Permanent lava lakes: observed facts and induced mechanisms

Tazieff, Haroun

doi:10.1016/0377-0273(94)90015-9

Cited by 68 publications

(38 citation statements)

References 3 publications

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“…The sustained presence of an actively convecting lava lake requires exceptional geodynamic conditions [Tazieff, 1994;Harris et al, 1999;Oppenheimer et al, 2009]. In most volcanic systems, the exsolution of magmatic volatiles and the cooling of lava at ambient atmospheric temperatures are sufficient to reduce the system's entropy and lead to rapid lava quenching or crystallization [Francis et al, 1993].…”

Section: Mass Fluxmentioning

confidence: 99%

Dynamics of the Mount Nyiragongo lava lake

et al. 2014

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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 m 2 ), which constrains, respectively, the lava lake volume (~9 × 10 6 m 3 ) and volume flow rate needed to keep the magma in a molten state (0.6 to 3.5 m 3 s À1

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Section: Mass Fluxmentioning

confidence: 99%

Dynamics of the Mount Nyiragongo lava lake

et al. 2014

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“…For comparison, the latitude and longitude of the hotspot as recorded by MODVOLC is shown alongside the coordinates of the summit of the volcano as published by Simkin and Seibert (1994). Persistently active lava lakes are known to have existed at Erta Ale (Ethiopia) and Mount Erebus (Antarctica) for at least 200 years, although ground observations are rare because of their geographical isolation Tazieff, 1994). MODVOLC regularly detects the hotspots associated with these lava lakes ( Fig.…”

Section: Volcanic Hotspotsmentioning

confidence: 99%

Automated volcanic eruption detection using MODIS

Wright¹,

Flynn²,

Garbeil³

et al. 2002

Remote Sensing of Environment

244

159

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The moderate resolution imaging spectroradiometer (MODIS) flown on-board NASA's first earth observing system (EOS) platform, Terra, offers complete global data coverage every 1 -2 days at spatial resolutions of 250, 500, and 1000 m. Its ability to detect emitted radiation in the short (4 Am)-and long (12 Am)-wave infrared regions of the electromagnetic spectrum, combined with the excellent geolocation of the image pixels ( f 200 m), makes it an ideal source of data for automatically detecting and monitoring high-temperature volcanic thermal anomalies. This paper describes the underlying principles of, and results obtained from, just such a system. Our algorithm interrogates the MODIS Level 1B data stream for evidence of high-temperature volcanic features. Once a hotspot has been identified, its details (location, emitted spectral radiance, satellite observational parameters) are written to an ASCII text file and transferred via file transfer protocol (FTP) to the Hawaii Institute of Geophysics and Planetology (HIGP), where the results are posted on the Internet (http:// modis.higp.hawaii.edu). The global distribution of volcanic hotspots can be examined visually at a variety of scales using this website, which also allows easy access to the quantitative data contained in the ASCII files themselves. We outline how the algorithm has proven robust as a hotspot detection tool for a wide range of eruptive styles at both permanently and sporadically active volcanoes including Soufriere Hills (Montserrat), Popocatépetl (Mexico), Bezymianny (Russia), and Merapi (Java), amongst others. We also present case studies of how the system has allowed the onset, development, and cessation of discrete eruptive events to be monitored at Nyamuragira (Congo), Piton de la Fournaise (Réunion Island), and Shiveluch (Russia). D

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“…Crater C has widened from a 60-m-diameter circular shape in early 1980 (Cigolini et al 1984) to a slightly elongated shape of some 150-200 m in diameter, which contains a lava pool (cf. Tazieff 1994). Because of the growth of the cone and the widening of the crater, the pool must have a funnel shape.…”

Section: Introductionmentioning

confidence: 98%

Pyroclastic flow generated by crater-wall collapse and outpouring of the lava pool of Arenal Volcano, Costa Rica

Alvarado¹,

Soto²

2001

Bull Volcanol

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The pyroclastic flow that issued from the Arenal summit crater on 28 August 1993 came from the collapse of the crater wall of the cone and the drainage of a lava pool. The 3-km-long pyroclastic flow, 2.2±0.8×10 6 m 3 in volume, was confined to narrow valleys (30-100 m wide). The thickness of the pyroclastic deposit ranged from 1 to 10 m, and its temperature was about 400°C, although single bombs were up to 1,000°C. The deposit is clast-supported, has a bimodal grain size distribution, and consists of an intimate mixture of finely pulverized rock ash, lapilli, small blocks, and cauliflower bread-crusted bombs, in which are set meter-size lava fragments and juvenile and non-juvenile angular blocks, and bombs up to 7 m in diameter. Large faceted blocks make up 50% of the total volume of the deposit. The cauliflower bombs have deep and intricate bread-crust texture and post-depositional vesiculation. It is proposed that the juvenile material was produced entirely from a lava pool, whereas faceted non-juvenile blocks come from the crater-wall collapse. The concentration and maximum diameter of cauliflower breadcrusted bombs increases significantly from the base (rockslide + pyroclastic flow) to the top (the pyroclastic flow) of the deposit. An ash cloud deposited accretionary lapilli in the proximal region (outside of the pyroclastic flow deposit), and very fine ash fell in the distal region (between 5 and 30 km). The accretionary lapilli deposit is derived from the fine, elutriated products of the flow as it moved. A turbulent overriding surge blew down the surrounding shrubbery in the flow direction. The pyroclastic flow from August 1993, similar to the flows of slid and rolled rather than being buoyed up by gas. They grooved, scratched, and polished the surfaces over which they swept, similar to a Merapi-type pyroclastic flow. However, the mechanism of the outpouring of a lava pool and the resulting flows composed of high-to moderate-vesiculated, cauliflower bread-crusted bombs and juvenile blocks have not been described before. Highfrequency earthquake swarms, followed by an increase in low-frequency volcanic events, preceded the 1975, 1993, and 2000 eruptions 2-4 months before. These pyroclastic flow events, therefore, may be triggered by internal expansion of the unstable cone in the upper part because of a slight change in the pressure of the magma column (gas content and/or effusive rate). This phenomenon has important short-term, volcanic hazard implications for touristic development of some parts on the flanks of the volcano.

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Permanent lava lakes: observed facts and induced mechanisms

Cited by 68 publications

References 3 publications

Dynamics of the Mount Nyiragongo lava lake

Dynamics of the Mount Nyiragongo lava lake

Automated volcanic eruption detection using MODIS

Pyroclastic flow generated by crater-wall collapse and outpouring of the lava pool of Arenal Volcano, Costa Rica

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