Chapter 55 - Lava Flow Hazards and Modeling

The integration of satellite data and modeling represents a step toward the next generation of quantitative hazard assessment in response to effusive volcano eruption onset. Satellite-based thermal remote sensing of hotspots related to effusive activity can effectively provide a variety of products suited to timing, locating, and tracking the radiant character of lava flows. Hotspots show the location and occurrence of eruptive events (vents). Discharge rate estimates may indicate the current intensity (effusion rate) and potential magnitude (volume). High-spatial-resolution multispectral satellite data can complement field observations for monitoring the front position (length) and extension of flows (area). Physics-based models driven, or validated, by satellite-derived parameters are now capable of fast and accurate forecast of lava flow inundation scenarios (hazard). Here, we demonstrate the potential of the integrated application of satellite remote-sensing techniques and lava flow models by using a retrospective analysis of the 2004–2005 effusive eruption at Mount Etna in Italy. The lava flow hazard was assessed by using the HOTSAT volcano hotspot detection system, which works with satellite thermal infrared data, and the MAGFLOW lava flow emplacement model, which is able to relate the flow evolution to eruption conditions at the vent. We used HOTSAT to analyze Moderate Resolution Imaging Spectroradiometer (MODIS) and Spinning Enhanced Visible and InfraRed Imager (SEVIRI) data to output hotspot 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-7 Enhanced Thematic Mapper+ (ETM+) and Earth Observing 1 ( EO-1 ) Advanced Land Imager (ALI) images complement the field observations to track the flow front position in time and add valuable data on lava flow advancement with which to validate the numerical simulations. Such integration at last makes timely forecasts of lava flow hazards during effusive crises possible at the great majority of volcanoes for which no monitoring exists.

Abstract. The 6-month-long effusive eruption at the Fagradalsfjall volcano in 2021 is the most visited eruption site in Iceland to date (June 2023), and it needed intense lava flow hazard assessment. In this study we document how strategies for lava flow modeling were implemented using the stochastic model MrLavaLoba to evaluate hazards during this effusive event. Overall, the purposes were threefold: (a) pre-eruption simulations to investigate potential lava inundation of critical infrastructure, (b) syn-eruption simulations for short-term (2-week time frame) lava flow hazard assessment and (c) syn-eruption simulations for long-term (months to years) hazard assessments. Additionally, strategies for lava barrier testing were developed, and syn-eruption topographic models were incorporated into simulations in near real time. The model provided promising results that were shared regularly at stakeholder meetings with the monitoring personnel, scientists and civil-protection representatives helping to identify potential short-term and long-term lava hazards. This included evaluation of the timing of barrier overflow and the filling and spilling of lava from one valley to another. During the crisis the MrLavaLoba model was updated to increase functionality such as by considering multiple active vents. Following the eruption, the model was optimized substantially, decreasing the computational time required for the simulations and speeding up the delivery of final products.

A GIS-based volcanic hazard and risk assessment of eruptions sourced within Valles Caldera, New Mexico

R.D. Ballard, Foreword. Origin and Transport of Magma: H. Sigurdsson, B. Houghton, H. Rymer, J. Stix, and S. McNutt, Introduction. H. Sigurdsson, The History of Volcanology. R. Jeanloz, Mantle of the Earth. P. Asimov, Melting the Mantle. M. Daines, Migration of Melt. M. Perfit and J. Davidson, Tectonics and Volcanism. N.W. Rogers and C.J. Hawkesworth, Composition of Magmas. T.L. Grove, Origin of Magmas. P.J. Wallace and A.T. Anderson, Volatiles in Magmas. F.J. Spera, Physical and Thermodynamic Properties of Magmas. B.D. Marsh, Reservoirs of Magma and Magma Chambers. M.J. Rutherford and J. Gardner, Rates of Magma Ascent. C. Carrigan, Plumbing Systems. C. Jaupart, Magma at Shallow Levels. Eruption: T. Simkin and L. Siebert, Active Volcanoes on the Earth. D.M. Pyle, Sizes of Volcanic Eruptions. H. Sigurdsson, Episodes of Volcanism. Effusive Volcanism: G.P.L. Walker, Basaltic Volcanoes and Volcanic Systems. C. Kilburn, Lava Flows. J. Fink and S. Anderson, Domes and Coulees. J. Wolff and J. Sumner, Spatter-Fed Lavas and Fire-Fountaining. C. Conner and M. Conway, Basaltic Volcanic Fields. P. Hooper, Flood Basalt Provinces. R. Batiza and J. White, Submarine Lavas and Hyaloclastite. R. Schmidt and H.-U. Schmincke, Seamounts, Submarine Volcanoes, and Volcanic Islands. J. Smellie, Sub-Glacial Eruptions. Explosive Volcanism: Cashman, B. Sturtevant, P. Papale, and O. Navon, Magmatic Fragmentation. M.M. Morrisey, B. Zimoriski, K. Wohletz, and R. Buettner, Phreatomagmatic Fragmentation. S. Vergniolle and M. Mangan, Strombolian and Hawaiian Eruptions. M.M. Morrissey and L.G. Mastin, Vulcanian Eruptions. Cioni, P. Marianelli, R. Santecroce, and A. Sbrana, Plinian Eruptions. J.D.L. White and B. Houghton, Pyroclastic Eruptions. B.F. Houghton, C.J.N. Wilson, R.T. Smith, and J.S. Gilbert, Phreatoplinian Eruptions. S. Carey and M.I. Bursik, Volcanic Plumes. C.J.N. Wilson and B.F. Houghton, Pyroclastic Transport and Deposition. B.F. Houghton, C.J.N. Wilson, and D.M. Pyle, Fall Deposits. G. Valentine and R.V. Fisher, Deposits of Surges and Directed Blasts. A. Freundt, S.N. Carey, and C.J.N. Wilson, Ignimbrites and Deposits of Block-and-Ash Flows. J.W. Vallance, Lahar Deposits. T. Ui and M. Yoshimoto, Debris Avalanche Deposits. S. Carey, Volcaniclastic Sedimentation Around Island Arces. P.W. Lipman, Calderas. J.P. Davidson and S. Da Silva, Composite Cones. D. Vespermann and H.U. Schmincke, Scoria Cones and Tuff Rings. Extraterrestrial Volcanism: P.D. Spudis, Volcanism on the Moon. R. Lopes-Gautier, Volcanism on IO. L. Crumpler, Volcanism on Venus.J.R. Zimbelman, Volcanism on Mars.P. Geissler, Cryovolcanism in the Outer Solar System. Volcano Interactions: P. delMelle and J. Stix, Volcanic Gases. F. Goff and C. Janik, Geothermal Systems. P. Browne and M. Hochstein, Surface Manifestations. D. Butterfield, Submarine Hydrothermal Vents. P. delMelle and A. Bernard, Volcanic Lakes. N.C. White and R.J. Harrington, Mineral Deposits Associated with Volcanism. Volcanic Hazards: T.P. Miller and T.J. Casadevall, Volcanic Ash Hazards to Aviation. M.J. Mills and O.B. Toon, Volcanic Aerosol and Global Atmospheric Effect. S. Nekada, Hazards from Pyroclastic Flows and Surges. D. Peterson and R.I. Tilling, Lava Flow Hazards. K. Rodolfo, Lahars and Jokulhlaup Hazards. H. Rymer and G. Williams-Jones, Volcanic Gas Hazards. J.E. Beget, Volcanic Tsunamis. S.R. McNutt, Volcanic Seismicity. P. Baxter, Impacts of Eruptions on Human Health. M. Arthur, The Volcanic Contribution to the Sulfur and Carbon Geochemical Cycle. I. Thornton, The Ecology of Volcanoes-Biological Recovery and Colonization. M. Rampino and S. Self, Volcanism and Biotic Extinction. Eruption Response and Mitigation: S.R. McNutt, Seismic Monitoring. J.B. Murray, C.A. Locke, and H.Rymer, Ground Deformation, Gravity, and Magnetics. J. Stix and H. Gaonach, Gas, Plume, and Thermal Monitoring. S. McNutt, J. Stix, and H. Rymer, Synthesis of Volcano Monitoring. C. Newhall, Volcano Warnings. S. de la Cruz, R. Quaas, and R. Meli, Volcanic Crisis Management. R. Blong, Volcanic Hazards and Risk Management. D. Johnson and K. Ronan, Risk Education and Intervention. Economic Benefits and Cultural Aspects of Volcanism: S. Arnorsson, Exploitation of Geothermal Resources. C-l. Ping, Volcanic Soils. J. Dehn and S.R. McNutt, Volcanic Materials for Commerce and Industry. H. Sigurdsson and R. Lopes-Gautier, Volcanoes and Tourism. S. Harris, Archaeology and Volcanism. H. Sigurdsson, Volcanoes in Art. H. Sigurdsson and R. Lopes, Volcanoes in Literature and Film. Appendices: Units and Physical Properties of the Earth Volcanoes of the Earth.

The dynamics and morphology of lava flows are influenced by lava viscosity. However, the rheological parameters used in lava flow modelling are often subject to considerable uncertainties. To address this, we analyse the influence of key rheological parameters on the advancement and morphology of lava flows using GPUFLOW, a two-dimensional cellular automaton model that simulates Bingham fluid flow on the flanks of Mt. Etna. Our results demonstrate that variations in the initial volume fraction of crystals, the volume fraction of crystals in the equilibrium state, the characteristic time of crystal content growth (i.e. the relaxation time), the melt viscosity, and yield strength significantly impact lava flow patterns. An increased volume fraction of crystals – either at the time of eruption or in the equilibrium state – is associated with reduced advancement of the lava flow. This reduction is attributed to increased viscosity, which promotes vertical thickening of the lava flow and limits its lateral extent. In contrast, when relaxation times exceed the lava flow runout times, the crystal content evolves slowly, allowing the lava flow to advance further with a viscosity close to that of the crystal-free melt viscosity. Lower melt viscosity enhances lava flow mobility, whereas higher melt viscosity encourages shorter and thicker flows. Additionally, the slope of the volcano flank, yield strength, and melt viscosity influence the lava critical thickness, thereby exerting control over the extent of lava advance. These findings provide improved insights into the rheological controls on lava flow dynamics and have important implications for flow hazard assessment and forecasting of lava flows.Graphical

Lapilli formed by a Strombolian eruption are associated with the formation of a large lava flow of natrocarbonatite on or about 21–22 July, 2000 at Oldoinyo Lengai volcano, Tanzania. Fresh lapilli consist of vesicular natrocarbonatite similar to that occurring in rapidly quenched lavas. The lapilli were altered at low temperature (<50°C) by degassing to aggregates of sodian sylvite, potassian halite, trona, thermonatrite and a novel F-bearing sodium phosphate-carbonate. The latter is considered to be a new mineral as it has a composition (Na5–4.5PO4(CO3,F,Cl) that is not similar to that of nahpoite (Na2HPO4), dorfmanite [Na2(PO3OH).2H2O] or natrophosphate [Na7(PO4)2F.19H2O]. However, in common with these minerals, it is ephemeral and undergoes rapid decomposition under normal atmospheric conditions. The sodium phosphate-carbonate and associated halide-sodium carbonate assemblages are considered to be a part of a previously unrecognized hyperagpaitic assemblage forming as sublimates at Oldoinyo Lengai.

Lava flows have severe impacts on the Earth’s surface, communities, and natural habitats. Accurate modeling of lava flow paths is crucial for volcanic hazard assessment and risk mitigation. This research integrated remote sensing, geographic information systems, geomorphological techniques, and hydrologic analysis to numerically determine the optimal ground sample distance (GSD) of digital elevation models (DEMs) for delineating lava flow paths. Two volcanic regions were analyzed: the Afar Region of Ethiopia (Alu, Dalaffilla, and Erta Ale volcanoes) and the Reykjanes Peninsula of Iceland (Fagradalsfjall volcano). Forward and backward modeling methods were used to simulate potential lava flow paths. Remote sensing data, including multispectral and thermal images as well as DEMs, were utilized for analysis. A large-scale mean-shift image segmentation method was applied to identify lava objects and extract the main centerline for analysis. The forward model was applied to the fissures between the Alu and Dalaffilla volcanoes. The main lava centerline was derived from a 2008 ASTER image, while flow paths were simulated using the 2000 SRTM DEM. An optimal GSD of 35 m resulted in the lowest root mean square error (RMSE) of 146.89 m. This was validated using the 2017 Erta Ale eruption, confirming 35 m as a suitable GSD for delineating a major lava polygon. In the backward model, hydrologic analysis on resampled DEMs using TauDEM identified an optimal GSD of 38 m with an RMSE of 123.44 m. In the study of the Fagradalsfjall volcano, an optimal GSD of 71 m with an RMSE of 98.84 m was obtained, while the backward model yielded an optimal GSD of 33 m with an RMSE of 173.56 m. Statistical analyses were conducted to validate the results. This research contributed to volcanic hazard assessment by providing a framework that integrated geospatial technologies into lava flow modeling. Initiating simulation from the observed lava outlet, the forward model addressed a key limitation of the backward model. Results indicate that lava flow path accuracy was sensitive to the GSD of a DEM. The findings further demonstrate that the forward model may aid emergency response planning and risk mitigation strategies in volcanic regions.

Eruption of stagnant lava from an inactive perched lava lake

Invasion of inhabited areas and destruction of human property by lava flows represents the greatest volcanic hazard at Mount Etna (Italy) in the short term, based on the character of the historically documented eruptions of the volcano. Virtually all eruptions of Etna produce lava flows, which are more likely to cause damage when emitted from flank vents. Since A.D. 1600, more than sixty eruptions have occurred on the flanks of Etna. About half of these caused damage to, or destruction of, human property, dwellings, and infrastructures, and at least two destroyed entire population centers. We present a quantitative analysis and...

<p>Piton de la Fournaise, situated on La Réunion Island (France), is one of the most active hot spot basaltic shield volcanoes worldwide, experiencing at least two eruptions per year since the establishment of the observatory in 1979. Eruptions are typically fissure-fed and form extensive lava flow fields. About 95 % of some ~250 historical events (since the first confidently dated eruption in 1708) have occurred inside an uninhabited horse-shoe shaped caldera (hereafter referred to as the Enclos) which is open to the ocean on its eastern side. Rarely (12 times since the 18th century), fissures have opened outside of the Enclos where housing units, population centers and infrastructure are at risk. In such a situation, lava flow hazard maps are a useful way of visualizing lava flow inundation probabilities over large areas. Here, we present a lava flow hazard map for Piton de la Fournaise volcano based on: i) vent distribution, ii) statistics of lava flow lengths, iii) lava flow recurrence times, and iv) simulations of lava flow paths across multi-temporal (i.e., regularly updated) topography using the DOWNFLOW stochastic numerical model. A map of the entire volcano highlights that the most probable (up to 12 %) location for future lava flow inundation is within the Enclos, where about 100,000 visitors are present each year. Hazard distribution changes throughout the analysis period due to the high frequency of eruptions that constantly modifies the vent opening distribution as well as the topography and the lava flow dimensional characteristics. Outside of the Enclos, probabilities reach 0.5 % along the well-defined rift zones and, although hazard occurrence in inhabited areas is deemed to be very low (<0.1 %), it may be underestimated here, as our study is only based on post-18th century records and neglects cycles of activity at the volcano. Specific hazard maps considering different event scenarios (i.e., events fed by different combinations of temporally evolving superficial and deep sources) are required to better assess affected areas in the future – especially by atypical, but potentially extremely hazardous, large volume eruptions. At such an active site, our method supports the need for regular updates of DEMs and associated lava flow hazard maps if we are to be effective in mitigating the associated risks.</p>

The Ngorongoro Crater, as the largest unflooded and not destroyed volcanic caldera on Earth, is one of the major geotouristic attractions of East Africa. Unique on the global scale richness of wildlife, exotic cultures of indigenous people and specific position of the Crater within the East African Rift System, each year attracts thousands of tourists eager for an unforgetable experience. Their number continues to grow from year to year, reaching the value of nearly half a million visitors within the last few years. Constantly developing tourism industry, besides many advantages, also causes a number of risks, both for the world of living nature and inanimate nature objects, as well as for the local population. In 1959, recognizing the unique and special touristic and geoeducative values of this location, the Ngorongoro Conservation Area (NCA) was established. Almost twenty years later, in 1978, the area was included in the UNESCO World Cultural and Natural Heritage List. Furthermore, within the Ngorongoro Conservation Area as well as in its immediate neighborhood there are many objects that also deserve to be called geotouristic attractions, such as: Olduvai Gorge, Crater Olmoti, Crater Empakai and Oldoinyo Lengai volcano. In a relatively short distance from the Crater also the highest mountain in Africa – the Kilimanjaro volcano and the biggest active volcano of this continent, Meru, are located.

New tephrostratigraphic data from Lake Emakat (northern Tanzania): Implications for the eruptive history of the Oldoinyo Lengai volcano

New mapping and 60 new radiocarbon ages define the age and distribution of latest Pleistocene and Holocene (past 13,000 years) lava flows at Haleakalā volcano, Island of Maui. Paleomagnetic directions were determined for 118 sites, of which 89 are in lava flows younger than 13,000 years. The paleomagnetic data, in conjunction with a reference paleosecular variation (PSV) curve for the Hawaiian Islands, are combined with our knowledge of age limitations based on stratigraphic control to refine age estimates for some of the undated lava flows. The resulting volumetric rate calculations indicate that within analytical error, the extrusion rate has remained nearly constant during the past 13,000 years, in the range 0.05–0.15 km3/kyr, only about half the long‐term rate required to produce the postshield strata emplaced in the past ∼1 Myr. Haleakalā's eruptive frequency is similar to that of Hualālai volcano on the Island of Hawai‘i, but its lava flows cover substantially less area per unit time. The reduced rates of lava coverage indicate a lower volcanic hazard than in similar zones at Hualālai.

Forecasting lava flow hazards during the 2006 Etna eruption: Using the MAGFLOW cellular automata model

The summit area of Mount Etna has undergone large morphological variations since the formation of the South-East Crater (SEC) in 1971 and New Southeast Crater (NSEC) in 2007, which have also marked a notable change in the eruptive activity of the volcano. Indeed, in less than 50 years, the SEC area has been the source of more than two hundreds of eruptions characterized by the emission of lava fountains, pyroclastic material, and short-lasting lava flows, which are the greatest hazard presented to the tourist facilities on the southern flank of Etna. Here we statistically analyze the main quantitative parameters (i.e. duration and lava volume) of 154 well-documented eruptive events occurred since 1998 with the aim of characterizing the time-volume evolution of the SEC activity. From 1998 to 2018, we find a cumulative volume of ∼135 millions of cubic meters that gives a long-term output rate of ~0.21 m3/s, with a remarkable change in the eruptive style (longer and more voluminous events) starting from 2011. Taking advantage of this analysis and lava flow simulations run on a Pleiades-derived topography updated to 2016, we also present the new hazard map from lava flow inundation in the SEC area, establishing an important basis for mitigation decisions. Our SEC hazard map covers an area of ~15 km2, with lava flows spreading both towards south-west and south-east, reaching the lowest altitude of about 1,500 m a.s.l.