April Seminar – Eva Eibl
Triggering, migration, and consequences of jökulhlaups in geothermally active regions from a seismological perspective
Thursday 4th April, 2024, 5 pm CEST
Jökulhlaups from Vatnajökull, Iceland, can be triggered by volcanic eruptions or geothermal activity in the ground. Within this talk I will focus on geothermally triggered floods from the Skaftá cauldrons. Following a slow start, the drainage quickly speeds up, water drains beneath the ice layer until the subaerial glacial river is reached and flooded. These processes can be ‘heard’ seismically. While the subglacial propagation can be tracked and used for early warning, the strength of the signal can also be linked to the size of the impending flood. However, we also detected icequakes at the onset of the drainage that likely reveal how the ice shelf above the lake collapsed. Finally, the flood generates signals once the water becomes turbulent near rapids.
September Seminar – Graham Zimmerman
Passion to Purpose with Graham Zimmerman
Thursday 7th September, 2023
December Seminar – Magnús Tumi Gudmundsson
Volcano-ice interaction in Iceland, how to monitor and what we have learned in the last 30 years of frequent eruptions
Wednesday 7th December, 2022
Volcanic eruptions in ice-covered volcanoes and geothermal activity under glaciers leads to melting of ice, formation of ice cauldrons, and cause jökulhlaups. The jökulhlaups can be a major hazard in the affected areas and can cause great damage to infrastructure. Sizable parts of the volcanic zones in Iceland are covered by glaciers and some of the most active volcanoes are partly or fully subglacial. After almost 60 years of relative quiescence, ice-covered volcanoes have been highly active in Iceland since 1996. Six confirmed eruptions and several other periods of unrest have occurred in the last 26 years. This includes the Gjálp eruption in 1996 where a 6 km long and up to 500 m high hyaloclastite ridge formed over 13 days, and activity in Bárðarbunga in 2014-15 with minor eruptive events under ice in connection with a major rifting event and the subsidence of the ice-filled caldera. In the eruptions since 1996, the volume of subglacially-erupted material varied between 0.001 km3 and 0.45 km3 (DRE), volume of melted ice from 0.01 to 4 km3, ice thickness between 50 and 750 m, and magma compositions ranged from basalt to trachyte. Observations of the course of events during these eruptions were obtained through using aerial surveying and other available methods. The styles of activity observed demonstrate the dominant role of magma fragmentation in most cases and very rapid melting in the initial stages. The observations also show that glacier thickness and glacier geometry play a key role in determining eruption behavior and glacier response and that bedrock and ice geometry play a major role in controlling the drainage of meltwater from the eruption site. In the talk, examples from all these eruptions will be shown, the principal lessons outlined, and the methods used for monitoring will be described, including airborne and ground-based surveying and the increasing use of various satellite data.
February Seminar – Linda Sobolewski & Christian Stenner
Subglacial Volcanism and the Formation of Glaciovolcanic Cave Systems
Tuesday 22nd February, 2022
Glaciovolcanism, which describes the interaction of heat from the Earth’s interior with various types of ice masses, can be found on several volcanoes worldwide. However, a rarely studied phenomenon is the formation of void spaces underneath the ice—glaciovolcanic caves. Examples are known from Mount Erebus (Antarctica), Mount Rainier and Mount St. Helens (USA). Although research was performed as early as the 1970s by W. Giggenbach on Mount Erebus, studies of void spaces created by volcano-ice interactions since then have been sporadic. Nevertheless, glaciovolcanic cave systems and their investigation have gained importance. Further advances have been made during the last decade, including research on volcanoes of the Cascade Volcanic Arc (USA), Mount Meager (Canada), and other parts of Antarctica. They have expediency as indicators of recurring volcanic activity, in hazard mitigation, and for understanding the hydrothermal cycles on volcanic edifies. Their expediency goes well beyond earth processes and facilitates discovery on several levels including as geobiological analogs for astrobiology/exobiology and as testing sites for precursor robotic technologies for solar system exploration.
December Seminar – Kat Scanlon & Jim Head
Volcano–Ice Interactions in The Tharsis Montes Glacial Deposits, Mars &
Volcano–Ice Interactions on Mars: Keys to Geologic and Atmospheric History
Wednesday 8th December, 2021
Kat Scanlon: Volcano–Ice Interactions in The Tharsis Montes Glacial Deposits, Mars
Orographic lifting by the three enormous Tharsis Montes volcanoes on Mars resulted in glaciation on their windward flanks as recently as ~125 million years ago, coinciding with volcanic activity in the region. I will review previous work on volcano-ice interactions in the glacial deposits adjoining the Arsia Mons volcano, and discuss new high-resolution images and digital terrain models of the better-exposed hypothesized glaciovolcanic landforms adjoining the Pavonis Mons volcano.
Jim Head: Volcano–Ice Interactions on Mars: Keys to Geologic and Atmospheric History
The current Mars ambient climate is a hypothermal, hyperarid desert with kilometers-thick accumulations of water ice at the poles. Geologically recent obliquity changes have transported significant quantities of ice equatorward to form glaciers of various types. The nature of the ancient ambient climate of Mars is currently debated (Is it ‘warm and wet’ or ‘cold and icy’?). All of these characteristics provide abundant opportunities to study volcano-ice interactions. Following a brief introduction to Mars environmental and volcanological histories, we will present several examples (volcanic edifices built under polar ice sheets, geothermal heating of volcano summit ice, top-down melting of ice sheets by lava flows, mega-lahars, dikes now exposed in former ice sheets, etc.). These illustrate how volcano-ice interaction analysis has helped to improve our understanding of Mars’ volcanic and climate histories and their interrelationships.
September Seminar – Ben Edwards & Alastair Hodgetts
Trouble with tuyas? Some thoughts on scholarship and definitions for the ‘new’ science of glaciovolcanism &
The Thórólfsfell tuya, South Iceland – A new type of basaltic glaciovolcano
Tuesday 14th September, 2021
Ben Edwards: Trouble with tuyas? Some thoughts on scholarship and definitions for the ‘new’ science of glaciovolcanism
Although scientists in the early 1900’s first recognized that some volcanic deposits in Iceland and British Columbia likely formed by volcano-ice interactions, definitions and classifications for these curious deposits have followed more slowly. For example, the now-standard term ‘glaciovolcanism’ was only first used in a publication in 2002. We will briefly discuss the history of a few of these terms and classifications with a special focus on better understanding the origins of the word ‘tuya’, and whether or not it should be used as a general synonym for ‘subglacial volcano’.
Alastair Hodgetts: The Thórólfsfell tuya, South Iceland – A new type of basaltic glaciovolcano
This talk will examine the first description and interpretation of Thórólfsfell, a basaltic tuya on the southern flank of Tindfjallajökull central volcano, S. Iceland. This asymmetrical, effusion-dominated glaciovolcano is constructed of an unusual set of lithofacies, unlike other tuyas described elsewhere, and displays no evidence for substantial and sustained meltwater accumulation. The atypical eruptive and glacio-hydrological conditions responsible will be explored and comparisons to other effusion-dominated tuyas (in Iceland and elsewhere) will allow us to question whether effusion-dominated tuyas are perhaps more diverse and varied than currently thought? A criterion for identifying other Thórólfsfell-type tuyas will be outlined and compared and contrasted to the ‘classic’ tuya model.
May Seminar – Alex Wilson
Glacial pumping of a magma-charged lithosphere: the link between ice and volcanoes in the Garibaldi volcanic belt
February Seminar – John Smellie
Glaciovolcanism – where we are and how we got here