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

Murcia, Hugo; Németh, Károly; Moufti, Mohammed Rashad; Lindsay, Jan M.; El-Masry, Nabil; Cronin, Shane J.; Qaddah, Atef; Smith, I. E.

doi:10.1016/j.jseaes.2013.10.002

Cited by 61 publications

(52 citation statements)

References 56 publications

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“…In extreme cases, this category could include "point sources" of flood lavas, as was raised in several intra-continental flood lava fields such as those that erupted through thick continental lithospheres, i.e. in the Arabian Peninsula (Murcia et al 2014). This problem was highlighted by recent research on determining the source volcanoes of typical large flood basalt regions, such as those in the Deccan (Sheth and Cañón-Tapia 2015).…”

Section: Departures From Monogenetic Signatures: Transitional Volcanoesmentioning

confidence: 99%

Monogenetic volcanism: personal views and discussion

Németh

Keresztúri

2015

Int J Earth Sci (Geol Rundsch)

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Section: Departures From Monogenetic Signatures: Transitional Volcanoesmentioning

confidence: 99%

Monogenetic volcanism: personal views and discussion

Németh

Keresztúri

2015

Int J Earth Sci (Geol Rundsch)

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220

130

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“…Over 950 eruption centres have been recognised in this field (Runge et al 2014). The youngest eruptions occurred in the north, termed Harrat Al-Madinah (Moufti 1985;Moufti et al 2010Moufti et al , 2012 or northern Harrat Rahat (Murcia et al 2014). The volcanism is thought to be associated with partial melting in both the lithosphere and asthenosphere (e.g.…”

Section: Geological and Hydrological Background Tectonic Settingmentioning

confidence: 99%

“…Most eruptions typically involve much larger magma volumes (>0.1 km 3 ; e.g. Camp et al 1987;Murcia et al 2014). This may explain, in part, the unidentified phreatomagmatism in this region, despite the presence of aquifers.…”

Section: Implications For Phreatomagmatism In Al-madinahmentioning

confidence: 99%

“…In addition, long and extensive lava flow fields comprise the main erupted volume of the field (e.g. Murcia et al 2014). Small individual cones occur, as well as Editorial responsibility: J. Taddeucci Electronic supplementary material The online version of this article (doi:10.1007/s00445-015-0936-9) contains supplementary material, which is available to authorized users.…”

Section: Introductionmentioning

confidence: 99%

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The Al-Du’aythah volcanic cones, Al-Madinah City: implications for volcanic hazards in northern Harrat Rahat, Kingdom of Saudi Arabia

et al. 2015

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The basaltic Al-Du'aythah volcanic cones lie in the northern part of the extensive lava field of Harrat Rahat, and only 13 km from the centre of Al-Madinah City, in the Kingdom of Saudi Arabia. Historical records indicate they may have erupted in AD 641. The four cones are formed by deposits that record a transition from phreatomagmatic to magmatic explosions followed by minor lava effusion. Three cones display elongated tuff rings at the base, and two produced late-stage lava flows. The cones themselves are symmetrical and constructed mostly by the accumulation of ballistically ejected pyroclasts. Spherical bombs and lapilli (cannonball bombs/lapilli), occasionally with country-rock fragments inside (both cored and loaded bombs/lapilli) are common within the tuff ring deposits. LiDAR data show a total volume of 1,664×10 −6 km 3 for the four cones (418×10 −6 km 3 DRE). Whole-rock chemical analyses indicate alkali-basalt compositions (SiO 2 44.7-45.9 wt%), with little compositional variation and no relationship between chemistry and eruptive styles. Small differences in composition may reflect variations in fractional crystallisation of clinopyroxene and olivine. A magnetotelluric 2D cross-section shows that the cones are located adjacent to a buried sediment-filled alluvial channel along a NNW-SSE fault dipping to the east. The AlDu'aythah eruption was related to the ascent of magma through this structure, with the first phase of the eruption triggered by the interaction of the magma with water from the northern Harrat Rahat aquifer that exists in the AlMadinah basin. This initial water source was rapidly exhausted, while the eruption progressed roughly from north to south and from west to east, the latter motion probably along the fault-controlled feeding dyke. Our work draws attention to the existence of recent explosive phreatomagmatic eruptions in the Al-Madinah basin, which, despite the hyperarid climate of the area, must be considered a potential future eruption hazard.

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“…Erupted products include extensive lava flows (Murcia et al 2014), as well as scoria and spatter cones, shield volcanoes, tuff rings, and lava domes (Camp and Roobol 1989). Eruptions in Harrat Rahat have been dated between 10 Ma and 1256 AD, with age data broadly suggesting a northward focussing of volcanism with time (Camp and Roobol 1989).…”

Section: Harrat Rahatmentioning

confidence: 99%

Sensitivity to volcanic field boundary

et al. 2015

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Volcanic hazard analyses are desirable where there is potential for future volcanic activity to affect a proximal population. This is frequently the case for volcanic fields (regions of distributed volcanism) where low eruption rates, fertile soil, and attractive landscapes draw populations to live close by. Forecasting future activity in volcanic fields almost invariably uses spatial or spatio-temporal point processes with model selection and development based on exploratory analyses of previous eruption data. For identifiability reasons, spatio-temporal processes, and practically also spatial processes, the definition of a spatial region is required to which volcanism is confined. However, due to the complex and predominantly unknown sub-surface processes driving volcanic eruptions, definition of a region based solely on geological information is currently impossible. Thus, the current approach is to fit a shape to the known previous eruption sites. The class of boundary shape is an unavoidable subjective decision taken by the forecaster that is often overlooked during subsequent analysis of results. This study shows the substantial effect that this choice may have on even the simplest exploratory methods for hazard forecasting, illustrated using four commonly used exploratory statistical methods and two very different regions: the Auckland Volcanic Field, New Zealand, and Harrat Rahat, Kingdom of Saudi Arabia. For Harrat Rahat, sensitivity of results to boundary definition is substantial. For the Auckland Volcanic Field, the range of options resulted in similar shapes, nevertheless, some of the statistical tests still showed substantial variation in results. This work highlights the fact that when carrying out any hazard analysis on volcanic fields, it is vital to specify how the volcanic field boundary has been defined, assess the sensitivity of boundary choice, and to carry these assumptions and related uncertainties through to estimates of future activity and hazard analyses.

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

Cited by 61 publications

References 56 publications

Monogenetic volcanism: personal views and discussion

Monogenetic volcanism: personal views and discussion

The Al-Du’aythah volcanic cones, Al-Madinah City: implications for volcanic hazards in northern Harrat Rahat, Kingdom of Saudi Arabia

Sensitivity to volcanic field boundary

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