Effusion rate estimation based on solidified lava flows: Implications for volcanic hazard assessment in the Negros de Aras monogenetic volcanic field, northern Chile

Abstract. Long-term hazard assessment, one of the bastions of risk-mitigation programs, is required for land-use planning and for developing emergency plans. To ensure quality and representative results, long-term volcanic hazard assessment requires several sequential steps to be completed, which include the compilation of geological and volcanological information, the characterisation of past eruptions, spatial and temporal probabilistic studies, and the simulation of different eruptive scenarios. Despite being a densely populated active volcanic region that receives millions of visitors per year, no systematic hazard assessment has ever been conducted on the Canary Islands. In this paper we focus our attention on El Hierro, the youngest of the Canary Islands and the most recently affected by an eruption. We analyse the past eruptive activity to determine the spatial and temporal probability, and likely style of a future eruption on the island, i.e. the where, when and how. By studying the past eruptive behaviour of the island and assuming that future eruptive patterns will be similar, we aim to identify the most likely volcanic scenarios and corresponding hazards, which include lava flows, pyroclastic fallout and pyroclastic density currents (PDCs). Finally, we estimate their probability of occurrence. The end result, through the combination of the most probable scenarios (lava flows, pyroclastic density currents and ashfall), is the first qualitative integrated volcanic hazard map of the island.

Download Full-text

Spatio-temporal hazard assessment of a monogenetic volcanic field, near México City

Journal of Volcanology and Geothermal Research ◽

10.1016/j.jvolgeores.2019.01.006 ◽

2019 ◽

Vol 371 ◽

pp. 46-58 ◽

Cited By ~ 5

Author(s):

Amiel Nieto-Torres ◽

Ana Lillian Martin Del Pozzo

Keyword(s):

Mexico City ◽

Hazard Assessment ◽

Volcanic Field ◽

Monogenetic Volcanic Field ◽

Spatio Temporal

Download Full-text

Drainage development on basaltic lava flows, Cima volcanic field, southeast California, and Lunar Crater volcanic field, south-central Nevada: Alternative interpretation

Geological Society of America Bulletin ◽

10.1130/0016-7606(1989)101<0595:ddoblf>2.3.co;2 ◽

1989 ◽

Vol 101 (4) ◽

pp. 595-599 ◽

Cited By ~ 3

Author(s):

MARK A. MELTON

Keyword(s):

Volcanic Field ◽

Alternative Interpretation ◽

Lava Flows ◽

Basaltic Lava ◽

Lunar Crater ◽

South Central ◽

Drainage Development ◽

Cima Volcanic Field

Download Full-text

Evidence of active magmatic rifting at the Ma’Alalta volcanic field (Afar, Ethiopia)

Bulletin of Volcanology ◽

10.1007/s00445-021-01461-4 ◽

2021 ◽

Vol 83 (6) ◽

Author(s):

Gianmaria Tortelli ◽

Anna Gioncada ◽

Carolina Pagli ◽

Mauro Rosi ◽

Laura De Dosso ◽

...

Keyword(s):

Seismic Data ◽

Volcanic Field ◽

Lava Flows ◽

Magmatic Activity ◽

Magma Storage ◽

Plumbing System ◽

Mafic Lava ◽

Cinder Cones ◽

Mafic Rocks ◽

Seismic Networks

AbstractDuring continental rifting, strain and magmatism are believed to localize to narrow magmatic segments, while the rift margin is progressively abandoned. We integrate volcanological, geochemical, petrological and seismic data from the Ma’Alalta volcanic field (MVF) near the western margin of Afar, to show that the MVF is an active magmatic segment. Magmatism in MVF initiated with lava flows and large-volume, caldera-forming ignimbrites from a central edifice. However, the most recent magmatic activity shifted towards mafic lava fields, cinder cones and obsidian-rich silicic domes erupted from vents aligned NNW-SSE, defining a ~ 35-km-long magmatic segment. Along the same area, a NNW-SSE alignment of earthquakes was recorded by two local seismic networks (2005–2009 and 2011–2013). The geochemistry of the mafic rocks is similar to those of nearby axial volcanoes. Inferred magma storage depth from mineral geobarometry shows that a shallow, silicic chamber existed at ~ 5-km depth below the stratovolcano, while a stacked plumbing system with at least three magma storage levels between 9 and 24 km depth fed the recent basalts. We interpret the wide set of observations from the MVF as evidence that the area is an active magmatic segment, showing that localised axial extension can be heavily offset towards the rift margin.

Download Full-text