The 1983 Etna eruption: Event chronology and morphological evolution of the lava flow

Frazzetta, G.; Romano, R.

doi:10.1007/bf01952364

Cited by 51 publications

(38 citation statements)

References 12 publications

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“…They noted that some of these changes reflected gas content and lava density variations rather than variations in the erupted volume flux. During the 1983 Etna eruption, fluctuations in flow velocity of ∼20% occurred over a periods of 2 to <24 h (Frazzetta and Romano 1984;Guest et al 1987). In our case, we observe large variations in flow rate on a timescale of tens of minutes.…”

Section: Discussionmentioning

confidence: 99%

“…Etna has allowed numerous studies of flow-field formation. Some of these studies have concentrated on overall flow-field morphology or its formation chronology, using either field-based measurements, e.g., Pinkerton and Sparks (1976), Frazzetta and Romano (1984), Guest et al (1987), Kilburn and Lopes (1988), Calvari et al (1994), Calvari et al (2002), Behncke and Neri (2003), or remote sensing data, e.g., Pieri et al (1990), Harris et al (1997Harris et al ( , 2000, Wright et al (2000Wright et al ( , 2001. Other studies have concentrated on changes within the channelized or tubed sections of a flow.…”

Section: Channelized 'A'ā Flows On Etnamentioning

confidence: 99%

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The changing morphology of an open lava channel on Mt. Etna

et al. 2006

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An open channel lava flow on Mt. Etna (Sicily) was observed during May [30][31] 2001. Data collected using a forward looking infrared (FLIR) thermal camera and a Minolta-Land Cyclops 300 thermal infrared thermometer showed that the bulk volume flux of lava flowing in the channel varied greatly over time. Cyclic changes in the channel's volumetric flow rate occurred over several hours, with cycle durations of 113-190 min, and discharges peaking at 0.7 m 3 s −1 and waning to 0.1 m 3 s −1 . Each cycle was characterized by a relatively short, high-volume flux phase during which a pulse of lava, with a well-defined flow front, would propagate down-channel, followed by a period of waning flow during which volume flux lowered. Pulses involved lava moving at relatively high velocities (up to 0.29 m s −1 ) and were related to some change in the flow conditions occurring up-channel, possibly at the vent. They implied either a change in the dense rock effusion rate at the source vent and/or cyclic-variation in the vesicle content of the lava changing its bulk volume flux. Pulses would generally overspill the channel to emplace pāhoehoe overflows.Editorial responsibility: A. Woods During periods of waning flow, velocities fell to 0.05 m s -1 . Blockages forming during such phases caused lava to back up. Occasionally backup resulted in overflows of slow moving 'a'ā that would advance a few tens of meters down the levee flank. Compound levees were thus a symptom of unsteady flow, where overflow levees were emplaced as relatively fast moving pāhoehoe sheets during pulses, and as slow-moving 'a'ā units during backup. Small, localized fluctuations in channel volume flux also occurred on timescales of minutes. Volumes of lava backed up behind blockages that formed at constrictions in the channel. Blockage collapse and/or enhanced flow under/around the blockage would then feed short-lived, wave-like, downchannel surges. Real fluctuations in channel volume flux, due to pulses and surges, can lead to significant errors in effusion rate calculations.

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Section: Discussionmentioning

confidence: 99%

Section: Channelized 'A'ā Flows On Etnamentioning

confidence: 99%

The changing morphology of an open lava channel on Mt. Etna

et al. 2006

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“…However, volumetric lava flux (or flow rate) is a difficult parameter to measure accurately in the field, and on Etna, the problems are compounded by changes in flux that have been previously reported over a wide range of timescales [Neal and Decker, 1983;Frazzetta and Romano, 1984;Guest et al, 1987;Harris et al, 2000;Calvari et al, 2002;Lautze et al, 2004;Bailey et al, 2006]. An example of short-term variations is given by Lautze et al [2004], who report observations of unsteady flow in a proximal lava channel on Etna in 2001, characterized by 10-30 minute surges, interspersed between 1-3 hours of waning flow.…”

Section: Introductionmentioning

confidence: 99%

Image‐based measurement of flux variation in distal regions of active lava flows

James

Pinkerton

Robson

2007

Geochem Geophys Geosyst

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[1] Understanding the processes involved with the advance of lava flows is critical for improving hazard assessments at many volcanoes. Here, we describe the application of computer vision and oblique photogrammetric techniques to visible and thermal images of active 'a' a flows in order to investigate distal flow processes at Mount Etna, Sicily. Photogrammetric surveys were carried out to produce repeated topographic data sets for calculation of volumetric lava flux at the flow-fronts. Velocity profiles from a distal channel were obtained by rectification of a thermal image sequence and are used to investigate the rheological properties of the lava. Significant variations of the magma flux were observed, and pulses of increased flux arrived within the flow-front region on timescales of several hours. The pulses are believed to be the distal result of more frequent flux changes observed in the vent region. Hence they reflect the importance of flow processes which are believed to cause the coalescence of flux pulses along the channel system as well as short-period variations in effusion rate. In considering advance processes for the individual flow-fronts, it must be assumed that they were fed by a highly unsteady flux, which was volumetrically at least an order of magnitude lower than that observed near the vent.

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“…during the 1983 flank eruption (Frazzetta and Romano 1984;Harris et al 2000) and 60-120 m 3 s -1 during fountain-fed phases of the 1999 summit eruption (Harris and Neri 2002). However, effusion rates are typically between 1 and 10 m 3 s -1 during the later stages of flank eruptions (e.g., Frazzetta and Romano 1984;Calvari et al 1994;Coltelli et al 2007) and non-fountain-fed summit eruptions (e.g., Harris et al 2000;Calvari et al 2003;Lautze et al 2004).…”

Section: 3mentioning

confidence: 99%

“…However, effusion rates are typically between 1 and 10 m 3 s -1 during the later stages of flank eruptions (e.g., Frazzetta and Romano 1984;Calvari et al 1994;Coltelli et al 2007) and non-fountain-fed summit eruptions (e.g., Harris et al 2000;Calvari et al 2003;Lautze et al 2004). …”

Section: 3mentioning

confidence: 99%

Hazard assessment at Mount Etna using a hybrid lava flow inundation model and satellite-based land classification

et al. 2011

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Using a lava flow emplacement model and a satellite-based land cover classification, we produce a map to allow assessment of the type and quantity of natural, agricultural and urban land cover at risk from lava flow invasion. The first step is to produce lava effusion rate contours, i.e., lines linking distances down a volcano's flank that a lava flow will likely extend if fed at a given effusion rate from a predetermined vent zone. This involves first identifying a vent mask and then running a downhill flow path model from the edge of every pixel around the vent mask perimeter to the edge of the DEM. To do this, we run a stochastic model whereby the flow path is projected 1,000 times from every pixel around the vent mask perimeter with random noise being added to the DEM with each run so that a slightly different flow path is generated with each run. The FLOWGO lava flow model is then run down each path, at a series of effusion rates, to determine likely run-out distance for channel-fed flow extending down each path. These results are used to plot effusion rate contours. Finally, effusion rate contours are projected onto a land classification map (produced from an ASTER image of Etna) to assess the type and amount of each land cover class falling within each contour. The resulting maps are designed to provide a quick look-up capability to assess the type of land at risk from lava extending from any location at a range of likely effusion rates. For our first (2,000 m) vent zone case used for Etna, we find a total of area of *680 km 2 is at risk from flows fed at 40 m 3 s -1 , of which *6 km 2 is urban, *150 km 2 is agriculture and *270 km 2 is grass/woodland. The model can also be run for specific cases, where we find that Etna's 1669 vent location, if active today, would likely inundate almost 11 km 2 of urban land, as well as 15.6 km 2 of agricultural land, including 9.5 km 2 of olive groves and 5.2 km 2 of vineyards and fruit/nut orchards.

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The 1983 Etna eruption: Event chronology and morphological evolution of the lava flow

Cited by 51 publications

References 12 publications

The changing morphology of an open lava channel on Mt. Etna

The changing morphology of an open lava channel on Mt. Etna

Image‐based measurement of flux variation in distal regions of active lava flows

Hazard assessment at Mount Etna using a hybrid lava flow inundation model and satellite-based land classification

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