of colors. Little is known about lava cave microbial diversity and how these subsurface mats differ from microbial communities in overlying surface soils. To investigate these differences, we analyzed bacterial 16S rDNA from 454 pyrosequencing from three colors of microbial mats (tan, white, and yellow) from seven lava caves in Lava Beds National Monument, CA, USA, and compared them with surface soil overlying each cave. The same phyla were represented in both surface soils and cave microbial mats, but the overlap in shared OTUs (operational taxonomic unit) was only 11.2%. Number of entrances per cave and temperature contributed to observed differences in diversity. In terms of species richness, diversity by mat color differed, but not significantly. Actinobacteria dominated in all cave samples, with 39% from caves and 21% from surface soils. Proteobacteria made up 30% of phyla from caves and 36% from surface soil. Other major phyla in caves were Nitrospirae (7%) followed by minor phyla (7%), compared to surface soils with Bacteroidetes (8%) and minor phyla (8%). Many of the most abundant sequences could not be identified to genus, indicating a high degree of novelty. Surface soil samples had more OTUs and greater diversity indices than cave samples. Although surface soil microbes immigrate into underlying caves, the environment selects for microbes able to live in the cave habitats, resulting in very different cave microbial communities. This study is the first comprehensive comparison of bacterial communities in lava caves with the overlying soil community.

  11. Comparison of bacterial communities from lava cave microbial mats to overlying surface soils from Lava Beds National Monument, USA

    PubMed Central

    Read, Kaitlyn J. H.; Hughes, Evan M.; Spilde, Michael N.

    2017-01-01

    Subsurface habitats harbor novel diversity that has received little attention until recently. Accessible subsurface habitats include lava caves around the world that often support extensive microbial mats on ceilings and walls in a range of colors. Little is known about lava cave microbial diversity and how these subsurface mats differ from microbial communities in overlying surface soils. To investigate these differences, we analyzed bacterial 16S rDNA from 454 pyrosequencing from three colors of microbial mats (tan, white, and yellow) from seven lava caves in Lava Beds National Monument, CA, USA, and compared them with surface soil overlying each cave. The same phyla were represented in both surface soils and cave microbial mats, but the overlap in shared OTUs (operational taxonomic unit) was only 11.2%. Number of entrances per cave and temperature contributed to observed differences in diversity. In terms of species richness, diversity by mat color differed, but not significantly. Actinobacteria dominated in all cave samples, with 39% from caves and 21% from surface soils. Proteobacteria made up 30% of phyla from caves and 36% from surface soil. Other major phyla in caves were Nitrospirae (7%) followed by minor phyla (7%), compared to surface soils with Bacteroidetes (8%) and minor phyla (8%). Many of the most abundant sequences could not be identified to genus, indicating a high degree of novelty. Surface soil samples had more OTUs and greater diversity indices than cave samples. Although surface soil microbes immigrate into underlying caves, the environment selects for microbes able to live in the cave habitats, resulting in very different cave microbial communities. This study is the first comprehensive comparison of bacterial communities in lava caves with the overlying soil community. PMID:28199330

  12. In situ thermal characterization of cooling/crystallizing lavas during rheology measurements and implications for lava flow emplacement

    NASA Astrophysics Data System (ADS)

    Kolzenburg, S.; Giordano, D.; Cimarelli, C.; Dingwell, D. B.

    2016-12-01

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

  13. Geochemistry and mineralogy of the phonolite lava lake, Erebus volcano, Antarctica: 1972 2004 and comparison with older lavas

    NASA Astrophysics Data System (ADS)

    Kelly, Peter J.; Kyle, Philip R.; Dunbar, Nelia W.; Sims, Kenneth W. W.

    2008-11-01

    Mount Erebus, Antarctica, is a large (3794 m) alkaline open-conduit stratovolcano that hosts a vigorously convecting and persistently degassing lake of anorthoclase phonolite magma. The composition of the lake was investigated by analyzing glass and mineral compositions in lava bombs erupted between 1972 and 2004. Matrix glass, titanomagnetite, olivine, clinopyroxene, and fluor-apatite compositions are invariant and show that the magmatic temperature (˜ 1000°C) and oxygen fugacity (ΔlogFMQ = - 0.9) have been stable. Large temperature variations at the lake surface (~ 400-500°C) are not reflected in mineral compositions. Anorthoclase phenocrysts up to 10 cm in length feature a restricted compositional range (An 10.3-22.9Ab 62.8-68.1Or 11.4-27.2) with complex textural and compositional zoning. Anorthoclase textures and compositions indicate crystallization occurs at low degrees of effective undercooling. We propose shallow water exsolution causes crystallization and shallow convection cycles the anorthoclase crystals through many episodes of growth resulting in their exceptional size. Minor variations in eruptive activity from 1972 to 2004 are decoupled from magma compositions. The variations probably relate to changes in conduit geometry within the volcano and/or variable input of CO 2-rich volatiles into the upper-level magma chamber from deeper in the system. Eleven bulk samples of phonolite lava from the summit plateau that range in age from 0 ± 4 ka to 17 ± 8 ka were analyzed for major and trace elements. Small compositional variations are controlled by anorthoclase content. The lavas are indistinguishable from modern bulk lava bomb compositions and demonstrate that Erebus volcano has been erupting lava and tephra from the summit region with the same bulk composition for ˜ 17 ka.

  14. High-Resolution Imaging of Lava Flow Terrains on Mars by MRO HiRISE

    NASA Astrophysics Data System (ADS)

    Crumpler, L. S.; Keszthelyi, L. P.; Jaeger, W. L.; McEwen, A. S.; HiRISE Team

    2007-12-01

    Lava flows account for a significant fraction of the surface of Mars and HiRISE has imaged a diverse selection of these areas at resolutions comparable to "air photos" on Earth. Although some lava are extensively impact "gardened" or mantled, many areas retain primary geomorphologic information at meter-scale. Primary characteristics similar to that of late Cenozoic lava flows in arid areas of Earth are visible in the HiRISE images of even some Hesperian lava plains. The extensive mantling by wind-blown deposits in some of the more youthful volcanic terrains (e.g., Tharsis) may, like terrestrial counterparts, be a result of the excessively rough surface trapping mobilized sand. Evidence for lava flow inflation, including lava-rise plateaus and pits and deformation both vertically and laterally of lava crusts, is documented in areas of flood lavas. Other lava flows are clearly fed from surface channels resulting in dispersive flow surface pattern. Lava flows with hummocky surface textures are comparable to terrestrial flows with auto-brecciated and disturbed surfaces, but the Martian flows are often much larger than typical terrestrial examples. Kilometer-scale areas of puzzle-work plates characterize some flood lava flows. The abundance of plate-like and rubbly deformation styles observed at many localities on Mars is consistent with examples of rubbly pahoehoe seen in situ by the Spirit rover. Rubbly pahoehoe may be a common primary surface texture for many areas of plains-like lava flow emplacement such as the Hesperian lava plains. Sinuous rill-like channels headed at distinct vents and collapse pits suggest significant lava erosion and correspondingly high effusion rates. While the Athabasca Valles channel bed forms appear to be associated with major aqueous outflows, the entire region is draped with lava.

  15. Constraints on Lava Flow Emplacement Derived From Precision Topographic Measurements

    NASA Astrophysics Data System (ADS)

    Zimbelman, J. R.; Bjonnes, E. E.

    2005-12-01

    Precision topography obtained with a Differential Global Positioning System (DGPS) was used to derive constraints on the physical properties of two lava flows on the Big Island of Hawaii. We used a Trimble 4800 DGPS to collect positional information across the lava flows with < 2 cm horizontal and < 4 cm vertical precision (but field tests show that points are usually repeatable to < 1 cm both horizontally and vertically). The DGPS data were overlaid on georeferenced aerial and satellite imaging data, allowing us to correlate the measured topographic points to field notes and photographs, as well as to the local setting evident in the vertical images. We combined field and imaging data for the eastern lobe of the 1907 basalt flow from the southwestern rift zone of Mauna Loa volcano, east of the Ocean View Estates subdivision, and for portions of a grass-covered Pleistocene benmoreite flow near Mana on the western flank of Mauna Kea volcano. Measured physical dimensions of the Hawaiian lava flows obtained from the DGPS data were then used to calculate the yield strength, average effusion rate, and effective viscosity of the lavas using published relationships derived from diverse theories of fluid flow. Yield strengths obtained from three different expressions ranged from 5800 to 56000 Pa for the Mauna Loa basalt flow and from 13000 to 28000 Pa for the Mauna Kea benmoreite flow. Total flow length could not be determined for the Mauna Kea flow, but the entire surface portion of the 1907 flow is well exposed; this allowed us to calculate an average effusion rate of 29 m/s and effective viscosities ranging from 17000 to 280000 Pa-s for this flow, broadly consistent with values published for the 1984 basalt flow from the eastern rift zone of Mauna Loa. These results improve our confidence in being able to derive similar constraints on the likely emplacement conditions of lava flows on other planets, such as the enormous lava flows commonly found on the martian, venusian

  16. Ridge-forming, ice-bounded lava flows at Mount Rainier, Washington

    NASA Astrophysics Data System (ADS)

    Lescinsky, D. T.; Sisson, T. W.

    1998-04-01

    Large (0.3 4 km3) andesite and dacite lava flows at Mount Rainier, Washington, sit atop or are perched along the sides of high ridges separating deep valleys. Early researchers proposed that these ridge-forming lavas flowed into paleovalleys and displaced rivers to their margins; entrenchment of the rivers then left the lavas atop ridges. On the basis of exceptional flow thickness, ice-contact features, and eruption age measurements, we propose that the lavas flowed beside and between valley glaciers that filled the adjacent valleys in the Pleistocene. When the glaciers retreated, the flows were left high on the adjacent ridges. These lavas were never situated at valley floors and do not represent products of reversed topography. Instead, ridge-forming and perched lava flows at Mount Rainier and at many other high stratovolcanoes illustrate the ability of ice to dam, deflect, and confine flowing lava.

  17. REE geochemistry of late Miocene lavas from Pioneertown, Fry Mountain and Ruby Mountain, California

    SciTech Connect

    Mehegan, J.M.; Thorpe, R. )

    1993-04-01

    A series of flows, dikes and cinder cones of alkaline and subalkaline basalts erupted in late Miocene time along the northeastern flank of the San Bernardino Mountains and in contiguous parts of the Mojave Desert. Previous studies of lavas from the region yielded K-Ar ages of 6 to 9 Ma, and reported that lavas from the Ruby Mountain locality often contain ultramafic inclusions of probable mantle origin. This study (1) characterizes the rare earth element (REE; light = LREE; heavy = HREE) and trace element compositions of the young lavas from this region, (2) discusses the relationship of the Pioneertown lavas with the hot-spring ( ) deposits stratigraphically beneath the lava flows, (3) speculates on the possible volcanic conduit for the Pioneertown lavas, and (4) discusses the petrogenesis of these late Miocene lavas.

  18. Estimates of Lava Eruption Rates at Alba Patera, Mars

    NASA Technical Reports Server (NTRS)

    Baloga, S. M.; Pieri, D. C.

    1985-01-01

    The Martian volcanic complex Alba Patera exhibits a suite of well-defined, long and relatively narrow lava flows qualitatively resembling those found in Hawaii. Even without any information on the duration of the Martian flows, eruption rates (total volume discharge/duration of the extrusion) estimates are implied by the physical dimensions of the flows and the likely conjecture that Stephan-Boltzmann radiation is the dominating thermal loss mechanism. The ten flows in this analysis emanate radially from the central vent and were recently measured in length, plan areas, and average thicknesses by shadow measurement techniques. The dimensions of interest are shown. Although perhaps morphologically congruent to certain Hawaiian flows, the dramatically expanded physical dimensions of the Martian flows argues for some markedly distinct differences in lava flow composition for eruption characteristics.

  19. Radiative temperature measurements at Kupaianaha lava lake, Kilauea Volcano, Hawaii

    NASA Technical Reports Server (NTRS)

    Flynn, Luke P.; Mouginis-Mark, Peter J.; Gradie, Jonathan C.; Lucey, Paul G.

    1993-01-01

    The radiative temperature of the surface of Kupaianaha lava lake is computed using field spectroradiometer data. Observations were made during periods of active overturning. The lake surface exhibits three stages of activity. Magma fountaining and overturning events characterize stage 1, which exhibits the hottest crustal temperatures and the largest fractional hot areas. Rifting events between plates of crust mark stage 2; crustal temperatures in this stage are between 100 C and 340 C, and fractional hot areas are at least an order of magnitude smaller than those in stage 1. Stage 3 is characterized by quiescent periods when the lake is covered by a thick crust. This stage dominates the activity of the lake more than 90 percent of the time. The results of this study are relevant for satellite and airborne measurement of the thermal characteristics of active volcanoes, and indicate that the thermal output of a lava lake varies on a time scale of seconds to minutes.

  20. Microscopic and macroscopic assessment of the emplacement of obsidian lavas

    NASA Astrophysics Data System (ADS)

    Befus, K. S.; Williams, M.; Gardner, J. E.

    2013-12-01

    Rhyolitic obsidian lavas are common in silicic volcanic systems, but quantitative data related to the emplacement of such lavas is rare. To assess the emplacement dynamics of rhyolitic obsidian lavas we measured the 3D orientation of microlites in samples collected systematically across five of the Central Plateau Member lavas of Yellowstone. Eruption volumes and maximum flow distances of targeted lava flows range from 0.01-70 km3 and 0.13-22 km, respectively. The dataset allows us to examine how deformation during emplacement varies with eruption size. Oriented thin sections were prepared from samples thought to be in place (i.e., not rotated by autobrecciation or erosion). In each sample, we petrographically measured the trend and plunge of >130 acicular Fe-Ti oxide microlites. The 3D microlite orientation can be used in two ways to understand the kinematics of emplacement. First, microlite orientations can be used to infer the dominant directions of fluid stretching because microlite long axes align in the direction of local extension. Second, the degree of alignment of a microlite population (i.e., standard deviation of trend and plunge), irrespective of preferred orientation, is dependent on the strain microlites experience during emplacement. We found that microlites are strongly aligned in all samples from all flows. Microlites are aligned roughly parallel to the direction of flow in samples collected near the flow front. Conversely, microlites are generally aligned orthogonal to the flow direction in samples collected from interior portions of the flows. In individual flows, the degree of alignment shows no correlation with distance travelled, instead it has slight random variations. Large- and small-volume flows display indistinguishable degrees of microlite alignment. Microlites provide a indicator of flow direction near flow fronts where strain is imparted by simple shear. In the interior portions of flows, strain is induced by pure shear via flattening

  1. Estimates of lava eruption rates at Alba Patera, Mars

    NASA Astrophysics Data System (ADS)

    Baloga, S. M.; Pieri, D. C.

    1985-04-01

    The Martian volcanic complex Alba Patera exhibits a suite of well-defined, long and relatively narrow lava flows qualitatively resembling those found in Hawaii. Even without any information on the duration of the Martian flows, eruption rates (total volume discharge/duration of the extrusion) estimates are implied by the physical dimensions of the flows and the likely conjecture that Stephan-Boltzmann radiation is the dominating thermal loss mechanism. The ten flows in this analysis emanate radially from the central vent and were recently measured in length, plan areas, and average thicknesses by shadow measurement techniques. The dimensions of interest are shown. Although perhaps morphologically congruent to certain Hawaiian flows, the dramatically expanded physical dimensions of the Martian flows argues for some markedly distinct differences in lava flow composition for eruption characteristics.

  2. Helium isotopes in some historical lavas from Mount Vesuvius

    NASA Astrophysics Data System (ADS)

    Graham, D. W.; Allard, P.; Kilburn, C. R. J.; Spera, F. J.; Lupton, J. E.

    1993-11-01

    3He/ 4He ratios in lavas erupted during the last 360 years at Mt. Vesuvius are between 2.2 and 2.7 RA ( RA = atmospheric ratio of 1.39 × 10 -6), and are among the lowest values measured in young volcanic rocks. They are also identical to values measured in summit crater fumaroles sampled during 1987-1991. This agreement indicates that the 3He/ 4He ratio in the crater fumaroles faithfully tracks the magmatic value. The relatively low and uniform 3He/ 4He ratio in the lavas reflects either a mantle source enriched in (U + Th)/ 3He, or a mixture of magmatic and crustal components.

  3. Acute renal toxicity after ingestion of Lava light liquid.

    PubMed

    Erickson, T B; Aks, S E; Zabaneh, R; Reid, R

    1996-06-01

    A 65-year-old man with a history of alcohol abuse and seizure disorder presented to the emergency department with altered mental status, increased anion gap acidosis, phenytoin toxicity, and acute kidney failure. The patient had ingested the liquid contents of a Lava light, which contained chlorinated paraffin, polyethylene glycol (molecular weight 200), kerosene, and micro-crystalline wax. Gas chromatography-mass spectrophotometry of the patient's blood produced results consistent with the same analysis of the Lava light contents. After 3 days of declining mental status and worsening kidney function, the patient required hemodialysis. After a prolonged hospitalization, the patient was discharged home with residual renal insufficiency. Although multifactorial, the associated renal toxicity was most probably related to the low molecular weight polyethylene glycol content of the lamp's liquid contents.

  4. Evoluton of polygonal fracture patterns in lava flows.

    PubMed

    Aydin, A; Degraff, J M

    1988-01-29

    Cooling-induced fractures, also known as columnar joints, divide basaltic lava flows into prismatic columns with polygonal cross sections. The regularity and symmetry of the fracture patterns have long fascinated naturalists. In view of the recent selection of two candidate nuclear waste sites in areas where polygonally fractured volcanic rocks are located, a better understanding of the fracture patterns is required. Field data indicate that the tetragonal networks at flow surfaces evolve systematically to hexagonal networks as the joints grow inward during solidification of lava. This evolution occurs by the gradual change of most orthogonal intersections to nonorthogonal intersections of about 120 degrees. The surface features and intersection geometries of columnar joints show that joint segments at any given level form sequentially yet harmoniously.

  5. Scientists Engage With the Public During Lava Flow Threat

    NASA Astrophysics Data System (ADS)

    McCarter, Tricia

    2014-11-01

    On 27 June, lava from Kīlauea, an active volcano on the island of Hawai`i, began flowing to the northeast, threatening the residents in Pāhoa, a community in the District of Puna, as well as the only highway accessible to this area. Scientists from the U.S. Geological Survey's Hawaiian Volcano Observatory (HVO) and the Hawai`i County Civil Defense have been monitoring the volcano's lava flow and communicating with affected residents through public meetings since 24 August. Eos recently spoke with Michael Poland, a geophysicist at HVO and a member of the Eos Editorial Advisory Board, to discuss how he and his colleagues communicated this threat to the public.

  6. Radiative temperature measurements at Kupaianaha lava lake, Kilauea Volcano, Hawaii

    NASA Technical Reports Server (NTRS)

    Flynn, Luke P.; Mouginis-Mark, Peter J.; Gradie, Jonathan C.; Lucey, Paul G.

    1993-01-01

    The radiative temperature of the surface of Kupaianaha lava lake is computed using field spectroradiometer data. Observations were made during periods of active overturning. The lake surface exhibits three stages of activity. Magma fountaining and overturning events characterize stage 1, which exhibits the hottest crustal temperatures and the largest fractional hot areas. Rifting events between plates of crust mark stage 2; crustal temperatures in this stage are between 100 C and 340 C, and fractional hot areas are at least an order of magnitude smaller than those in stage 1. Stage 3 is characterized by quiescent periods when the lake is covered by a thick crust. This stage dominates the activity of the lake more than 90 percent of the time. The results of this study are relevant for satellite and airborne measurement of the thermal characteristics of active volcanoes, and indicate that the thermal output of a lava lake varies on a time scale of seconds to minutes.

  7. An Overview of Recent Observations on Lava-H2Ointeractions

    NASA Astrophysics Data System (ADS)

    Edwards, B. R.

    2014-12-01

    Lava flows can be sensitive recorders of their environments of formation (e.g., pillow lava). However, while deposits formed during interactions between lava and frozen water are increasing critical for constraining paleoclimate reconstructions on Earth and Mars, those interactions are subtle and complex. Fortunately, recent observations made during eruptions (2010 Fimmvorduhals/Eyjafjallajokull, Iceland; 2012-13 Tolbachik, Russia; 2013 Veniaminof, Alaska), during large-scale experiments (Syracuse Lava Lab), and on ancient deposits are shedding new light on these complexities. To understand these observations, it is critical to constrain the nature (porosity, permeability, ability to deform) of the boundary between the lava and the substrate. When lava travels directly on top of non-permeable ice, meltwater is produced rapidly enough to significantly accelerate lava movement (e.g., 'hydroplaning' or 'Leidenfrost effect'). The lack of surface permeability also facilitates ingestion of steam into the base of the lava for several minutes on the scale of experiments (dm); anomalously large gas cavities are also present in modern and ancient lava flow deposits inferred to have formed in water/ice-rich environments. When lava is emplaced directly on snow, the permeability of the substrate controls meltwater accumulation, which can facilitate/hinder heat transfer but can also weaken the substrate. Finally, the presence of basal lava flow breccia ('a'a flows) or an earlier erupted tephra blanket at the lava-H2O boundary acts to significantly slow heat transfer. The speed of lava emplacement may also be important. The lavas emplaced during most of the eruptions above were not able to cover a large enough area to quickly generate significant volumes of meltwater. However, at the high discharge rates for the first few days of the Tolbachik eruption (~400 m3 s-1), effusion onto a less permeable surface (e.g., ice instead of snow) could generate significant volumes of meltwater.

  8. Pāhoehoe, `a`ā, and block lava: an illustrated history of the nomenclature

    NASA Astrophysics Data System (ADS)

    Harris, Andrew J. L.; Rowland, Scott K.; Villeneuve, Nicolas; Thordarson, Thor

    2017-01-01

    Lava flows occur worldwide, and throughout history, various cultures (and geologists) have described flows based on their surface textures. As a result, surface morphology-based nomenclature schemes have been proposed in most languages to aid in the classification and distinction of lava surface types. One of the first to be published was likely the nine-class, Italian-language description-based classification proposed by Mario Gemmellaro in 1858. By far, the most commonly used terms to describe lava surfaces today are not descriptive but, instead, are merely words, specifically the Hawaiian words `a`ā (rough brecciated basalt lava) and pāhoehoe (smooth glassy basalt lava), plus block lava (thick brecciated lavas that are typically more silicic than basalt). `A`ā and pāhoehoe were introduced into the Western geological vocabulary by American geologists working in Hawai`i during the 1800s. They and other nineteenth century geologists proposed formal lava-type classification schemes for scientific use, and most of them used the Hawaiian words. In 1933, Ruy Finch added the third lava type, block lava, to the classification scheme, with the tripartite system being formalized in 1953 by Gordon Macdonald. More recently, particularly since the 1980s and based largely on studies of lava flow interiors, a number of sub-types and transitional forms of all three major lava types have been defined. This paper reviews the early history of the development of the pāhoehoe, `a`ā, and block lava-naming system and presents a new descriptive classification so as to break out the three parental lava types into their many morphological sub-types.

  9. Subglacial lava propagation, ice melting and heat transfer during emplacement of an intermediate lava flow in the 2010 Eyjafjallajökull eruption

    NASA Astrophysics Data System (ADS)

    Oddsson, Björn; Gudmundsson, Magnús T.; Edwards, Benjamin R.; Thordarson, Thorvaldur; Magnússon, Eyjólfur; Sigurðsson, Gunnar

    2016-07-01

    During the 2010 Eyjafjallajökull eruption in South Iceland, a 3.2-km-long benmoreite lava flow was emplaced subglacially during a 17-day effusive-explosive phase from April 18 to May 4. The lava flowed to the north out of the ice-filled summit caldera down the outlet glacier Gígjökull. The flow has a vertical drop of about 700 m, an area of ca. 0.55 km2, the total lava volume is ca. 2.5·107 m3 and it is estimated to have melted 10-13·107 m3 of ice. During the first 8 days, the lava advanced slowly (<100 m day-1), building up to a thickness of 80-100 m under ice that was initially 150-200 m thick. Faster advance (up to 500 m day-1) formed a thinner (10-20 m) lava flow on the slopes outside the caldera where the ice was 60-100 m thick. This subglacial lava flow was emplaced along meltwater tunnels under ice for the entire 3.2 km of the flow field length and constitutes 90 % of the total lava volume. The remaining 10 % belong to subaerial lava that was emplaced on top of the subglacial lava flow in an ice-free environment at the end of effusive activity, forming a 2.7 km long a'a lava field. About 45 % of the thermal energy of the subglacial lava was used for ice melting; 4 % was lost with hot water; about 1 % was released to the atmosphere as steam. Heat was mostly released by forced convection of fast-flowing meltwater with heat fluxes of 125-310 kWm-2.

  10. Morphology of the 1984 open-channel lava flow at Krafla volcano, northern Iceland

    NASA Astrophysics Data System (ADS)

    Rossi, Matti J.

    1997-09-01

    An open-channel lava flow of olivine tholeiite basalt, 9 km long and 1-2 km wide, formed in a volcanic eruption that took place in the Krafla volcano, Iceland, on the 4-18 September 1984. The eruption started with emplacement of a pahoehoe sheet which was fed by a 8.5-km-long fissure. After two days of eruption, lava effusion from the fissure ceased but one crater at the northern end of the fissure continued to release lava for another twelve days. That crater supplied an open-channel flow that moved toward the north along the rift valley. The lava was emplaced on a slope of 1°. The final lava flow is composed of five flow facies: (1) the initial pahoehoe sheet; (2) proximal slab pahoehoe and aa; (3) shelly-type overflows from the channel; (4) distal rubbly aa lava; and (5) secondary outbreaks of toothpaste lava and cauliflower aa. The main lava channel within the flow is 6.4 km long. The mean width of this channel is 189 m (103 m S.D.). An initial lava channel that forms in a Bingham plastic substance is fairly constant in width. This channel, however, varies in width especially in the proximal part indicating channel erosion. Large drifted blocks of channel walls are found throughout the flow front area and on the top of overflow levees. This suggests that the channel erosion was mainly mechanical. The lava flow has a mean height of 6 m above its surroundings, measured at the flow margins. However, a study of the pre-flow topography indicates that the lava filled a considerable topographic depression. Combined surface and pre-flow profiles give an average lava-flow thickness of 11 m; the thickness of the initial sheet-flow is estimated as 2 m. The volume of the lava flow calculated from these figures is 0.11 km 3. The mean effusion rate was 91 m 3/s. When lava flow models are used to deduce the rheological properties of this type of lava flow, the following points must be considered: (1) when a lava flow is emplaced along tectonic lineaments, its depth and

  11. Preferential Weathering of Carbonatite Lava at Ol Doinyo Lengai, Tanzania

    NASA Astrophysics Data System (ADS)

    Robertson, C. H.; Harpp, K. S.; Geist, D.; Bosselait, M.

    2014-12-01

    Although carbonatites have been produced since the Archean and are preserved in the geologic record, the East African Rift is home to the only active carbonatite volcano, at Ol Doinyo Lengai. It has long been known that the natrocarbonatites become strongly weathered the first time they are exposed to rain. We studied the weathering patterns in the field and have determined the mineralogical transformations via petrography and XRD. Mass transport is assessed by XRF and ICP-MS analyses. Water preferentially dissolves specific minerals in the pristine lava, permeating through earlier layers of flow to form stalactites, which have differing mineralogical composition. These hang both from the host flow and from the bottom of underlying earlier flows. The weathering product is characterized by trona, a hydrated carbonate mineral, as well as the sodium sulfate mineral aphthitalite. Data from XRD analysis of the carbonatite lava confirm transformation of its original minerals, nyerereite and gregoryite, into secondary hydrated carbonate minerals gaylussite and pirssonite (e.g., Zaitsev and Keller, 2006). This transformation is attributed to the instability of the erupted minerals at atmospheric conditions. Data from XRF analysis indicate a 4-fold increase in the amount of sodium present in the stalactite as well as a 8-fold increase in potassium. Trace element analysis by ICP-MS indicates significantly elevated levels of vanadium, copper, and rubidium in the weathering product, whereas strontium, barium, lanthanum, and cesium are left behind in high concentrations in the carbonatite lava. Our results provide further evidence supporting the proposal by Dawson et al. (1987) that calcium carbonate dominated lava flows result from extensive weathering of sodic carbonatite flows.

  12. Topographic and Stochastic Influences on Pahoehoe Lava Lobe Emplacement

    NASA Technical Reports Server (NTRS)

    Hamilton, Christopher W.; Glaze, Lori S.; James, Mike R.; Baloga, Stephen M.

    2013-01-01

    A detailed understanding of pahoehoe emplacement is necessary for developing accurate models of flow field development, assessing hazards, and interpreting the significance of lava morphology on Earth and other planetary surfaces. Active pahoehoe lobes on Kilauea Volcano, Hawaii, were examined on 21-26 February 2006 using oblique time-series stereo-photogrammetry and differential global positioning system (DGPS) measurements. During this time, the local discharge rate for peripheral lava lobes was generally constant at 0.0061 +/- 0.0019 m3/s, but the areal coverage rate of the lobes exhibited a periodic increase every 4.13 +/- 0.64 minutes. This periodicity is attributed to the time required for the pressure within the liquid lava core to exceed the cooling induced strength of its margins. The pahoehoe flow advanced through a series of down slope and cross-slope breakouts, which began as approximately 0.2 m-thick units (i.e., toes) that coalesced and inflated to become approximately meter-thick lobes. The lobes were thickest above the lowest points of the initial topography and above shallow to reverse facing slopes, defined relative to the local flow direction. The flow path was typically controlled by high-standing topography, with the zone directly adjacent to the final lobe margin having an average relief that was a few centimeters higher than the lava inundated region. This suggests that toe-scale topography can, at least temporarily, exert strong controls on pahoehoe flow paths by impeding the lateral spreading of the lobe. Observed cycles of enhanced areal spreading and inflated lobe morphology are also explored using a model that considers the statistical likelihood of sequential breakouts from active flow margins and the effects of topographic barriers.

  13. Lava effusion rate definition and measurement--A review

    USGS Publications Warehouse

    Calvari, Sonia; Dehn, Jonathan; Harris, A.

    2007-01-01

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

  14. Fractal geometry of some Martian lava flow margins: Alba Patera

    NASA Technical Reports Server (NTRS)

    Kauhanen, K.

    1993-01-01

    Fractal dimension for a few lava flow margins on the gently sloping flanks of Alba Patera were measured using the structured walk method. Fractal behavior was observed at scales ranging from 20 to 100 pixels. The upper limit of the linear part of log(margin length) vs. log(scale) profile correlated well to the margin length. The lower limit depended on resolution and flow properties.

  15. The Wind-Scoured Lava Flows of Pavonis Mons

    NASA Image and Video Library

    2016-09-21

    Click on the image for larger version This image shows a circular impact crater and an oval volcanic caldera on the southern flank of a large volcano on Mars called Pavonis Mons. The caldera is also the source of numerous finger-like lava flows and at least one sinuous lava channel. Both the caldera and the crater are degraded by aeolian (wind) erosion. The strong prevailing winds have apparently carved deep grooves into the terrain. When looking at the scene for the first time, the image seems motion blurred. However, upon a closer look, the smaller, young craters are pristine, so the image must be sharp and the "blurriness" is due to the processes acting on the terrain. This suggests that the deflation-produced grooves, along with the crater and the caldera, are old features and deflation is not very active today. Alternatively, perhaps these craters are simply too young to show signs of degradation. This deeply wind-scoured terrain type is unique to Mars. Wind-carved stream-lined landforms on Earth are called "yardangs," but they don't form extensive terrains like this one. The basaltic lavas on the flanks of this volcano have been exposed to wind for such a long time that there are no parallels on Earth. Terrestrial landscapes and terrestrial wind patterns change much more rapidly than on Mars. http://photojournal.jpl.nasa.gov/catalog/PIA21064

  16. Map showing lava-flow hazard zones, Island of Hawaii

    USGS Publications Warehouse

    Wright, Thomas L.; Chun, Jon Y.F.; Exposo, Jean; Heliker, Christina; Hodge, Jon; Lockwood, John P.; Vogt, Susan M.

    1992-01-01

    This map shows lava-flow hazard zones for the five volcanoes on the Island of Hawaii. Volcano boundaries are shown as heavy, dark bands, reflecting the overlapping of lava flows from adjacent volcanoes along their common boundary. Hazard-zone boundaries are drawn as double lines because of the geologic uncertainty in their placement. Most boundaries are gradational, and the change In the degree of hazard can be found over a distance of a mile or more. The general principles used to place hazard-zone boundaries are discussed by Mullineaux and others (1987) and Heliker (1990). The differences between the boundaries presented here and in Heliker (1990) reflect new data used in the compilation of a geologic map for the Island of Hawaii (E.W. Wolfe and Jean Morris, unpub. data, 1989). The primary source of information for volcano boundaries and generalized ages of lava flows for all five volcanoes on the Island of Hawaii is the geologic map of Hawaii (E.W. Wolfe and Jean Morris, unpub. data, 1989). More detailed information is available for the three active volcanoes. For Hualalai, see Moore and others (1987) and Moore and Clague (1991); for Mauna Loa, see Lockwood and Lipman (1987); and for Kilauea, see Holcomb (1987) and Moore and Trusdell (1991).

  17. Calculated viscosity-distance dependence for some actively flowing lavas

    NASA Astrophysics Data System (ADS)

    Pieri, David

    1987-05-01

    The importance of viscosity as a gauge of the various energy and momentum dissipation regimes of lava flows has been realized for a long time. Nevertheless, despite its central role in lava dynamics and kinematics, it remains among the most difficult of flow physical properties to measure in situ during an eruption. Attempts at reconstructing the actual emplacement viscosities of lava flows from their solidified topographic form are difficult. Where data are available on the position of an advancing flow front as a function of time, it is possible to calculate the effective viscosity of the front as a function of distance from the vent, under the assumptions of a steady state regime. As an application and test of an equation given, relevant parameters from five recent flows on Mauna Loa and Kilauea were utilized to infer the dynamic structure of their aggregate flow front viscosity as they advanced, up to cessation. The observed form of the viscosity-distance relation for the five active Hawaiian flows examined appears to be exponential, with a rapid increase just before the flows stopped as one would expect.

  18. Cosmogenic He in terrestrial rocks: The summit lavas of Maui.

    PubMed

    Craig, H; Poreda, R J

    1986-04-01

    We have identified terrestrial cosmic rayproduced (3)He in three lava flows on the crest of Haleakala Volcano on Maui, 3 km above sea level, and approximately 0.5 million years old. Although these lavas, like all oceanic basalts, contain primordial (3)He from the mantle, the "cosmogenic" component ((3)He(C)) can be identified unambiguously because it is extractable only by high-temperature vacuum fusion. In contrast, a large fraction of the mantle helium resides in fluid inclusions and can be extracted by vacuum crushing, leaving a residual component with (3)He/(4)He ratios as high as 75x those in the atmosphere, which can be liberated by melting the crushed grains. Cosmogenic (3)He is present in both olivines and clinopyroxenes at 0.8-1.2 x 10(-12) ml(STP)/g and constitutes 75% +/- 5% of the total (3)He present. The observed (3)He(C) levels require a cosmic ray exposure age of only some 64,000 years, much less than the actual age of the lavas, if there is no erosion. Using a model that includes effects of uplift or submergence as well as erosion, we calculate an apparent "erosion rate" of the order of 8.5 m/10(6) years for the western rim of the summit crater, as an example of the application of measurements of cosmogenic rare gases to terrestrial geological problems.

  19. The formation of vesicular cylinders in pahoehoe lava flows

    NASA Astrophysics Data System (ADS)

    Fowler, A. C.; Rust, Alison C.; Vynnycky, M.

    2015-01-01

    Vertical cylinders of bubble-enriched, chemically evolved volcanic rock are found in many inflated pahoehoe lava flows. We provide a putative theoretical explanation for their formation, based on a description of a crystallising three-phase (liquid, solid, gas) crystal pile in which the water-saturated silicate melt exsolves steam and becomes more silica-rich as it crystallises anhydrous minerals. These cylinders resemble pipes that form in solidifying binary alloys as a result of sufficiently vigorous porous medium convection within the mush. A convection model with the addition of gas bubbles that provide the buoyancy source indicates that the effective Rayleigh number is too low for convection to occur in the mush of a basalt lava flow. However, the formation of gas bubbles during crystallisation means that the base state includes fluid migration up through the crystal mush even without convection. Stability considerations suggest that it is plausible to form a positive feedback where increased local porosity causes increased upwards fluid flow, which brings more silicic melt up and lowers the liquidus temperature, promoting locally higher porosity. Numerical solutions show that there are steady solutions in which cylinders form, and we conclude that this model provides a viable explanation for vesicular cylinder formation in inflated basalt lava flows.

  20. Calculated viscosity-distance dependence for some actively flowing lavas

    NASA Technical Reports Server (NTRS)

    Pieri, David

    1987-01-01

    The importance of viscosity as a gauge of the various energy and momentum dissipation regimes of lava flows has been realized for a long time. Nevertheless, despite its central role in lava dynamics and kinematics, it remains among the most difficult of flow physical properties to measure in situ during an eruption. Attempts at reconstructing the actual emplacement viscosities of lava flows from their solidified topographic form are difficult. Where data are available on the position of an advancing flow front as a function of time, it is possible to calculate the effective viscosity of the front as a function of distance from the vent, under the assumptions of a steady state regime. As an application and test of an equation given, relevant parameters from five recent flows on Mauna Loa and Kilauea were utilized to infer the dynamic structure of their aggregate flow front viscosity as they advanced, up to cessation. The observed form of the viscosity-distance relation for the five active Hawaiian flows examined appears to be exponential, with a rapid increase just before the flows stopped as one would expect.

  1. The internal structure of lava flows—insights from AMS measurements II: Hawaiian pahoehoe, toothpaste lava and 'a'ā

    NASA Astrophysics Data System (ADS)

    Cañón-Tapia, Edgardo; Walker, George P. L.; Herrero-Bervera, Emilio

    1997-03-01

    We studied the anisotropy of magnetic susceptibility (AMS) of 22 basaltic flow units, including S-type pahoehoe, P-type pahoehoe, toothpaste lava and 'a'ā emplaced over different slopes in two Hawaiian islands. Systematic differences occur in several aspects of AMS (mean susceptibility, degree of anisotropy, magnetic fabric and orientation of the principal susceptibilities) among the morphological types that can be related to different modes of lava emplacement. AMS also detects systematic changes in the rate of shear with position in a unit, allowing us to infer local flow direction and some other aspects of the velocity field of each unit. 'A'ā flows are subject to stronger deformation than pahoehoe, and also their internal parts behave more like a unit. According to AMS, the central part of pahoehoe commonly reveals a different deformation history than the upper and lower extremes, probably resulting from endogenous growth.

  2. Key variables influencing patterns of lava dome growth and collapse

    NASA Astrophysics Data System (ADS)

    Husain, T.; Elsworth, D.; Voight, B.; Mattioli, G. S.; Jansma, P. E.

    2013-12-01

    Lava domes are conical structures that grow by the infusion of viscous silicic or intermediate composition magma from a central volcanic conduit. Dome growth can be characterized by repeated cycles of growth punctuated by collapse, as the structure becomes oversized for its composite strength. Within these cycles, deformation ranges from slow long term deformation to sudden deep-seated collapses. Collapses may range from small raveling failures to voluminous and fast-moving pyroclastic flows with rapid and long-downslope-reach from the edifice. Infusion rate and magma rheology together with crystallization temperature and volatile content govern the spatial distribution of strength in the structure. Solidification, driven by degassing-induced crystallization of magma leads to the formation of a continuously evolving frictional talus as a hard outer shell. This shell encapsulates the cohesion-dominated soft ductile core. Here we explore the mechanics of lava dome growth and failure using a two-dimensional particle-dynamics model. This meshless model follows the natural evolution of a brittle carapace formed by loss of volatiles and rheological stiffening and avoids difficulties of hour-glassing and mesh-entangelment typical in meshed models. We test the fidelity of the model against existing experimental and observational models of lava dome growth. The particle-dynamics model follows the natural development of dome growth and collapse which is infeasible using simple analytical models. The model provides insight into the triggers that lead to the transition in collapse mechasnism from shallow flank collapse to deep seated sector collapse. Increase in material stiffness due to decrease in infusion rate results in the transition of growth pattern from endogenous to exogenous. The material stiffness and strength are strongly controlled by the magma infusion rate. Increase in infusion rate decreases the time available for degassing induced crystallization leading to a

  3. Fragmentation Mechanisms Associated with Lacustrine Lava-Water Explosions

    NASA Astrophysics Data System (ADS)

    Fitch, E. P.; Fagents, S. A.; Thordarson, T.; Hamilton, C.

    2015-12-01

    Rootless cones form when degassed lava interacts explosively with water contained in the near-surface substrate, and represents an end-member system that can elucidate mechanisms of magma-water interactions due to the absence of primary degassing-induced fragmentation. The proportion of finely fragmented ejecta (i.e. ash), generated in rootless explosions, even if the volume is small relative to coarser ejecta, may contribute significantly to the explosion energy release. Explosive melt-water experiments indicate that the degree of melt-water mixing and energy release are proportional to the abundance of blocky grains, fragmented by brittle disintegration, which effectively contribute thermal energy to the explosive lava-water interaction. In order to determine the state of the lava at the point of ash-grade fragmentation in rootless explosions we examined grain morphology over the following size ranges: 0.5-0 ϕ (1.41-1 mm, very coarse ash), 1.5-2 ϕ (0.354-0.250 mm, medium ash), and 3.5-4 ϕ (0.088-0.062 mm, very fine ash). We found that rootless ash is composed of blocky, mossy, and fluidal grains with a minor component of aggregates (≤ 2%) and glassy shards (< 35%). Typically, (1) very coarse ash contains blocky (9-58%), mossy (8-36%) and fluidal (28-67%) grains only, (2) medium ash contains blocky (32-76%), mossy (9-39%) and fluidal (15-43%) grains with a minor abundance of glassy shards (≤ 8%), and (3) very fine ash is dominated by blocky clasts (53-80%), with lower shard (12-34%) and fluidal (4-24%) components. We observe that the abundance of fluidal grains decreases while the abundance of blocky grains increases with decreasing grain size. Also, the abundance of blocky grains decreases with increasing stratigraphic height, indicating that as rootless explosions progressed, brittle fragmentation of lava is less pronounced, suggesting that the efficiency of lava-water mixing dropped, most likely due to reduced availability of external water. However, we

  4. Discriminating lava flows of different age within Nyamuragira's volcanic field using spectral mixture analysis

    NASA Astrophysics Data System (ADS)

    Li, Long; Canters, Frank; Solana, Carmen; Ma, Weiwei; Chen, Longqian; Kervyn, Matthieu

    2015-08-01

    In this study, linear spectral mixture analysis (LSMA) is used to characterize the spectral heterogeneity of lava flows from Nyamuragira volcano, Democratic Republic of Congo, where vegetation and lava are the two main land covers. In order to estimate fractions of vegetation and lava through satellite remote sensing, we made use of 30 m resolution Landsat Enhanced Thematic Mapper Plus (ETM+) and Advanced Land Imager (ALI) imagery. 2 m Pleiades data was used for validation. From the results, we conclude that (1) LSMA is capable of characterizing volcanic fields and discriminating between different types of lava surfaces; (2) three lava endmembers can be identified as lava of old, intermediate and young age, corresponding to different stages in lichen growth and chemical weathering; (3) a strong relationship is observed between vegetation fraction and lava age, where vegetation at Nyamuragira starts to significantly colonize lava flows ∼15 years after eruption and occupies over 50% of the lava surfaces ∼40 years after eruption. Our study demonstrates the capability of spectral unmixing to characterize lava surfaces and vegetation colonization over time, which is particularly useful for poorly known volcanoes or those not accessible for physical or political reasons.

  5. Rootless shield and perched lava pond collapses at Kīlauea Volcano, Hawai'i

    USGS Publications Warehouse

    Patrick, Matthew R.; Orr, Tim R.

    2012-01-01

    Effusion rate is a primary measurement used to judge the expected advance rate, length, and hazard potential of lava flows. At basaltic volcanoes, the rapid draining of lava stored in rootless shields and perched ponds can produce lava flows with much higher local effusion rates and advance velocities than would be expected based on the effusion rate at the vent. For several months in 2007–2008, lava stored in a series of perched ponds and rootless shields on Kīlauea Volcano, Hawai'i, was released episodically to produce fast-moving 'a'ā lava flows. Several of these lava flows approached Royal Gardens subdivision and threatened the safety of remaining residents. Using time-lapse image measurements, we show that the initial time-averaged discharge rate for one collapse-triggered lava flow was approximately eight times greater than the effusion rate at the vent. Though short-lived, the collapse-triggered 'a'ā lava flows had average advance rates approximately 45 times greater than that of the pāhoehoe flow field from which they were sourced. The high advance rates of the collapse-triggered lava flows demonstrates that recognition of lava accumulating in ponds and shields, which may be stored in a cryptic manner, is vital for accurately assessing short-term hazards at basaltic volcanoes.

  6. Erosion by flowing lava: Geochemical evidence in the Cave Basalt, Mount St. Helens, Washington

    USGS Publications Warehouse

    Williams, D.A.; Kadel, S.D.; Greeley, R.; Lesher, C.M.; Clynne, M.A.

    2004-01-01

    We sampled basaltic lava flows and underlying dacitic tuff deposits in or near lava tubes of the Cave Basalt, Mount St. Helens, Washington to determine whether the Cave Basalt lavas contain geochemical evidence of substrate contamination by lava erosion. The samples were analyzed using a combination of wavelength-dispersive X-ray fluorescence spectrometry and inductively-coupled plasma mass spectrometry. The results indicate that the oldest, outer lava tube linings in direct contact with the dacitic substrate are contaminated, whereas the younger, inner lava tube linings are uncontaminated and apparently either more evolved or enriched in residual liquid. The most heavily contaminated lavas occur closer to the vent and in steeper parts of the tube system, and the amount of contamination decreases with increasing distance downstream. These results suggest that erosion by lava and contamination were limited to only the initially emplaced flows and that erosion was localized and enhanced by vigorous laminar flow over steeper slopes. After cooling, the initial Cave Basalt lava flows formed an insulating lining within the tubes that prevented further erosion by later flows. This interpretation is consistent with models of lava erosion that predict higher erosion rates closer to sources and over steeper slopes. A greater abundance of xenoliths and xenocrysts relative to xenomelts in hand samples indicates that mechanical erosion rather than thermal erosion was the dominant erosional process in the Cave Basalt, but further sampling and petrographic analyses must be performed to verify this hypothesis. ?? Springer-Verlag 2003.

  7. Lava flow hazard modeling during the 2014-2015 Fogo eruption, Cape Verde

    NASA Astrophysics Data System (ADS)

    Cappello, Annalisa; Ganci, Gaetana; Calvari, Sonia; Pérez, Nemesio M.; Hernández, Pedro A.; Silva, Sónia V.; Cabral, Jeremias; Del Negro, Ciro

    2016-04-01

    Satellite remote sensing techniques and lava flow forecasting models have been combined to enable a rapid response during effusive crises at poorly monitored volcanoes. Here we used the HOTSAT satellite thermal monitoring system and the MAGFLOW lava flow emplacement model to forecast lava flow hazards during the 2014-2015 Fogo eruption. In many ways this was one of the major effusive eruption crises of recent years, since the lava flows actually invaded populated areas. Combining satellite data and modeling allowed mapping of the probable evolution of lava flow fields while the eruption was ongoing and rapidly gaining as much relevant information as possible. HOTSAT was used to promptly analyze MODIS and SEVIRI data to output hot spot location, lava thermal flux, and effusion rate estimation. This output was used to drive the MAGFLOW simulations of lava flow paths and to continuously update flow simulations. We also show how Landsat 8 OLI and EO-1 ALI images complement the field observations for tracking the flow front position through time and adding considerable data on lava flow advancement to validate the results of numerical simulations. The integration of satellite data and modeling offers great promise in providing a unified and efficient system for global assessment and real-time response to effusive eruptions, including (i) the current state of the effusive activity, (ii) the probable evolution of the lava flow field, and (iii) the potential impact of lava flows.

  8. Disruption of tephra fall deposits caused by lava flows during basaltic eruptions

    NASA Astrophysics Data System (ADS)

    Brown, R. J.; Thordarson, T.; Self, S.; Blake, S.

    2015-10-01

    Observations in the USA, Iceland and Tenerife, Canary Islands reveal how processes occurring during basaltic eruptions can result in complex physical and stratigraphic relationships between lava and proximal tephra fall deposits around vents. Observations illustrate how basaltic lavas can disrupt, dissect (spatially and temporally) and alter sheet-form fall deposits. Complexity arises through synchronous and alternating effusive and explosive activity that results in intercalated lavas and tephra deposits. Tephra deposits can become disrupted into mounds and ridges by lateral and vertical displacement caused by movement (including inflation) of underlying pāhoehoe lavas and clastogenic lavas. Mounds of tephra can be rafted away over distances of 100 s to 1,000 s m from proximal pyroclastic constructs on top of lava flows. Draping of irregular topography by fall deposits and subsequent partial burial of topographic depressions by later lavas can result in apparent complexity of tephra layers. These processes, deduced from field relationships, have resulted in considerable stratigraphic complexity in the studied proximal regions where fallout was synchronous or alternated with inflation of subjacent lava sheets. These mechanisms may lead to diachronous contact relationships between fall deposits and lava flows. Such complexities may remain cryptic due to textural and geochemical quasi-homogeneity within sequences of interbedded basaltic fall deposits and lavas. The net effect of these processes may be to reduce the usefulness of data collected from proximal fall deposits for reconstructing basaltic eruption dynamics.

  9. Origin and deformation of high porosity bands in the Takanoobane Rhyolite lava of Aso volcano, Japan

    NASA Astrophysics Data System (ADS)

    Furukawa, K.; Uno, K.

    2015-10-01

    In rhyolite lavas, the high porosity bands are often developed. They potentially act as pathways for gas movement to the lava surface. Since explosive activities of lavas are generally considered to be controlled by degassing system, understanding the origin and deformation process of the high porosity bands is important to assessing volcanic hazards. The Takanoobane rhyolite lava in the middle of Kyushu Island in SW Japan is effused at 51 ± 5 ka. The volume, flow length, and thickness are 0.14 km3, > 2 km, and about 90 m, respectively. The central crystalline part of the lava is characterized by the light-colored bands defined by the high porosity zone (HPZ). On the basis of geological and petrographical studies, we revealed that the HPZ was primary formed by ductile-brittle tearing of the lava (known as cavitation). According to the AMS results, the HPZs were subsequently stretched and flattened laterally during the concentric spreading of the lava. This deformation process could stretch the HPZ not only radially but also laterally. This effective stretching developed the HPZ into pervasive thin bands. Since the HPZs act as degassing pathways to the lava surface, the pervasive HPZ bands may play a role in providing volcanic gasses to void spaces created in surface fold hinges of rhyolite lavas. Thus, this degassing system may promote explosive activity of the lava surface.

  10. Composition and isotopic constraints on the petrogenesis of alkaline arc lavas: Lihir Island, Papua New Guinea

    SciTech Connect

    Kennedy, A.K.; Hart, S.R.; Frey, F.A. )

    1990-05-10

    The SiO{sub 2}-undersaturated lavas from Lihir island, Papua New Guinea, like most arc lavas are highly enriched in Sr, Ba, K, Rb, and Cc and depleted in Hf, Ta, Nb, and Ti relative to ocean floor basalts and oceanic island basalts. These alkali-rich lavas have arc trace element signatures and Nd, Sr, and Pb isotopic systematics. However, they are not a product of present-day subduction, as this volcanism has tapped mantle which was enriched by prior subduction episodes. The narrow range of Pb isotopic compositions suggest a cogenetic origin for these lavas. During the fractionation of the primitive Lihir lavas, elements normally considered incompatible (i.e., the light rare earth elements (LREE), Rb, Th, and P) have high bulk solid/melt partition coefficients (0.15-1.5). Relatively higher partition coefficients during formation of the evolved lavas produced crossing rare earth element (REE) patterns, and primitive lavas have higher incompatible elements abundances than evolved lavas. The Lihir lavas have lower alkali, Sr, Ba, K, Rb, Cs, and LREE abundances than other Tabar-Feni lavas. They are derived from a less enriched mantle source rather than by a higher degree of melting of a source similar to that of the other islands. The similarity of Sm/Nd ratios of these undersaturated arc lavas to those of tholeiitic and calc-alkaline arc lavas and the moderate chondrite-normalized La/Yb (la/Yb{sub cn} = 3-7) indicates that there has been limited enrichment of the LREE relative to the heavy REE during generation of the arc-modified source mantle. The alkaline nature of these lavas reflects their generation, in a tensional tectonic environment, from a fossil arc mantle region that has undergone extreme arc enrichment of alkali and alkaline earth elements during two earlier subduction episodes.

  11. Constraints on Determining the Eruption Style and Composition of Terrestrial Lavas from Space

    NASA Technical Reports Server (NTRS)

    Wright, Robert; Glaze, Lori; Baloga, Stephen M.

    2011-01-01

    The surface temperatures of active lavas relate to cooling rates, chemistry, and eruption style. We analyzed 61 hyperspectral satellite images acquired by the National Aeronautics and Space Administration s Earth Observing-1 (EO-1) Hyperion imaging spectrometer to document the surface temperature distributions of active lavas erupted at 13 volcanoes. Images were selected to encompass the range of common lava eruption styles, specifically, lava fountains, flows, lakes, and domes. Our results reveal temperature distributions for terrestrial lavas that correlate with composition (i.e., a statistically significant difference in the highest temperatures retrieved for mafic lavas and intermediate and felsic lavas) and eruption style. Maximum temperatures observed for mafi c lavas are approx.200 C higher than for intermediate and felsic lavas. All eruption styles exhibit a low-temperature mode at approx.300 C; lava fountains and 'a' a flows also exhibit a higher-temperature mode at approx.700 C. The observed differences between the temperatures are consistent with the contrasting rates at which the lava surfaces are thermally renewed. Eruption styles that allow persistent and pervasive thermal renewal of the lava surface (e.g., fractured crusts on channel-fed 'a' a flows) exhibit a bimodal temperature distribution; eruption styles that do not (e.g., the continuous skin of pahoehoe lavas) exhibit a single mode. We conclude that insights into composition and eruption style can only be gained remotely by analyzing a large spatio-temporal sample of data. This has implications for determining composition and eruption style at the Jovian moon Io, for which no in situ validation is available.

  12. Lava flow hazard at Fogo Volcano, Cabo Verde, before and after the 2014-2015 eruption

    NASA Astrophysics Data System (ADS)

    Richter, Nicole; Favalli, Massimiliano; de Zeeuw-van Dalfsen, Elske; Fornaciai, Alessandro; da Silva Fernandes, Rui Manuel; Pérez, Nemesio M.; Levy, Judith; Silva Victória, Sónia; Walter, Thomas R.

    2016-08-01

    Lava flow simulations help to better understand volcanic hazards and may assist emergency preparedness at active volcanoes. We demonstrate that at Fogo Volcano, Cabo Verde, such simulations can explain the 2014-2015 lava flow crisis and therefore provide a valuable base to better prepare for the next inevitable eruption. We conducted topographic mapping in the field and a satellite-based remote sensing analysis. We produced the first topographic model of the 2014-2015 lava flow from combined terrestrial laser scanner (TLS) and photogrammetric data. This high-resolution topographic information facilitates lava flow volume estimates of 43.7 ± 5.2 × 106 m3 from the vertical difference between pre- and posteruptive topographies. Both the pre-eruptive and updated digital elevation models (DEMs) serve as the fundamental input data for lava flow simulations using the well-established DOWNFLOW algorithm. Based on thousands of simulations, we assess the lava flow hazard before and after the 2014-2015 eruption. We find that, although the lava flow hazard has changed significantly, it remains high at the locations of two villages that were destroyed during this eruption. This result is of particular importance as villagers have already started to rebuild the settlements. We also analysed satellite radar imagery acquired by the German TerraSAR-X (TSX) satellite to map lava flow emplacement over time. We obtain the lava flow boundaries every 6 to 11 days during the eruption, which assists the interpretation and evaluation of the lava flow model performance. Our results highlight the fact that lava flow hazards change as a result of modifications of the local topography due to lava flow emplacement. This implies the need for up-to-date topographic information in order to assess lava flow hazards. We also emphasize that areas that were once overrun by lava flows are not necessarily safer, even if local lava flow thicknesses exceed the average

  13. Subsurface architecture of Las Bombas volcano circular structure (Southern Mendoza, Argentina) from geophysical studies

    NASA Astrophysics Data System (ADS)

    Prezzi, Claudia; Risso, Corina; Orgeira, María Julia; Nullo, Francisco; Sigismondi, Mario E.; Margonari, Liliana

    2017-08-01

    The Plio-Pleistocene Llancanelo volcanic field is located in the south-eastern region of the province of Mendoza, Argentina. This wide back-arc lava plateau, with hundreds of monogenetic pyroclastic cones, covers a large area behind the active Andean volcanic arc. Here we focus on the northern Llancanelo volcanic field, particularly in Las Bombas volcano. Las Bombas volcano is an eroded, but still recognizable, scoria cone located in a circular depression surrounded by a basaltic lava flow, suggesting that Las Bombas volcano was there when the lava flow field formed and, therefore, the lava flow engulfed it completely. While this explanation seems reasonable, the common presence of similar landforms in this part of the field justifies the need to establish correctly the stratigraphic relationship between lava flow fields and these circular depressions. The main purpose of this research is to investigate Las Bombas volcano 3D subsurface architecture by means of geophysical methods. We carried out a paleomagnetic study and detailed topographic, magnetic and gravimetric land surveys. Magnetic anomalies of normal and reverse polarity and paleomagnetic results point to the occurrence of two different volcanic episodes. A circular low Bouguer anomaly was detected beneath Las Bombas scoria cone indicating the existence of a mass deficit. A 3D forward gravity model was constructed, which suggests that the mass deficit would be related to the presence of fracture zones below Las Bombas volcano cone, due to sudden degassing of younger magma beneath it, or to a single phreatomagmatic explosion. Our results provide new and detailed information about Las Bombas volcano subsurface architecture.

  14. A meta-analysis of aneurysm formation in laser assisted vascular anastomosis (LAVA)

    NASA Astrophysics Data System (ADS)

    Chen, Chen; Peng, Fei; Xu, Dahai; Cheng, Qinghua

    2009-08-01

    Laser assisted vascular anastomosis (LAVA) is looked as a particularly promising non-suture method in future. However, aneurysm formation is one of the main reasons delay the clinical application of LAVA. Some scientists investigated the incidence of aneurysms in animal model. To systematically analyze the literature on reported incidence of aneurysm formation in LAVA therapy, we performed a meta-analysis comparing LAVA with conventional suture anastomosis (CSA) in animal model. Data were systematically retrieved and selected from PUBMED. In total, 23 studies were retrieved. 18 studies were excluded, and 5 studies involving 647 animals were included. Analysis suggested no statistically significant difference between LAVA and CSA (OR 1.24, 95%CI 0.66-2.32, P=0.51). Result of meta analysis shows that the technology of LAVA is very close to clinical application.

  15. The role of lava erosion in the formation of lunar rilles and Martian channels

    USGS Publications Warehouse

    Carr, M.H.

    1974-01-01

    Lava tubes and channels develop around active sources of low viscosity lava. The channels normally form without erosion; however, sustained flow can result in the incision of a lava channel and simulation of fluvial erosion features. Lava erosion by means of thermal incision was modelled by computer, erosion rates calculated, and these compared with rates observed terrestrially. Lunar sinuous rilles are examined in light of the proposed lava erosion. The mechanism explains many features of lunar rilles that were heretofore puzzling and implies erosion rates comparable to terrestrial rates. Many Mars channels also appear to form by the action of lava; however, the larger, more spectacular Mars channels do not appear to have been formed by the same process. ?? 1974.

  16. Controls on lava lake level at Halema`uma`u Crater, Kilauea Volcano

    NASA Astrophysics Data System (ADS)

    Patrick, M. R.; Orr, T. R.

    2013-12-01

    Lava level is a fundamental measure of lava lake activity, but very little continuous long-term data exist worldwide to explore this aspect of lava lake behavior. The ongoing summit eruption at Kilauea Volcano began in 2008 and is characterized by an active lava lake within the eruptive vent. Lava level has been measured nearly continuously at Kilauea for several years using a combination of webcam images, laser rangefinder, and terrestrial LIDAR. Fluctuations in lava level have been a common aspect of the eruption and occur over several timescales. At the shortest timescale, the lava lake level can change over seconds to hours owing to two observed shallow gas-related processes. First, gas pistoning is common and is driven by episodic gas accumulation and release from the surface of the lava lake, causing the lava level to rise and fall by up to 20 m. Second, rockfalls into the lake trigger abrupt gas release, and lava level may drop as much as 10 m as a result. Over days, cyclic changes in lava level closely track cycles of deflation-inflation (DI) deformation events at the summit, leading to level changes up to 50 m. Rift zone intrusions have caused large (up to 140 m) drops in lava level over several days. On the timescale of weeks to months, the lava level follows the long-term inflation and deflation of the summit region, resulting in level changes up to 140 m. The remarkable correlation between lava level and deflation-inflation cycles, as well as the long-term deformation of the summit region, indicates that the lava lake acts as a reliable 'piezometer' (a measure of liquid pressure in the magma plumbing system); therefore, assessments of summit pressurization (and rift zone eruption potential) can now be carried out with the naked eye. The summit lava lake level is closely mirrored by the lava level within Pu`u `O`o crater, the vent area for the 30-year-long eruption on Kilauea's east rift zone, which is 20 km downrift of the summit. The coupling of these

  17. Gusev Rocks Solidified from Lava (Approximate True Color)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    In recent weeks, as NASA's Mars Exploration Rover Spirit has driven through the basin south of 'Husband Hill,' it has been traversing mainly sand and dune deposits. This week, though, Spirit has been maneuvering along the edge of an arc-shaped feature called 'Lorre Ridge' and has encountered some spectacular examples of basaltic rocks with striking textures. This panoramic camera (Pancam) image shows a group of boulders informally named 'FuYi.' These basaltic rocks were formed by volcanic processes and may be a primary constituent of Lorre Ridge and other interesting landforms in the basin.

    Spirit first encountered basalts at its landing site two years ago, on a vast plain covered with solidified lava that appeared to have flowed across Gusev Crater. Later, basaltic rocks became rare as Spirit climbed Husband Hill. The basaltic rocks that Spirit is now seeing are interesting because they exhibit many small holes or vesicles, similar to some kinds of volcanic rocks on Earth. Vesicular rocks form when gas bubbles are trapped in lava flows and the rock solidifies around the bubbles. When the gas escapes, it leaves holes in the rock. The quantity of gas bubbles in rocks on Husband Hill varies considerably; some rocks have none and some, such as several here at FuYi, are downright frothy.

    The change in textures and the location of the basalts may be signs that Spirit is driving along the edge of a lava flow. This lava may be the same as the basalt blanketing the plains of Spirit's landing site, or it may be different. The large size and frothy nature of the boulders around Lorre Ridge might indicate that eruptions once took place at the edge of the lava flow, where the lava interacted with the rocks of the basin floor. Scientists hope to learn more as Spirit continues to investigate these rocks.

    As Earth approaches the Chinese New Year (The Year of the Dog), the Athena science team decided to use nicknames representing Chinese culture and geography

  18. Thermal anomaly at the Earth's surface associated with a lava tube

    NASA Astrophysics Data System (ADS)

    Piombo, Antonello; Di Bari, Marco; Tallarico, Andrea; Dragoni, Michele

    2016-10-01

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

  19. Coastal lava flows from Mauna Loa and Hualalai volcanoes, Kona, Hawaii

    USGS Publications Warehouse

    Moore, J.G.; Clague, D.

    1987-01-01

    A major carbonate reef which drowned 13 ka is now submerged 150 m below sea level on the west coast of the island of Hawaii. A 25-km span of this reef was investigated using the submersible Makali'i. The reef occurs on the flanks of two active volcanoes, Mauna Loa and Hualalai, and the lavas from both volcanoes both underlie and overlie the submerged reef. Most of the basaltic lava flows that crossed the reef did so when the water was much shallower, and when they had to flow a shorter distance from shoreline to reef face. Lava flows on top of the reef have protected it from erosion and solution and now occur at seaward-projecting salients on the reef face. These relations suggest that the reef has retreated shoreward as much as 50 m since it formed. A 7-km-wide "shadow zone" occurs where no Hualalai lava flows cross the reef south of Kailua. These lava flows were probably diverted around a large summit cone complex. A similar "shadow zone" on the flank of Mauna Loa volcano in the Kealakekua Bay region is downslope from the present Mauna Loa caldera, which ponds Mauna Loa lava and prevents it from reaching the coastline. South of the Mauna Loa "shadow zone" the - 150 m reef has been totally covered and obscured by Mauna Loa lava. The boundary between Hualalai and Mauna Loa lava on land occurs over a 6-km-wide zone, whereas flows crossing the - 150 m reef show a sharper boundary offshore from the north side of the subaerial transition zone. This indicates that since the formation of the reef, Hualalai lava has migrated south, mantling Mauna Loa lava. More recently, Mauna Loa lava is again encroaching north on Hualalai lava. ?? 1987 Springer-Verlag.

  20. LAVA Simulations for the AIAA Sonic Boom Prediction Workshop

    NASA Technical Reports Server (NTRS)

    Housman, Jeffrey A.; Sozer, Emre; Moini-Yekta , Shayan; Kiris, Cetin C.

    2014-01-01

    Computational simulations using the Launch Ascent and Vehicle Aerodynamics (LAVA) framework are presented for the First AIAA Sonic Boom Prediction Workshop test cases. The framework is utilized with both structured overset and unstructured meshing approaches. The three workshop test cases include an axisymmetric body, a Delta Wing-Body model, and a complete low-boom supersonic transport concept. Solution sensitivity to mesh type and sizing, and several numerical convective flux discretization choices are presented and discussed. Favorable comparison between the computational simulations and experimental data of nearand mid-field pressure signatures were obtained.

  1. Quenching and disruption of lunar KREEP lava flows by impacts

    NASA Technical Reports Server (NTRS)

    Ryder, Graham

    1988-01-01

    The results of a reexamination of petrography of the Apollo 15 KREEP basalts are reported. Several of the basalts contain yellow residual glasses which cross-cut the crystallized phases; some show more extreme disruption. The features of the glasses appear to be compatible only with impact disruption, ejection, and quenching from actively crystallizing flows, indicating a high impact flux immediately after the impact that formed the Imbrium basin. No other example of impacts into active lava flows is known in the solar system.

  2. NVP melt/magma viscosity: insight on Mercury lava flows

    NASA Astrophysics Data System (ADS)

    Rossi, Stefano; Morgavi, Daniele; Namur, Olivier; Vetere, Francesco; Perugini, Diego; Mancinelli, Paolo; Pauselli, Cristina

    2016-04-01

    After more than four years of orbiting Mercury, NASA's MESSENGER spacecraft came to an end in late April 2015. MESSENGER has provided many new and surprising results. This session will again highlight the latest results on Mercury based on MESSENGER observations or updated modelling. The session will further address instrument calibration and science performance both retrospective on MESSENGER and on the ESA/JAXA BepiColombo mission. Papers covering additional themes related to Mercury are also welcomed. Please be aware that this session will be held as a PICO session. This will allow an intensive exchange of expertise and experience between the individual instruments and mission. NVP melt/magma viscosity: insight on Mercury lava flows S. Rossi1, D. Morgavi1, O. Namur2, D. Perugini1, F.Vetere1, P. Mancinelli1 and C. Pauselli1 1 Dipartimento di Fisica e Geologia, Università di Perugia, piazza Università 1, 06123 Perugia, Italy 2 Uni Hannover Institut für Mineralogie, Leibniz Universität Hannover, Callinstraβe 3, 30167 Hannover, Germany In this contribution we report new measurements of viscosity of synthetic komatitic melts, used the behaviour of silicate melts erupted at the surface of Mercury. Composition of Mercurian surface magmas was calculated using the most recent maps produced from MESSENGER XRS data (Weider et al., 2015). We focused on the northern hemisphere (Northern Volcanic Province, NVP, the largest lava flow on Mercury and possibly in the Solar System) for which the spatial resolution of MESSENGER measurements is high and individual maps of Mg/Si, Ca/Si, Al/Si and S/Si were combined. The experimental starting material contains high Na2O content (≈7 wt.%) that strongly influences viscosity. High temperature viscosity measurements were carried out at 1 atm using a concentric cylinder apparatus equipped with an Anton Paar RheolabQC viscometer head at the Department of Physics and Geology (PVRG_lab) at the University of Perugia (Perugia, Italy

  3. A model for the evolution of opaques in mare lavas

    NASA Technical Reports Server (NTRS)

    Haselton, J. D.; Nash, W. P.

    1975-01-01

    The apparent 'reduced' state of the opaque mineral assemblages of mare basalts has led to various hypotheses on their origin through reduction by various media. A model is developed whereby the presence of trivalent titanium (Ti/3+/) and metallic iron in mare lavas at low oxygen fugacities automatically leads to the production of the observed assemblages by cooling near the mare basalt solidus. The 'reduced' assemblages may evolve isochemically at oxygen fugacities near the iron-ilmenite-ferropseudobrookite buffer by a reaction of the form Fe(2+)+2 Ti(3+) = metallic iron +2 Ti(4+).

  4. The transition of spatter to lava-like body in lava fountain deposits: features and examples from the Cabezo Segura volcano (Calatrava, Spain)

    NASA Astrophysics Data System (ADS)

    Carracedo Sánchez, M.; Sarrionandia, F.; Arostegui, J.; Eguiluz, L.; Gil Ibarguchi, J. I.

    2012-05-01

    The Cabezo Segura II volcanic cone (Calatrava volcanic province, Iberian microplate) comprises proximal wall deposits with a well defined crater wall unconformity and crater-fill deposits. The complex volcanic succession, that shows evidence of several eruptive episodes, was built by magmatic and hydrovolcanic explosions of different styles (Strombolian, Hawaiian, sub-Plinian and phreato-Strombolian) generated from a multiple feeder ultrabasic dyke. Intra-crater rock units at the volcano summit include spatter deposits together with up to 10 m thick and more than 200 m long lava-like bodies. Geological logs for the main lava-like bodies define a characteristic facies model that involves a central lava-like mass which grades vertically into a transition zone of apparently coherent spatter, then dense spatter and, finally, into vuggy spatter deposits. These units are inferred to have formed during pulsating lava fountain-type explosive eruptions; the depicted facies distribution being the result of progressive increase in welding grade and densification of the spatter in response to variations in the accumulation rate. Their field features may be used as a guide for the precise identification of vent sites in deposits of Hawaiian eruptions. Also, structures like those here recognised, that might have survived in lava-like flows, could be of help to identify when lava-producing eruptions represented an explosive Hawaiian event (lava fountains) and not a purely effusive event.

  5. 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.

  6. 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.

  7. Low sulfur content in submarine lavas: An unreliable indicator of subaerial eruption

    SciTech Connect

    Davis, A.S.; Clague, D.A.; Schulz, M.S.; Hein, J.R. )

    1991-07-01

    Low S content (< 250 ppm) has been used to identify subaerially erupted Hawaiian and Icelandic lavas. Large differences in S content of submarine-erupted lavas from different tectonic settings indicate that the behavior of S is complex. Variations is S abundance in undegassed, submarine-erupted lavas can result from different source compositions, different percentages of partial melting, and crystal fractionation. Low S concentrations in highly vesicular submarine lavas suggest that partial degassing can occur despite great hydrostatic pressure. These processes need to be evaluated before using S content as an indicator of eruption depth.

  8. Thermal and Dynamic Properties of Volcanic Lava Inferred from Measurements on its Surface

    NASA Astrophysics Data System (ADS)

    Ismail-Zadeh, A.; Korotkii, A.; Kovtunov, D.; Tsepelev, I.; Melnik, O. E.

    2015-12-01

    Modern remote sensing technologies allow for detecting the absolute temperature at the surface of volcanic lava, and the heat flow could be then inferred from the Stefan-Boltzmann law. Is it possible to use these surface thermal data to constrain the thermal and dynamic conditions inside the lava? We propose a quantitative approach to reconstruct temperature and velocity in the steady-state volcanic lava flow from thermal observations at its surface. This problem is reduced to a combination of the direct and inverse problems of mass- and heat transport. Namely, using known conditions at the lava surface we determine the missing condition at the bottom of lava (the inverse problem) and then search for the physical properties of lava - temperature and flow velocity - inside the lava (the direct problem). Assuming that the lava rheology and the thermal conductivity are temperature-dependent, we determine the flow characteristics in the model domain using an adjoint method. We show that in the case of smooth input data (observations) the lava temperature and the flow velocity can be reconstructed with a high accuracy. The noise imposed on the smooth input data results in a less accurate solution, but still acceptable below some noise level.

  9. A preliminary thermal budget for lava tubes on the Earth and planets

    NASA Astrophysics Data System (ADS)

    Keszthelyi, Laszlo

    1995-10-01

    Lava tubes are a very common and important feature in mafic lava flows. The insulation provided by lava tubes allows molten lava to travel large distances from the vent with little cooling. This paper presentes the first attempt to quantify the processes that control this cooling. The resulting thermal budget balances heat loss by (1) conduction, (2) convection of air in the wall rocks, (3) vaporization of rainwater, and (4) radiation out of skylights against (1) viscous dissipation, (2) latent heat released during crystallization, and (3) the cooling of the lava. When applied to the Waha'ula tube on Kilauea Volcano, Hawaii, this thermal budget reproduces the observed ~1°C/km cooling of the lava inside the active tube. The thermal budget is also used to compare the insulating ability of hypothetical lava tubes in a continental flood basalt setting, on the ocean floor, Venus, the Moon, and Mars. This analysis demonstrates the large effect of rainfall and atmospheric convection, the importance of the volumetric flux of lava through the tube, and the overwhelming importance of compositional (i.e., rheological) differences. This work suggests that basaltic tube-fed flows several hundred kilometers long can be produced by eruptions with effusion rates of only a few tens of cubic meters per second. Thus even the longest lava flows observed in our solar system could have been produced by low to moderate effusion rate eruptions, if they were tube-fed. .

  10. Observations of actively forming lava tubes and associated structures, Hawaii, part 2

    NASA Technical Reports Server (NTRS)

    Greeley, R.

    1971-01-01

    A ground examination is made of lave tubes and channels. The surface morphology and the changes noted through lava flow activity are cited, and compared to earlier aerial observations. The lava activity was believed to be caused by a small lava lake exposed by the collapse of a crust covering it. Drainage of the lake was caused by a fissure erruption. New tubes or extensions of existing ones were noted from the flow. Molten lava was not seen in any tubes examined on the ground, but some of the flows were not sufficiently cooled to allow subsurface examination and survey of the tubes.

  11. Basalt models for the Mars penetrator mission: Geology of the Amboy Lava Field, California

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Bunch, T. E.

    1976-01-01

    Amboy lava field (San Bernardino County, California) is a Holocene basalt flow selected as a test site for potential Mars Penetrators. A discussion is presented of (1) the general relations of basalt flow features and textures to styles of eruptions on earth, (2) the types of basalt flows likely to be encountered on Mars and the rationale for selection of the Amboy lava field as a test site, (3) the general geology of the Amboy lava field, and (4) detailed descriptions of the target sites at Amboy lava field.

  12. Lava Flows, Rivers, and Lakes: Complex Interactions Along the McKenzie River, Central Oregon

    NASA Astrophysics Data System (ADS)

    Deligne, N. I.; Cashman, K. V.; Grant, G. E.

    2008-12-01

    There are few studies of lava - surface water interactions, undoubtedly because most contemporary research on lava flows has been carried out in places with little surface water (e.g., Hawaii and Mt Etna). However, as described by a written account of the 1783 Laki eruption in Iceland, this interaction can be quite dynamic and dramatic: lava flows can disrupt water sources and rivers, simultaneously causing water shortages downstream and severe flooding upstream. In the Cascade volcanic range there are numerous examples of pre-historic Holocene lava - surface water interaction. For example, multiple lava flows have entered the McKenzie River, which occupies the western margin of High Cascades graben. Clear Lake, at the head of the McKenzie River, formed when lava flows from the Sand Mountain chain entered the ancestral McKenzie River and dammed it; dated drowned trees preserved on the lake bottom suggest that damming occurred c. 3000 years ago. While the modern forest masks the location and extent of the damming lava flow, principle components analysis of Landsat imagery helps to define flow boundaries and areal extent. This extensive flow is at least 54 meters thick and flowed west until it encountered the graben wall, at which point it flowed south, burying and damming the ancestral McKenzie River. The river currently overtops the lava dam and travels south along the graben wall. Poorly vegetated flows enter Clear Lake on its eastern margin; while early workers mapped two separate flow units around Clear Lake with younger flows distinguished by their lack of vegetation, recent workers have mapped all flows bordering Clear Lake as part of the same complex. We agree with earlier interpretations and additionally use bathymetric studies to show that the lake prematurely stopped the advance of these younger lava flows. Further downstream, flows from Belknap volcano entered the McKenzie River approximately 1500 years after the formation of Clear Lake. While these flows

  13. The 1719 1721 eruptions of potassium-rich lavas at Wudalianchi, China

    NASA Astrophysics Data System (ADS)

    Feng, Maoseng; Whitford-Stark, J. L.

    1986-11-01

    Eruptions between 1719 and 1721 at Wudalianchi produced two monogenetic strombolian cones Laoheishan and Huoshaoshan and the 65 km 2 Shilong lava field. The lavas are unusual in that they are leucite-bearing and lack modal plagioclase. Together with the earlier cones, the historic cones form an orthogonal network with a 4-km average separation. Differences in the morphology of the historic cones are attributed to differences in explosivity. The Shilong lava is predominantly pahoehoe (70%), of compound form, and similar to "plains-style" lavas. It is concluded that there is little possibility that an eruption will take place at Wudalianchi in the near future.

  14. Structures and facies associated with the flow of subaerial basaltic lava into a deep freshwater lake: The Sulphur Creek lava flow, North Cascades, Washington

    NASA Astrophysics Data System (ADS)

    Tucker, David S.; Scott, Kevin M.

    2009-09-01

    The ca. 8800 14C yrs BP Sulphur Creek lava flowed eastward 12 km from the Schriebers Meadow cinder cone into the Baker River valley, on the southeast flank of Mount Baker volcano. The compositionally-zoned basaltic to basaltic andesite lava entered, crossed and partially filled the 2-km-wide and > 100-m-deep early Holocene remnant of Glacial Lake Baker. The valley is now submerged beneath a reservoir, but seasonal drawdown permits study of the distal entrant lava. As a lava volume that may have been as much as 180 × 10 6 m 3 entered the lake, the flow invaded the lacustrine sequence and extended to the opposite (east) side of the drowned Baker River valley. The volume and mobility of the lava can be attributed to a high flux rate, a prolonged eruption, or both. Basalt exposed below the former level of the remnant glacial lake is glassy or microcrystalline and sparsely vesicular, with pervasive hackly or blocky fractures. Together with pseudopillow fractures, these features reflect fracturing normal to penetrative thermal fronts and quenching by water. A fine-grained hyaloclastite facies was probably formed during quench fragmentation or isolated magma-water explosions. Although the structures closely resemble those developed in lava-ice contact environments, establishing the depositional environment for lava exhibiting similar intense fracturing should be confirmed by geologic evidence rather than by internal structure alone. The lava also invaded the lacustrine sequence, forming varieties of peperite, including sills that are conformable within the invaded strata and resemble volcaniclastic breccias. The peperite is generally fragmental and clast- or matrix-supported; fine-grained and rounded fluidal margins occur locally. The lava formed a thickened subaqueous plug that, as the lake drained in the mid-Holocene, was exposed to erosion. The Baker River then cut a 52-m-deep gorge through the shattered, highly erodible basalt.

  15. Mapping Exposed and Buried Lava Flows Using Synthetic Aperture and Ground-Penetrating Radar in Craters of the Moon Lava Field

    NASA Astrophysics Data System (ADS)

    Khan, S. D.; Heggy, E.; Fernandez, J.

    2007-10-01

    The Craters of the Moon (COM) lava field in central Idaho has a multiple eruptive history. Burial of older flows by younger eruptive events has resulted in complex surface geomorphology and subsurface stratigraphy. For the older eruptive periods, the locations of source vents and the extension of lava flows are either speculative or unknown, as they are buried under earlier pyroclastistics. In this study, we used surface and subsurface backscatter characteristics of the P- and L-band polarimetric Airborne Synthetic Aperture Radar (AIRSAR) data and Ground-Penetrating Radar (GPR) soundings to resolve different exposed and buried lava flows. Our primary objective is to define the most effective polarization and frequency for mapping, resolving, and characterizing different lava types in the volcanic field. Polarimetric analysis of AIRSAR images from COM allows a clear recognition of the aa' and pahoehoe lava types as a result of the variability in their roughness. Our results suggest that the HV cross-polarized, AIRSAR L band is capable of producing a detailed map delineating surface lava with different surface backscattering properties. An accuracy assessment utilizing the geological map of the Inferno Cone area and in situ observations showed a significant reliability of differentiating lava types and mapping the lava flows extension below loose pyroclastics using AIRSAR data. The P-band, results suggest a constrained ability for mapping buried structures up to 3 meters deep under loose and dry cinder and ash deposits, resolving buried fissures, outcrops, and lava flows that were validated with ground-truth GPR surveys. Investigating subsurface stratigraphy with remote sensing and GPR techniques can be applied in other arid locations on Earth and other planets. Analyzing the radar backscattering penetration depth at higher frequencies is valuable for future planetary subsurface exploration missions for telluric planets.

  16. Mapping exposed and buried lava flows using synthetic aperture and ground-penetrating radar in Craters of the Moon lava field

    NASA Astrophysics Data System (ADS)

    Khan, Shuhab D.; Heggy, Essam; Fernandez, Jaime

    2007-11-01

    The Craters of the Moon (COM) lava field has a multiple eruptive history. Burial of older flows has resulted in complex subsurface stratigraphy. For the older eruptive periods, the locations of source vents and the extension of lava flows are either speculative or unknown, because they are buried under more recent pyroclastics. In this study, we used surface and subsurface backscatter characteristics of the P- and L-band polarimetric airborne synthetic aperture radar (AIRSAR) data and ground-penetrating radar (GPR) soundings to resolve different exposed and buried lava flows. Our primary objective is to define the most effective polarization and frequency for mapping, resolving, and characterizing different lava types in the volcanic field. Polarimetric analysis of AIRSAR images from COM allows a clear recognition of the aa and pahoehoe lava types as a result of the variability in their roughness. Our results suggest that the HV cross-polarized, AIRSAR L-band is capable of producing a detailed map delineating surface lava with different surface backscattering properties. An accuracy assessment utilizing the geological map of the Inferno Cone area was performed to quantify the reliability of differentiating lava types and mapping the lava flows extension below loose pyroclastics using AIRSAR data. Results shows an ability of P-band SAR to map buried structures up to 3 meters deep under loose cinder and ash deposits, resolving buried fissures, outcrops, and lava flows that were validated with ground-truth GPR surveys. The techniques used in this study provide a tool to assess volcanic hazards in remote and inaccessible places. Also it could be an aid in the study of other planets and planetary bodies in the solar system.

  17. Late Holocene lava flow morphotypes of northern Harrat Rahat, Kingdom of Saudi Arabia: Implications for the description of continental lava fields

    NASA Astrophysics Data System (ADS)

    Murcia, H.; Németh, K.; Moufti, M. R.; Lindsay, J. M.; El-Masry, N.; Cronin, S. J.; Qaddah, A.; Smith, I. E. M.

    2014-04-01

    A "lava morphotype" refers to the recognizable and distinctive characteristics of the surface morphology of a lava flow after solidification, used in a similar way to a sedimentary facies. This classification method is explored on an example volcanic field in the Kingdom of Saudi Arabia, where copious lava outpourings may represent an important transition between monogenetic and flood basalt fields. Here, young and well-preserved mafic lava fields display a wide range of surface morphologies. We focussed on four post-4500 yrs. BP lava flow fields in northern Harrat Rahat (<10 Ma) and propose a framework for describing systematic changes in morphotypes down-flow. The morphotypes give insight into intrinsic and extrinsic parameters of emplacement, rheology and dominant flow behavior, as well as the occurrence and character of other lava structures. The Harrat Rahat lava flow fields studied extend up to 23 km from the source, and vary between 1-2 m and 12 m in thickness. Areas of the lava flow fields are between ˜32 and ˜61 km2, with individual flow field volumes estimated between ˜0.085 and ˜0.29 km3. They exhibit Shelly-, Slabby-, and Rubbly-pahoehoe, Platy-, Cauliflower-, and Rubbly-a'a, and Blocky morphotypes. Morphotypes reflect the intrinsic parameters of: composition, temperature, crystallinity and volatile-content/vesicularity; along with external influences, such as: emission mechanism, effusion rate, topography and slope control of flow velocity. One morphotype can transition to another in individual flow-units or lobes and they may dominate zones. Not all morphotypes were found in a single lava flow field. Pahoehoe morphotypes are related to the simple mechanical disaggregation of the crust, whereas a'a morphotypes are related to the transitional emergence and subsequent transitional disappearance of clinker. Blocky morphotypes result from fracturing and auto-brecciation. A'a morphotypes (i.e. platy-, cauliflower-, rubbly-a'a) dominate the lava flow

  18. Post-emplacement cooling and contraction of lava flows: InSAR observations and thermal model for lava fields at Hekla volcano, Iceland

    NASA Astrophysics Data System (ADS)

    Wittmann, Werner; Dumont, Stephanie; Lavallee, Yan; Sigmundsson, Freysteinn

    2016-04-01

    Gradual post-emplacement subsidence of lava flows has been observed at various volcanoes, e.g. Okmok volcano in Alaska, Kilauea volcano on Hawaii and Etna volcano on Sicily. In Iceland, this effect has been observed at Krafla volcano and Hekla volcano. The latter was chosen as a case study for investigating subsidence mechanisms, specifically thermal contraction. Effects like gravitational loading, clast repacking or creeping of a hot and liquid core can contribute to subsidence of emplaced lava flows, but thermal contraction is considered being a crucial effect. The extent to which it contributes to lava flow subsidence is investigated by mapping the relative movement of emplaced lava flows and flow substrate, and modeling the observed signal. The slow vegetation in Iceland is advantageous for Interferometric Synthetic Aperture Radar (InSAR) and offers great coherence over long periods after lava emplacement, expanding beyond the outlines of lava flows. Due to this reason, InSAR observations over volcanoes in Iceland have taken place for more than 20 years. By combining InSAR tracks from ERS, Envisat and Cosmo-SkyMed satellites we gain six time series with a total of 99 interferograms. Making use of the high spatial resolution, a temporal trend of vertical lava movements was investigated over a course of over 23 years over the 1991 lava flow of Hekla volcano, Iceland. From these time series, temporal trends of accumulated subsidence and subsidence velocities were determined in line of sight of the satellites. However, the deformation signal of lava fields after emplacement is vertically dominated. Subsidence on this lava field is still ongoing and subsidence rates vary from 14.8 mm/year in 1995 to about 1.0 mm/year in 2014. Fitting a simple exponential function suggests a exponential decay constant of 5.95 years. Additionally, a one-dimensional, semi-analytical model was fitted to these data. While subsidence due to phase change is calculated analytically

  19. Oxygen isotope thermometry of basic lavas and mantle nodules

    USGS Publications Warehouse

    Kyser, T.K.; O'Neil, J.R.; Carmichael, I.S.E.

    1981-01-01

    Measurements have been made of the oxygen isotope and chemical composition of glass and phenocrysts in lavas and coexisting minerals in mantle nodules. Temperatures of formation of these assemblages have been estimated from various chemical thermometers and range from 855?? to 1,300?? C. The permil fractionations between coexisting orthopyroxene and clinopyroxene in the lavas and nodules are all near zero. The fractionations between pyroxene and olivine vary from +1.2 to -1.4 and are a smooth function of temperature over the entire range. This function is given by T(?? C)=1151-173?? (px-d)-68??2(px-d) and has an uncertainty of ??60?? (2??). At temperatures above 1,150?? C, olivine in the nodules becomes more18O-rich than coexisting clinopyroxene, orthopyroxene, and plagioclase. In combination with the experimental work of Muehlenbachs and Kushiro (1974), the olivine-pyroxene fractionations indicate that olivine also becomes substantially more18O-rich than basaltic liquids above 1,200?? C. Geothermometers based on the oxygen isotope equilibration of basaltic liquid with olivine, pyroxene, and plagioclase are presented. ?? 1981 Springer-Verlag.

  20. Absolute paleointensity from Hawaiian lavas younger than 35 ka

    USGS Publications Warehouse

    Valet, J.-P.; Tric, E.; Herrero-Bervera, E.; Meynadier, L.; Lockwood, J.P.

    1998-01-01

    Paleointensity studies have been conducted in air and in argon atmosphere on nine lava flows with radiocarbon ages distributed between 3.3 and 28.2 ka from the Mauna Loa volcano in the big island of Hawaii. Determinations of paleointensity obtained at eight sites depict the same overall pattern as the previous results for the same period in Hawaii, although the overall average field intensity appears to be lower. Since the present results were determined at higher temperatures than in the previous studies, this discrepancy raises questions regarding the selection of low versus high-temperature segments that are usually made for absolute paleointensity. The virtual dipole moments are similar to those displayed by the worldwide data set obtained from dated lava flows. When averaged within finite time intervals, the worldwide values match nicely the variations of the Sint-200 synthetic record of relative paleointensity and confirm the overall decrease of the dipole field intensity during most of this period. The convergence between the existing records at Hawaii and the rest of the world does not favour the presence of persistent strong non-dipole components beneath Hawaii for this period.

  1. Recovery of datable charcoal beneath young lavas: lessons from Hawaii.

    USGS Publications Warehouse

    Lockwood, J.P.; Lipman, P.W.

    1980-01-01

    Field studies in Hawaii aimed at providing a radiocarbon-based chronology of prehistoric eruptive activity have led to a good understanding of the processes that govern the formation and preservation of charcoal beneath basaltic lava flows. Charcoal formation is a rate-dependent process controlled primarily by temperature and duration of heating, as well as by moisture content, density, and size of original woody material. Charcoal will form wherever wood buried by lava is raised to sufficiently high temperatures, but owing to the availability of oxygen it is commonly burned to ash soon after formation. Wherever oxygen circulation is sufficiently restricted, charcoal will be preserved, but where atmospheric oxygen circulates freely, charcoal will only be preserved at a lower temperature, below that required for charcoal ignition or catalytic oxidation. These factors cause carbonized wood, especially that derived from living roots, to be commonly preserved beneath all parts of pahoehoe flows (where oxygen circulation is restricted), but only under margins of aa. Practical guidelines are given for the recovery of datable charcoal beneath pahoehoe and aa. Although based on Hawaiian basaltic flows, the guidelines should be applicable to other areas. -Authors

  2. Reequilibration of chromite within Kilauea Iki lava lake, Hawaii

    USGS Publications Warehouse

    Scowen, P.A.H.; Roeder, P.L.; Helz, R.T.

    1991-01-01

    Chromite mainly occurs as tiny inclusions within or at the edges of olivine phenocrysts in the 1959 Kilauea Iki lava lake. Liquilus chromite compositions are only preserved in scoria that was rapidly quenched from eruption temperatures. Analyses of drill core taken from the lava lake in 1960, 1961, 1975, 1979, and 1981 show that chromite becomes richer in Fe+2, Fe+3, Ti and poorer in Mg, Al, Cr than the liquidus chromite. The amount of compositional change depends on the time elapsed since eruption, the cooling history of the sample, the extent of differentiation of the interstitial melt, and the position of the chromite inclusion within the olivine phenocryst. Compositional changes of the chromite inclusions are thought to be a result of reequilibration with the residual melt by cationic diffusion (Mg, Al, Cr outwards and Fe+2, Fe+3, Ti inwards) through olivine. The changing chemical potential gradients produced as the residual melt cools, crystallizes and differentiates drives the reequilibration process. Major and minor element zoning profiles in olivine phenocrysts suggest that volume diffusion through olivine may have been the major mechanism of cationic transport through olivine. The dramatic compositional changes observed in chromite over the 22 years between eruption and 1981 has major implications for othe molten bodies. ?? 1991 Springer-Verlag.

  3. Lava and Snow on Klyuchevskaya Volcano [high res

    NASA Image and Video Library

    2017-09-28

    IDL TIFF file This false-color (shortwave infrared, near infrared, green) satellite image reveals an active lava flow on the western slopes of Klyuchevskaya Volcano. Klyuchevskaya is one of several active volcanoes on the Kamchatka Peninsula in far eastern Russia. The lava flow itself is bright red. Snow on Klyuchevskaya and nearby mountains is cyan, while bare ground and volcanic debris is gray or brown. Vegetation is green. The image was collected by Landsat 8 on September 9, 2013. NASA Earth Observatory image by Jesse Allen and Robert Simmon, using Instrument: Landsat 8 - OLI More info: 1.usa.gov/1evspH7 NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  4. Remagnetization of lava flows spanning the last geomagnetic reversal

    NASA Astrophysics Data System (ADS)

    Vella, Jérôme; Carlut, Julie; Valet, Jean-Pierre; Goff, Maxime Le; Soler, Vicente; Lopes, Fernando

    2017-08-01

    Large directional changes of remanent magnetization within lava flows that cooled during geomagnetic reversals have been reported in several studies. A geomagnetic scenario implies extremely rapid geomagnetic changes of several degrees per day, thus difficult to reconcile with the rate of the earth's core liquid motions. So far, no complete rock magnetic model provides a clear explanation. We revisited lava flows sandwiched between an underlying reverse and an overlying normal polarity flow marking the last reversal in three distinct volcanic sequences of the La Palma Island (Canary archipelago, Spain) that are characterized by a gradual evolution of the direction of their remanent magnetization from bottom to top. Cleaning efficiency of thermal demagnetization was not improved by very rapid heating and cooling rates as well as by continuous demagnetization using a Triaxe magnetometer. We did not observe partial self-reversals and minor changes in magnetic grain sizes are not related to the within-flow directional changes. Microscopic observations indicate poor exsolution, which suggests post-cooling thermochemical remagnetization processes. This scenario is strongly reinforced by laboratory experiments that show large resistance to thermal demagnetization when thermoremanence was acquired over a long time period. We speculate that in the present situation exsolution was reactivated during in field reheating and yielded formation of new magnetite, yet magnetic domain state rearrangements could also play a role. Initial reheating when the overlying flow took place, albeit moderate (less than 200-300 °C), was enough to produce overlying components with significantly higher unblocking temperatures.

  5. Volcanic eruptions on Io: Heat flow, resurfacing, and lava composition

    NASA Technical Reports Server (NTRS)

    Blaney, Diana L.; Johnson, Torrence V.; Matson, Dennis L.; Veeder, Glenn J.

    1995-01-01

    We model an infrared outburst on Io as being due to a large, erupting lava flow which increased its area at a rate of 1.5 x 10(exp 5)/sq m and cooled from 1225 to 555 K over the 2.583-hr period of observation. The inferred effusion rate of 3 x 10(exp 5) cu m/sec for this eruption is very high, but is not unprece- dented on the Earth and is similar to the high eruption rates suggested for early lunar volcanism. Eruptions occur approxi- mately 6% of the time on Io. These eruptions provide ample resurfacing to explain Io's lack of impact craters. We suggest that the large total radiometric heat flow, 10(exp 14) W, and the size and temperature distribution of the thermal anomalies (McEwen et al. 1992; Veeder et al. 1994) can be accounted for by a series of silicate lava flows in various stages of cooling. We propose that the whole suite of Io's currently observed thermal anomalies was produced by multiple, high-eruptive-rate silicate flows within the past century.

  6. Crystallization of tholeiitic basalt in Alae Lava Lake, Hawaii

    USGS Publications Warehouse

    Peck, D.L.; Wright, T.L.; Moore, J.G.

    1966-01-01

    The eruption of Kilauea Volcano August 21-23, 1963, left 600,000 cubic meters of basaltic lava in a lava lake as much as 15 meters deep in Alae pit crater. Field studies of the lake began August 27 and include repeated core drilling, measurements of temperature in the crust and melt, and precise level surveys of the lake surface. The last interstitial melt in the lake solidified late in September 1964; by mid August 1965 the maximum temperature was 690??C at a depth of 11.5 meters. Pumice air-quenched from about 1140??C contains only 5 percent crystals - clinopyroxene, cuhedral olivine (Fo 80), and a trace of plagioclase, (An 70). Drill cores taken from the zone of crystallization in the lake show that olivine continued crystallizing to about 1070??C; below that it reacts with the melt, becoming corroded and mantled by pyroxene and plagioclase. Below 1070??C, pyroxene and plagioclase crystallized at a constant ratio. Ilmenite first appeared at about 1070??C and was joined by magnetite at about 1050??C; both increased rapidly in abundance to 1000??C. Apatite first appeared as minute needles in interstitial glass at 1000??C. Both the abundance and index of refraction of glass quenched from melt decreased nearly linearly with falling temperature. At 1070??C the quenched lava contains about 65 percent dark-brown glass with an index of 1.61; at 980??C it contains about 8 percent colorless glass with an index of 1.49. Below 980??C, the percentage of glass remained constant. Progressive crystallization forced exsolution of gases from the melt fraction; these formed vesicles and angular pores, causing expansion of the crystallizing lava and lifting the surface of the central part of the lake an average of 19.5 cm. The solidified basalt underwent pneumatolitic alteration, including deposition of cristobalite at 800??C, reddish alteration of olivine at 700??C, tarnishing of ilmenite at 550??C, deposition of anhydrite at 250??C, and deposition of native sulfur at 100??C

  7. Interacting Convective Processes in Kilauea Iki Lava Lake, Hawaii

    NASA Astrophysics Data System (ADS)

    Helz, R. T.

    2007-12-01

    Kilauea Iki lava lake formed in 1959 as a closed magma chamber of 40 million m3 of picritic magma. Repeated drilling and sampling of the lake allows recognition of processes of magmatic differentiation, and places time restrictions on the periods when they operated. Two processes, double-diffusive convection and finger diapirism, occurred because melt density decreases as olivine crystallization and re-equilibration proceeds, until after plagioclase begins to crystallize. Finger diapirism, described in previous work, occurred from 1961 to 1971 and affected most the lava lake between depths of 13 to 94 m. The period of inferred double- diffusive convection occurred between mid-1962 and 1964 and affected only the most olivine-poor part of the lava lake. Recent re-evaluation of petrographic and chemical data refine our understanding of this second process. The overall variation of bulk MgO content with depth in Kilauea Iki is an S-curve, consistent with gravitative redistribution of the abundant olivine phenocrysts present in the erupted lava. The olivine-poor zone (MgO <11 weight percent) is a sill-like volume found between depths of 21 to 43 m in the lake. This zone is bisected by a median layer containing more and slightly coarser olivine phenocrysts, which has an MgO content 2 weight percent higher than the minimum in the layers above and below. This configuration, not achievable by gravitative settling, suggests that the olivine-poor zone at some point contained a two-layer convective system. The upper and median layers of the olivine-poor zone contain a sparse population of augite microphenocrysts (0.2-0.4 mm in length), often in monomineralic clusters (1-3 mm in length), while the lower layer contains only olivine. Plagioclase and other phases occur only in the groundmass in all samples. If the layers developed before groundmass crystallization began, then the assemblage in the upper layer was olivine + augite, and was olivine-only in the lower. Because melt

  8. Reconstruction of lava fields based on 3D and conventional images. Arenal volcano, Costa Rica.

    NASA Astrophysics Data System (ADS)

    Horvath, S.; Duarte, E.; Fernandez, E.

    2007-05-01

    Conventional air photographs, multi-spectral images and a map scale 1:10 000 were used to upgrade Arenal volcano's lava field. Arenal volcano located in NW Costa Rica has been active for 39 years. Fifty two days after the initial explosive events that opened three craters on the west flank, lava flows were erupted from crater A (1050 m) in September, 1968 and continued flowing until November, 1973. These lavas were the most voluminous of the eruption and the effusion rate of lava was relatively high in this period. In April, 1974 lava flows were erupted from crater C (1460 m) and continue to present time. Younger lava flows extended over uncovered ground to the south and southwest in the 1980s and early 1990s and onto the northern slopes in the 1990s and 2000s. Lava flows are becoming shorter and narrower with time. Therefore, the centre of mass of the whole lava flow-field has migrated closer to the vent. Above crater C a cone has been growing steadily, reaching a height of 1670 m, 36 m higher than the prehistoric Arenal cone by 2004. After 39 years of continuous emission of lava flows, the profile of Arenal volcano consists of a duplet of cones whose summits are separated by less than 500 meters. Most of the build up around the new cone comes from varied lava flows. For near 30 years volcano monitoring staff (from OVSICORI-UNA) has recorded field observations of regular and extraordinary events, in paper. Several drafts maps have been used for teaching, academic presentations and for graphic explanations to specific audiences and to the general public. An upgraded version was needed. The purpose of this work is to present the most recent lava flows giving a visual presentation of them by computer methods. Combined SIG techniques (Arc View 3.3) and ERDAS produced a base map in which layers containing the recorded lava flows from the recent 16 years, were depicted. Each lava flow has its own characteristics: direction, year of origin, width, length, surface texture

  9. Incorporation of seawater into mid-ocean ridge lava flows during emplacement

    USGS Publications Warehouse

    Soule, S.A.; Fornari, D.J.; Perfit, M.R.; Ridley, W.I.; Reed, M.H.; Cann, J.R.

    2006-01-01

    Evidence for the interaction between seawater and lava during emplacement on the deep seafloor can be observed in solidified flows at a variety of scales including rapid quenching of their outer crusts and the formation of lava pillars through the body of the flow. Recently, an additional interaction, incorporation of heated seawater (vapor) into the body of a flow, has been proposed. Large voids and vesicles beneath the surface crusts of mid-ocean ridge crest lobate and sheet lava flows and lava drips found within those cavities have been cited as evidence for this interaction. The voids resulting from this interaction contribute to the high porosity of the shallow ocean crust and play an important role in crustal permeability and hydrothermal circulation at mid-ocean ridges, and thus it is important to understand their origin. We analyze lava samples from the fast-spreading East Pacific Rise and intermediate-spreading Galapagos Spreading Center to characterize this process, identify the source of the vapor, and investigate the implications this would have on submarine lava flow dynamics. We find that lava samples that have interacted with a vapor have a zone of increased vesicularity on the underside of the lava crust and a coating of precipitate minerals (i.e., crystal fringe) that are distinct in form and composition from those crystallized from the melt. We use thermochemical modeling to simulate the reaction between the lava and a vapor and find that only with seawater can we reproduce the phase assemblage we observe within the crystal fringes present in the samples. Model results suggest that large-scale contamination of the lava by mass exchange with the vapor is unlikely, but we observe local enrichment of the lava in Cl resulting from the incorporation of a brine phase separated from the seawater. We suggest that high eruption rates are necessary for seawater incorporation to occur, but the mechanism by which seawater enters the flow has yet to be

  10. Owyhee River intracanyon lava flows: does the river give a dam?

    USGS Publications Warehouse

    Ely, Lisa L.; Brossy, Cooper C.; House, P. Kyle; Safran, Elizabeth B.; O'Connor, Jim E.; Champion, Duane E.; Fenton, Cassandra R.; Bondre, Ninad R.; Orem, Caitlin A.; Grant, Gordon E.; Henry, Christopher D.; Turrin, Brent D.

    2013-01-01

    Rivers carved into uplifted plateaus are commonly disrupted by discrete events from the surrounding landscape, such as lava flows or large mass movements. These disruptions are independent of slope, basin area, or channel discharge, and can dominate aspects of valley morphology and channel behavior for many kilometers. We document and assess the effects of one type of disruptive event, lava dams, on river valley morphology and incision rates at a variety of time scales, using examples from the Owyhee River in southeastern Oregon. Six sets of basaltic lava flows entered and dammed the river canyon during two periods in the late Cenozoic ca. 2 Ma–780 ka and 250–70 ka. The dams are strongly asymmetric, with steep, blunt escarpments facing up valley and long, low slopes down valley. None of the dams shows evidence of catastrophic failure; all blocked the river and diverted water over or around the dam crest. The net effect of the dams was therefore to inhibit rather than promote incision. Once incision resumed, most of the intracanyon flows were incised relatively rapidly and therefore did not exert a lasting impact on the river valley profile over time scales >106 yr. The net long-term incision rate from the time of the oldest documented lava dam, the Bogus Rim lava dam (≤1.7 Ma), to present was 0.18 mm/yr, but incision rates through or around individual lava dams were up to an order of magnitude greater. At least three lava dams (Bogus Rim, Saddle Butte, and West Crater) show evidence that incision initiated only after the impounded lakes filled completely with sediment and there was gravel transport across the dams. The most recent lava dam, formed by the West Crater lava flow around 70 ka, persisted for at least 25 k.y. before incision began, and the dam was largely removed within another 35 k.y. The time scale over which the lava dams inhibit incision is therefore directly affected by both the volume of lava forming the dam and the time required for sediment

  11. Features of lava lake filling and draining and their implications for eruption dynamics

    USGS Publications Warehouse

    Stovall, W.K.; Houghton, B.F.; Harris, A.J.L.; Swanson, D.A.

    2009-01-01

    Lava lakes experience filling, circulation, and often drainage depending upon the style of activity and location of the vent. Features formed by these processes have proved difficult to document due to dangerous conditions during the eruption, inaccessibility, and destruction of features during lake drainage. Kilauea Iki lava lake, Kilauea, Hawai'i, preserves many such features, because lava ponded in a pre-existing crater adjacent to the vent and eventually filled to the level of, and interacted with, the vent and lava fountains. During repeated episodes, a cyclic pattern of lake filling to above vent level, followed by draining back to vent level, preserved features associated with both filling and draining. Field investigations permit us to describe the characteristic features associated with lava lakes on length scales ranging from centimeters to hundreds of meters in a fashion analogous to descriptions of lava flows. Multiple vertical rinds of lava coating the lake walls formed during filling as the lake deepened and lava solidified against vertical faces. Drainage of the lake resulted in uneven formation of roughly horizontal lava shelves on the lakeward edge of the vertical rinds; the shelves correlate with stable, staggered lake stands. Shelves either formed as broken relict slabs of lake crust that solidified in contact with the wall or by accumulation, accretion, and widening at the lake surface in a dynamic lateral flow regime. Thin, upper lava shelves reflect an initially dynamic environment, in which rapid lake lowering was replaced by slower and more staggered drainage with the formation of thicker, more laterally continuous shelves. At all lava lakes experiencing stages of filling and draining these processes may occur and result in the formation of similar sets of features. ?? Springer-Verlag 2009.

  12. Lava flow hazard at Nyiragongo volcano, D.R.C.. 1. Model calibration and hazard mapping

    NASA Astrophysics Data System (ADS)

    Favalli, Massimiliano; Chirico, Giuseppe D.; Papale, Paolo; Pareschi, Maria Teresa; Boschi, Enzo

    2009-05-01

    The 2002 eruption of Nyiragongo volcano constitutes the most outstanding case ever of lava flow in a big town. It also represents one of the very rare cases of direct casualties from lava flows, which had high velocities of up to tens of kilometer per hour. As in the 1977 eruption, which is the only other eccentric eruption of the volcano in more than 100 years, lava flows were emitted from several vents along a N-S system of fractures extending for more than 10 km, from which they propagated mostly towards Lake Kivu and Goma, a town of about 500,000 inhabitants. We assessed the lava flow hazard on the entire volcano and in the towns of Goma (D.R.C.) and Gisenyi (Rwanda) through numerical simulations of probable lava flow paths. Lava flow paths are computed based on the steepest descent principle, modified by stochastically perturbing the topography to take into account the capability of lava flows to override topographic obstacles, fill topographic depressions, and spread over the topography. Code calibration and the definition of the expected lava flow length and vent opening probability distributions were done based on the 1977 and 2002 eruptions. The final lava flow hazard map shows that the eastern sector of Goma devastated in 2002 represents the area of highest hazard on the flanks of the volcano. The second highest hazard sector in Goma is the area of propagation of the western lava flow in 2002. The town of Gisenyi is subject to moderate to high hazard due to its proximity to the alignment of fractures active in 1977 and 2002. In a companion paper (Chirico et al., Bull Volcanol, in this issue, 2008) we use numerical simulations to investigate the possibility of reducing lava flow hazard through the construction of protective barriers, and formulate a proposal for the future development of the town of Goma.

  13. Lava flow hazard at Nyiragongo Volcano, DRC. 2. Hazard reduction in urban areas

    NASA Astrophysics Data System (ADS)

    Chirico, Giuseppe D.; Favalli, Massimiliano; Papale, Paolo; Boschi, Enzo; Pareschi, Maria Teresa; Mamou-Mani, Arthur

    2009-05-01

    Mt. Nyiragongo is one of the most dangerous volcanoes in the world for the risk associated with the propagation of lava flows. In 2002 several vents opened along a huge system of fractures, pouring out lava which reached and destroyed a considerable part of Goma, a town of about 500,000 inhabitants on the shore of Lake Kivu. In a companion paper (Favalli et al. in Bull Volcanol, this issue, 2008) we employed numerical simulations of probable lava flow paths to evaluate the lava flow hazard on the flanks of the volcano, including the neighbouring towns of Goma (DRC) and Gisenyi (Rwanda). In this paper we use numerical simulations to investigate the possibility of significantly reducing the lava flow hazard in the city through the construction of protective barriers. These barriers are added to the DEM of the area as additional morphological elements, and their effect is evaluated by repeating numerical simulations with and without the presence of barriers. A parametric study on barrier location, size, shape and orientation led to the identification of barriers which maximize protection while minimizing their impact. This study shows that the highest hazard area corresponding to eastern Goma, which was largely destroyed by lava flows in 2002, cannot be effectively protected from future lava flows towards Lake Kivu and should be abandoned. On the contrary, the rest of the town can be sheltered from lava flows by means of two barriers that deviate or contain the lava within the East Goma sector. A proposal for the future development of the town is formulated, whereby “new” Goma is completely safe from the arrival of lava flows originating from vents outside its boundaries. The proposal minimizes the risk of further destruction in town due to future lava flows.

  14. Lava Flow Hazard Modeling during the 2014-2015 Fogo eruption, Cape Verde

    NASA Astrophysics Data System (ADS)

    Del Negro, C.; Cappello, A.; Ganci, G.; Calvari, S.; Perez, N. M.; Hernandez Perez, P. A.; Victoria, S. S.; Cabral, J.

    2015-12-01

    Satellite remote sensing techniques and lava flow forecasting models have been combined to allow an ensemble response during effusive crises at poorly monitored volcanoes. Here, we use the HOTSAT volcano hot spot detection system that works with satellite thermal infrared data and the MAGFLOW lava flow emplacement model that considers the way in which effusion rate changes during an eruption, to forecast lava flow hazards during the 2014-2015 Fogo eruption. In many ways this was one of the major effusive eruption crises of recent years, since the lava flows actually invaded populated areas. HOTSAT is used to promptly analyze MODIS and SEVIRI data to output hot spot location, lava thermal flux, and effusion rate estimation. We use this output to drive the MAGFLOW simulations of lava flow paths and to update continuously flow simulations. Satellite-derived TADR estimates can be obtained in real time and lava flow simulations of several days of eruption can be calculated in a few minutes, thus making such a combined approach of paramount importance to provide timely forecasts of the areas that a lava flow could possibly inundate. In addition, such forecasting scenarios can be continuously updated in response to changes in the eruptive activity as detected by satellite imagery. We also show how Landsat-8 OLI and EO-1 ALI images complement the field observations for tracking the flow front position through time, and add considerable data on lava flow advancement to validate the results of numerical simulations. Our results thus demonstrate how the combination of satellite remote sensing and lava flow modeling can be effectively used during eruptive crises to produce realistic lava flow hazard scenarios and for assisting local authorities in making decisions during a volcanic eruption.

  15. Emplacement conditions of the 1256 AD Al-Madinah lava flow field in Harrat Rahat, Kingdom of Saudi Arabia - Insights from surface morphology and lava flow simulations

    NASA Astrophysics Data System (ADS)

    Kereszturi, Gábor; Németh, Károly; Moufti, Mohammed R.; Cappello, Annalisa; Murcia, Hugo; Ganci, Gaetana; Del Negro, Ciro; Procter, Jonathan; Zahran, Hani Mahmoud Ali

    2016-01-01

    Lava flow hazard modelling requires detailed geological mapping, and a good understanding of emplacement settings and the processes involved in the formation of lava flows. Harrat Rahat, Kingdom of Saudi Arabia, is a large volcanic field, comprising about 1000 predominantly small-volume volcanoes most of which have emitted lava flows of various lengths. A few eruptions took place in this area during the Holocene, and they were located in the northern extreme of the Harrat Rahat, a close proximity to critical infrastructure and population living in Al-Madinah City. In the present study, we combined field work, high resolution digital topography and morphometric analysis to infer the emplacement history of the last historical event in the region represented by the 1256 AD Al-Madinah lava flow field. These data were also used to simulate 1256 AD-type lava flows in the Harrat Rahat by the MAGFLOW lava flow emplacement model, which is able to relate the flow evolution to eruption conditions. The 1256 AD lava flow field extent was mapped at a scale of 1:1000 from a high resolution (0.5 m) Light Detection And Ranging (LiDAR) Digital Terrain Model (DTM), aerial photos with field support. The bulk volume of the lava flow field was estimated at 0.4 km3, while the source volume represented by seven scoria cone was estimated at 0.023 km3. The lava flow covered an area of 60 km2 and reached a maximum length of 23.4 km. The lava flow field comprises about 20.9% of pāhoehoe, 73.8% of 'a'ā, and 5.3% of late-stage outbreaks. Our field observation, also suggests that the lava flows of the Harrat Rahat region are mainly core-dominated and that they formed large lava flow fields by amalgamation of many single channels. These channels mitigated downslope by topography-lava flow and channel-channel interactions, highlighting this typical process that needs to be considered in the volcanic hazard assessment in the region. A series of numerical lava flow simulations was carried out

  16. Application of Bistatic TanDEM-X Interferometry to Measure Lava Flow Volume and Lava Extrusion Rates During the 2012-13 Tolbachik, Kamchatka Fissure Eruption

    NASA Astrophysics Data System (ADS)

    Kubanek, J.; Westerhaus, M.; Heck, B.

    2015-12-01

    Aerial imaging methods are a well approved source for mapping lava flows during eruptions and can serve as a base to assess the eruption dynamics and to determine the affected area. However, clouds and smoke often hinder optical systems like the Earth Observation Advanced Land Imager (EO-1-ALI, operated by NASA) to map lava flows properly, which hence affects its reliability. Furthermore, the amount of lava that is extruded during an eruption cannot be determined from optical images - however, it can significantly contribute to assess the accompanying hazard and risk. One way to monitor active lava flows is to quantify the topographic changes over time while using up-to-date high-resolution digital elevation models (DEMs). Whereas photogrammetric methods still fail when clouds and fume obstruct the sight, innovative radar satellite missions have the potential to generate high-resolution DEMs at any time. The innovative bistatic TanDEM-X (TerraSAR-X Add-on for Digital Elevation Measurements) satellite mission enables for the first time generating high-resolution DEMs from synthetic aperture radar satellite data repeatedly with reasonable costs and high resolution. The satellite mission consists of the two nearly identical satellites TerraSAR-X and TanDEM-X that build a large synthetic aperture radar interferometer with adaptable across- and along-track baselines aiming to generate topographic information globally. In the present study, we apply the TanDEM-X data to study the lava flows that were emplaced during the 2012-13 Tolbachik, Kamchatka fissure eruption. The eruption was composed of very fluid lava flows that effused along a northeast-southwest trending fissure. We used about fifteen bistatic data pairs to generate DEMs prior to, during, and after the eruption. The differencing of the DEMs enables mapping the lava flow field at different times. This allows measuring the extruded volume and to derive the changes in lava extrusion over time.

  17. Las Vegas

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image of Las Vegas, NV was acquired on August, 2000 and covers an area 42 km (25 miles) wide and 30 km (18 miles) long. The image displays three bands of the reflected visible and infrared wavelength region, with a spatial resolution of 15 m. McCarran International Airport to the south and Nellis Air Force Base to the NE are the two major airports visible. Golf courses appear as bright red areas of worms. The first settlement in Las Vegas (which is Spanish for The Meadows) was recorded back in the early 1850s when the Mormon church, headed by Brigham Young, sent a mission of 30 men to construct a fort and teach agriculture to the Indians. Las Vegas became a city in 1905 when the railroad announced this city was to be a major division point. Prior to legalized gambling in 1931, Las Vegas was developing as an agricultural area. Las Vegas' fame as a resort area became prominent after World War II. The image is located at 36.1 degrees north latitude and 115.1 degrees west longitude.

    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.

  18. Las Vegas

    NASA Image and Video Library

    2001-10-22

    This image of Las Vegas, NV was acquired on August, 2000 and covers an area 42 km (25 miles) wide and 30 km (18 miles) long. The image displays three bands of the reflected visible and infrared wavelength region, with a spatial resolution of 15 m. McCarran International Airport to the south and Nellis Air Force Base to the NE are the two major airports visible. Golf courses appear as bright red areas of worms. The first settlement in Las Vegas (which is Spanish for The Meadows) was recorded back in the early 1850s when the Mormon church, headed by Brigham Young, sent a mission of 30 men to construct a fort and teach agriculture to the Indians. Las Vegas became a city in 1905 when the railroad announced this city was to be a major division point. Prior to legalized gambling in 1931, Las Vegas was developing as an agricultural area. Las Vegas' fame as a resort area became prominent after World War II. The image is located at 36.1 degrees north latitude and 115.1 degrees west longitude. http://photojournal.jpl.nasa.gov/catalog/PIA11096

  19. Interpretation of volcanic gas data from tholeiitic and alkaline mafic lavas

    SciTech Connect

    Gerlach, T. M.

    1980-01-01

    Data are tabulated for approximately 150 previously reported collections of high-temperature volcanic gases from basic lavas using computational techniques recently introduced by the author. Research problems dealing with the composition of volcanic gases and their relation to lava chemistry are outlined. The need for more accurate data on the volume of gases released during eruptions is also noted. (PCS)

  20. Numerical modeling of fluid flow with rafts: An application to lava flows

    NASA Astrophysics Data System (ADS)

    Tsepelev, Igor; Ismail-Zadeh, Alik; Melnik, Oleg; Korotkii, Alexander

    2016-07-01

    Although volcanic lava flows do not significantly affect the life of people, its hazard is not negligible as hot lava kills vegetation, destroys infrastructure, and may trigger a flood due to melting of snow/ice. The lava flow hazard can be reduced if the flow patterns are known, and the complexity of the flow with debris is analyzed to assist in disaster risk mitigation. In this paper we develop three-dimensional numerical models of a gravitational flow of multi-phase fluid with rafts (mimicking rigid lava-crust fragments) on a horizontal and topographic surfaces to explore the dynamics and the interaction of lava flows. We have obtained various flow patterns and spatial distribution of rafts depending on conditions at the surface of fluid spreading, obstacles on the way of a fluid flow, raft landing scenarios, and the size of rafts. Furthermore, we analyze two numerical models related to specific lava flows: (i) a model of fluid flow with rafts inside an inclined channel, and (ii) a model of fluid flow from a single vent on an artificial topography, when the fluid density, its viscosity, and the effusion rate vary with time. Although the studied models do not account for lava solidification, crust formation, and its rupture, the results of the modeling may be used for understanding of flows with breccias before a significant lava cooling.

  1. Determination of thermal/dynamic characteristics of lava flow from surface thermal measurements

    NASA Astrophysics Data System (ADS)

    Ismail-Zadeh, Alik; Melnik, Oleg; Korotkii, Alexander; Tsepelev, Igor; Kovtunov, Dmitry

    2016-04-01

    Rapid development of ground based thermal cameras, drones and satellite data allows getting repeated thermal images of the surface of the lava flow. Available instrumentation allows getting a large amount of data during a single lava flow eruption. These data require development of appropriate quantitative techniques to link subsurface dynamics with observations. We present a new approach to assimilation of thermal measurements at lava's surface to the bottom of the lava flow to determine lava's thermal and dynamic characteristics. Mathematically this problem is reduced to solving an inverse boundary problem. Namely, using known conditions at one part of the model boundary we determine the missing condition at the remaining part of the boundary. Using an adjoint method we develop a numerical approach to the mathematical problem based on the determination of the missing boundary condition and lava flow characteristics. Numerical results show that in the case of smooth input data lava temperature and velocity can be determined with a high accuracy. A noise imposed on the smooth input data results in a less accurate solution, but still acceptable below some noise level. The proposed approach to assimilate measured data brings an opportunity to estimate thermal budget of the lava flow.

  2. Zeolites in Eocene basaltic pillow lavas of the Siletz River Volcanics, Central Coast Range, Oregon.

    USGS Publications Warehouse

    Keith, T.E.C.; Staples, L.W.

    1985-01-01

    Zeolites and associated minerals occur in a tholeiitic basaltic pillow lava sequence. Although the zeolite assemblages are similar to those found in other major zeolite occurrences in basaltic pillow lavas, regional zoning of the zeolite assemblages is not apparent. The formation of the different assemblages is discussed.-D.F.B.

  3. Lava rise ridges of the Toomba basalt flow, north Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Whitehead, P. W.; Stephenson, P. J.

    1998-11-01

    Unusually long lava rises occur in the distal portion of the Toomba basalt flow, up to 120 km from the source. In the Lolworth creek region, three parallel lava rise ridges occur over a 6 km section. Two of these ridges are continuous for the entire 6 km. The ridges average 7 m in height and range from 35 m to 300 m in width. Lava inflation clefts are numerous, and lava rise pits also occur. Down flow, a single lava rise ridge, averaging 18 m high and up to 500 m wide, extends for a further 10 km. This ridge has a generally level surface with abrupt edges sloping between 45° and 90°. Accurate surveys across the ridges show that in some cases there has been some stretching of the surface, presumably prior to the formation of the prominent clefts. The ridges were formed from an initially thin flow that was inflated by a continuous layer of lava that underlay almost the entire width of each ridge, rather than by a system of lava tubes of more limited dimensions. Inflated material represents over 90% of the volume of the distal parts of the flow. Estimates of the time required to inflate the lava rise ridges range from 60 days to a year.

  4. Retrieving geomagnetic secular variations from lava flows: evidence from Mounts Arso, Etna and Vesuvius (southern Italy)

    NASA Astrophysics Data System (ADS)

    Incoronato, Alberto; Angelino, Antimo; Romano, Romolo; Ferrante, Agostino; Sauna, Renata; Vanacore, Gianpio; Vecchione, Claudio

    2002-06-01

    Mean directions of magnetization from Mounts Arso (Ischia Island, Gulf of Naples), Etna and Vesuvius lava flows have been determined based on very stringent linearity criteria. These indicate that, regardless of the source volcano, the lava flow mean directions of magnetization form a common path, the SISVC (Southern Italy Secular Variation Curve). This curve enables a reassessment of the age of eruption of several lavas. A date of AD 1169 is demonstrated to be the only possible time of emplacement for one Etna lava flow previously assigned an age of AD 812/1169. It is also demonstrated that two Etna lava flows, which, according to the literature, were emplaced in AD 1536 and 1595 respectively, were actually both emplaced around AD 1037. Three other Etna lava flows, one ascribed to AD 1566 and two to AD 1595, were actually emplaced between AD 1169 and 1284/85. The same time window also holds for a Vesuvius lava flow for which only an upper time threshold was previously available. Only one of the studied flows needs further sampling and analysis to verify whether this flow has been affected by a complete remagnetization or has an erroneous historical dating. The applied procedure seems to be the most appropriate one in carrying out palaeomagnetic surveys of lava flows, as also suggested by the broad agreement with some 17th and 19th century measurements of the geomagnetic field in Rome, relocated to Etna, and is likely to improve knowledge of past history of a volcano significantly.

  5. Melting processes and mantle sources of lavas on Mercury

    NASA Astrophysics Data System (ADS)

    Namur, Olivier; Collinet, Max; Charlier, Bernard; Grove, Timothy L.; Holtz, Francois; McCammon, Catherine

    2016-04-01

    The MESSENGER spacecraft provided geochemical data for surface rocks on Mercury. In this study, we use the major element composition of these lavas to constrain melting conditions and residual mantle sources on Mercury. We combine modelling and high-temperature (1320-1580 °C), low- to high-pressure (0.1 to 3 GPa) experiments on average compositions for the Northern Volcanic Plains (NVP) and the high-Mg region of the Intercrater Plains and Heavily Cratered Terrains (High-Mg IcP-HCT). Near-liquidus phase relations show that the S-free NVP and High-Mg IcP-HCT compositions are multiply saturated with forsterite and enstatite at 1450 °C - 1.3 GPa and 1570 °C - 1.7 GPa, respectively. For S-saturated melts (1.5-3 wt.% S), the multiple saturation point (MSP) is shifted to 1380 °C - 0.75 GPa for NVP and 1480 °C - 0.8 GPa for High-Mg IcP-HCT. To expand our experimental results to the range of surface compositions, we used and calibrated the pMELTS thermodynamic calculator and estimated phase equilibria of ∼5800 compositions from the Mercurian surface and determined the P-T conditions of liquid-forsterite-enstatite MSP (1300-1600 °C; 0.25-1.25 GPa). Surface basalts were produced by 10 to 50% partial melting of variably enriched lherzolitic mantle sources. The relatively low pressure of the olivine-enstatite-liquid MSP seems most consistent with decompression batch melting and melts being segregated from their residues near the base of Mercury's ancient lithosphere. The average melting degree is lower for the young NVP (0.27 ± 0.04) than for the older IcP-HCT (0.46 ± 0.02), indicating that melt productivity decreased with time. The mantle potential temperature required to form Mercurian lavas and the initial depth of melting also decreased from the older High-Mg IcP-HCT terrane (1650 °C and 360 km) to the younger lavas covering the NVP regions (1410 °C and 160 km). This evolution supports strong secular cooling of Mercury's mantle between 4.2 and 3.7 Ga and

  6. Petrogenesis of High-CaO Lavas Recovered from Hawaii Scientific Drilling Project

    NASA Astrophysics Data System (ADS)

    Huang, S.

    2015-12-01

    Mauna Kea tholeiitic lavas recovered from Hawaii Scientific Drilling Project (HSDP) can be divided into three groups based on their major element compositions: High-SiO2, Low-SiO2, and High-CaO groups. Detailed geochemical and isotopic studies have been focused on the High- and Low-SiO2 group lavas, and High-CaO lavas were not well studied because they were not included in the original reference suite samples. Here we report trace element compositions determined on a suite of High-CaO glasses, and use these data to constrain the petrogenesis of High-CaO lavas. When normalized to Low-SiO2 lavas, High-CaO lavas form a U-shaped trace element pattern. That is, High-CaO lavas are enriched in both the most (Nb, Th) and the least (Sc, V) incompatible elements. This trace element difference is best explained if High-CaO parental magma represents a mixture of low degree partial melt of the Low-SiO2 mantle source and a mafic cumulate component. This mafic cumulate must be clinopyroxene-rich, and it could be delaminated mafic cumulate formed under arcs during continent formation, lower continental crust, or lower oceanic crust.Mauna Kea tholeiitic lavas recovered from Hawaii Scientific Drilling Project (HSDP) can be divided into three groups based on their major element compositions: High-SiO2, Low-SiO2, and High-CaO groups. Detailed geochemical and isotopic studies have been focused on the High- and Low-SiO2 group lavas, and High-CaO lavas were not well studied because they were not included in the original reference suite samples. Here we report trace element compositions determined on a suite of High-CaO glasses, and use these data to constrain the petrogenesis of High-CaO lavas. When normalized to Low-SiO2 lavas, High-CaO lavas form a U-shaped trace element pattern. That is, High-CaO lavas are enriched in both the most (Nb, Th) and the least (Sc, V) incompatible elements. This trace element difference is best explained if High-CaO parental magma represents a mixture of

  7. New Evidence for the Low-Pressure Origin of Lava-Hyaloclastite Sequences in South Iceland

    NASA Astrophysics Data System (ADS)

    Banik, T.; Hoskuldsson, A.; Miller, C. F.; Furbish, D. J.; Wallace, P. J.

    2011-12-01

    In the Sida-Fljotshverfi District of south Iceland, Pleistocene basaltic lava forms flame-like apophyses, dikes, and disaggregation structures (cf. Bergh and Sigvaldason, 1991; Smellie, 2008) that invade overlying hyaloclastite. These features are exposed in valley walls composed of at least 14 (Bergh and Sigvaldason, 1991) paired basalt-hyaloclastite +/- diamictite depositional units. These units are dominated by hyaloclastite deposits that reach over 100 m in thickness, with underlying lava up to 50 m thick. Apophyses as well as underlying lavas show "kubbaberg" or cube jointing, indicating rapid cooling due to formation in a wet environment and suggesting that hyaloclastite and lava were emplaced virtually concurrently, while hyaloclastite was wet and weak. Dissolved volatile concentrations in glass give an indication of ambient pressure on quenching and cessation of degassing. Sulfur contents in basaltic glasses from chilled margins of lava and from hyaloclastite glasses obtained by electron microprobe (lava glasses range from 0-525 ppm with the majority of samples less than 300 ppm; hyaloclastite glasses have 0-900 ppm S) suggest degassing at shallow depths (< a few hundred m) or at the surface. This is further supported by FTIR analyses for CO2 and H2O contents in both glass types that yield low total water contents (0-0.570 %, although the vast majority of samples fall below 0.2 %, for the lava glasses; hyaloclastite glasses are 0-0.147%) and no measureable CO2, indicating quenching pressures for over half of both the lava and the hyaloclastite samples were near atmospheric P. These data support an eruption that occurred under significantly lower-pressure conditions than previously proposed (Smellie, 2008). The presence of a large volume of hyaloclastite as well as extensive lava suggests the possibility of eruptions with both subglacial and subaerial phases. In one possible scenario, a subglacial eruption under a shallow glacier may have produced

  8. LAVA: an open-source approach to designing LAMP (loop-mediated isothermal amplification) DNA signatures.

    PubMed

    Torres, Clinton; Vitalis, Elizabeth A; Baker, Brian R; Gardner, Shea N; Torres, Marisa W; Dzenitis, John M

    2011-06-16

    We developed an extendable open-source Loop-mediated isothermal AMPlification (LAMP) signature design program called LAVA (LAMP Assay Versatile Analysis). LAVA was created in response to limitations of existing LAMP signature programs. LAVA identifies combinations of six primer regions for basic LAMP signatures, or combinations of eight primer regions for LAMP signatures with loop primers, which can be used as LAMP signatures. The identified primers are conserved among target organism sequences. Primer combinations are optimized based on lengths, melting temperatures, and spacing among primer sites. We compare LAMP signature candidates for Staphylococcus aureus created both by LAVA and by PrimerExplorer. We also include signatures from a sample run targeting all strains of Mycobacterium tuberculosis. We have designed and demonstrated new software for identifying signature candidates appropriate for LAMP assays. The software is available for download at http://lava-dna.googlecode.com/.

  9. LAVA: An Open-Source Approach To Designing LAMP (Loop-Mediated Isothermal Amplification) DNA Signatures

    PubMed Central

    2011-01-01

    Background We developed an extendable open-source Loop-mediated isothermal AMPlification (LAMP) signature design program called LAVA (LAMP Assay Versatile Analysis). LAVA was created in response to limitations of existing LAMP signature programs. Results LAVA identifies combinations of six primer regions for basic LAMP signatures, or combinations of eight primer regions for LAMP signatures with loop primers, which can be used as LAMP signatures. The identified primers are conserved among target organism sequences. Primer combinations are optimized based on lengths, melting temperatures, and spacing among primer sites. We compare LAMP signature candidates for Staphylococcus aureus created both by LAVA and by PrimerExplorer. We also include signatures from a sample run targeting all strains of Mycobacterium tuberculosis. Conclusions We have designed and demonstrated new software for identifying signature candidates appropriate for LAMP assays. The software is available for download at http://lava-dna.googlecode.com/. PMID:21679460

  10. Exploring Inflated Pahohoe Lava Flow Morphologies and the Effects of Cooling Using a New Simulation Approach

    NASA Technical Reports Server (NTRS)

    Glaze, L. S.; Baloga, S. M.

    2014-01-01

    Pahoehoe lavas are recognized as an important landform on Earth, Mars and Io. Observations of such flows on Earth (e.g., Figure 1) indicate that the emplacement process is dominated by random effects. Existing models for lobate a`a lava flows that assume viscous fluid flow on an inclined plane are not appropriate for dealing with the numerous random factors present in pahoehoe emplacement. Thus, interpretation of emplacement conditions for pahoehoe lava flows on Mars requires fundamentally different models. A new model that implements a simulation approach has recently been developed that allows exploration of a variety of key influences on pahoehoe lobe emplacement (e.g., source shape, confinement, slope). One important factor that has an impact on the final topographic shape and morphology of a pahoehoe lobe is the volumetric flow rate of lava, where cooling of lava on the lobe surface influences the likelihood of subsequent breakouts.

  11. Formation of Venusian canali - Considerations of lava types and their thermal behaviors

    NASA Astrophysics Data System (ADS)

    Gregg, T. K. P.; Greeley, R.

    1993-06-01

    Because liquid water is unstable at present venusian surface conditions, the discovery of channels (termed 'canali') on Venus thousands of kilometers long was not predicted. Low viscosity lavas that remain fluid for several thousand kilometers are considered to be the canali-forming agents; possible compositions of Venusian canali-forming lavas include komatiite and high-Fe-Ti 'lunar'-type basalts. Results of analytical and numerical models of these lavas reveal that total cooling is more efficient on Venus than on Earth, suggesting that Venusian lavas rapidly form insulating crusts, and, thus, that the canali lavas were essentially 'tube-fed.' The models also reveal that thermal erosion should be less efficient on Venus than on Earth, suggesting that Venusian channels are either the product of mechanical (rather than thermal) erosion or constructional processes.

  12. Emplacement of the final lava dome of the 2009 eruption of Redoubt Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Bull, Katharine F.; Anderson, Steven W.; Diefenbach, Angela K.; Wessels, Rick L.; Henton, Sarah M.

    2013-06-01

    After more than 8 months of precursory activity and over 20 explosions in 12 days, Redoubt Volcano, Alaska began to extrude the fourth and final lava dome of the 2009 eruption on April 4. By July 1 the dome had filled the pre-2009 summit crater and ceased to grow. By means of analysis and annotations of time-lapse webcam imagery, oblique-image photogrammetry techniques and capture and analysis of forward-looking infrared (FLIR) images, we tracked the volume, textural, effusive-style and temperature changes in near-real time over the entire growth period of the dome. The first month of growth (April 4-May 4) produced blocky intermediate- to high-silica andesite lava (59-62.3 wt.% SiO2) that initially formed a round dome, expanding by endogenous growth, breaking the surface crust in radial fractures and annealing them with warmer, fresh lava. On or around May 1, more finely fragmented and scoriaceous andesite lava (59.8-62.2 wt.% SiO2) began to appear at the top of the dome coincident with increased seismicity and gas emissions. The more scoriaceous lava spread radially over the dome surface, while the dome continued to expand from endogenous growth and blocky lava was exposed on the margins and south side of the dome. By mid-June the upper scoriaceous lava had covered 36% of the dome surface area. Vesicularity of the upper scoriaceous lava range from 55 to 66%, some of the highest vesicularity measurements recorded from a lava dome. We suggest that the stability of the final lava dome primarily resulted from sufficient fracturing and clearing of the conduit by preceding explosions that allowed efficient degassing of the magma during effusion. The dome was thus able to grow until it was large enough to exceed the magmastatic pressure in the chamber, effectively shutting off the eruption.

  13. Satellite Measurements of Lava Extrusion Rate at Volcán Reventador, Ecuador

    NASA Astrophysics Data System (ADS)

    Arnold, D. W. D.; Biggs, J.; Ebmeier, S. K.; Vallejo Vargas, S.; Naranjo, M. F.

    2015-12-01

    The extrusion rate of lava at active volcanoes provides a principle control on the style of eruptive behavior and the extent of lava flows, while also providing information about magma supply to the volcano. Measurements of extrusion rate at active volcanoes are therefore important for assessing hazard, and improving understanding of volcanic systems. Volcán Reventador is an asymmetric stratovolcano in the Cordillera Real of Ecuador. The largest historically observed eruption at Reventador in 2002 has been followed by several periods of eruptive activity. Eruptions are characterised by effusion of andesitic to basaltic-andesitic lava flows, and Vulcanian explosions. The ongoing eruption at Reventador therefor provides an excellent target for investigating the link between effusion rate, explosivity, and lava flow behaviour. Satellite InSAR provides regular observations of the volcano, even during night or periods of cloud cover. We use a dataset of Radarsat-2 and TanDEM-X imagery, with intervals of 11 to 192 days, over the period 2011 to 2014 to measure the extent, thickness and volume of new lava flows at Reventador. We use radar amplitude and inteferometric coherence to map 25 individual lava flows, as well as pyroclastic deposits and changes in lava dome morphology. We observe 43 Mm3 of deposits over a three year period, giving an average effusion rate of 0.5 m3s-1. We do not observe any ground deformation due to magmatic sources at Reventador, therefore variations in lava effusion rate can be interpreted as changes in the magma supply to the volcano. We investigate the link between variations in effusion rate and the length, area, thickness, and aspect ratio of lava flows, and the explosive-effusive transition. We also characterise the relationship between lava flow age, thickness, and subsidence rate.

  14. Rock magnetic evidence of inflation of a flood basalt lava flow

    NASA Astrophysics Data System (ADS)

    Cañón-Tapia, Edgardo; Coe, Robert

    2002-07-01

    The anisotropy of magnetic susceptibility (AMS) of lava flows is an innovative method which has been proved to be directly related to the shear history of lava. One of the advantages of this method is that it can be used in the absence of other morphological features commonly employed to study the mechanism of emplacement of lava flows. This feature of the AMS method makes it very attractive to gain insight into the mechanism of emplacement of massive, relatively featureless, long lava flows such as those forming flood basalt provinces. In this work, we report the results of the measurement of AMS as a function of vertical position within the Birkett lava flow, one of the Columbia River Basalt Group flows. The observed variation of AMS allows us to identify at least 16 discrete events of lava injection and to estimate the thickness of individual injection events. The AMS-estimated thickness of each injection event (in the range of 0.5-4.0 m) coincides with the range inferred for injected lava pulses in modern Hawaiian lava flows. Thus, the evidence provided by the AMS method supports the notion that at least some flood basalt lava flows were emplaced by the same mechanism as many present-day inflated pahoehoe flows. Regarding the orientation of the principal susceptibilities, in the central part of the flow they define a preferred orientation along an E-W trend, whereas in the outer parts of the flow they have a NNE-SSW trend. This difference in the orientation of the principal susceptibilities is interpreted as the result of a change of flow direction of the lava as emplacement progressed. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00445-002-0203-8.

  15. Biological deodorization of hydrogen sulfide using porous lava as a carrier of Thiobacillus thiooxidans.

    PubMed

    Cho, K S; Ryu, H W; Lee, N Y

    2000-01-01

    Biological deodorization of hydrogen sulfide (H2S) was studied using porous lava as a carrier of Thiobacillus thiooxidans in a laboratory-scale biofilter. Three different samples of porous lava, A, B, and C, which were obtained from Cheju Island in Korea, were used. The water-holding capacities of samples A, B and C were 0.38, 0.25, and 0.47 g-H2O/g-lava, respectively. The pHs and densities of the lava samples ranged from 8.25-9.24 and 920-1190 kg/m3, respectively. The buffering capacities, expressed as the amount of sulfate added to lower the pH to 4, were 60 g-SO4(2-)/kg-lava for sample A, 50 g-SO4(2-)/kg-lava for B, and 90 g-SO4(2-)/kg-lava for C. To investigate the removal characteristics of H2S by the lava biofilters, T. thiooxidans was immobilized on the lava samples. Biofilters A and C showed a removal capacity of 428 g-S.m(-3).h(-1) when H2S was supplied with 428 g-S.m(-3).h(-1) of inlet load at a space velocity (SV) of 300 h(-1). At the same inlet load and SV, the removal capacity of biofilter B was 396 g-S.m(-3).h(-1). The H2S critical loads of biofilters A, B and C at a SV of 400 h(-1) were 396, 157 and 342 g-S.m(-3).h(-1), respectively. It is suggested that natural, porous lava is a promising candidate as a carrier of microorganisms in biofiltration.

  16. Verification and Validation Studies for the LAVA CFD Solver

    NASA Technical Reports Server (NTRS)

    Moini-Yekta, Shayan; Barad, Michael F; Sozer, Emre; Brehm, Christoph; Housman, Jeffrey A.; Kiris, Cetin C.

    2013-01-01

    The verification and validation of the Launch Ascent and Vehicle Aerodynamics (LAVA) computational fluid dynamics (CFD) solver is presented. A modern strategy for verification and validation is described incorporating verification tests, validation benchmarks, continuous integration and version control methods for automated testing in a collaborative development environment. The purpose of the approach is to integrate the verification and validation process into the development of the solver and improve productivity. This paper uses the Method of Manufactured Solutions (MMS) for the verification of 2D Euler equations, 3D Navier-Stokes equations as well as turbulence models. A method for systematic refinement of unstructured grids is also presented. Verification using inviscid vortex propagation and flow over a flat plate is highlighted. Simulation results using laminar and turbulent flow past a NACA 0012 airfoil and ONERA M6 wing are validated against experimental and numerical data.

  17. Archean recycled oceanic crust sampled in Azores lavas

    NASA Astrophysics Data System (ADS)

    Beguelin, P.; Bizimis, M.; Beier, C.; Turner, S.

    2016-12-01

    Azores lava compositions extend below the mantle array in ɛNd-ɛHf space and define the steepest slope of all plume provinces [1], but this pattern is largely controlled by low ɛHf lavas from Eastern São Miguel island (SM). Here we present new Hf isotope data on well-characterized on-land and submarine Azores lavas from several islands, the Terceira Rift and João do Castro seamount (JdC), in order to further constrain this trend. While Azores lavas fall along the mantle array with relatively steep slopes (e.g. São Jorge slope = 2.1), both SM and JdC fall below the mantle array as two distinct steep arrays with slopes of 2.0 and 2.6 respectively, extending to ɛHf = 0 at ɛNd = 2 (SM) and 4 (JdC). This is a unique feature in OIBs. The new Hf-Nd data overlaps the HIMU-type Mangaia and St Helena compositions. However, SM and JdC have distinctly less radiogenic and more variable Pb isotopes (e.g. 206Pb/204Pb = 18.8 to 20.2) than HIMU. Hf-Nd isotope decoupling below the mantle array is therefore not an exclusive HIMU signature. The coupled Hf-Nd-Pb-Sr isotope compositions of the enriched SM and JdC end-members can be modeled by recycled 2.5-3.0 Ga N-MORB, with some E-MORB affinity for SM. Unlike HIMU however, no Pb-loss during subduction is required for recycled MORB to explain their Pb isotopes. The relatively high κ (232Th/238U 4.3) required by the Azores data is also consistent with a high Th/U Archean mantle [2]. Aged, metasomatised mantle lithosphere based on a global peridotite and pyroxenite compilation is too variable and only fortuitously could explain the Azores compositions. Both enriched JdC and SM endmembers can therefore be explained by a recycled Archean oceanic crust that is locally heterogeneous, as presently observed in some MOR segments where N-and E-MORB exist closely [3, 4]. The lack of mixing between SM and JdC end-members some 100 km apart further implies that this recycled crust has retained its distinct signature through mantle convection

  18. Modeling lava lake heat loss, rheology, and convection

    NASA Astrophysics Data System (ADS)

    Harris, Andrew J. L.

    2008-04-01

    Measurements at Erta Ale's lava lake and theoretical equations for lake rheology, density driven convection and thermally-driven plume ascent allow the constraint of lake dynamics. Cooling and crystallization expected from surface heat losses imply a viscosity increase from 150 Pa s to 300-1800 Pa s for cooled surface layers. Convection is expected to proceed vigorously under low viscosity conditions driving rapid (0.1-0.4 m s-1) surface motions and sluggishly under moderate-to-high viscosity conditions to drive slower motions (<0.08 m s-1). Convection is likely driven by small (~6 kg m-3) density differences, where surface cooling can influence lake rheology and explain variable rates of surface convective motion.

  19. The degassing and crystallisation behaviour of basaltic lavas

    NASA Astrophysics Data System (ADS)

    Applegarth, L. J.; Tuffen, H.; Pinkerton, H.; James, M. R.

    2010-12-01

    Degassing is a fundamental volcanic process that can play a major role in controlling eruptive styles. Volatile loss during magma ascent and decompression increases the liquidus temperature of the residual melt, resulting in undercooling that can trigger crystallisation (1,2). Late-stage crystallisation and vesiculation are significant factors in controlling the eruptive behaviour of volcanoes of intermediate composition (2), but their effects on basaltic volcanic activity have yet to be fully investigated. We present the results of experiments designed to measure the degassing and crystallisation behaviour of volcanic rocks at temperatures up to 1250°C, using thermo-gravimetric analysis coupled with differential scanning calorimetry and mass spectrometry (TGA-DSC-MS). During TGA-DSC-MS analysis, volatiles released from a sample under a controlled heating programme are identified in a mass spectrometer whilst changes to the sample weight and heat flow are simultaneously recorded. By subjecting samples of basaltic lava and bombs to two heating cycles, we have shown that the onset of degassing (mass loss) is systematically followed by crystallisation (exothermic events) on the first heating cycle. During the second cycle, when the sample has been fully degassed, no mass loss or crystallisation are recorded. Our results also highlight complexities in the processes; in some cases up to four pulses of degassing and crystallisation have been identified during a single heating cycle. Our results allow us to measure the total volatile content of samples, the onset temperatures of degassing and crystallisation and the time lag between the two processes, and the enthalpy, hence percentage, of crystallisation taking place. These results have important implications for our understanding of basaltic volcanic eruptions. During effusive basaltic eruptions, lava can travel many kilometres, threatening property and infrastructure. The final areal flow extent is partly dependent on

  20. Endogenic craters on basaltic lava flows - Size frequency distributions

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Gault, D. E.

    1979-01-01

    Circular crater forms, termed collapse depressions, which occur on many basalt flows on the earth have also been detected on the moon and Mars and possibly on Mercury and Io. The admixture of collapse craters with impact craters would affect age determinations of planetary surface units based on impact crater statistics by making them appear anomalously old. In the work described in the present paper, the techniques conventionally used in planetary crater counting were applied to the determination of the size range and size frequency distribution of collapse craters on lava flows in Idaho, California, and New Mexico. Collapse depressions range in size from 3 to 80 m in diameter; their cumulative size distributions are similar to those of small impact craters on the moon.

  1. Lava flows during the continuing eruption of Mt. Etna, Italy

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The current eruption of Mt. Etna started on July 17, and has continued to the present. This ASTER image was acquired on Sunday, July 29 and shows advancing lava flows on the southern flank of Mt. Etna above the town of Nicolosi, which is potentially threatened if the eruption increases in magnitude. Also visible are glowing summit craters above the main lava flows, and a small fissure eruption. The bright puffy clouds were formed from water vapor released during the eruption. The image covers an area of 24 x 30 km.

    The image is centered at 37.7 degrees north latitude, 15 degrees east longitude.

    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 ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

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

  2. Dynamics of a fluid flow on Mars: Lava or mud?

    NASA Astrophysics Data System (ADS)

    Wilson, Lionel; Mouginis-Mark, Peter J.

    2014-05-01

    A distinctive flow deposit southwest of Cerberus Fossae on Mars is analyzed. The flow source is a ∼20 m deep, ∼12 × 1.5 km wide depression within a yardang associated with the Medusae Fossae Formation. The flow traveled for ∼40 km following topographic lows to leave a deposit on average 3-4 km wide. The surface morphology of the deposit suggests that it was produced by the emplacement of a fluid flowing in a laminar fashion and possessing a finite yield strength. We use topographic data from a digital elevation model (DEM) to model the dynamics of the motion and infer that the fluid had a Bingham rheology with a plastic viscosity of ∼1 Pa s and a yield strength of ∼185 Pa. Although the low viscosity is consistent with the properties of komatiite-like lava, the combination of values of viscosity and yield strength, as well as the surface morphology of the flow, suggests that this was a mud flow. Comparison with published experimental data implies a solids content close to 60% by volume and a grain size dominated by silt-size particles. Comparison of the ∼1.5 km3 deposit volume with the ∼0.03 km3 volume of the source depression implies that ∼98% of the flow material was derived from depth in the crust. There are similarities between the deposit studied here, which we infer to be mud, and other flow deposits on Mars currently widely held to be lavas. This suggests that a re-appraisal of many of these deposits is now in order.

  3. Late Oligocene OIB-like lavas in northern Idaho

    NASA Astrophysics Data System (ADS)

    Stadnik, S.; Wolff, J. A.; Hart, G. L.

    2008-12-01

    The 26.3 to 25.3 Ma Potlatch volcanics in northern Idaho (Kuffman et al., 2006) consist of a suite of basalts, hawaiites, mugearites, benmoreites, trachytes and nepheline trachytes. The volcanic field was erupted on North American cratonic basement well to the northeast of the regional crustal suture with Phanerozoic terranes accreted during the Mesozoic, and predates Columbia River flood basalt activity in the area by 9 million years. The most primitive Potlatch lavas are porphyritic olivine basalts with 6 percent MgO and strongly OIB-like chemical affinities (La/Nb = 0.69 - 0.76, Th/Ta = 0.92 to 1.08, Pb/Ce = 0.029 to 0.033, 87Sr/86Sr = 0.70367 to 0.70476, 206Pb/204Pb = 19.254 to 19.504). Similarly, intermediate and felsic lavas and pyroclastics closely resemble differentiated members of typical sodic ocean island suites, but have additionally been affected by AFC involving small amounts of regional continental crust, which has acted to increase 87Sr/86Sr up to 0.70516. The Potlatch volcanics are geochemically unlike other regional Cenozoic volcanic suites including Eocene Challis rocks, basalts and rhyolites of the John Day Formation and other volcanic fields around the Blue Mountains to the south and southwest, and the later Columbia River basalts. Their occurrence represents a modification to the southward retreat pattern of early to mid-Cenozoic magmatism in northwestern North America. Kauffman, Bush, and Lewis (2006) ID Geol. Surv. Tech. Rep. 06-7, 11 pp.

  4. Downflow Width Behavior of Martian and Terrestrial Lava Flows

    NASA Astrophysics Data System (ADS)

    Peitersen, M. N.; Crown, D. A.

    1996-03-01

    Lava flow morphology is typically the primary type of data available for constraining planetary volcanic processes. Flow emplacement (and hence morphology) is controlled by topography, rheology, and thermal history, but the exact relationship between these factors and the resulting flow shape is not well understood. Accurate interpretation of flow dynamics is dependent upon well-constrained flow geometry. Previous modeling studies have commonly assumed relatively constant flow widths and/or cross-sectional areas, use a single value for width based upon a limited number of measurements, or do not consider width at all. Recent analysis of individual flow lobes in the Puu Oo flow field on the east rift zone of Kilauea Volcano show that flow widths vary by up to an order of magnitude. Significant width variations in Martian flows on Tyrhenna Patera, Alba Patera, and Elysium Mons are also observed. Complex flow-forms may be the result of spatially-interacting, temporally-discrete episodes in addition to contemporaneously emplaced flows. Variations in width with downflow distance from the vent may provide critical clues to flow emplacement processes and volcanic stratigraphy; furthermore, flow width is one of the few characteristics that can easily be measured from planetary mission data. The relative widths and lengths of lava flows are presumably a function of the relationship between the lateral spreading rate and flow front advance. Width/length "aspect ratios" are used to quantify this; however, they are highly dependent upon flow history interpretations. Although topography is thought to be a primary control, recent studies have demonstrated a marked insensitivity of flow morphology to topographic variations at 20 to 40 foot scales.

  5. Nyiragongo Volcano, Congo, Map View with Lava, Landsat / ASTER / SRTM

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Nyiragongo volcano in the Congo erupted on January 17, 2002, and subsequently sent streams of lava into the city of Goma on the north shore of Lake Kivu. More than 100 people were killed, more than 12,000 homes were destroyed, and hundreds of thousands were forced to flee the broader community of nearly half a million people. This Landsat satellite image shows the volcano (right of center), the city of Goma, and surrounding terrain. Image data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite were used to supply a partial map of the recent lava flows (red overlay), including a complete mapping of their intrusion into Goma as of January 28, 2002. Lava is also apparent within the volcanic crater and at a few other locations. Thick (but broken) cloud cover during the ASTER image acquisition prevented a complete mapping of the lava distribution, but future image acquisitions should complete the mapping.

    Goma has a light pink speckled appearance along the shore of Lake Kivu. The city airport parallels, and is just right (east) of, the larger lava flow. Nyiragongo peaks at about 3,470 meters (11,380 feet) elevation and reaches almost exactly 2,000 meters (6,560 feet) above Lake Kivu. The shorter but much broader Nyamuragira volcano appears in the upper left.

    Goma, Lake Kivu, Nyiragongo, Nyamuragira and other nearby volcanoes sit within the East African Rift Valley, a zone where tectonic processes are cracking, stretching, and lowering the Earth's crust. Volcanic activity is common here, and older but geologically recent lava flows (magenta in this depiction) are particularly apparent on the flanks of the Nyamuragira volcano.

    The Landsat image used here was acquired on December 11, 2001, about a month before the eruption, and shows an unusually cloud-free view of this tropical terrain. Minor clouds and their shadows were digitally removed to clarify the view and topographic shading derived from the SRTM

  6. Nyiragongo Volcano, Congo, Map View with Lava, Landsat / ASTER / SRTM

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Nyiragongo volcano in the Congo erupted on January 17, 2002, and subsequently sent streams of lava into the city of Goma on the north shore of Lake Kivu. More than 100 people were killed, more than 12,000 homes were destroyed, and hundreds of thousands were forced to flee the broader community of nearly half a million people. This Landsat satellite image shows the volcano (right of center), the city of Goma, and surrounding terrain. Image data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite were used to supply a partial map of the recent lava flows (red overlay), including a complete mapping of their intrusion into Goma as of January 28, 2002. Lava is also apparent within the volcanic crater and at a few other locations. Thick (but broken) cloud cover during the ASTER image acquisition prevented a complete mapping of the lava distribution, but future image acquisitions should complete the mapping.

    Goma has a light pink speckled appearance along the shore of Lake Kivu. The city airport parallels, and is just right (east) of, the larger lava flow. Nyiragongo peaks at about 3,470 meters (11,380 feet) elevation and reaches almost exactly 2,000 meters (6,560 feet) above Lake Kivu. The shorter but much broader Nyamuragira volcano appears in the upper left.

    Goma, Lake Kivu, Nyiragongo, Nyamuragira and other nearby volcanoes sit within the East African Rift Valley, a zone where tectonic processes are cracking, stretching, and lowering the Earth's crust. Volcanic activity is common here, and older but geologically recent lava flows (magenta in this depiction) are particularly apparent on the flanks of the Nyamuragira volcano.

    The Landsat image used here was acquired on December 11, 2001, about a month before the eruption, and shows an unusually cloud-free view of this tropical terrain. Minor clouds and their shadows were digitally removed to clarify the view and topographic shading derived from the SRTM

  7. Nyiragongo Volcano, Congo, Map View with Lava, Landsat / ASTER / SRTM

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Nyiragongo volcano in the Congo erupted on January 17, 2002, and subsequently sent streams of lava into the city of Goma on the north shore of Lake Kivu. More than 100 people were killed, more than 12,000 homes were destroyed, and hundreds of thousands were forced to flee the broader community of nearly half a million people. This Landsat satellite image shows the volcano (right of center), the city of Goma, and surrounding terrain. Image data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite were used to supply a partial map of the recent lava flows (red overlay), including a complete mapping of their intrusion into Goma as of January 28, 2002. Lava is also apparent within the volcanic crater and at a few other locations. Thick (but broken) cloud cover during the ASTER image acquisition prevented a complete mapping of the lava distribution, but future image acquisitions should complete the mapping.

    Goma has a light pink speckled appearance along the shore of Lake Kivu. The city airport parallels, and is just right (east) of, the larger lava flow. Nyiragongo peaks at about 3,470 meters (11,380 feet) elevation and reaches almost exactly 2,000 meters (6,560 feet) above Lake Kivu. The shorter but much broader Nyamuragira volcano appears in the upper left.

    Goma, Lake Kivu, Nyiragongo, Nyamuragira and other nearby volcanoes sit within the East African Rift Valley, a zone where tectonic processes are cracking, stretching, and lowering the Earth's crust. Volcanic activity is common here, and older but geologically recent lava flows (magenta in this depiction) are particularly apparent on the flanks of the Nyamuragira volcano.

    The Landsat image used here was acquired on December 11, 2001, about a month before the eruption, and shows an unusually cloud-free view of this tropical terrain. Minor clouds and their shadows were digitally removed to clarify the view and topographic shading derived from the SRTM

  8. Magma discharge and lava flow field growth in the Nornahraun/Bardarbunga eruption Iceland.

    NASA Astrophysics Data System (ADS)

    Hoskuldsson, Armann; Jónsdóttir, Ingibjörg; Riishus, Morten S.; Pedersen, Gro B. M.; Gudmundsson, Magnus T.; Thordarson, Torvaldur; Drouin, Vincent; Futurevolc IES field work Team

    2015-04-01

    Bardarbunga volcano was reactivated by an intense seismic swarm on 16/8 2014. The seismic swarm originating at the central volcano propagated north out into the associated fissure swarm during following days. As it reached the outwash plains of Jokulsa a fjollum a subaerial eruption began. Three eruptions have taken place on the outwash plane in the event, on the 29/8, 31/8 to present and on 5/9. In this presentation we discuss the second eruption that began on the 31/8 and how we do approach magma discharge parameters by combination of field observation and satellite photogrammetry. The eruption took place at the northern end of the eruptive fissure from AD 1797 and the lava was expelled out onto to relatively flat outwash plains of the glacial river Jokulsa a Fjollum thus access to eruptive products was relatively easy. It was clear from the first moments of the eruption that it had a high initial effusion rate, with lava covering the sandur plains at the rate of 25-30 m2/s. Within the first week the lava flow had covered more than 18 km2. That amounts to an average effusion rate between 195 to 280 m3/s. On the 11/9 the lava flow had grown to 25 km2, at that time effusion rate was between 140 to 247 m3/s, The lava stopped advancing and started to grow sideways and inflating. This reoccurred on the 26/9 and 12/10, with clockwise horizontal stacking of lobes to the south. From mid-November the lava growth has been controlled by tube-fed lava streams, at first generating breakouts close to the vent area and then during the last week before Christmas breaking out at the far NE end of the lava flow. As the eruption proceeded effusion rate gradually decreased and at the time of writing it is down to 9 to 76 m3/s. For assessment of areal extent of the lava field a combination of ground gps tracking and satellite photogrammetry was used. However one of the main challenges in the monitoring of the eruption was to obtain volumetric effusion rates. In the beginning of the

  9. Rheological control on the radiant density of active lava flows and domes

    NASA Astrophysics Data System (ADS)

    Coppola, D.; Laiolo, M.; Piscopo, D.; Cigolini, C.

    2013-01-01

    During an effusive-extrusive eruption, the capability of an active lava body (flow or dome) to radiate thermal energy depends on how the lava discharge rate is accommodated by the expansion of the magma body and by the cooling of its surface. This feature can be described by a single empirical parameter, defined "radiant density" (crad; in J m- 3) that, for a given discharge rate, expresses the efficiency of the lava body to change its area and/or to insulate its inner core, thus modulating the heat radiated from the active surface. By comparing the Volcanic Radiative Energy (VRE; in J), detected by MODIS during 28 eruptions at 18 active volcanoes, with their erupted lava volumes (Vol; in m3), we show that the radiant density (crad = VRE/Vol) is inversely proportional to the silica content of the erupted lava. Basic lavas (45-52 wt.% SiO2) have the highest observed radiant density (1 to 4 × 108 J m- 3) while intermediate (52-63 wt.% SiO2) and acidic (> 63 wt.% SiO2) lavas show a gradually lower radiant densities (1.5 to 9 × 107 J m- 3 and 0.2 to 1 × 107 J m- 3 for intermediate and acidic composition, respectively). We regard this correlation as the result of the control that the rheology of lavas exerts on cooling and spreading processes of related bodies. In particular, we found that for any given compositional group the radiant density is essentially related to a "characteristic thickness" of active lavas, at the time of a satellite acquisition. We suggest that the radiant density of effusive/extrusive lava bodies can be predicted (± 50%) by means of an empirical relationship based on the SiO2 content of the erupted lava. This makes this parameter very useful in observing volcanic activity, especially in remote regions where access may not be possible. By measuring the energy radiated during an eruption and by assuming a lava composition (based on the tectonic setting or magmatic province), we suggest that the radiant density can be used to estimate lava

  10. Geochemical discrimination of five pleistocene Lava-Dam outburst-flood deposits, western Grand Canyon, Arizona

    USGS Publications Warehouse

    Fenton, C.R.; Poreda, R.J.; Nash, B.P.; Webb, R.H.; Cerling, T.E.

    2004-01-01

    Pleistocene basaltic lava dams and outburst-flood deposits in the western Grand Canyon, Arizona, have been correlated by means of cosmogenic 3He (3Hec) ages and concentrations of SiO2, Na2O, K2O, and rare earth elements. These data indicate that basalt clasts and vitroclasts in a given outburst-flood deposit came from a common source, a lava dam. With these data, it is possible to distinguish individual dam-flood events and improve our understanding of the interrelations of volcanism and river processes. At least five lava dams on the Colorado River failed catastrophically between 100 and 525 ka; subsequent outburst floods emplaced basalt-rich deposits preserved on benches as high as 200 m above the current river and up to 53 km downstream of dam sites. Chemical data also distinguishes individual lava flows that were collectively mapped in the past as large long-lasting dam complexes. These chemical data, in combination with age constraints, increase our ability to correlate lava dams and outburst-flood deposits and increase our understanding of the longevity of lava dams. Bases of correlated lava dams and flood deposits approximate the elevation of the ancestral river during each flood event. Water surface profiles are reconstructed and can be used in future hydraulic models to estimate the magnitude of these large-scale floods.

  11. Characteristics, depositional environment, and tectonic interpretations of the Proterozoic Cardenas Lavas, eastern Grand Canyon, Arizona

    NASA Astrophysics Data System (ADS)

    Lucchitta, Ivo; Hendricks, John D.

    1983-03-01

    The 1.1-b.y.-old Cardenas Lavas were deposited in shallow, hypersaline water, probably under tidal-flat conditions, and in an epicratonic basin that subsided without tilting at about the same rate as the lavas built up. Late in Cardenas time the lavas were deposited subaerially in at least some places. Subsequently, the lavas were probably tilted gently to the northeast, then eroded and buried by the Nankoweap Formation, which was deposited in shallow sea water. Most of the lavas exposed today issued from nearby vents. The pre-Nankoweap tilting is in the same direction as a later and more intense pre-Tapeats tilting, suggesting reactivation of existing structures. If the earlier tilting occurred shortly after deposition of the lavas, the reactivation occurred following a very long period of relative quiescence (300+ m.y.). If the pre-Nankoweap erosion interval was long, the tilting events would have been relatively close in time, the erosion interval would have been a major hiatus in the Grand Canyon sequence, and the Nankoweap Formation and Chuar Group would be much younger than the Unkar Group, of which the Cardenas Lavas are part.

  12. Geochemical constraints on possible subduction components in lavas of Mayon and Taal Volcanoes, Southern Luzon, Philippines

    USGS Publications Warehouse

    Castillo, P.R.; Newhall, C.G.

    2004-01-01

    Mayon is the most active volcano along the east margin of southern Luzon, Philippines. Petrographic and major element data indicate that Mayon has produced a basaltic to andesitic lava series by fractional crystallization and magma mixing. Trace element data indicate that the parental basalts came from a heterogeneous mantle source. The unmodified composition of the mantle wedge is similar to that beneath the Indian Ocean. To this mantle was added a subduction component consisting of melt from subducted pelagic sediment and aqueous fluid dehydrated from the subducted basaltic crust. Lavas from the highly active Taal Volcano on the west margin of southern Luzon are compositionally more variable than Mayon lavas. Taal lavas also originated from a mantle wedge metasomatized by aqueous fluid dehydrated from the subducted basaltic crust and melt plus fluid derived from the subducted terrigenous sediment. More sediment is involved in the generation of Taal lavas. Lead isotopes argue against crustal contamination. Some heterogeneity of the unmodified mantle wedge and differences in whether the sediment signature is transferred into the lava source through an aqueous fluid or melt phase are needed to explain the regional compositional variation of Philippine arc lavas. ?? Oxford University Press 2004; all rights reserved.

  13. The Dynamics of Rapidly Emplaced Terrestrial Lava Flows and Implications for Planetary Volcanism

    NASA Technical Reports Server (NTRS)

    Baloga, Stephen; Spudis, Paul D.; Guest, John E.

    1995-01-01

    The Kaupulehu 1800-1801 lava flow of Hualalai volcano and the 1823 Keaiwa flow from the Great Crack of the Kilauea southwest rift zone had certain unusual and possibly unique properties for terrestrial basaltic lava flows. Both flows apparently had very low viscosities, high effusion rates, and uncommonly rapid rates of advance. Ultramafic xenolith nodules in the 1801 flow form stacks of cobbles with lava rinds of only millimeter thicknesses. The velocity of the lava stream in the 1801 flow was extremely high, at least 10 m/s (more than 40 km/h). Observations and geological evidence suggest similarly high velocities for the 1823 flow. The unusual eruption conditions that produced these lava flows suggest a floodlike mode of emplacement unlike that of most other present-day flows. Although considerable effort has gone into understanding the viscous fluid dynamics and thermal processes that often occur in basaltic flows, the unusual conditions prevalent for the Kaupulehu and Keaiwa flows necessitate different modeling considerations. We propose an elementary flood model for this type of lava emplacement and show that it produces consistent agreement with the overall dimensions of the flow, channel sizes, and other supporting field evidence. The reconstructed dynamics of these rapidly emplaced terrestrial lava flows provide significant insights about the nature of these eruptions and their analogs in planetary volcanism.

  14. Interaction of sea water and lava during submarine eruptions at mid-ocean ridges

    USGS Publications Warehouse

    Perfit, M.R.; Cann, J.R.; Fornari, D.J.; Engels, J.; Smith, D.K.; Ridley, W.I.; Edwards, M.H.

    2003-01-01

    Lava erupts into cold sea water on the ocean floor at mid-ocean ridges (at depths of 2,500 m and greater), and the resulting flows make up the upper part of the global oceanic crust. Interactions between heated sea water and molten basaltic lava could exert significant control on the dynamics of lava flows and on their chemistry. But it has been thought that heating sea water at pressures of several hundred bars cannot produce significant amounts of vapour and that a thick crust of chilled glass on the exterior of lava flows minimizes the interaction of lava with sea water. Here we present evidence to the contrary, and show that bubbles of vaporized sea water often rise through the base of lava flows and collect beneath the chilled upper crust. These bubbles of steam at magmatic temperatures may interact both chemically and physically with flowing lava, which could influence our understanding of deep-sea volcanic processes and oceanic crustal construction more generally. We infer that vapour formation plays an important role in creating the collapse features that characterize much of the upper oceanic crust and may accordingly contribute to the measured low seismic velocities in this layer.

  15. Wax Modeling and Image Analysis for Classroom-Scale Lava Flow Simulations.

    NASA Astrophysics Data System (ADS)

    Rader, E. L.; Clarke, A. B.; Vanderkluysen, L.

    2016-12-01

    The use of polyethylene glycol wax (PEG 600) as an analog for lava allows for a visual representation of the complex physical process occurring in natural lava flows, including cooling, breakouts, and crust and lobe formation. We used a series of cameras positioned around a tank filled with chilled water as a lab bench to observe and quantify lava flow morphology and motion. A peristaltic pump connected to a vent at the base of the tank delivered dyed wax simulating effusive eruptions similar to those of Kilauea in Hawai`i. By varying the eruptive conditions such as wax temperature and eruption rate, students can observe how the crust forms on wax flows, how different textures result, and how a flow field evolves with time. Recorded footage of the same `eruption' can then be quantitatively analyzed using free software like ImageJ and Tracker to quantify time-series of spreading rate, change in height, and appearance of different surface morphologies. Additional dye colors can be added periodically to further illustrate how lava is transported from the vent to the periphery of a flow field (e.g., through a tube system). Data collected from this activity can be compared to active lava flow footage from Hawai`i and with numerical models of lava flow propagation, followed by discussions of the application of these data and concepts to predicting the behavior of lava in hazard management situations and interpreting paleomagnetic, petrologic, and mapping of older eruptions.

  16. Lava Eruption and Emplacement: Using Clues from Hawaii and Iceland to Probe the Lunar Past

    NASA Technical Reports Server (NTRS)

    Needham, Debra Hurwitz; Hamilton, C. W.; Bleacher, J. E.; Whelley, P. L.; Young, K. E.; Scheidt, S. P.; Richardson, J. A.; Sutton, S. S.

    2017-01-01

    Investigating recent eruptions on Earth is crucial to improving understanding of relationships between eruption dynamics and final lava flow morphologies. In this study, we investigated eruptions in Holuhraun, Iceland, and Kilauea, Hawaii to gain insight into the lava dynamics near the source vent, the initiation of lava channels, and the origin of down-channel features. Insights are applied to Rima Bode on the lunar nearside to deduce the sequence of events that formed this lunar sinuous rille system. These insights are crucial to correctly interpreting whether the volcanic features associated with Rima Bode directly relate to eruption conditions at the vent and, thus, can help us understand those eruption dynamics, or, alternatively, whether the features formed as a result of more localized influences on lava flow dynamics. For example, if the lava channel developed early in the eruption and was linked to pulses in vent activity, its morphology can be analyzed to interpret the flux and duration of the eruption. Conversely, if the lava channel initiated late in the eruption as the result of a catastrophic breaching of lava that had previously pooled within the vent [e.g., 1], then the final channel morphology will not indicate eruption dynamics but rather local dynamics associated with that breach event. Distinguishing between these two scenarios is crucial for correctly interpreting the intensity and duration of volcanic history on the Moon.

  17. Lava Eruption and Emplacement: Using Clues from Hawaii and Iceland to Probe the Lunar Past

    NASA Technical Reports Server (NTRS)

    Needham, D. H.; Hamilton, C. W.; Bleacher, J. E.; Whelley, P. L.; Young, K. E.; Scheidt, S. P.; Richardson, J. A.; Sutton, S. S.

    2017-01-01

    Investigating recent eruptions on Earth is crucial to improving understanding of relationships between eruption dynamics and final lava flow morphologies. In this study, we investigated eruptions in Holuhraun, Iceland, and Kilauea, Hawaii to gain insight into the lava dynamics near the source vent, the initiation of lava channels, and the origin of down-channel features. Insights are applied to Rima Bode on the lunar nearside to deduce the sequence of events that formed this lunar sinuous rille system.These insights are crucial to correctly interpreting whether the volcanic features associated with Rima Bode directly relate to eruption conditions at the vent and, thus, can help us understand those eruption dynamics, or, alternatively, whether the features formed as a result of more localized influences on lava flow dynamics. For example, if the lava channel developed early in the eruption and was linked to pulses in vent activity, its morphology can be analyzed to interpret the flux and duration of the eruption. Conversely, if the lava channel initiated late in the eruption as the result of a catastrophic breaching of lava that had previously pooled within the vent [e.g., 1], then the final channel morphology will not indicate eruption dynamics but rather local dynamics associated with that breach event. Distinguishing between these two scenarios is crucial for correctly interpreting the intensity and duration of volcanic history on the Moon.

  18. Interaction of sea water and lava during submarine eruptions at mid-ocean ridges.

    PubMed

    Perfit, Michael R; Cann, Johnson R; Fornari, Daniel J; Engels, Jennifer; Smith, Deborah K; Ridley, W Ian; Edwards, Margo H

    2003-11-06

    Lava erupts into cold sea water on the ocean floor at mid-ocean ridges (at depths of 2,500 m and greater), and the resulting flows make up the upper part of the global oceanic crust. Interactions between heated sea water and molten basaltic lava could exert significant control on the dynamics of lava flows and on their chemistry. But it has been thought that heating sea water at pressures of several hundred bars cannot produce significant amounts of vapour and that a thick crust of chilled glass on the exterior of lava flows minimizes the interaction of lava with sea water. Here we present evidence to the contrary, and show that bubbles of vaporized sea water often rise through the base of lava flows and collect beneath the chilled upper crust. These bubbles of steam at magmatic temperatures may interact both chemically and physically with flowing lava, which could influence our understanding of deep-sea volcanic processes and oceanic crustal construction more generally. We infer that vapour formation plays an important role in creating the collapse features that characterize much of the upper oceanic crust and may accordingly contribute to the measured low seismic velocities in this layer.

  19. Submarine lavas from Mauna Kea Volcano, Hawaii: Implications for Hawaiian shield stage processes

    NASA Astrophysics Data System (ADS)

    Yang, Huai-Jen; Frey, Frederick A.; Garcia, Michael O.; Clague, David A.

    1994-08-01

    The island of Hawaii is composed of five voluminous shields but only the youngest, active and well-exposed shields of Mauna Loa and Kilauea have been studied in detail. The shield lavas forming Kohala, Hualalai, and Mauna Kea are largely covered by postshield lavas with geochemical characteristics that differ from the shield lavas. In order to determine the geochemical characteristics of the Mauna Kea shield which is adjacent to the Kilauea and Mauna Loa shields, 12 Mauna Kea shield basalts dredged from the submarine east rift were analyzed for major and trace element contents and isotopic (Sr, Nd, and Pb) ratios. The lavas are MgO-rich (11 to 20%), submarine erupted, tholeiitic basalts, but they are not representative of crystallized MgO-rich melts. Their whole rock and mineral compositions are consistent with mixing of an evolved magma, less than 7% MgO, with a magma containing abundant olivine xenocrysts, probably disaggregated from a dunitic cumulate. At a given MgO content, some of the Mauna Kea whole rocks have lower abundances of CaO and higher abundances of incompatible elements. The evolved melt component in these lavas reflects significant fractionation of plagioclase and clinopyroxene and in some cases even the late crystallizing phases orthopyroxene and Fe-Ti oxide. Although these Mauna Kea lavas are not isotopically homogenous, in general their Sr, Nd, and Pb isotopic ratios overlap with the fields for lavas from Loihi and Kilauea volcanoes.

  20. Carbonatitic lavas in Catanda (Kwanza Sul, Angola): Mineralogical and geochemical constraints on the parental melt

    NASA Astrophysics Data System (ADS)

    Campeny, Marc; Kamenetsky, Vadim S.; Melgarejo, Joan C.; Mangas, José; Manuel, José; Alfonso, Pura; Kamenetsky, Maya B.; Bambi, Aurora C. J. M.; Gonçalves, Antonio O.

    2015-09-01

    A set of small volcanic edifices with tuff ring and maar morphologies occur in the Catanda area, which is the only locality with extrusive carbonatites reported in Angola. Four outcrops of carbonatite lavas have been identified in this region and considering the mineralogical, textural and compositional features, we classify them as: silicocarbonatites (1), calciocarbonatites (2) and secondary calciocarbonatites produced by the alteration of primary natrocarbonatites (3). Even with their differences, we interpret these lava types as having been a single carbonatite suite related to the same parental magma. We have also estimated the composition of the parental magma from a study of melt inclusions hosted in magnetite microphenocrysts from all of these lavas. Melt inclusions revealed the presence of 13 different alkali-rich phases (e.g., nyerereite, shortite, halite and sylvite) that argues for an alkaline composition of the Catanda parental melts. Mineralogical, textural, compositional and isotopic features of some Catanda lavas are also similar to those described in altered natrocarbonatite localities worldwide such as Tinderet or Kerimasi, leading to our conclusion that the formation of some Catanda calciocarbonatite lavas was related to the occurrence of natrocarbonatite volcanism in this area. On the other hand, silicocarbonatite lavas, which are enriched in periclase, present very different mineralogical, compositional and isotopic features in comparison to the rest of Catanda lavas. We conclude that its formation was probably related to the decarbonation of primary dolomite bearing carbonatites.

  1. Raman spectroscopy of volcanic lavas and inclusions of relevance to astrobiological exploration.

    PubMed

    Jorge-Villar, Susana E; Edwards, Howell G M

    2010-07-13

    Volcanic eruptions and lava flows comprise one of the most highly stressed terrestrial environments for the survival of biological organisms; the destruction of botanical and biological colonies by molten lava, pyroclastic flows, lahars, poisonous gas emissions and the deposition of highly toxic materials from fumaroles is the normal expectation from such events. However, the role of lichens and cyanobacteria in the earlier colonization of volcanic lava outcrops has now been recognized. In this paper, we build upon earlier Raman spectroscopic studies on extremophilic colonies in old lava flows to assess the potential of finding evidence of biological colonization in more recent lava deposits that would inform, first, the new colonization of these rocks and also provide evidence for the relict presence of biological colonies that existed before the volcanism occurred and were engulfed by the lava. In this research, samples were collected from a recent expedition to the active volcano at Kilauea, Hawaii, which comprises very recent lava flows, active fumaroles and volcanic rocks that had broken through to the ocean and had engulfed a coral reef. The Raman spectra indicated that biological and geobiological signatures could be identified in the presence of geological matrices, which is encouraging for the planned exploration of Mars, where it is believed that there is evidence of an active volcanism that perhaps could have preserved traces of biological activity that once existed on the planet's surface, especially in sites near the old Martian oceans.

  2. Emplacement of the youngest flood lava on Mars: A short, turbulent story

    USGS Publications Warehouse

    Jaeger, W.L.; Keszthelyi, L.P.; Skinner, J.A.; Milazzo, M.P.; McEwen, A.S.; Titus, T.N.; Rosiek, M.R.; Galuszka, D.M.; Howington-Kraus, E.; Kirk, R.L.

    2010-01-01

    Recently acquired data from the High Resolution Imaging Science Experiment (HiRISE), Context (CTX) imager, and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) onboard the Mars Reconnaissance Orbiter (MRO) spacecraft were used to investigate the emplacement of the youngest flood-lava flow on Mars. Careful mapping finds that the Athabasca Valles flood lava is the product of a single eruption, and it covers 250,000 km2 of western Elysium Planitia with an estimated 5000-7500 km3 of mafic or ultramafic lava. Calculations utilizing topographic data enhanced with MRO observations to refine the dimensions of the channel system show that this flood lava was emplaced turbulently over a period of only a few to several weeks. This is the first well-documented example of a turbulently emplaced flood lava anywhere in the Solar System. However, MRO data suggest that this same process may have operated in a number of martian channel systems. The magnitude and dynamics of these lava floods are similar to the aqueous floods that are generally believed to have eroded the channels, raising the intriguing possibility that mechanical erosion by lava could have played a role in their incision. ?? 2009.

  3. Emplacement of the youngest flood lava on Mars: A short, turbulent story

    USGS Publications Warehouse

    Jaeger, W.L.; Keszthelyi, L.P.; Skinner, J.A.; Milazzo, M.P.; McEwen, A.S.; Titus, T.N.; Rosiek, M.R.; Galuszka, D.M.; Howington-Kraus, E.; Kirk, R.L.

    2009-01-01

    Recently acquired data from the High Resolution Imaging Science Experiment (HiRISE), Context (CTX) imager, and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) onboard the Mars Reconnaissance Orbiter (MRO) spacecraft were used to investigate the emplacement of the youngest flood-lava flow on Mars. Careful mapping finds that the Athabasca Valles flood lava is the product of a single eruption, and it covers 250,000 km2 of western Elysium Planitia with an estimated 5000-7500 km3 of mafic or ultramafic lava. Calculations utilizing topographic data enhanced with MRO observations to refine the dimensions of the channel system show that this flood lava was emplaced turbulently over a period of only a few to several weeks. This is the first well-documented example of a turbulently emplaced flood lava anywhere in the Solar System. However, MRO data suggest that this same process may have operated in a number of martian channel systems. The magnitude and dynamics of these lava floods are similar to the aqueous floods that are generally believed to have eroded the channels, raising the intriguing possibility that mechanical erosion by lava could have played a role in their incision.

  4. A review of mass and energy flow through a lava flow system: insights provided from a non-equilibrium perspective

    NASA Astrophysics Data System (ADS)

    Tarquini, Simone

    2017-08-01

    A simple formula relates lava discharge rate to the heat radiated per unit time from the surface of active lava flows (the "thermal proxy"). Although widely used, the physical basis of this proxy is still debated. In the present contribution, lava flows are approached as open, dissipative systems that, under favorable conditions, can attain a non-equilibrium stationary state. In this system framework, the onset, growth, and demise of lava flow units can be explained as a self-organization phenomenon characterized by a given temporal frequency defined by the average life span of active lava flow units. Here, I review empirical, physical, and experimental models designed to understand and link the flow of mass and energy through a lava flow system, as well as measurements and observations that support a "real-world" view. I set up two systems: active lava flow system (or ALFS) for flowing, fluid lava and a lava deposit system for solidified, cooling lava. The review highlights surprising similarities between lava flows and electric currents, which typically work under stationary conditions. An electric current propagates almost instantaneously through an existing circuit, following the Kirchhoff law (a least dissipation principle). Flowing lavas, in contrast, build up a slow-motion "lava circuit" over days, weeks, or months by following a gravity-driven path down the steepest slopes. Attainment of a steady-state condition is hampered (and the classic thermal proxy does not hold) if the supply stops before completion of the "lava circuit." Although gravity determines initial flow path and extension, the least dissipation principle means that subsequent evolution of mature portions of the active lava flow system is controlled by increasingly insulated conditions.

  5. Nyiragongo volcano, Congo, Perspective View with Lava SRTM / ASTER / Landsat

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Nyiragongo volcano in the Congo erupted on January 17, 2002, and subsequently sent streams of lava into the city of Goma on the north shore of Lake Kivu. More than 100 people were killed, more than 12,000 homes were destroyed, and hundreds of thousands were forced to flee the broader community of nearly half a million people. This computer-generated visualization combines a Landsat satellite image and an elevation model from the Shuttle Radar Topography Mission (SRTM) to provide a view of both the volcano and the city of Goma, looking slightly east of north. Additionally, image data from the Advanced Spaceborne Thermal Emission and reflection Radiometer (ASTER) on NASA's Terra satellite were used to supply a partial map of the recent lava flows (red), including a complete mapping of their intrusion into Goma as of January 28, 2002. Lava is also apparent within the volcanic crater and at a few other locations. Thick (but broken) cloud cover during the ASTER image acquisition prevented a complete mapping of the lava distribution, but future image acquisitions should complete the mapping.

    Nyiragongo is the steep volcano on the right, Lake Kivu is in the foreground, and the city of Goma has a light pink speckled appearance along the shoreline. Nyiragongo peaks at about 3,470 meters (11,380 feet) elevation and reaches almost exactly 2,000 meters (6,560 feet) above Lake Kivu. The shorter but broader Nyamuragira volcano appears in the left background. Topographic expression has been exaggerated vertically by a factor of 1.5 for this visualization.

    Goma, Lake Kivu, Nyiragongo, Nyamuragira and other nearby volcanoes sit within the East African Rift Valley, a zone where tectonic processes are cracking, stretching, and lowering the Earth's crust. Volcanic activity is common here, and older but geologically recent lava flows (magenta in this depiction) are particularly apparent on the flanks of the Nyamuragira volcano.

    The Landsat image used here was acquired

  6. Nyiragongo volcano, Congo, Perspective View with Lava SRTM / ASTER / Landsat

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Nyiragongo volcano in the Congo erupted on January 17, 2002, and subsequently sent streams of lava into the city of Goma on the north shore of Lake Kivu. More than 100 people were killed, more than 12,000 homes were destroyed, and hundreds of thousands were forced to flee the broader community of nearly half a million people. This computer-generated visualization combines a Landsat satellite image and an elevation model from the Shuttle Radar Topography Mission (SRTM) to provide a view of both the volcano and the city of Goma, looking slightly east of north. Additionally, image data from the Advanced Spaceborne Thermal Emission and reflection Radiometer (ASTER) on NASA's Terra satellite were used to supply a partial map of the recent lava flows (red), including a complete mapping of their intrusion into Goma as of January 28, 2002. Lava is also apparent within the volcanic crater and at a few other locations. Thick (but broken) cloud cover during the ASTER image acquisition prevented a complete mapping of the lava distribution, but future image acquisitions should complete the mapping.

    Nyiragongo is the steep volcano on the right, Lake Kivu is in the foreground, and the city of Goma has a light pink speckled appearance along the shoreline. Nyiragongo peaks at about 3,470 meters (11,380 feet) elevation and reaches almost exactly 2,000 meters (6,560 feet) above Lake Kivu. The shorter but broader Nyamuragira volcano appears in the left background. Topographic expression has been exaggerated vertically by a factor of 1.5 for this visualization.

    Goma, Lake Kivu, Nyiragongo, Nyamuragira and other nearby volcanoes sit within the East African Rift Valley, a zone where tectonic processes are cracking, stretching, and lowering the Earth's crust. Volcanic activity is common here, and older but geologically recent lava flows (magenta in this depiction) are particularly apparent on the flanks of the Nyamuragira volcano.

    The Landsat image used here was acquired

  7. Nyiragongo volcano, Congo, Perspective View with Lava SRTM / ASTER / Landsat

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Nyiragongo volcano in the Congo erupted on January 17, 2002, and subsequently sent streams of lava into the city of Goma on the north shore of Lake Kivu. More than 100 people were killed, more than 12,000 homes were destroyed, and hundreds of thousands were forced to flee the broader community of nearly half a million people. This computer-generated visualization combines a Landsat satellite image and an elevation model from the Shuttle Radar Topography Mission (SRTM) to provide a view of both the volcano and the city of Goma, looking slightly east of north. Additionally, image data from the Advanced Spaceborne Thermal Emission and reflection Radiometer (ASTER) on NASA's Terra satellite were used to supply a partial map of the recent lava flows (red), including a complete mapping of their intrusion into Goma as of January 28, 2002. Lava is also apparent within the volcanic crater and at a few other locations. Thick (but broken) cloud cover during the ASTER image acquisition prevented a complete mapping of the lava distribution, but future image acquisitions should complete the mapping.

    Nyiragongo is the steep volcano on the right, Lake Kivu is in the foreground, and the city of Goma has a light pink speckled appearance along the shoreline. Nyiragongo peaks at about 3,470 meters (11,380 feet) elevation and reaches almost exactly 2,000 meters (6,560 feet) above Lake Kivu. The shorter but broader Nyamuragira volcano appears in the left background. Topographic expression has been exaggerated vertically by a factor of 1.5 for this visualization.

    Goma, Lake Kivu, Nyiragongo, Nyamuragira and other nearby volcanoes sit within the East African Rift Valley, a zone where tectonic processes are cracking, stretching, and lowering the Earth's crust. Volcanic activity is common here, and older but geologically recent lava flows (magenta in this depiction) are particularly apparent on the flanks of the Nyamuragira volcano.

    The Landsat image used here was acquired

  8. Io's Volcanism: Thermo-Physical Models of Silicate Lava Compared with Observations of Thermal Emission

    NASA Technical Reports Server (NTRS)

    Davies, Ashely G.

    1996-01-01

    Analyses of thermal infrared outbursts from the jovian satellite Io indicate that at least some of these volcanic events are due to silicate lava. Analysis of the January 9, 1990 outburst indicates that this was an active eruption consisting of a large lava flow (with mass eruption rate of order 10(exp 5) cubic m/sec) and a sustained area at silicate liquidus temperatures. This is interpreted as a series of fire fountains along a rift zone. A possible alternative scenario is that of an overflowing lava lake with extensive fire fountaining. The January 9, 1990 event is unique as multispectral observations with respect to time were obtained. In this paper, a model is presented for the thermal energy lost by active and cooling silicate lava flows and lakes on Io. The model thermal emission is compared with Earth-based observations and Voyager IRIS data. The model (a) provides an explanation of the thermal anomalies on Io's surface; (b) provides constraints on flow behavior and extent and infers some flow parameters; and (c) determines flow geometry and change in flow size with time, and the temperature of each part of the flow or lava lake surface as a function of its age. Models of heat output from active lava flows or inactive but recently emplaced lava flows or overturning lava lakes alone are unable to reproduce the observations. If the January 9, 1990 event is the emplacement of a lava flow, the equivalent of 27 such events per year would yield a volume of material sufficient, if uniformly distributed, to resurface all of Io at a rate of 1 cm/year.

  9. Mapping lava flow textures using three-dimensional measures of surface roughness

    NASA Astrophysics Data System (ADS)

    Mallonee, H. C.; Kobs-Nawotniak, S. E.; McGregor, M.; Hughes, S. S.; Neish, C.; Downs, M.; Delparte, D.; Lim, D. S. S.; Heldmann, J. L.

    2016-12-01

    Lava flow emplacement conditions are reflected in the surface textures of a lava flow; unravelling these conditions is crucial to understanding the eruptive history and characteristics of basaltic volcanoes. Mapping lava flow textures using visual imagery alone is an inherently subjective process, as these images generally lack the resolution needed to make these determinations. Our team has begun mapping lava flow textures using visual spectrum imagery, which is an inherently subjective process involving the challenge of identifying transitional textures such as rubbly and slabby pāhoehoe, as these textures are similar in appearance and defined qualitatively. This is particularly problematic for interpreting planetary lava flow textures, where we have more limited data. We present a tool to objectively classify lava flow textures based on quantitative measures of roughness, including the 2D Hurst exponent, RMS height, and 2D:3D surface area ratio. We collected aerial images at Craters of the Moon National Monument (COTM) using Unmanned Aerial Vehicles (UAVs) in 2015 and 2016 as part of the FINESSE (Field Investigations to Enable Solar System Science and Exploration) and BASALT (Biologic Analog Science Associated with Lava Terrains) research projects. The aerial images were stitched together to create Digital Terrain Models (DTMs) with resolutions on the order of centimeters. The DTMs were evaluated by the classification tool described above, with output compared against field assessment of the texture. Further, the DTMs were downsampled and reevaluated to assess the efficacy of the classification tool at data resolutions similar to current datasets from other planetary bodies. This tool allows objective classification of lava flow texture, which enables more accurate interpretations of flow characteristics. This work also gives context for interpretations of flows with comparatively low data resolutions, such as those on the Moon and Mars. Textural maps based on

  10. Geochemistry of tholeiitic and alkalic lavas from the Koolau Range, Oahu, Hawaii: implications for Hawaiian volcanism

    USGS Publications Warehouse

    Roden, M.F.; Frey, F.A.; Clague, D.A.

    1984-01-01

    Lavas of the post-erosional, alkalic Honolulu Volcanics have significantly lower 87Sr 86Sr and higher 143Nd 144Nd than the older and underlying Koolau tholeiites which form the Koolau shield of eastern Oahu, Hawaii. Despite significant compositional variation within lavas forming the Honolulu Volcanics, these lavas are isotopically (Sr, Nd, Pb) very similar which contrasts with the isotopic heterogeneity of the Koolau tholeiites. Among Hawaiian tholeiitic suites, the Koolau lavas are geochemically distinct because of their lower iron contents and Sr and Nd isotopic ratios which range to bulk earth values. These geochemical data preclude simple models such as derivation of the Honolulu Volcanics and Koolau tholeiites from a common source by different degrees of melting or by mixing of two geochemically distinct sources. There may be no genetic relationship between the origin and evolution of these two lava suites; however, the trend shown by Koolau Range lavas of increasing 143Nd 144Nd and decreasing 87Sr 86Sr with decreasing eruption age and increasing alkalinity also occurs at Haleakala, East Molokai and Kauai volcanoes. A complex mixing model proposed for Haleakala lavas can account for the variations in Sr and Nd isotopic ratios and incompatible element abundances found in lavas from the Koolau Range. This model may reflect mixing and melting processes occurring during ascent of relatively enriched mantle through relatively depleted MORB-related lithosphere. Although two isotopically distinct components may be sufficient to explain Sr and Nd isotopic variations at individual Hawaiian volcanoes, more than two isotopically distinct materials are required to explain variations of Sr, Nd and Pb isotopic ratios in all Hawaiian lavas. ?? 1984.

  11. Investigating Cooling Rates of a Controlled Lava Flow using Infrared Imaging and Three Heat Diffusion Models

    NASA Astrophysics Data System (ADS)

    Tarlow, S.; Lev, E.; Zappa, C. J.; Karson, J.; Wysocki, B.

    2011-12-01

    Observation and investigation of surface cooling rates of active lava flows can help constrain thermal parameters necessary for creating of more precise lava flow models. To understand how the lava cools, temperature data was collected using an infrared video camera. We explored three models of the release of heat from lava stream; one based on heat conduction, another based on crust thickness and radiation, and a third model based on radiative cooling and variable crust thickness. The lava flow, part of the Syracuse University Lava Project (http://lavaproject.syr.edu), was made by pouring molten basalt at 1300 Celsius from a furnace into a narrow trench of sand. Hanging roughly 2 m over the trench, the infrared camera, records the lava's surface temperature for the duration of the flow. We determine the average surface temperature of the lava flow at a fixed location downstream as the mean of the lateral cross section of each frame of the IR imagery. From the recorded IR frames, we calculate the mean cross-channel temperature for each downstream distance. We then examine how this mean temperature evolves over time, and plot cooling curves for selected down-stream positions. We then compared the observed cooling behavior to that predicted by three cooling models: a conductive cooling model, a radiative cooling model with constant crust thickness, and a radiative cooling model with variable crust thickness. All three models are solutions to the one-dimensional heat equation. To create the best fit for the conductive model, we constrained thermal diffusivity and to create the best fit for the radiative model, we constrained crust thickness. From the comparison of our data to the models we can conclude that the lava flow's cooling is primarily driven by radiation.

  12. Factors Influencing Lava-Substrate Heat Transfer and Implications for Thermomechanical Erosion

    NASA Technical Reports Server (NTRS)

    Fagents, S. A.; Greeley, R.; Lenat, J. F. (Editor)

    2001-01-01

    We develop numerical simulations of basaltic lava flowing laminarly over a basalt substrate in order to examine the details of the lava dynamics and thermal boundary layers and to understand the implications for substrate heating. As the initial stage of a larger study of thermomechanical erosion in different planetary environments, we aim to understand why erosion occurs on Earth, why erosion features are not ubiquitous given the high temperatures involved, and whether it is a plausible mechanism for the formation of planetary channels such as lunar sinuous rilles and Venusian canali. Here we confine our attention to terrestrial lavas with well-known properties and eruption parameters. With relatively simple computational fluid dynamic simulations, most closely representing tube-fed hawaiian basalts (for which erosion has been documented), we demonstrate the importance of incorporating several key factors in models of lava flow/ substrate heat transfer, which have commonly been neglected in previous treatments. By addressing the interaction of the flow dynamics and heat transfer in the lava, our work suggests that the development of a temperature gradient in the base of the lava, even for undeveloped flow, has a significant influence on substrate temperature. The sensitivity of the lava-substrate interface temperature to the thermophysical properties of the lava and substrate suggests that a delicate balance is required for partial melting to occur. Thus, it might take weeks of continuous flow to initiate partial melting of the substrate at distances of several kilometers from the vent. These durations exceed the periods of stability typical of lava flowing in tubes; pauses, blockages, surges, and break-outs frequently disrupt the flow. However, natural irregularities in the flow dynamics or substrate topography might help to initiate and maintain substrate melting on shorter timescales by disturbing the intimately coupled dynamic and thermal boundary layers

  13. The chemistry of lava-seawater interactions: The generation of acidity

    SciTech Connect

    Resing, J.A.; Sansone, F.J.

    1999-08-01

    High concentrations of acid were found to arise from the interaction between molten rock and seawater at the shoreline of Kilauea Volcano, Hawaii. A series of field samplings and experiments show that the acid was derived from two sources: the release of magmatic volatiles and water-rock reactions. Although the bulk of the magmatic volatiles (CO{sub 2}, H{sub 2}O, and SO{sub 2}) are vented at Puu Oo cinder cone before the lava`s transit downslope to the ocean, a portion of the sulfur (S) and fluoride (F) gases are retained by the lava and then are released partially when the lava is quenched by seawater. The primary water-rock reaction responsible for acid formation appears to be Na-metasomatism, which is much different from the predominant acid-forming reaction found in submarine hydrothermal systems, Mg-metasomatism. Analyses of surface seawater and of precipitation (rain) deposited at the shore show that {approximately}30% of the acid comes from magmatic gases with the balance from reactions between the rock and the salts found in seawater. Experimental results show that {approximately}4 {+-} 1.5 mEq of acid are formed per kilogram of lava entering the ocean, and of this 1 {+-} 0.5 mEq/kg of lava came from S and F, with the balance coming from water-rock reactions. On the basis of lava extrusion rates, {approximately}200--720 {times} 10{sup 6} Eq/yr of acid are being formed at this site. The deposition of the acid results in the alteration of subaerial lava flows along the coast, and the lowering of the pH of the adjacent surface ocean waters by more than 1 unit. The ejection of this acid into the atmosphere contributes to the formation of an extensive haze downwind of the lava entries.

  14. 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.

  15. Dating Young Lava Flows with Cosmogenic 36Cl: AN Example from the Late Pleistocene - Early Holocene ERCİYES Monogenetic Lava Domes in Central Turkey

    NASA Astrophysics Data System (ADS)

    Akif Sarıkaya, M.; Çiner, Attila; Şen, Erdal; Ersoy, Orkun; Zreda, Marek

    2017-04-01

    Precise dating of young lava flows is generally problematic because of the limiting factors of the applied technique. In-situ produced cosmogenic nuclides can be used to date very young lava flows if they show simple exposure histories and proper geochemistries. The Erciyes stratovolcano in the central Turkey has several dacite-rhyodacite monogenic parasitic lava domes that show clear exposure histories. Four young volcanic domes on the flanks of Erciyes Volcano have fresh-looking surfaces that are datable by cosmogenic surface exposure dating. We collected 36 cosmogenic samples from four lava flows namely Karagüllü, Perikartını, Dikkartın and Çarık, and obtained 36Cl exposure ages, all around Early Holocene, except for Çarık Lava flow which gave much older ages. Karagüllü, Perikartını and Dikkartın eruptions yielded average exposure ages at around 7.2±0.9 ka (n=11), 7.7±0.4 ka (n=6) and 8.8±0.6 ka (n=9), respectively. Two different eruption histories were determined from the Çarık Lava flow. They were centred at around 98.4±3.6 ka (n=7) and 36.1±1.1 ka (n=3). We also tested our results by an independent dating method. The Perikartını eruption generated a pyroclastic flow that buried trees that were converted to charcoal. Two charcoal samples found in this flow were dated using the 14C method, and yielded an average age of 9735±155 years BP (calibrated using Calib 7.1). Our results show that the cosmogenic 36Cl ages from Perikartını flow (7.7±0.4 ka) are younger than the radiocarbon ages (9.7±0.2 ka). This discrepancy might be related either to the high Cl content (963 ppm) of the lava flow or high nucleogenic production of 36Cl due to the above average U (5.1 ppm) and Th (15.6 ppm) concentrations. The high Cl content of the samples may result erroneously (>20%) underestimated the low-energy neutron capture (epithermal and thermal) production rates. On the other hand, the calculated nucleogenic 36Cl makes up almost one-third of the

  16. Insight Into Lava Sheet Inflation and Deflation Events From the McCartys Flow, New Mexico, and Implications for Planetary Lava Flow Emplacement

    NASA Astrophysics Data System (ADS)

    Bleacher, J. E.; Garry, W. B.; Zimbelman, J. R.; Crumpler, L. S.

    2007-12-01

    Basaltic lavas typically form channels or tubes during flow away from a vent. However, the importance of sheet flow in the development of basaltic terrains has gained attention within the last 15 years. The McCartys lava flow field (NM) is among the youngest (~3000 yrs) basaltic lava flows in the continental United States. It was emplaced over slopes of < 1 degree, displaying features suggested to represent lava sheet inflation and deflation. Therefore, it among the most pristine examples of sheet flow morphologies in the United States. Here we present field observations of this flow field. At the meter scale the interior flow surface typically forms smooth, undulating lobes that appear to represent breakouts from adjacent lobes. These features display grooved surfaces and occasional squeeze-ups along lobe contacts. At the scale of 10s to 100s of meters the flow comprises multiple topographic platforms and depressions. Some depressions display level floors with surfaces as described above, while some are bowl shaped with floors covered in broken lava slabs. The boundaries between platforms and depressions are also typically smooth, grooved surfaces that have been tilted to angles sometimes approaching vertical. The upper margin of these tilted surfaces typically displays large cracks parallel to the boundary, sometimes containing squeeze-ups. The bottom boundary with smooth floored depressions typically shows embayment by younger lavas. The superposition relationships between platforms, depressions, and small lava flows within depressions are complex. It appears that this style of terrain represents the emplacement of an extensive, sheet, likely as one large unit. The sheet experiences inflation episodes within preferred regions, which produce platforms of varied elevations. Inflation events appear to be associated with breakouts of lava which flood the floors of accessible depressions. Depressions are the result of non-inflation, or collapse of an inflated surface

  17. Magma ascent dynamic through Ti diffusion in magnetites. Application to lava dome-forming eruptions. Implications to lava dome superifical explosivity.

    NASA Astrophysics Data System (ADS)

    Boudon, Georges; Balcone-Boissard, Hélène; Morgan, Dan J.

    2016-04-01

    Superficial lava dome explosivity represents a major hazard during lava dome growth. But the origin of this explosive activity remains unclear until recently. By using geochemical (residual water content, silica abundance) and textural (vesicularity, microcristallinity) data, we constrain the occurrence of such hazard to the beginning of the lava dome activity. During the first stages of growth, the lava dome is small enough to develop an impermeable carapace that isolates a less degassed batch of magma inside, thus allowing an internal overpressurization of the volcano (Boudon et al., 2015). This study more precisely details the petrology and the texture of titano-magnetites as archive of magma ascent dynamic within the conduit. Titano-magnetites may exhibit two types of textures: exsolved or "limpid". When they are exsolved, no time constrain may be extracted as they re-equilibrate. On the contrary, when they are unexsolved, major element distribution, in particular Ti, may act as a powerful tool to decipher magma dynamic (differentiation, mixing) and estimate time that corresponds to the magma ascent time. The composition and elemental diffusion profiles are acquired by EPMA, following textural investigations by SEM. The time is then obtained by modelling the profile as a diffusion profile using the intracristalline diffusion coefficients published in literature. We applied this methodology to examples of lava dome superficial explosivity on Montagne Pelée in Martinique (Lesser Antilles Arc), and on Puy Chopine volcano in La Chaine des Puys, (French Massif Central). More precisely, the first phase of the Puy Chopine lava dome growth experienced a superficial explosion, as for Montagne Pelée, the first stages of the 1902 eruption (several superficial explosions occurred) and the 650 y. BP eruption (two superficial explosions destroyed the growing lava dome). We show that, for a single event, the vesiculated, undegassed batch of magma responsible of the

  18. The formation of perched lava ponds on basaltic volcanoes: the influence of flow geometry on cooling-limited lava flow lengths

    NASA Astrophysics Data System (ADS)

    Wilson, Lionel; Parfitt, Elisabeth A.

    1993-05-01

    Analysis of the formation of morphologically distinctive perched lava ponds produced in effusive basaltic eruptions focusses attention on the ways in which cooling and fluid dynamics interact to limit the distance a lava flow can travel. If a previously channelised flow spreads laterally on encountering a sudden decrease in the slope of the substrate or some other abrupt change in topography, its speed and thickness decrease progressively, in a way dictated by the requirements of mass and energy conservation. There is a consequent dramatic increase in heat loss from the lava as it thins. Where a flow spreads approximately radially in this way, it may form a perched lava pond. The high heat loss limits the size of any such pond to be at most a few hundred meters under almost all circumstances. Pond size depends much more strongly on lava volume flux than on any other physical parameter involved in the system, and the formation of these features provides a means of estimating eruption rates in paleo-eruptive episodes.

  19. Explosive lava-water interactions II: self-organization processes among volcanic rootless eruption sites in the 1783-1784 Laki lava flow, Iceland

    NASA Astrophysics Data System (ADS)

    Hamilton, Christopher W.; Fagents, Sarah A.; Thordarson, Thorvaldur

    2010-05-01

    We have applied quantitative geospatial analyses to rootless eruption sites in the Hnúta and Hrossatungur groups of the 1783-1784 Laki lava flow to establish how patterns of spatial distribution can be used to obtain information about rootless cone emplacement processes and paleo-environments. This study utilizes sample-size-dependent nearest neighbor (NN) statistics and Voronoi tessellations to quantify the spatial distribution of rootless eruption sites and validate the use of statistical NN analysis as a remote sensing tool. Our results show that rootless eruption sites cluster in environments with abundant lava and water resources, but competition for limited groundwater in these clusters can cause rootless eruption sites to develop repelled distributions. This pattern of self-organization can be interpreted within the context of resource availability and depletion. Topography tends to concentrate lava (fuel) and water (coolant) within topographic lows, thereby promoting explosive lava-water interactions in these regions. Given an excess supply of lava within broad sheet lobes, rootless eruption sites withdraw groundwater from their surroundings until there is insufficient water to maintain analogs to explosive molten fuel-coolant interactions. Rootless eruption sites may be modeled as a network of water extraction wells that draw down the water table in their vicinity. Rootless eruptions at locations with insufficient groundwater may either fail to initiate or terminate before explosive activity has ceased at nearby locations with a greater supply of water, thus imparting a repelled distribution to observed rootless eruption sites.

  20. Lava-flow characterization at Pisgah Volcanic Field, California, with multiparameter imaging radar

    USGS Publications Warehouse

    Gaddis, L.R.

    1992-01-01

    Multi-incidence-angle (in the 25?? to 55?? range) radar data aquired by the NASA/JPL Airborne Synthetic Aperture Radar (AIRSAR) at three wavelengths simultaneously and displayed at three polarizations are examined for their utility in characterizing lava flows at Pisgah volcanic field, California. Pisgah lava flows were erupted in three phases; flow textures consist of hummocky pahoehoe, smooth pahoehoe, and aa (with and without thin sedimentary cover). Backscatter data shown as a function of relative age of Pisgah flows indicate that dating of lava flows on the basis of average radar backscatter may yield ambiguous results if primary flow textures and modification processes are not well understood. -from Author

  1. Using submarine lava pillars to record mid-ocean ridge eruption dynamics

    USGS Publications Warehouse

    Gregg, Tracy K.P.; Fornari, Daniel J.; Perfit, Michael R.; Ridley, W. Ian; Kurz, Mark D.

    2000-01-01

    Submarine lava pillars are hollow, glass-lined, basaltic cylinders that occur at the axis of the mid-ocean ridge, and within the summit calderas of some seamounts. Typically, pillars are ~1-20 m tall and 0.25-2.0 m in diameter, with subhorizontal to horizontal glassy selvages on their exterior walls. Lava pillars form gradually during a single eruption, and are composed of lava emplaced at the eruption onset as well as the last lava remaining after the lava pond has drained. On the deep sea floor, the surface of a basaltic lava flow quenches to glass within 1 s, thereby preserving information about eruption dynamics, as well as chemical and physical properties of lava within a single eruption. Investigation of different lava pillars collected from a single eruption allows us to distinguish surficial lava-pond or lava-lake geochemical processes from those operating in the magma chamber. Morphologic, major-element, petrographic and helium analyses were performed on portions of three lava pillars formed during the April 1991 eruption near 9°50'N at the axis of the East Pacific Rise. Modeling results indicate that the collected portions of pillars formed in ~2-5 h, suggesting a total eruption duration of ~8-20 h. These values are consistent with observed homogeneity in the glass helium concentrations and helium diffusion rates. Major-element compositions of most pillar glasses are homogeneous and identical to the 1991 flow, but slight chemical variations measured in the outermost portions of some pillars may reflect post-eruptive processes rather than those occurring in subaxial magma bodies. Because lava pillars are common at mid-ocean ridges (MORs), the concepts and techniques we present here may have important application to the study of MOR eruptions, thereby providing a basis for quantitative comparisons of volcanic eruptions in geographically and tectonically diverse settings. More research is needed to thoroughly test the hypotheses presented here. (C) 2000

  2. Diversion of lava flows by aerial bombing — lessons from Mauna Loa volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Lockwood, J. P.; Torgerson, F. A.

    1980-12-01

    Lava flows from Mauna Loa volcano can travel the long distances from source vents to populated areas of east Hawaii only if heat-insulating supply conduits (lava channels and/or lava tubes) are constructed and maintained, so as to channelize the flow and prevent heat loss during transport. Lava is commonly directed into such conduits by horseshoe-or lyre-shaped spatter cones-loose accumulations of partially welded scoria formed around principal vents during periods of high fountaining. These conduit systems commonly develop fragile areas amenable to artificial disruption by explosives during typical eruptions. If these conduits can be broken or blocked, lava supply to the threatening flow fronts will be cut off or reduced. Explosives were first suggested as a means to divert lava flows threatening Hilo, Hawaii during the eruption of 1881. They were first used in 1935, without significant success, when the Army Air Force bombed an active pahoehoe channel and tube system on Mauna Loa’s north flank. Channel walls of a Mauna Loa flow were also bombed in 1942, but again there were no significant effects. The locations of the 1935 and 1942 bomb impact areas were determined and are shown for the first time, and the bombing effects are documented. Three days after the 1942 bombing the spatter cone surrounding the principal vent partially collapsed by natural processes, and caused the main flow advancing on Hilo to cease movement. This suggested that spatter cones might be a suitable target for future lava diversion attempts. Because ordnance, tactics, and aircraft delivery systems have changed dramatically since 1942, the U.S. Air Force conducted extensive testing of large aerial bombs (to 900 kg) on prehistoric Mauna Loa lavas in 1975 and 1976, to evaluate applicability of the new systems to lava diversion. Thirty-six bombs were dropped on lava tubes, channels, and a spatter cone in the tests, and it was verified that spatter cones are especially fragile. Bomb crater

  3. Measurements of wind friction speeds over lava surfaces and assessment of sediment transport

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald; Iversen, James D.

    1987-01-01

    Wind velocity profiles were obtained over alluvial plains, lava flows, and a cinder cone in the Mojave Desert to determine the wind shear and the potential for particle transport. It was found that aerodynamic roughness for winds increases nearly a factor of 5 as flow crosses from the alluvium to the lava surface, resulting in wind shear that is 21 percent greater. Thus, wind erosion and sand flux may be substantially enhanced over the lava field. Moreover, wind flow turbulence is enhanced in the wake of the cinder cone, which also increases erosion and sediment transportation by the wind.

  4. The cooling rates of pahoehoe flows: The importance of lava porosity

    NASA Technical Reports Server (NTRS)

    Jones, Alun C.

    1993-01-01

    Many theoretical models have been put forward to account for the cooling history of a lava flow; however, only limited detailed field data exist to validate these models. To accurately model the cooling of lava flows, data are required, not only on the heat loss mechanisms, but also on the surface skin development and the causes of differing cooling rates. This paper argues that the cause of such variations in the cooling rates are attributed, primarily, to the vesicle content and degassing history of the lava.

  5. Lunar and Hawaiian lava tubes: Analogs and uses based on terrestrial field data

    NASA Technical Reports Server (NTRS)

    Coombs, Cassandra R.; Hawke, B. Ray

    1991-01-01

    Presented here is an analysis of the data collected for a large number of Hawaiian lava tubes on the islands of Oahu, Molokai, and Hawaii. The results are extrapolated to lunar conditions. It is argued that lava tubes that formed on the Earth and the Moon are relatively stable over time, as illustrated by the ridigity of the Hawaiian prehistoric lava tubes as well as the historic tubes located in the bombing range near Mauna Loa. These natural structures should be considered for use in planning for the expansion and advanced stages of the future manned lunar base.

  6. RIS4E at Kilauea's December 1974 Flow: Lava Flow Texture LiDAR Signatures

    NASA Astrophysics Data System (ADS)

    Whelley, P.; Garry, W. B.; Scheidt, S. P.; Bleacher, J. E.; Hamilton, C.

    2015-12-01

    High-resolution point clouds and digital terrain models (DTMs) are used to investigate lava textures on the Big Island of Hawaii. Lava texture (e.g., ´áā and pāhoehoe) depends significantly on eruption conditions, and it is therefore instructive, if accurately determined. In places where field investigations are prohibitive (e.g., on other planets and remote regions of Earth) lava texture must be assessed from remote sensing data. A reliable method for doing so remains elusive. The December 1974 flow from Kilauea, in the Kau desert, presents an excellent field site to develop techniques for identifying lava texture. The eruption is young and the textures are well preserved. We present results comparing properties of lava textures observed in Terrestrial Laser Scanning (TLS) data. The authors collected the TLS data during May 2014 and June 2015 field seasons. Scans are a quantitative representation of what a geologist, or robotic system, sees "on the ground" and provides "ground truth" for airborne or orbital remote sensing analysis by enabling key parameters of lava morphology to be quantified. While individual scans have a heterogeneous point density, multiple scans are merged such that sub-cm lava textures can be quantified. Results indicate that TLS-derived surface roughness (i.e., de-trended RMS roughness) is useful for differentiating lava textures and assists volcanologic interpretations. As many lava types are quite rough, it is not simply roughness that is the most advantageous parameter for differentiating lava textures; rather co-occurrence patterns in surface roughness are used. Gradually forming textures (e.g., pāhoehoe) are elevated in statistics that measure smoothness (e.g., homogeneity) while lava with disrupted crusts (e.g., slabby and platy flow) have more random distributions of roughness (i.e., high entropy). A similar technique will be used to analyze high-resolution DTMs of martian lava flows using High Resolution Imaging Science

  7. Topaz rhyolites of Nathrop, Colorado: Lava domes or rheomorphic flows?

    NASA Astrophysics Data System (ADS)

    Hernandez, B. M.; Panter, K. S.; Van Der Voo, R.

    2013-12-01

    Deposits of topaz-bearing rhyolite at Ruby and Sugarloaf Mountains in central Colorado are considered to be remnants of lava domes. The deposits are part of the Late Eocene-Oligocene Central Colorado Volcanic Field [1] that lies along the eastern margin of the Arkansas Graben of the Rio Grande Rift. Topaz-bearing rhyolite lava domes and flows have been identified elsewhere in Colorado and the western U.S., but an assortment of geomorphological, lithostratigraphical, and textural features of Ruby and Sugarloaf Mountains call into question their strict classification as such. Alternatively, the lava flows may be interpreted as rheomorphic ignimbrites. The volcanic deposits encompass a sequence of steeply (~70°) west-dipping units that form two N-S elongated edifices ~0.5 km long and a few hundred meters high. Their common lithostratigraphy from bottom to top is tuff breccia, vitrophyre, and flow-banded rhyolite. The tuff breccia includes large (up to ~1 m) pumice blocks and lithics that vary from nearly absent to moderately abundant (10-20%). At Sugarloaf lithics include rare cobble-sized clasts of granite, but the majority consists of flow-banded rhyolite. The tuff breccia grades normally upward into the vitrophyre with increased welding and a eutaxitic fabric defined by fiamme with increasing aspect ratios. Lithics are abundant in the vitrophyre at Sugarloaf but are rare or absent in the vitrophyre at Ruby Mountain. The transition from the vitrophyre to the flow-banded rhyolite is abrupt (<1 m) at both locations, though the lower rhyolite is less competent. The flow-banded rhyolite at Sugarloaf is crystal-rich (up to 50%), containing plagioclase, sanidine, smoky quartz, and biotite, while at Ruby the rhyolite is relatively crystal poor (2-3%) and biotite is absent. Pumiceous zones and lithophysae occur within the rhyolite at both locations. Zones of auto-brecciation are often associated with convoluted flow banding, especially along a vertical contact with

  8. Pb isotope geochemistry of Piton de la Fournaise historical lavas

    NASA Astrophysics Data System (ADS)

    Vlastélic, Ivan; Deniel, Catherine; Bosq, Chantal; Télouk, Philippe; Boivin, Pierre; Bachèlery, Patrick; Famin, Vincent; Staudacher, Thomas

    2009-07-01

    Variations of Pb isotopes in historical lavas (1927-2007) from Piton de la Fournaise are investigated based on new (116 samples) and published (127 samples) data. Lead isotopic signal exhibits smooth fluctuations (18.87 < 206Pb/ 204Pb < 18.94) on which superimpose unradiogenic spikes ( 206Pb/ 204Pb down to 18.70). Lead isotopes are decoupled from 87Sr/ 86Sr and 143Nd/ 144Nd, which display small and barely significant variations, respectively. No significant change of Pb isotope composition occurred during the longest (> 3 years) periods of inactivity of the volcano (1939-1942, 1966-1972, 1992-1998), supporting previous inferences that Pb isotopic variations occur mostly during and not between eruptions. Intermediate compositions (18.904 < 206Pb/ 204Pb < 18.917) bracket the longest periods of quiescence. In this respect, the highly frequent occurrence of an intermediate composition (18.90 < 206Pb/ 204Pb < 18.91), which clearly defines an isotopic baseline during the most recent densely sampled period (1975-2007), either suggests direct sampling of plume melts or sampling of a voluminous magma reservoir that buffers Pb isotopic composition. Deviations from this prevalent composition occurred during well-defined time periods, namely 1977-1986 (radiogenic signature), 1986-1990 and 1998-2005 (unradiogenic signatures). The three periods display a progressive isotopic drift ending by a rapid return (mostly during a single eruption) to the isotopic baseline. The isotopic gradients could reflect progressive emptying of small magma reservoirs or magma conduits, which are expected to be more sensitive to wall-rock interactions than the main magma chamber. These gradients provide a lower bound ranging from 0.1 to 0.17 km 3 for the size of the shallow magma storage system. The isotopic shifts (March 1986, January 1990 and February 2005) are interpreted as refilling the plumbing system with deep melts that have not interacted with crustal components. The volume of magma

  9. Dynamics of a fluid flow on Mars: lava or mud?

    NASA Astrophysics Data System (ADS)

    Wilson, L.; Mouginis-Mark, P. J.

    2013-12-01

    We have identified an enigmatic flow in S.W. Cerberus Fossae, Mars. The flow originates from an almost circular pit within a remnant of a yardang at 0.58 degrees N, 155.28 degrees E, within the lower unit of the Medusae Fossae Formation. The flow is ~42 km long and 0.5 to 2.0 km wide. The surface textures of the resulting deposit show that the material flowed in such a way that the various deformation patterns on its surface were generally preserved as it moved, only being distorted or disrupted when the flow encountered major topographic obstacles or was forced to make rapid changes of direction. This observation of a stiff, generally undeformed surface layer overlying a relatively mobile base suggests that, while it was moving, the fluid material flowed in a laminar, and possibly non-Newtonian, fashion. The least-complicated non-Newtonian fluids are Bingham plastics. On this basis we use measurements of flow width, length, thickness and substrate slope obtained from images, a DEM constructed from stereo pairs of Context Camera (CTX) images, and Mars Orbiter Laser Altimeter (MOLA) altimetry points to deduce the rheological properties of the fluid, treating it as both a Newtonian and a Bingham material for comparison. The Newtonian option requires the fluid to have a viscosity close to 100 Pa s and to have flowed everywhere in a turbulent fashion. The Bingham option requires laminar flow, a plastic viscosity close to 1 Pa s, and a yield strength of ~185 Pa. We compare these parameters values with those of various environmental fluids on Earth in an attempt to narrow the range of possible materials forming the martian flow. A mafic to ultramafic lava would fit the Newtonian option but the required turbulence does not seem consistent with the surface textures. The Bingham option satisfies the morphological constraint of laminar motion if the material is a mud flow consisting of ~40% water and ~60% silt-sized silicate solids. Elsewhere on Mars, deposits with similar

  10. An RET Experience with Geochemical Analysis of Azores Lavas

    NASA Astrophysics Data System (ADS)

    Carpenter, C.; D'Albany, D.; Humayun, M.; Dixon, P.

    2009-12-01

    Each summer, the Center for Integrating Research and Learning (CIRL) at the National High Magnetic Field Laboratory (NHMFL) operates a Research Experiences for Teachers (RET) program. This six-week program provides stipends for teachers to work in the laboratories of NHMFL scientists. Faculty members of the Geochemistry Program at the NHMFL frequently host RET teachers to facilitate the broader dissemination of Geoscience knowledge among K-12 educators. During the summer of 2009, David d’Albany and Charles Carpenter, participated in the RET program for K-12 teachers at the NHMFL in Tallahassee, Florida. Mr. d’Albany is a Biology teacher at King IB High School in Tampa, Florida. Mr. Carpenter is a Physics teacher at Lawton Chiles High School in Tallahassee, Florida. Both teachers had the opportunity to analyze the elemental composition of a volcanic rock from the Azores Islands, in the North Atlantic. The Azores Islands represent a set of nine volcanic islands, near the active Azores Triple Junction, on the mid-Atlantic Ridge around 38°N, generally conceived as the products of a deep mantle plume. The analytical method used was Laser Ablation Inductively Coupled Plasma Mass Spectrometry (ICP-MS) using a New Wave UP193FX excimer laser ablation system coupled to a Thermo Element XR magnetic sector ICP-MS. This method allowed solid sampling of a large area of the basaltic matrix, and separately of the olivine (peridot) crystals within the matrix, from a lava sample from the island of Faial. Elemental data were obtained on a broader spectrum of elements (65 elements) than currently available in the geochemical literature for these islands. Chondrite-normalized rare earth element abundances for the sample provided a precise match with data for other lavas from the island of Faial from the GEOROC database. It should be noted that all 14 lanthanides, excluding Pm, were measured with ICP-MS, compared with about 8 elements determined by previous bulk rock techniques

  11. Characteristics of a young lava-hyaloclastite sheet, Snaebylisheidi, Iceland

    NASA Astrophysics Data System (ADS)

    White, J. D.; Gorny, C. F.; Gudmundsson, M. T.

    2009-12-01

    Extensive sheets of hyaloclastite volcaniclastic debris, coupled with and intruded by largely underlying layers of coherent basalt, are common in the Sida area of southeastern Iceland. They were initially interpreted as submarine deposits, but have recently been re-interpreted as nonmarine deposits formed in the presence of glaciers. Detailed interpretation of the units has been challenging, because their source areas are not preserved. A younger deposit of the same type forms an elongate flat-topped ridge in the Snaebylisheidi area. Its volume of ca. 35 cubic km is similar to that of the larger Sida units, its source area is preserved, and parts of the deposit remain unlithified. Our initial investigation reveals that the source area is dominated by clastic deposits. There is no evidence for a source edifice of pillow or sheet lavas, but there are extensive low-level intrusions near the base, and a plexus of smaller high-level intrusions showing evidence of high viscosities during emplacement. Isolated pillows and other fluidal juvenile clasts near the source lie within matrices of highly vesicular ash and lapilli, or of mixed vesicular and dense glassy fragments. Downstream in the unit, deposits are dominated by dense clasts, and these can in places be demonstrated to have been derived locally from the underlying to intruding basalt sheet. Larger dense clasts are commonly highly irregular, vuggy, and composite; in places many are rolled into subspherical forms enclosing matrix material comprising dense angular glass fragments. The clastic part of the unit has an upper subunit dominated by well-developed bedding in complex geometries with multiple internal truncation surfaces. Lower subunits include thick structureless to alignment-bedded layers, along with intrusion-dominated zones. Soft-sediment deformation is ubiquitous along the edges of the deposit, with many layers broken and tilted to subvertical inclinations. Taken together, these features indicate that

  12. Observations on lava, snowpack and their interactions during the 2012-13 Tolbachik eruption, Klyuchevskoy Group, Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Edwards, Benjamin R.; Belousov, Alexander; Belousova, Marina; Melnikov, Dmitry

    2015-12-01

    Observations made during January and April 2013 show that interactions between lava flows and snowpack during the 2012-13 Tolbachik fissure eruption in Kamchatka, Russia, were controlled by different styles of emplacement and flow velocities. `A`a lava flows and sheet lava flows generally moved on top of the snowpack with few immediate signs of interaction besides localized steaming. However, lavas melted through underlying snowpack 1-4 m thick within 12 to 24 h, and melt water flowed episodically from the beneath flows. Pahoehoe lava lobes had lower velocities and locally moved beneath/within the snowpack; even there the snow melting was limited. Snowpack responses were physical, including compressional buckling and doming, and thermal, including partial and complete melting. Maximum lava temperatures were up to 1355 K (1082 °C; type K thermal probes), and maximum measured meltwater temperatures were 335 K (62.7 °C). Theoretical estimates for rates of rapid (e.g., radiative) and slower (conductive) snowmelt are consistent with field observations showing that lava advance was fast enough for `a`a and sheet flows to move on top of the snowpack. At least two styles of physical interactions between lava flows and snowpack observed at Tolbachik have not been previously reported: migration of lava flows beneath the snowpack, and localized phreatomagmatic explosions caused by snowpack failure beneath lava. The distinctive morphologies of sub-snowpack lava flows have a high preservation potential and can be used to document snowpack emplacement during eruptions.

  13. Cohnella collisoli sp. nov., isolated from lava forest soil.

    PubMed

    Lee, Keun Chul; Kim, Kwang Kyu; Kim, Jong-Shik; Kim, Dae-Shin; Ko, Suk-Hyung; Yang, Seung-Hoon; Lee, Jung-Sook

    2015-09-01

    A novel bacterial strain, NKM-5(T), was isolated from soil of a lava forest in Nokkome Oreum, Jeju, Republic of Korea. Cells of strain NKM-5(T) were Gram-stain-positive, motile, endospore-forming, rod-shaped and oxidase- and catalase-positive. Strain NKM-5(T) contained anteiso-C15 : 0 and iso-C16 : 0 as the major fatty acids; menaquinone-7 (MK-7) as the predominant isoprenoid quinone; diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, lysyl-phosphatidylglycerol, an unidentified phospholipid and three unidentified aminophospholipids as the polar lipids; and meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan. The DNA G+C content was 48.3 mol%. Phylogenetic analysis, based on 16S rRNA gene sequencing, showed that strain NKM-5(T) was most closely related to Cohnella lupini RLAHU4B(T) (96.9% sequence similarity) and fell into a clade in the genus Cohnella. On the basis of phylogenetic, chemotaxonomic and phenotypic data, strain NKM-5(T) represents a novel species of the genus Cohnella, for which the name Cohnella collisoli sp. nov. is proposed. The type strain is NKM-5(T) ( = KCTC 33634(T) = CECT 8805(T)).

  14. Boundary condition optimal control problem in lava flow modelling

    NASA Astrophysics Data System (ADS)

    Ismail-Zadeh, Alik; Korotkii, Alexander; Tsepelev, Igor; Kovtunov, Dmitry; Melnik, Oleg

    2016-04-01

    We study a problem of steady-state fluid flow with known thermal conditions (e.g., measured temperature and the heat flux at the surface of lava flow) at one segment of the model boundary and unknown conditions at its another segment. This problem belongs to a class of boundary condition optimal control problems and can be solved by data assimilation from one boundary to another using direct and adjoint models. We derive analytically the adjoint model and test the cost function and its gradient, which minimize the misfit between the known thermal condition and its model counterpart. Using optimization algorithms, we iterate between the direct and adjoint problems and determine the missing boundary condition as well as thermal and dynamic characteristics of the fluid flow. The efficiency of optimization algorithms - Polak-Ribiere conjugate gradient and the limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) algorithms - have been tested with the aim to get a rapid convergence to the solution of this inverse ill-posed problem. Numerical results show that temperature and velocity can be determined with a high accuracy in the case of smooth input data. A noise imposed on the input data results in a less accurate solution, but still acceptable below some noise level.

  15. Dielectric properties of lava flows west of Ascraeus Mons, Mars

    USGS Publications Warehouse

    Carter, L.M.; Campbell, B.A.; Holt, J.W.; Phillips, R.J.; Putzig, N.E.; Mattei, S.; Seu, R.; Okubo, C.H.; Egan, A.F.

    2009-01-01

    The SHARAD instrument on the Mars Reconnaissance Orbiter detects subsurface interfaces beneath lava flow fields northwest of Ascraeus Mons. The interfaces occur in two locations; a northern flow that originates south of Alba Patera, and a southern flow that originates at the rift zone between Ascraeus and Pavonis Montes. The northern flow has permittivity values, estimated from the time delay of echoes from the basal interface, between 6.2 and 17.3, with an average of 12.2. The southern flow has permittivity values of 7.0 to 14.0, with an average of 9.8. The average permittivity values for the northern and southern flows imply densities of 3.7 and 3.4 g cm-3, respectively. Loss tangent values for both flows range from 0.01 to 0.03. The measured bulk permittivity and loss tangent values are consistent with those of terrestrial and lunar basalts, and represent the first measurement of these properties for dense rock on Mars. Copyright 2009 by the American Geophysical Union.

  16. Field temperature measurements at Erta'Ale Lava Lake, Ethiopia

    NASA Astrophysics Data System (ADS)

    Burgi, Pierre-Yves; Caillet, Marc; Haefeli, Steven

    2002-06-01

    The shield volcano Erta'Ale, situated in the Danakil Depression, Ethiopia, is known for its active lava lake. In February 2001, our team visited this lake, located inside an 80-m-deep pit, to perform field temperature measurements. The distribution and variation of temperature inside the lake were obtained on the basis of infrared radiation measurements performed from the rim of the pit and from the lake shores. The crust temperature was also determined from the lake shores with a thermocouple to calibrate the pyrometer. We estimated an emissivity of the basalt of 0.74 from this experiment. Through the application of the Stefan-Boltzmann law, we then obtained an estimate of the total radiative heat flux, constrained by pyrometer measurements of the pit, and visual observations of the lake activity. Taking into account the atmospheric convective heat flux, the convected magma mass flux needed to balance the energy budget was subsequently derived and found to represent between 510 and 580 kg s-1. The surface circulation of this mass flux was also analyzed through motion processing techniques applied to video images of the lake. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00445-002-0224-3.

  17. Reevaluation of vesicle distributions in basaltic lava flows

    USGS Publications Warehouse

    Cashman, K.V.; Kauahikaua, J.P.

    1997-01-01

    A fundamental dichotomy in the study of basaltic lava flows is that observations of active flows are restricted to flow surfaces, yet older flows are often exposed only in vertical cross section. Cross-sectional exposures of an inflated basaltic sheet flow emplaced in Kalapana, Hawaii, from 1990 to 1991 provide an unusual opportunity to merge these two viewpoints, permitting the development of the internal structure of the flow to be viewed in the context of its known emplacement history. We demonstrate that fundamental features of the flow structure - a thick upper vesicular crust that diminishes downward in overall vesicularity, a dense flow interior, and a thin lower vesicular zone - are generated through syn-emplacement cooling of upper and lower flow crusts. Both the inverse correlation of overall vesicularity and vesicle size and the constant relative thickness of the upper vesicular zone are unique to inflated flows and permit a reinterpretation of flows previously interpreted to be ponded (rapidly emplaced). Identification of inflation, in turn, implies near-horizontal paleoslopes and permits estimates of flow duration based on upper flow crust thickness.

  18. Rovers and Lasers: The Autonomous, Non-Destructive Search for Life in Lava Tubes

    NASA Astrophysics Data System (ADS)

    Ruiz, A.; Messenger, S.; Yang, J.; Kim, S.; Paudel, S.; Lyzenga, G.; Clark, C.; Storrie-Lombardi, M.

    2014-07-01

    We report here on work conducted at Harvey Mudd College by undergraduate students to build the optical science probes and the cooperative, autonomous rovers necessary to map and search for life in the radiation-shielded lava tubes of Mars.

  19. Venusian pancake domes: Insights from terrestrial voluminous silicic lavas and thermal modeling

    NASA Technical Reports Server (NTRS)

    Manley, Curtis R.

    1993-01-01

    The so-called 'pancake' domes, and several other volcanoes on Venus, appear to represent large extrusions of silicic lava. Similar voluminous rhyolite lava flows, often associated with mantle plumes, are known on Earth. Venus' high ambient temperature, and insulation by the dome's brecciated carapace, both act to prolong cooling of a dome's interior, allowing for episodic lava input over an extended period of time. Field relations and aspect ratios of terrestrial voluminous rhyolite lavas imply continuous, non-episodic growth, reflecting tapping of a large volume of dry, anatectic silicic magma. Petrogenetically, the venusian domes may be analogous to chains of small domes on Earth, which represent 'leakage' of evolved material from magma bodies fractionating from much more mafic liquids.

  20. New Geochemical and Isotopic Data on São Jorge Island Submarine Lavas (Azores)

    NASA Astrophysics Data System (ADS)

    Ribeiro, L. P.; França, Z.; Madureira, P.

    2012-12-01

    Dredging operations performed on the Azores Archipelago, during LEG 1 of cruise EMEPC/Açores/G3/2007 (Lourenço et al., 2008), recovered the first lava samples on São Jorge Island south flank, at approximately 1200m depth. Subsequent EMEPC cruises in 2008 and 2009, EMEPC/Açores/LUSO/G3/2008 (Calado et al., 2008) and EMEPC/Açores/LUSO/G3/2009 respectively, using the Luso ROV, carried out four successful geological surveys along São Jorge south flank, at depths between 800 and 1000m, recovering more lava samples. New geochemical and isotopic data on the lavas recovered in the 2008 and 2009 cruises is reported and will be compared with the existing data from the 2007 cruise and the onshore lavas (Ribeiro, 2011). The island of São Jorge is located in the Central Island Group of the Azores Archipelago, exhibiting an elongated shape, 55km long and 6.75km wide, which extends along the main regional tectonic direction (N120°). The imposing geomorphology of the island, which formed mainly by fissural volcanic activity, continues on its submarine flanks, along abrupt cliffs, rooting the island in the Azores Plateau. The lavas from the 2007 cruise, which dredge the southeast end of the island, are alkaline basaltic pillow lavas, with MgO>7.5% and with a geochemical and isotopic signature similar to the composition of the onshore lavas located immediately north of this locations (Ribeiro, 2011). The 2008 ROV survey collected samples closer to the western side of São Jorge, on a site south of Rosais Village, while the 2009 ROV survey covered the central part of São Jorge south flank, on a site south of Urzelina Village, a site south of Manadas Village and a site south of Fajã da Fragueira. These lavas are alkaline basalts and hawaiites with enrichment in LREE and in incompatible trace elements. The basalts have MgO between 6.8 and 6.2%, and average (La/Sm)n ratios of 2.1 and (La/Yb)n ratios ranging between 6.3 and 9.6. The hawaiites, which reveal some degree of magma

  1. Lava Eruption and Emplacement: Using Clues from Hawaii and Iceland to Probe the Lunar Past

    NASA Astrophysics Data System (ADS)

    Needham, D. H.; Hamilton, C. W.; Bleacher, J. E.; Whelley, P. L.; Young, K. E.; Scheidt, S. P.; Richardson, J. A.; Sutton, S. S.

    2016-11-01

    We investigate the 2014/15 Holuhraun, Iceland and December 1974 Kilauea, Hawaii eruptions to improve understanding of relationships between eruption dynamics and final lava flow morphology. Insights are used to deduce the origin of Rima Bode on the Moon.

  2. Near-IR Reflectance Spectra in a Lava Tube Cave from a Robotic Platform

    NASA Astrophysics Data System (ADS)

    Chanover, N. J.; Uckert, K.; Voelz, D. G.; Xiao, X.; Hull, R.; Boston, P. J.; Parness, A.; Abcouwer, N.; Willig, A.; Fuller, C.

    2015-10-01

    We present preliminary field measurements of biovermiculations and other mineral deposits made at a lava tube cave in El Malpais National Monument, NM, using a rock climbing robot equipped with a near-infrared point spectrometer.

  3. Lava flow surface textures - SIR-B radar image texture, field observations, and terrain measurements

    NASA Technical Reports Server (NTRS)

    Gaddis, Lisa R.; Mouginis-Mark, Peter J.; Hayashi, Joan N.

    1990-01-01

    SIR-B images, field observations, and small-scale (cm) terrain measurements are used to study lave flow surface textures related to emplacement processes of a single Hawaiian lava flow. Although smooth pahoehoe textures are poorly characterized on the SIR-B data, rougher pahoehoe types and the a'a flow portion show image textures attributed to spatial variations in surface roughness. Field observations of six distinct lava flow textural units are described and used to interpret modes of emplacement. The radar smooth/rough boundary between pahoehoe and a'a occurs at a vertical relief of about 10 cm on this lava flow. While direct observation and measurement most readily yield information related to lava eruption and emplacement processes, analyses of remote sensing data such as those acquired by imaging radars and altimeters can provide a means of quantifying surface texture, identifying the size and distribution of flow components, and delineating textural unit boundaries.

  4. Laser assisted vascular anastomosis (LAVA): a promising nonsuture technique for surgery

    NASA Astrophysics Data System (ADS)

    Chen, Chen; Peng, Fei; Xu, Dahai; Cheng, Qinghua

    2009-08-01

    The first successful experiment of laser vascular welding was reported in 1979. Laser assisted vascular anastomosis (LAVA) is looked as a particularly promising non-suture method in future. We performed a Medline literature search on laser vessel welding combined with cross-referencing. According to the former experimental animal studies, CO2-, argon-, diode-, KTP-, Holmium:YAG-, and Nd:YAG-lasers have been used for LAVA. Almost all lasers have been used in combination with stay suture and/or solders in order to improve the strength on anastomosis site. Advantages of LAVA are minimal vessel damage, faster operation and the potential for minimally invasive application. However, the clinical application of LAVA is still seldom employed because of aneurysm formation. In conclusion of the literature study, the diode laser is the most popular, but long-term evaluation is required.

  5. Lava lake level as a gauge of magma reservoir pressure and eruptive hazard

    USGS Publications Warehouse

    Patrick, Matthew R.; Anderson, Kyle R.; Poland, Michael P.; Orr, Tim R.; Swanson, Donald A.

    2015-01-01

    Forecasting volcanic activity relies fundamentally on tracking magma pressure through the use of proxies, such as ground surface deformation and earthquake rates. Lava lakes at open-vent basaltic volcanoes provide a window into the uppermost magma system for gauging reservoir pressure changes more directly. At Kīlauea Volcano (Hawaiʻi, USA) the surface height of the summit lava lake in Halemaʻumaʻu Crater fluctuates with surface deformation over short (hours to days) and long (weeks to months) time scales. This correlation implies that the lake behaves as a simple piezometer of the subsurface magma reservoir. Changes in lava level and summit deformation scale with (and shortly precede) changes in eruption rate from Kīlauea's East Rift Zone, indicating that summit lava level can be used for short-term forecasting of rift zone activity and associated hazards at Kīlauea.

  6. Progress of Icelandic Lava Flows Charted by NASA EO-1 Spacecraft

    NASA Image and Video Library

    2014-09-09

    On the night of Sept. 6, 2014 NASA Earth Observing 1 EO-1 spacecraft observed the ongoing eruption at Holuhraun, Iceland. Partially covered by clouds, this scene shows the extent of the lava flows that have been erupting.

  7. Mauna Loa lava accumulation rates at the Hilo drill site: Formation of lava deltas during a period of declining overall volcanic growth

    USGS Publications Warehouse

    Lipman, P.W.; Moore, J.G.

    1996-01-01

    Accumulation rates for lava flows erupted from Mauna Loa, as sampled in the uppermost 280 m of the Hilo drill hole, vary widely for short time intervals (several thousand years), but overall are broadly similar to those documented elsewhere on this volcano since 100 ka. Thickness variations and accumulation rates for Mauna Loa lavas at the Hilo drill site have been strongly affected by local paleotopography, including funneling and ponding between Mauna Kea and Kilauea. In addition, gentle submerged slopes of Mauna Kea in Hilo Bay have permitted large shoreline displacements by Mauna Loa flows. Ages of eruptive intervals have been determined from published isotopic data and from eustatic sea level curves modified to include the isostatic subsidence of the island of Hawaii at 2.2-2.6 mm/yr. Prior to 10 ka, rates of Mauna Loa lava accumulation at the drill site varied from 0.6 to 4.3 mm/yr for dateable intervals, with an overall rate of 1.8 mm/yr. Major eruptive pulses at about 1.3 and 10 ka, each probably representing a single long-lived eruption based on lack of weathering between flow units, increase the overall accumulation rate to 2.4 mm/yr. The higher rate since 10 ka reflects construction of thick near-shoreline lava deltas as postglacial sea levels rose rapidly. Large lava deltas form only along coastal segments where initially subaerial slopes have been submerged by the combined effects of eustatic sea level rise, isostatic subsidence, or spreading of volcano flanks. Overall accumulation of 239 m of lava at the drill site since 100-120 ka closely balances submergence of the Hilo area, suggesting that processes of coastal lava deposition have been modulated by rise in sea level. The Hilo accumulation rate is slightly higher than average rates of 1-2 mm/yr determined elsewhere along the Mauna Loa coast, based on rates of shoreline coverage and dated sea cliff and fault scarp exposures. Low rates of coastal lava accumulation since 100 ka, near or below the rate

  8. Near-Vent, Fissure-Fed Lava Channel Network Morphologies in the Kīlauea December 1974 Flow: Implications for Differentiating Lava Construction From Fluvial Erosion on Planets

    NASA Astrophysics Data System (ADS)

    Bleacher, J. E.

    2015-12-01

    Streamlined islands are often assumed to be the product of erosion by water and are cited as evidence of aqueous flows on Mars. However, lava can build streamlined islands in a manner that is more easily explained by flow thickening followed by partial drainage of preferred lava pathways. Kīlauea's December 1974 (D1974) flow was emplaced as a broad sheet-like flow from a series of en echelon fissures across an older hummocky pāhoehoe tumulus field. The lavas surrounded the tumuli and coalesced to fill a topographic low near the basal scarp of the Koae Fault System. As these obstacles were inundated by the D1974 flow, the lava preferentially cooled around the tumuli to form a higher viscosity zone beneath a smooth crust. Stagnation of these thinner, cooler, and more viscous zones focused the flow into a series of preferred lava pathways located between the stagnant islands. Changes in the local discharge rate disrupted the crust of the flow above the lower viscosity pathways. Older tumuli adjacent to the D1974 flow display the same relief as the flow's islands and uncovered portions of this older flow are exposed at the tops of many islands, supporting an interpretation that islands were anchored by high-standing pre-flow tumuli. As the local lava supply waned, partial drainage of the preferred pathways occurred between the higher-standing surfaces anchored to the older tumuli. The resulting morphology consists of a relatively smooth flow field with thin margins that is dissected by depressed pathways or channels. This morphology resembles an erosional surface incised into a smooth plain, but actually represents an initial constructional process followed by partial drainage within a viscous lava flow. Many other Hawaiian rift zone, fissure-fed flow fields display comparable morphologies in the near vent facies, including islands, terraces, thin flow margins and a lack of well defined topographic levees along channels. Thus, branching channel networks and

  9. Real-time satellite monitoring of Nornahraun lava flow NE Iceland

    NASA Astrophysics Data System (ADS)

    Jónsdóttir, Ingibjörg; Þórðarson, Þorvaldur; Höskuldsson, Ármann; Davis, Ashley; Schneider, David; Wright, Robert; Kestay, Laszlo; Hamilton, Christopher; Harris, Andrew; Coppola, Diego; Tumi Guðmundsson, Magnús; Durig, Tobias; Pedersen, Gro; Drouin, Vincent; Höskuldsson, Friðrik; Símonarson, Hreggviður; Örn Arnarson, Gunnar; Örn Einarsson, Magnús; Riishuus, Morten

    2015-04-01

    An effusive eruption started in Holuhraun, NE Iceland, on 31 August 2014, producing the Nornahraun lava flow field which had, by the beginning of 2015, covered over 83 km2. Throughout this event, various satellite images have been analyzed to monitor the development, active areas and map the lava extent in close collaboration with the field group, which involved regular exchange of direct observations and satellite based data for ground truthing and suggesting possible sites for lava sampling. From the beginning, satellite images in low geometric but high temporal resolution (NOAA AVHRR, MODIS) were used to monitor main regions of activity and position new vents to within 1km accuracy. As they became available, multispectral images in higher resolution (LANDSAT 8, LANDSAT 7, ASTER, EO-1 ALI) were used to map the lava channels, study lava structures and classify regions of varying activity. Hyper spectral sensors (EO-1 HYPERION), though with limited area coverage, have given a good indication of vent and lava temperature and effusion rates. All available radar imagery (SENTINEL-1, RADARSAT, COSMO SKYMED, TERRASAR X) have been used for studying lava extent, landscape and roughness. The Icelandic Coast Guard has, on a number of occasions, provided high resolution radar and thermal images from reconnaissance flights. These data sources compliment each other well and have improved analysis of events. Whilst classical TIR channels were utilized to map the temperature history of the lava, SWIR and NIR channels caught regions of highest temperature, allowing an estimate of the most active lava channels and even indicating potential changes in channel structure. Combining thermal images and radar images took this prediction a step further, improving interpretation of both image types and studying the difference between open and closed lava channels. Efforts are underway of comparing different methods of estimating magma discharge and improving the process for use in real

  10. Lava invasion of urban areas at monogentic systems: Examples from the Chaine des Puys

    NASA Astrophysics Data System (ADS)

    Harris, A. J. L.; Van Wyk De Vries, B.; Latutrie, B.; Saubin, E.; Langlois, E.

    2014-12-01

    Close to becoming part of a UNESCO world heritage site, the Chaine des Puys monogenetic alignment has > 80 effusive centers. Lava flows extending east enter valleys cut into the Limagne fault scarp. Flow emplacement dynamics depend on the slope of the terrain. We focus here on two cases: (i) the Grave Noire (60 ka) lavas - emplaced on steep slopes before transiting abruptly to shallow slopes; (ii) the Tiretaine (44 ka) lava - emplaced on gentle slopes, before entering a steeply sloping valley. Both flow fields underlie the city of Clermont Ferrand, and so have been used to test a GIS to assess impact due to lava inundation of an urban area close to an active monogenetic system. The fountain-fed flows of Grave Noire poured down the Limagne fault scarp at velocities of 8 m/s. On encountering shallower slopes at 1 km, the lava stalled to form a perched pond contained by a barrier of its own breccia and ramped-up sediment. Intrusions through the barrier fed flow that advanced a further 4 km at velocities of a few tens of m/day. Distally, Tiretaine lavas built an inflated flow field with its front at the head of the Tiretaine valley. Failure of this front fed lava that entered the valley at effusion rates of several hundred m3/s. Lava descended as far as the current town of Royat, where it encountered, and ponded behind, a barrier built by Grave Noire lavas. If occurring today, these flows would impact more than 8422 addresses, 0.065 km² industrial land, 177 km of roads and 110 ha of agricultural land. Outcrop exposure of lavas is outstanding throughout the Chaine des Puys, allowing 3D viewing of such effusive systems. At Grave Noire and Tiretaine, we have analogs for perched ponds, channels, and satellite shields experiencing flank collapse to feed flow at high local effusion rates. The juxtaposition of central France's capital, and the lavas themselves, vividly demonstrate effusive hazards faced by urban areas located in active monogenetic systems.

  11. Emplacement and erosive effects of the south Kasei Valles lava on Mars

    USGS Publications Warehouse

    Dundas, Colin M.; Keszthelyi, Laszlo P.

    2014-01-01

    Although it has generally been accepted that the Martian outflow channels were carved by floods of water, observations of large channels on Venus and Mercury demonstrate that lava flows can cause substantial erosion. Recent observations of large lava flows within outflow channels on Mars have revived discussion of the hypothesis that the Martian channels are also produced by lava. An excellent example is found in south Kasei Valles (SKV), where the most recent major event was emplacement of a large lava flow. Calculations using high-resolution Digital Terrain Models (DTMs) demonstrate that this flow was locally turbulent, similar to a previously described flood lava flow in Athabasca Valles. The modeled peak local flux of approximately 106 m3 s−1 was approximately an order of magnitude lower than that in Athabasca, which may be due to distance from the vent. Fluxes close to 107 m3 s−1 are estimated in some reaches but these values are probably records of local surges caused by a dam-breach event within the flow. The SKV lava was locally erosive and likely caused significant (kilometer-scale) headwall retreat at several cataracts with tens to hundreds of meters of relief. However, in other places the net effect of the flow was unambiguously aggradational, and these are more representative of most of the flow. The larger outflow channels have lengths of thousands of kilometers and incision of a kilometer or more. Therefore, lava flows comparable to the SKV flow did not carve the major Martian outflow channels, although the SKV flow was among the largest and highest-flux lava flows known in the Solar System.

  12. Limited role for thermal erosion by turbulent lava in proximal Athabasca Valles, Mars

    USGS Publications Warehouse

    Cataldo, Vincenzo; Williams, David A.; Dundas, Colin M.; Kestay, Laszlo P.

    2015-01-01

    The Athabasca Valles flood lava is among the most recent (<50 Ma) and best preserved effusive lava flows on Mars and was probably emplaced turbulently. The Williams et al. (2005) model of thermal erosion by lava has been applied to what we term “proximal Athabasca,” the 75 km long upstream portion of Athabasca Valles. For emplacement volumes of 5000 and 7500 km3and average flow thicknesses of 20 and 30 m, the duration of the eruption varies between ~11 and ~37 days. The erosion of the lava flow substrate is investigated for three eruption temperatures (1270°C, 1260°C, and 1250°C), and volatile contents equivalent to 0–65 vol % bubbles. The largest erosion depths of ~3.8–7.5 m are at the lava source, for 20 m thick and bubble-free flows that erupted at their liquidus temperature (1270°C). A substrate containing 25 vol % ice leads to maximum erosion. A lava temperature 20°C below liquidus reduces erosion depths by a factor of ~2.2. If flow viscosity increases with increasing bubble content in the lava, the presence of 30–50 vol % bubbles leads to erosion depths lower than those relative to bubble-free lava by a factor of ~2.4. The presence of 25 vol % ice in the substrate increases erosion depths by a factor of 1.3. Nevertheless, modeled erosion depths, consistent with the emplacement volume and flow duration constraints, are far less than the depth of the channel (~35–100 m). We conclude that thermal erosion does not appear to have had a major role in excavating Athabasca Valles.

  13. Elemental and Topographic Mapping of Lava Flowstructures in Mare Serenitatis on the Moon

    NASA Astrophysics Data System (ADS)

    Wöhler, C.; Grumpe, A.; Rommel, D.; Bhatt, M.; Mall, U.

    2017-07-01

    The detection of lunar lava flows based on local morphology highly depends on the available images. The thickness of lava flows, however, has been studied by many researchers and lunar lava flows are shown to be as thick as 200 m. Lunar lava flows are supposed to be concentrated on the northwestern lunar nearside. In this study we present elemental abundance maps, a petrological map and a digital terrain model (DTM) of a lava flow structure in northern Mare Serenitatis at (18.0° E, 32.4° N) and two possible volcanic vents at (11.2° E, 24.6° N) and (13.5° E, 37.5° N), respectively. Our abundance maps of the refractory elements Ca, Mg and our petrological map were obtained based on hyperspectral image data of the Moon Mineralogy Mapper (M3) instrument. Our DTM was constructed using GLD100 data in combination with a shape from shading based method to M3 and Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) image data. The obtained NAC-based DEM has a very high effective resolution of about 1-2 m which comes close to the resolution of the utilized NAC images without requiring intricate processing of NAC stereo image pairs. As revealed by our elemental maps and DEM, the examined lava flow structure occurs on a boundary between basalts consisting of low-Ca/high-Mg pyroxene and high-Ca/low-Mg pyroxene, respectively. The total thickness of the lava flow is about 100 m, which is a relatively large value, but according to our DEM the lava flow may also be composed of two or more layers.

  14. Influence of basal slip on the propagation and cooling of lava flows

    NASA Astrophysics Data System (ADS)

    Melnik, Oleg; Vedeneeva, Elena; Utkin, Ivan

    2015-04-01

    A thin layer approximation is used for studying of viscous gravity currents on the horizontal topography from a point source. The main difference from a self-similar solution obtained in Huppert (1982) is the account for partial slip of lava on the ground surface. We assume that the slip velocity is proportional to the tangential stress in some positive power. This condition is widely used in polymer science and for the flows on superhydrophobic surfaces. This condition is also applicable for lava flows because of a large roughness of volcanic terrains and the presence of unconsolidated material (ash, lapilli). The system of Stokes equations was reduced to a non-linear parabolic differential equation. Its solution was found both numerically and by a reduction to an ODE that describes similarity solution. In the latter case there is a dependence between lava mass growth rate and the power exponent in the friction law. It was shown that the presence of basal slip allows much faster propagation of lava flows in comparison with no-slip condition at the ground surface. Analytical solutions were proved by a good comparison with fully 2D axisymmetric finite volume simulations. Based on the velocity field obtained from a thin layer theory the heat budget of a lava flow was studied for the case of constant lava viscosity. Heat equation was solved in the lava domain with no flux condition at the bottom, radiative and convective fluxes at the free surface and the influx of a fresh magma from a point source. It was shown that due to a strong difference in the velocity profile the distribution of the temperature inside the lava flow is different in the cases of no-slip and partial slip conditions.

  15. 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.

  16. Shallow and deep controls on lava lake surface motion at Kīlauea Volcano

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    Lava lakes provide a rare window into magmatic behavior, and lake surface motion has been used to infer deeper properties of the magmatic system. At Halema'uma'u Crater, at the summit of Kīlauea Volcano, multidisciplinary observations for the past several years indicate that lava lake surface motion can be broadly divided into two regimes: 1) stable and 2) unstable. Stable behavior is driven by lava upwelling from deeper in the lake (presumably directly from the conduit) and is an intrinsic process that drives lava lake surface motion most of the time. This stable behavior can be interrupted by periods of unstable flow (often reversals) driven by spattering - a shallowly-rooted process often extrinsically triggered by small rockfalls from the crater wall. The bursting bubbles at spatter sources create void spaces and a localized surface depression which draws and consumes surrounding surface crust. Spattering is therefore a location of lava downwelling, not upwelling. Stable (i.e. deep, upwelling-driven) and unstable (i.e. shallow, spattering-driven) behavior often alternate through time, have characteristic surface velocities, flow directions and surface temperature regimes, and also correspond to changes in spattering intensity, outgassing rates, lava level and seismic tremor. These results highlight that several processes, originating at different depths, can control the motion of the lava lake surface, and long-term interdisciplinary monitoring is required to separate these influences. These observations indicate that lake surface motion is not always a reliable proxy for deeper lake or magmatic processes. From these observations, we suggest that shallow outgassing (spattering), not lake convection, drives the variations in lake motion reported at Erta 'Ale lava lake.

  17. 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.

  18. Coupled pulsing of lava fountains: Video monitoring reveals systematic height and velocity variations of adjacent vents

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.

    2014-05-01

    Lava fountains are a common eruption form at basaltic volcanoes. Many of the lava fountains occur at fissure eruptions, associated with the alignment of active vents. We observed that the lava fountain pulses may occur in chorus at several adjacent vents, implying that activity at these vents is coupled. The mechanisms behind such a coupling of adjacent lava fountains and the underlying connection between the different craters are not fully understood, however. Here we employ video images to measure the height, width and velocity of the ejecta leaving the vent. With a Sobel edge-detection algorithm, our aim is to measure the height of the different fountains occurring along fissure eruptions. Video data acquired from Puu'oo (Hawaii) and from Eyjafjallajökull (Iceland) are showing major similarities in fountaining behavior. Based on the fountain activity times series we estimate the sign and degree of correlation of the different vents. We find that the height and velocity of adjacent lava fountains are often in chorus. The velocity is calculated by a correlation in the Fourier space of contiguous images. We observed that episodically and sporadically the correlation regime can change. Despite these changes, both the frequency of the lava pulses and the eruption and rest time between the pulses remain similar for adjacent lava fountains, implying, a controlling process in the magma feeder system itself. We interpret the initial vertical velocity at the vent to be proportional to the extent of bubbles, and layers of bubbles rising. Lateral migration of fountains and their dynamics, in turn, is associated to lateral magma and gas flow or inclined layers of bubbles developing along the fissure at depth. Systematic recording and analysis of video data from different volcanoes hence result in a better understanding of the mechanisms of parallel and non-parallel lava fountain pulses.

  19. K-Ar ages of Pleistocene lava dams in the Grand Canyon in Arizona

    PubMed Central

    Dalrymple, G. Brent; Hamblin, W. K.

    1998-01-01

    At least 13 times during the Pleistocene Epoch lava flowed into the inner gorge of the Grand Canyon and formed lava dams, as high as 600 m, that temporarily blocked the flow of the Colorado River. K-Ar ages on these lava dams indicate that the seven youngest formed within a short period of time between about 0.6 and 0.4 mega-annum (Ma). The physiography of the lava dam remnants within the canyon shows that each dam was destroyed by erosion, the Colorado River rapidly reaching its pre-existing grade level, before the next dam was emplaced by new eruptions. The total time for emplacement and destruction for an individual lava dam was probably as little as 0.01–0.02 million years. The K-Ar ages of the two oldest dams, the Lava Butte dam (0.577 ± 0.054 Ma) and the Prospect dam (0.684 ± 0.051 Ma) are somewhat younger than the physiography of their remnants suggest. PMID:9707546

  20. Comparison of Bacterial Diversity in Azorean and Hawai’ian Lava Cave Microbial Mats

    PubMed Central

    MARSHALL HATHAWAY, JENNIFER J.; GARCIA, MATTHEW G.; BALASCH, MONICA MOYA; SPILDE, MICHAEL N.; STONE, FRED D.; DAPKEVICIUS, MARIA DE LURDES N. E.; AMORIM, ISABEL R.; GABRIEL, ROSALINA; BORGES, PAULO A. V.; NORTHUP, DIANA E.

    2015-01-01

    Worldwide, lava caves host colorful microbial mats. However, little is known about the diversity of these microorganisms, or what role they may play in the subsurface ecosystem. White and yellow microbial mats were collected from four lava caves each on the Azorean island of Terceira and the Big Island of Hawai’i, to compare the bacterial diversity found in lava caves from two widely separated archipelagos in two different oceans at different latitudes. Scanning electron microscopy of mat samples showed striking similarities between Terceira and Hawai’ian microbial morphologies. 16S rRNA gene clone libraries were constructed to determine the diversity within these lava caves. Fifteen bacterial phyla were found across the samples, with more Actinobacteria clones in Hawai’ian communities and greater numbers of Acidobacteria clones in Terceira communities. Bacterial diversity in the subsurface was correlated with a set of factors. Geographical location was the major contributor to differences in community composition (at the OTU level), together with differences in the amounts of organic carbon, nitrogen and copper available in the lava rock that forms the cave. These results reveal, for the first time, the similarity among the extensive bacterial diversity found in lava caves in two geographically separate locations and contribute to the current debate on the nature of microbial biogeography. PMID:26924866

  1. Compositional evolution of lava plains in the Syria-Thaumasia Block, Mars

    NASA Astrophysics Data System (ADS)

    Huang, Jun; Xiao, Long

    2014-05-01

    Tharsis is the most prominent volcanic province on Mars, yet the compositions of lava flows and how composition relates to the development of Tharsis are poorly known. Most of Tharsis is covered with air-fall dust, which inhibits spectroscopic determination of lava mineralogy. The Syria-Thaumasia Block (STB) is a complex tectono-volcanic province closely related to the Tharsis bulge. The lava plains of STB have different emplacement ages, which provide an opportunity to examine whether magma composition changed with the evolution of Tharsis. In this study, we assessed the lava plains using Thermal Emission Spectrometer (TES) data. Using derived physical properties, we targeted dust-free regions from four different-aged geological units' surfaces and determined the mineralogical composition by modeling the average TES surface spectrum from each of the four surfaces. All units have similar mineralogy but the younger two units have elevated abundance of high-SiO2 phases. The spatial distribution of wrinkle ridges indicates lava plains of unit HNr (older ridged plains material) and Hr (younger ridged plains material) were emplaced before the rise of Tharsis, whereas Hsl (flows of lower member) and Hsu (upper member) were emplaced after Tharsis uplift was initiated. We show that the magma composition differed in the lava plains of STB after the uplift of Tharsis. This study further characterizes early martian magma composition and evolution.

  2. Comparison of Bacterial Diversity in Azorean and Hawai'ian Lava Cave Microbial Mats.

    PubMed

    Marshall Hathaway, Jennifer J; Garcia, Matthew G; Balasch, Monica Moya; Spilde, Michael N; Stone, Fred D; Dapkevicius, Maria DE Lurdes N E; Amorim, Isabel R; Gabriel, Rosalina; Borges, Paulo A V; Northup, Diana E

    Worldwide, lava caves host colorful microbial mats. However, little is known about the diversity of these microorganisms, or what role they may play in the subsurface ecosystem. White and yellow microbial mats were collected from four lava caves each on the Azorean island of Terceira and the Big Island of Hawai'i, to compare the bacterial diversity found in lava caves from two widely separated archipelagos in two different oceans at different latitudes. Scanning electron microscopy of mat samples showed striking similarities between Terceira and Hawai'ian microbial morphologies. 16S rRNA gene clone libraries were constructed to determine the diversity within these lava caves. Fifteen bacterial phyla were found across the samples, with more Actinobacteria clones in Hawai'ian communities and greater numbers of Acidobacteria clones in Terceira communities. Bacterial diversity in the subsurface was correlated with a set of factors. Geographical location was the major contributor to differences in community composition (at the OTU level), together with differences in the amounts of organic carbon, nitrogen and copper available in the lava rock that forms the cave. These results reveal, for the first time, the similarity among the extensive bacterial diversity found in lava caves in two geographically separate locations and contribute to the current debate on the nature of microbial biogeography.

  3. Littoral hydrovolcanic explosions: A case study of lava-seawater interaction at Kilauea Volcano

    USGS Publications Warehouse

    Mattox, T.N.; Mangan, M.T.

    1997-01-01

    A variety of hydrovolcanic explosions may occur as basaltic lava flows into the ocean. Observations and measurements were made during a two-year span of unusually explosive littoral activity as tube-fed pahoehoe from Kilauea Volcano inundated the southeast coastline of the island of Hawai'i. Our observations suggest that explosive interactions require high entrance fluxes (??? 4 m3/s) and are most often initiated by collapse of a developing lava delta. Two types of interactions were observed. "Open mixing" of lava and seawater occurred when delta collapse exposed the mouth of a severed lava tube or incandescent fault scarp to wave action. The ensuing explosions produced unconsolidated deposits of glassy lava fragments or lithic debris. Interactions under "confined mixing" conditions occurred when a lava tube situated at or below sea level fractured. Explosions ruptured the roof of the tube and produced circular mounds of welded spatter. We estimate a water/rock mass ratio of 0.15 for the most common type of littoral explosion and a kinetic energy release of 0.07-1.3 kJ/kg for the range of events witnessed.

  4. K-Ar ages of Pleistocene lava dams in the Grand Canyon in Arizona.

    PubMed

    Dalrymple, G B; Hamblin, W K

    1998-08-18

    At least 13 times during the Pleistocene Epoch lava flowed into the inner gorge of the Grand Canyon and formed lava dams, as high as 600 m, that temporarily blocked the flow of the Colorado River. K-Ar ages on these lava dams indicate that the seven youngest formed within a short period of time between about 0.6 and 0.4 mega-annum (Ma). The physiography of the lava dam remnants within the canyon shows that each dam was destroyed by erosion, the Colorado River rapidly reaching its pre-existing grade level, before the next dam was emplaced by new eruptions. The total time for emplacement and destruction for an individual lava dam was probably as little as 0. 01-0.02 million years. The K-Ar ages of the two oldest dams, the Lava Butte dam (0.577 +/- 0.054 Ma) and the Prospect dam (0.684 +/- 0.051 Ma) are somewhat younger than the physiography of their remnants suggest.

  5. Monitoring the cooling of the 1959 Kīlauea Iki lava lake using surface magnetic measurements

    USGS Publications Warehouse

    Gailler, Lydie; Kauahikaua, James P.

    2017-01-01

    Lava lakes can be considered as proxies for small magma chambers, offering a unique opportunity to investigate magma evolution and solidification. Repeated magnetic ground surveys over more than 50 years each show a large vertical magnetic intensity anomaly associated with Kīlauea Iki Crater, partly filled with a lava lake during the 1959 eruption of Kīlauea Volcano (Island of Hawai’i). The magnetic field values recorded across the Kīlauea Iki crater floor and the cooling lava lake below result from three simple effects: the static remnant magnetization of the rocks forming the steep crater walls, the solidifying lava lake crust, and the hot, but shrinking, paramagnetic non-magnetic lens (>540 °C). We calculate 2D magnetic models to reconstruct the temporal evolution of the geometry of this non-magnetic body, its depth below the surface, and its thickness. Our results are in good agreement with the theoretical increase in thickness of the solidifying crust with time. Using the 2D magnetic models and the theoretical curve for crustal growth over a lava lake, we estimate that the former lava lake will be totally cooled below the Curie temperature in about 20 years. This study shows the potential of magnetic methods for detecting and monitoring magmatic intrusions at various scales.

  6. Sustaining persistent lava lakes: Observations from high-resolution gas measurements at Villarrica volcano, Chile

    NASA Astrophysics Data System (ADS)

    Moussallam, Yves; Bani, Philipson; Curtis, Aaron; Barnie, Talfan; Moussallam, Manuel; Peters, Nial; Schipper, C. Ian; Aiuppa, Alessandro; Giudice, Gaetano; Amigo, Álvaro; Velasquez, Gabriela; Cardona, Carlos

    2016-11-01

    Active lava lakes - as the exposed upper part of magmatic columns - are prime locations to investigate the conduit flow processes operating at active, degassing volcanoes. Persistent lava lakes require a constant influx of heat to sustain a molten state at the Earth's surface. Several mechanisms have been proposed to explain how such heat transfer can operate efficiently. These models make contrasting predictions with respect to the flow dynamics in volcanic conduits and should result in dissimilar volatile emissions at the surface. Here we look at high-frequency SO2 fluxes, plume composition, thermal emissions and aerial video footage from the Villarrica lava lake in order to determine the mechanism sustaining its activity. We found that while fluctuations are apparent in all datasets, none shows a stable periodic behaviour. These observations suggest a continuous influx of volatiles and magma to the Villarrica lava lake. We suggest that ascending volatile-rich and descending degassed magmas are efficiently mixed within the volcanic conduit, resulting in no clear periodic oscillations in the plume composition and flux. We compare our findings to those of other lava lakes where equivalent gas emission time-series have been acquired, and suggest that gas flux, magma viscosity and conduit geometry are key parameters determining which flow mechanism operates in a given volcanic conduit. The range of conduit flow regimes inferred from the few studied lava lakes gives a glimpse of the potentially wide spectrum of conduit flow dynamics operating at active volcanoes.

  7. The probability of lava inundation at the proposed and existing Kulani prison sites

    USGS Publications Warehouse

    Kauahikaua, J.P.; Trusdell, F.A.; Heliker, C.C.

    1998-01-01

    The State of Hawai`i has proposed building a 2,300-bed medium-security prison about 10 km downslope from the existing Kulani medium-security correctional facility. The proposed and existing facilities lie on the northeast rift zone of Mauna Loa, which last erupted in 1984 in this same general area. We use the best available geologic mapping and dating with GIS software to estimate the average recurrence interval between lava flows that inundate these sites. Three different methods are used to adjust the number of flows exposed at the surface for those flows that are buried to allow a better representation of the recurrence interval. Probabilities are then computed, based on these recurrence intervals, assuming that the data match a Poisson distribution. The probability of lava inundation for the existing prison site is estimated to be 11- 12% in the next 50 years. The probability of lava inundation for the proposed sites B and C are 2- 3% and 1-2%, respectively, in the same period. The probabilities are based on estimated recurrence intervals for lava flows, which are approximately proportional to the area considered. The probability of having to evacuate the prison is certainly higher than the probability of lava entering the site. Maximum warning times between eruption and lava inundation of a site are estimated to be 24 hours for the existing prison site and 72 hours for proposed sites B and C. Evacuation plans should take these times into consideration.

  8. Monitoring the cooling of the 1959 Kīlauea Iki lava lake using surface magnetic measurements

    NASA Astrophysics Data System (ADS)

    Gailler, Lydie; Kauahikaua, Jim

    2017-06-01

    Lava lakes can be considered as proxies for small magma chambers, offering a unique opportunity to investigate magma evolution and solidification. Repeated magnetic ground surveys over more than 50 years each show a large vertical magnetic intensity anomaly associated with Kīlauea Iki Crater, partly filled with a lava lake during the 1959 eruption of Kīlauea Volcano (Island of Hawai'i). The magnetic field values recorded across the Kīlauea Iki crater floor and the cooling lava lake below result from three simple effects: the static remnant magnetization of the rocks forming the steep crater walls, the solidifying lava lake crust, and the hot, but shrinking, paramagnetic non-magnetic lens (>540 °C). We calculate 2D magnetic models to reconstruct the temporal evolution of the geometry of this non-magnetic body, its depth below the surface, and its thickness. Our results are in good agreement with the theoretical increase in thickness of the solidifying crust with time. Using the 2D magnetic models and the theoretical curve for crustal growth over a lava lake, we estimate that the former lava lake will be totally cooled below the Curie temperature in about 20 years. This study shows the potential of magnetic methods for detecting and monitoring magmatic intrusions at various scales.

  9. The Flow of the Gibbon LAVA Element Is Facilitated by the LINE-1 Retrotransposition Machinery

    PubMed Central

    Meyer, Thomas J.; Held, Ulrike; Nevonen, Kimberly A.; Klawitter, Sabine; Pirzer, Thomas; Carbone, Lucia; Schumann, Gerald G.

    2016-01-01

    LINE-Alu-VNTR-Alu-like (LAVA) elements comprise a family of non-autonomous, composite, non-LTR retrotransposons specific to gibbons and may have played a role in the evolution of this lineage. A full-length LAVA element consists of portions of repeats found in most primate genomes: CT-rich, Alu-like, and VNTR regions from the SVA retrotransposon, and portions of the AluSz and L1ME5 elements. To evaluate whether the gibbon genome currently harbors functional LAVA elements capable of mobilization by the endogenous LINE-1 (L1) protein machinery and which LAVA components are important for retrotransposition, we established a trans-mobilization assay in HeLa cells. Specifically, we tested if a full-length member of the older LAVA subfamily C that was isolated from the gibbon genome and named LAVAC, or its components, can be mobilized in the presence of the human L1 protein machinery. We show that L1 proteins mobilize the LAVAC element at frequencies exceeding processed pseudogene formation and human SVAE retrotransposition by > 100-fold and ≥3-fold, respectively. We find that only the SVA-derived portions confer activity, and truncation of the 3′ L1ME5 portion increases retrotransposition rates by at least 100%. Tagged de novo insertions integrated into intronic regions in cell culture, recapitulating findings in the gibbon genome. Finally, we present alternative models for the rise of the LAVA retrotransposon in the gibbon lineage. PMID:27635049

  10. Benchmarking Computational Fluid Dynamics Models for Application to Lava Flow Simulations and Hazard Assessment

    NASA Astrophysics Data System (ADS)

    Dietterich, H. R.; Lev, E.; Chen, J.; Cashman, K. V.; Honor, C.

    2015-12-01

    Recent eruptions in Hawai'i, Iceland, and Cape Verde highlight the need for improved lava flow models for forecasting and hazard assessment. Existing models used for lava flow simulation range in assumptions, complexity, and the degree to which they have been validated against analytical solutions, experiments, and natural observations. In order to assess the capabilities of existing models and test the development of new codes, we conduct a benchmarking study of computational fluid dynamics models for lava flows, including VolcFlow, OpenFOAM, Flow3D, and COMSOL. Using new benchmark scenarios defined in Cordonnier et al. (2015) as a guide, we model Newtonian, Herschel-Bulkley and cooling flows over inclined planes, obstacles, and digital elevation models with a wide range of source conditions. Results are compared to analytical theory, analogue and molten basalt experiments, and measurements from natural lava flows. Our study highlights the strengths and weakness of each code, including accuracy and computational costs, and provides insights regarding code selection. We apply the best-fit codes to simulate the lava flows in Harrat Rahat, a predominately mafic volcanic field in Saudi Arabia. Input parameters are assembled from rheology and volume measurements of past flows using geochemistry, crystallinity, and present-day lidar and photogrammetric digital elevation models. With these data, we use our verified models to reconstruct historic and prehistoric events, in order to assess the hazards posed by lava flows for Harrat Rahat.

  11. The Flow of the Gibbon LAVA Element Is Facilitated by the LINE-1 Retrotransposition Machinery.

    PubMed

    Meyer, Thomas J; Held, Ulrike; Nevonen, Kimberly A; Klawitter, Sabine; Pirzer, Thomas; Carbone, Lucia; Schumann, Gerald G

    2016-10-30

    LINE-Alu-VNTR-Alu-like (LAVA) elements comprise a family of non-autonomous, composite, non-LTR retrotransposons specific to gibbons and may have played a role in the evolution of this lineage. A full-length LAVA element consists of portions of repeats found in most primate genomes: CT-rich, Alu-like, and VNTR regions from the SVA retrotransposon, and portions of the AluSz and L1ME5 elements. To evaluate whether the gibbon genome currently harbors functional LAVA elements capable of mobilization by the endogenous LINE-1 (L1) protein machinery and which LAVA components are important for retrotransposition, we established a trans-mobilization assay in HeLa cells. Specifically, we tested if a full-length member of the older LAVA subfamily C that was isolated from the gibbon genome and named LAVAC, or its components, can be mobilized in the presence of the human L1 protein machinery. We show that L1 proteins mobilize the LAVAC element at frequencies exceeding processed pseudogene formation and human SVAE retrotransposition by > 100-fold and ≥3-fold, respectively. We find that only the SVA-derived portions confer activity, and truncation of the 3' L1ME5 portion increases retrotransposition rates by at least 100%. Tagged de novo insertions integrated into intronic regions in cell culture, recapitulating findings in the gibbon genome. Finally, we present alternative models for the rise of the LAVA retrotransposon in the gibbon lineage.

  12. Tracking the hidden growth of a lava flow field: the 2014-15 eruption of Fogo volcano (Cape Verde)

    NASA Astrophysics Data System (ADS)

    Silva, Sonia; Calvari, Sonia; Hernandez, Pedro; Perez, Nemesio; Ganci, Gaetana; Alfama, Vera; Barrancos, José; Cabral, Jeremias; Cardoso, Nadir; Dionis, Samara; Fernandes, Paulo; Melian, Gladys; Pereira, José; Semedo, Hélio; Padilla, German; Rodriguez, Fatima

    2017-04-01

    Fogo volcano erupted in 2014-15 producing an extensive lava flow field in the summit caldera that destroyed two villages, Portela and Bangaeira. The eruption started with powerful explosive activity, lava fountaining, and a substantial ash column accompanying the opening of an eruptive fissure. Lava flows spreading from the base of the eruptive fissure produced three arterial lava flows, spreading S (Flow 1), N-NW (Flow 2) and W (Flow 3). By a week after the start of the eruption, a master lava tube had already developed within the eruptive fissure and along Flow 2. When Flow 2 front stopped against the N caldera cliff, the whole flow field behind it inflated, and eventually its partial drainage produced a short tube that fed Flow 3, but no lava tube formed within Flow 1. Here we analyze the emplacement processes on the basis of observations carried out directly on the lava flow field and through satellite image, in order to unravel the key factors leading to the development of lava tubes. These tubes were responsible for the rapid expansion of lava for the 7.9 km length of the flow field, as well as the destruction of the Portela and Bangaeira villages. Comparing time-averaged effusion rates (TADR) obtained from satellite and Supply Rate (SR) derived from SO2 flux data, we estimate the amount and timing of the lava flow field endogenous growth, with the aim of developing a tool that could be used for risk mitigation at this and other volcanoes.

  13. Applications of GIS to the estimation of lava flow hazards on Mauna Loa Volcano, Hawai'i

    NASA Astrophysics Data System (ADS)

    Kauahikaua, Jim; Margriter, Sandy; Lockwood, Jack; Trusdell, Frank

    Vector-based GIS computer software is used with preliminary digital geologic maps of the active volcano Mauna Loa, Hawai'i to assess the probability that lava flows from this volcano might adversely affect certain areas more than others. A few possible GIS strategies are explored with the maps completed thus far. Traditional coverage rates and probabilities of lava flow occurrence are calculated for target regions of different sizes and shapes. Probability of lava flow occurrence is the probability that one lava flow will enter the target region within the target time period. Probability of coverage is the probability that a particular point will be covered by one or more lava flows within the target time period. The results show that the two approaches yield similar results, with the occurrence of lava flows in a predefined region being more probable than coverage by lava flows. The probabilities of lava flow occurrence reflect all effects of lava flows, whereas the coverage rate estimates reflect only the most serious effect, that of coverage by lava flows.

  14. Structure and organization of submarine basaltic flows: sheet flow transformation into pillow lavas in shallow submarine environments

    NASA Astrophysics Data System (ADS)

    Carracedo Sánchez, M.; Sarrionandia, F.; Juteau, T.; Gil Ibarguchi, J. I.

    2012-11-01

    Distal pillows occur associated with a sheet flow and megapillows in the meñakoz outcrops of the Basque-Cantabrian Basin (N Spain). Basaltic volcanic rocks are interbedded with Turonian sediments and depict typical features of shallow submarine emissions. An exceptional basaltic flow displays four types of morphology: (1) sheet lava with columnar jointing, (2) welded columnar breccia, (3) megapillows, and (4) pillow lavas with sparse megapillows. The field data from meñakoz combined with experimental and field data from the literature for similar volcanic facies can be integrated into a new propagation model for the transition from sheet flows to pillow lavas in underwater environments. At near vent high emission rates, lava flows develop a thin crust immediately after its emplacement and break at the front under the magma pressure allowing for the massive propagation of lava as a sheet flow. Increased cooling promotes thickening of the lava outer crust far from the vent while continuous supply of fresh magma increases the pressure onto the thick crust until its rupture. The lava emitted in small volumes from the flow front promotes the formation of megapillows and pillow lavas that are later on covered by the advancing sheet flow. The lava flow freezes progressively toward more distal parts, gradually increasing its viscosity until it stops. The crust temporarily holds the residual melt pressure increasing the volume of the flow distal section by inflation. Finally, the internal magma pressure breaks the crust and liberates lava at moderate-to-low flow rates producing pillows, while lava drainage inside the inflated sheet flow produces lava tunnels and gravitational collapse of the roofs by hydrostatic pressure to form breccias nurtured by columnar lava fragments.

  15. Structural analysis of flow-related textures in lavas

    NASA Astrophysics Data System (ADS)

    Smith, John V.

    2002-05-01

    The textures of coherent volcanic rocks, including lavas and volcanic intrusives, commonly contain features that are attributed to flowage. Previous applications of structural analysis to volcanic rocks are expanded here to provide a framework for analysis. Textures, defined as the crystallinity, granularity and shapes and arrangements of the components (crystals, glass and voids) of a rock, together with structures, defined as individual features composed of the disposition, attitude, arrangement or relative positions of the components of a rock, are first described. Second, the spatial fabrics (shapes and arrangements of the components of a rock and the orientation of textures and structures) are identified. Third, textures, structures and fabrics are placed in the spatial and temporal geological context. Finally, detailed interpretations of the kinematics and rheology of structures and fabrics is made, leading to an integrated flow history of the rock. Illustrative case studies include rhyolite from the basal part of the Tertiary Minyon Falls dome, northeastern New South Wales, Australia, which has a texture comprising planar domains of differing crystal abundance (flow bands), multiple folds of these domains, relatively homogeneous crystal alignment parallel to the fold axes and microfolding of these domains in the zone of interaction between phenocrysts and matrix, including retrorotation of phenocrysts on short limbs of inequant folds. Trachyte dykes on Fraser Island, Queensland, Australia have a texture comprising crystal alignment, planar concentration domains (banding), two planar domains of crystal alignment interpreted to be conjugate shear zones. Phenocrysts influence the spacing and distribution of the domains and interacted with shear zones by undergoing small amounts of rotation. The shear zones overprinted a homogeneous crystal alignment during the last stage of flow before solidification as a result of dilatant granular interactions. Lava from

  16. Basalt: Biologic Analog Science Associated with Lava Terrains

    NASA Astrophysics Data System (ADS)

    Lim, D. S. S.; Abercromby, A.; Kobs-Nawotniak, S. E.; Kobayashi, L.; Hughes, S. S.; Chappell, S.; Bramall, N. E.; Deans, M. C.; Heldmann, J. L.; Downs, M.; Cockell, C. S.; Stevens, A. H.; Caldwell, B.; Hoffman, J.; Vadhavk, N.; Marquez, J.; Miller, M.; Squyres, S. W.; Lees, D. S.; Fong, T.; Cohen, T.; Smith, T.; Lee, G.; Frank, J.; Colaprete, A.

    2015-12-01

    This presentation will provide an overview of the BASALT (Biologic Analog Science Associated with Lava Terrains) program. BASALT research addresses Science, Science Operations, and Technology. Specifically, BASALT is focused on the investigation of terrestrial volcanic terrains and their habitability as analog environments for early and present-day Mars. Our scientific fieldwork is conducted under simulated Mars mission constraints to evaluate strategically selected concepts of operations (ConOps) and capabilities with respect to their anticipated value for the joint human and robotic exploration of Mars. a) Science: The BASALT science program is focused on understanding habitability conditions of early and present-day Mars in two relevant Mars-analog locations (the Southwest Rift Zone (SWRZ) and the East Rift Zone (ERZ) flows on the Big Island of Hawai'i and the eastern Snake River Plain (ESRP) in Idaho) to characterize and compare the physical and geochemical conditions of life in these environments and to learn how to seek, identify, and characterize life and life-related chemistry in basaltic environments representing these two epochs of martian history. b) Science Operations: The BASALT team will conduct real (non-simulated) biological and geological science at two high-fidelity Mars analogs, all within simulated Mars mission conditions (including communication latencies and bandwidth constraints) that are based on current architectural assumptions for Mars exploration missions. We will identify which human-robotic ConOps and supporting capabilities enable science return and discovery. c) Technology: BASALT will incorporate and evaluate technologies in to our field operations that are directly relevant to conducting the scientific investigations regarding life and life-related chemistry in Mars-analogous terrestrial environments. BASALT technologies include the use of mobile science platforms, extravehicular informatics, display technologies, communication

  17. Phosphorus zoning in olivine of Kilauea Iki lava lake, Hawaii

    NASA Astrophysics Data System (ADS)

    Fabbrizio, Alessandro; Beckett, John R.; Baker, Michael B.; Stolper, Edward M.

    2010-05-01

    Kilauea Iki lava lake was formed when the lavas of the 1959 summit eruption of Kilauea volcano ponded in Kilauea Iki pit crater, as described by [1]. The main chamber of this lake has been drilled repeatedly from 1960 to 1981 as the lake has cooled and crystallized and partial descriptions of core can be found in [2-7]. The bulk of the core consists of a gray, olivine-phyric basalt matrix [3]. Rapid diffusion of divalent cations through olivine at magmatic temperatures can delete information on early-formed zoning and thus information on early magmatic history, recorded in olivine during its growth, is often largely lost [8-11]. In the last years many studies [8-11] have shown that natural olivine, terrestrial and extraterrestrial, from several localities and rock types can preserve a complex zoning in P (sometimes associated with Cr and Al). Simple crystallization experiments conducted by [10] and [11] were able to replicate these features (i.e., sector and oscillatory zoning). Here, we describe P, Cr and Al zoning in olivine from the 1981 drilling of Kilauea Iki lava lake hole #1 (KI81-1) [6]. Kα X-ray intensity maps and major and minor element quantitative analyses were obtained using the Caltech JEOL JXA-8200 electron microprobe. We acquired P, Cr, Al, Fe and Ti X-ray maps simultaneously at 15 kV and 400 nA, a beam diameter of 1 μm, pixel spacing of 1-2 μm, and count times of 420-1500 msec/step were used depending on the dimension of the crystal. 15 kV and 40 nA with a beam diameter of 1 μm were used to collect quantitative analyses. P2O5 contents of the Iki olivines range from below detection limit to 0.30 wt%. Zoning in phosphorus, based on X-ray intensity maps, was observed in all olivines we examined. The P zoning patterns of the olivines display several styles. P shows oscillatory zoning comparable to that seen in terrestrial and extraterrestrial igneous olivines and in experimentally grown olivine [8-11]; high P regions, inside the crystals, outline

  18. High-resolution mapping of the 1998 lava flows at Axial Seamount

    NASA Astrophysics Data System (ADS)

    Chadwick, B.; Clague, D. A.; Embley, R. W.; Caress, D. W.; Paduan, J. B.; Sasnett, P.

    2011-12-01

    Axial Seamount (an active hotspot volcano on the Juan de Fuca Ridge) last erupted in 1998 and produced two lava flows (a "northern" and a "southern" flow) along the upper south rift zone separated by a distance of 4 km. Geologic mapping of the 1998 lava flows has been carried out with a combination of visual observations from multiple submersible dives since 1998, and with high-resolution bathymetry, most recently collected with the MBARI mapping AUV (the D. Allan B.) since 2007. The new mapping results revise and update the previous preliminary flow outlines, areas, and volumes. The high-resolution bathymetry (1-m grid cell size) allows eruptive fissures fine-scale morphologic features to be resolved with new and remarkable clarity. The morphology of both lava flows can be interpreted as a consequence of a specific sequence of events during their emplacement. The northern sheet flow is long (4.6 km) and narrow (500 m), and erupted in the SE part of Axial caldera, where it temporarily ponded and inflated on relatively flat terrain before draining out southward toward steeper slopes. The inflation and drain-out of this sheet flow by ~ 3.5 m over 2.5 hours was previously documented by a monitoring instrument that was caught in the lava flow. Our geologic mapping shows that the morphology of the northern sheet flow varies along its length primarily due to gradients in the underlying slope and processes active during flow emplacement. The original morphology of the sheet flow where it ponded is lobate, with pillows near the margins, whereas the central axis of drain-out and collapse is floored with lineated, ropy, and jumbled lava morphologies. The southern lava flow, in contrast, is mostly pillow lava where it cascaded down the steep slope on the east flank of the south rift zone, but also has a major area of collapse where lava ponded temporarily near the rift axis. These results show that submarine lava flows have more subsurface hydraulic connectivity than has