J. Ruch

University of Geneva

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Valerio Acocella

Roma Tre University

Sigurjón Jónsson

King Abdullah University of Science and Technology

Daniele Trippanera

King Abdullah University of Science and Technology

Thomas R. Walter

Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences

Marco Neri

Istituto Nazionale di Geofisica e Vulcanologia

Giuseppe Solaro

Istituto per il Rilevamento Elettromagnetico dell'Ambiente

Adriano Nobile

King Abdullah University of Science and Technology

Ghebrebrhan Ogubazghi

University of Asmara

Stefano Mannini

University of Geneva

E. Sansosti

Istituto per il Rilevamento Elettromagnetico dell'Ambiente

Cooperative Institutions

Istituto Nazionale di Geofisica e Vulcanologia

University of Geneva

Centre National de la Recherche Scientifique

National Research Council

University of Iceland

Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences

National Academies of Sciences, Engineering, and Medicine

Roma Tre University

University of Florence

Weatherford College

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Kinematic analysis of vertical collapse on volcanoes using experimental models time series

Journal of Geophysical Research Atmospheres (2012)

J. Ruch Valerio Acocella Nobuo Geshi Adriano Nobile Fabio Corbi

Volcanoes are often associated with vertical collapse, due to deeper magma withdrawal. Calderas are the most notable type of vertical collapse, on the summit of volcanoes. Caldera collapse has been observed and monitored only at Miyakejima (Japan; 2000), Dolomieu (Reunion; 2007) and Fernandina (Galapagos; 1968), highlighting our limited knowledge on its kinematic behavior. Here we use experimental models to investigate the kinematic evolution of calderas and vertical collapses in general. We extract velocity and strain fields using the Particle Image Velocimetry (PIV) technique, generating time series. Experimental vertical collapses undergoing constant subsidence velocity show three main kinematic behaviors: (1) continuous collapse, whose velocity is similar to the source subsidence velocity; (2) incremental collapse, with episodic (stepwise) accelerations along pre‐existing ring structures; (3) sudden collapse, resulting from the upward migration of a cavity, only for T/D > 2 (T and D are the depth and width of the magma chamber, respectively) and without ring structures. The velocity in the collapsing column may increase up to four orders of magnitude with regard to the constant subsidence velocity of the source. Comparison to nature suggests that: (1) there are close kinematic similarities with monitored collapse calderas, explaining their incremental subsidence after the development of ring structures; (2) sudden pit crater formation is induced by the upward propagation of cavities, due to magma removal at depth and in absence of ring structures; (3) all these types of vertical collapses have a consistent mechanism of formation and kinematic behavior, function of T/D and the presence/absence of ring structures.

Caldera

Magma chamber

10.1029/2012jb009229

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Citations (45)

Influence of ring faulting in localizing surface deformation at subsiding calderas

Earth and Planetary Science Letters (2019)

Yuan‐Kai Liu J. Ruch Hannes Vasyura‐Bathke Sigurjón Jónsson

Caldera

Magma chamber

Sill

Unrest

10.1016/j.epsl.2019.115784

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Citations (28)

Seismicity Associated With the Formation of a New Island in the Southern Red Sea

Frontiers in Earth Science (2018)

Jade H. W. Eyles Finnigan Illsley‐Kemp Derek Keir J. Ruch Sigurjón Jónsson

Volcanic eruptions at mid-ocean ridges are rarely witnessed due to their inaccessibility, and are therefore poorly understood. Shallow waters in the Red Sea allow the study of ocean ridge related volcanism observed close to sea level. On the 18th December 2011, Yemeni fishermen witnessed a volcanic eruption in the southern Red Sea that led to the formation of Sholan Island. Previous research efforts to constrain the dynamics of the intrusion and subsequent eruption relied primarily on GPS and InSAR methods, data for which was relatively sparse. Our study integrates InSAR analysis with seismic data from Eritrea, Yemen and Saudi Arabia to provide additional insights into the transport of magma in the crust that fed the eruption. Twenty-three earthquakes of magnitude 2.1 to 3.9 were located using the Oct-tree sampling algorithm. The earthquakes propagated southeastward from north of Sholan Island, mainly between December 12th and December 13th. The seismicity is interpreted as being induced by emplacement of a ~12 km-long dike. Earthquake focal mechanisms are primarily normal faulting and suggest the seismicity was caused through a combination of dike propagation and inflation. We combine these observations with new deformation modeling to constrain the location and orientation of the dike. The best-fit dike orientation that satisfies both geodetic and seismic data is NNW-SSE, parallel to the overall strike of the Red Sea. Further, the timing of the seismicity suggests the volcanic activity began as a submarine eruption on the 13th December. The new intrusion and eruption along the ridge suggests seafloor spreading is active in this region.

Dike

Vulcanian eruption

10.3389/feart.2018.00141

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Citations (19)

Birth of two volcanic islands in the southern Red Sea

Nature Communications (2015)

Wenbin Xu J. Ruch Sigurjón Jónsson

Abstract Submarine eruptions that lead to the formation of new volcanic islands are rare and far from being fully understood; only a few such eruptions have been witnessed since Surtsey Island emerged to the south of Iceland in the 1960s. Here we report on two new volcanic islands that were formed in the Zubair archipelago of the southern Red Sea in 2011–2013. Using high-resolution optical satellite images, we find that the new islands grew rapidly during their initial eruptive phases and that coastal erosion significantly modified their shapes within months. Satellite radar data indicate that two north–south-oriented dykes, much longer than the small islands might suggest, fed the eruptions. These events occurred contemporaneously with several local earthquake swarms of the type that typically accompany magma intrusions. Earthquake activity has been affecting the southern Red Sea for decades, suggesting the presence of a magmatically active zone that has previously escaped notice.

Archipelago

Submarine volcano

10.1038/ncomms8104

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Citations (47)

New findings on compositionally distinct maar volcanoes: A case study from Acıgöl (Nevşehir) caldera (Central Anatolia, Turkey)

Frontiers in Earth Science (2022)

Göksu Uslular Gonca Gençalioğlu Kuşcu Florence Bégué J. Ruch Matteo Lupi

Recent experiments have largely reshaped our knowledge of maar volcanism. A new evolutionary model promoting the role of explosion depth and vent migration during the formation of maars has provided an alternative approach to previous models. Despite a few attempts to test this model with real cases, there is still a need for field-based studies exploring the depositional characteristics of maars to better understand the factors affecting the model constraints. More investigations on less known felsic maars are required to elucidate the possible differences from their more common mafic counterparts. Here, we explore compositionally distinct monogenetic clusters within the Acıgöl caldera (NW of Central Anatolian Volcanic Province, CAVP), with four felsic maars (İnallı, Kalecitepe, Acıgöl, and Korudağ) and one mafic maar (İcik). Our field observations reveal a successive formation between rhyolitic maars and adjacent lava domes. The mugearitic İcik coalescent maar and the adjacent scoria cone are synchronously formed, which is disclosed by the intercalation of the maar and scoria cone deposits. The geochemistry of the maar juveniles suggests a parental basaltic magma source that has been possibly differentiated by varying degrees of fractional crystallization. Our findings identify the main factors in maar formation (i.e., optimum scaled depth-OSD, water-magma interaction, and basement lithology). We also determine some differences between the felsic and mafic maars in the region, such as higher juvenile content, less amount of sedimentary structure, and a clear transition from phreatomagmatic to magmatic explosions through the end of stratigraphy. All these reflect the complexity of maars, mainly formed by different depths of explosions that occurred in the shallowest few hundred meters rather than a systematic incremental decrease of the eruption locus. Further geophysical and geochronological studies will complete our proposed evolutionary model for the youngest monogenetic activity in the Acıgöl caldera that would also warrant volcanic hazard assessment due to the presence of low-velocity anomalies, shallow Curie depths, and prevalent geothermal activity.

Maar

Cinder cone

Phreatomagmatic eruption

Felsic

Lava field

Caldera

Scoria

Xenolith

10.3389/feart.2022.909951

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Citations (5)

Tectonostratigraphic evolution and significance of the Afar Depression

Earth-Science Reviews (2023)

Valentin Rime Anneleen Foubert J. Ruch Tesfaye Kidane

The Afar Depression is a unique place on Earth where active rift processes can be directly observed. It is believed to be close to continental breakup. The Afar hotspot has a strong influence on the geology of the Depression. Despite the strong geological interest in the region, difficult field access slowed scientific discoveries. During the last two decades, new projects and studies resulted in a better characterization of the region. New field data and global advances in understanding rift processes call for an integrative and holistic review of the tectonostratigraphic evolution of the Afar Depression. This study compiles new geological maps and reviews the stratigraphy and the geological history of the Afar Depression and the Afro-Arabian Rift System. A new kinematic evolution model and integrative paleogeological maps are proposed. Results show that geological events are diachronous throughout the region. We consider the Afar Rift to be distinct from the Red Sea Rift, both being separated by the Arrata Microplate. The Afar Rift is propagating northwards and forms a relay structure with the Red Sea Rift, linked to the counter-clockwise rotation of the Danakil Block since the Mid- to Late Miocene. The Afar Depression can be segmented into two distinct domains, Central Afar and the Danakil Depression. Central Afar experienced significant extension, protracted and extensive magmatism and magma-compensated thinning. It is believed to be strongly influenced by the Afar hotspot. In comparison, the Danakil Depression is younger and went through less extension and less magmatic activity until Recent (~0.6 Ma) times. The absence of magma-compensated thinning allowed the development of an evolved stage of continental breakup. The tectonostratigraphic evolution of the Afar Depression with distinct rifting styles shows the complexity of continental break-up.

Diachronous

East African Rift

10.1016/j.earscirev.2023.104519

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Citations (13)

Insight on the recent magmatic system of Lipari and Vulcano on the basis of new structural and geochemical data

Rosanna De Rosa Riccardo Di Lorenzo Paola Donato L. Francalanci Anna Gioncada

Wolframite

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Tracking magma pathways and surface faulting in the Southwest Rift Zone and the Koaʻe fault system (Kīlauea volcano) using photogrammetry and structural observations

Research Square (Research Square) (2023)

Stefano Mannini J. Ruch Richard W. Hazlett Drew T. Downs C. E. Parcheta

Abstract Volcanic islands are often subject to flank instability, resulting from a combination of magma intrusions along rift zones, gravitational spreading and extensional faulting observed at the surface. Here we study the Kīlauea volcano in Hawaiʻi, one of the most active volcanoes on Earth, prone to flank instability. Two rift zones and the Koaʻe fault system are major structures controlling volcano flank instability and magma propagation. The connection between surface faulting and magma intrusions at depth is poorly studied despite the importance of faults in controlling magma pathways and forecasting future eruptions. In March 2022, we completed a helicopter photogrammetric survey covering part of the south flank of Kīlauea. We generated a high-resolution DEM (~ 8 cm) and orthomosaic (~ 4 cm) to map the fracture field in detail. We also collected ~ 1000 ground structural measurements of extensional fractures during our three field missions (2019, 2022, 2023) to better understand the kinematics of the Kīlauea’s south flank. In our analysis, we include many small, interconnected grabens, monoclines, rollover structures, and en-echelon fractures that were in part previously undocumented. Additionally, we estimate the cumulative displacement across the Koaʻe fault system during the last 600 years and found an average of 6 cm and 3 cm per year for vertical and horizontal directions, respectively, consistent with short-term GNSS data. These data provide a clearer picture of the structural linkages between the fault zone, which is largely a tectonic feature, and the rift zones, which are largely magmagenic. Finally, we propose a kinematic model of Kīlauea’s south flank suggesting a clockwise rotation and translation of a triangular wedge in response to the gravitational spreading and the nearby rift zones.

Rift zone

Flank

Echelon formation

East African Rift

Magma chamber

10.21203/rs.3.rs-3625698/v1

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Citations (0)

Kinematic analysis of vertical collapse on volcanoes using experimental models time series

AGUFM (2012)

J. Ruch Valerio Acocella Nobuo Geshi Adriano Nobile Fabio Corbi

[1] Volcanoes are often associated with vertical collapse, due to deeper magma withdrawal. Calderas are the most notable type of vertical collapse, on the summit of volcanoes. Caldera collapse has been observed and monitored only at Miyakejima (Japan; 2000), Dolomieu (Reunion; 2007) and Fernandina (Galapagos; 1968), highlighting our limited knowledge on its kinematic behavior. Here we use experimental models to investigate the kinematic evolution of calderas and vertical collapses in general. We extract velocity and strain fields using the Particle Image Velocimetry (PIV) technique, generating time series. Experimental vertical collapses undergoing constant subsidence velocity show three main kinematic behaviors: (1) continuous collapse, whose velocity is similar to the source subsidence velocity; (2) incremental collapse, with episodic (stepwise) accelerations along pre-existing ring structures; (3) sudden collapse, resulting from the upward migration of a cavity, only for T/D > 2 (T and D are the depth and width of the magma chamber, respectively) and without ring structures. The velocity in the collapsing column may increase up to four orders of magnitude with regard to the constant subsidence velocity of the source. Comparison to nature suggests that: (1) there are close kinematic similarities with monitored collapse calderas, explaining their incremental subsidence after the development of ring structures; (2) sudden pit crater formation is induced by the upward propagation of cavities, due to magma removal at depth and in absence of ring structures; (3) all these types of vertical collapses have a consistent mechanism of formation and kinematic behavior, function of T/D and the presence/absence of ring structures.

Caldera

Magma chamber

Source

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Rift obliquity in the Northern Volcanic Zone in Iceland using UAV-based structural data

Journal of Volcanology and Geothermal Research (2024)

Elisabetta Panza J. Ruch Nicolas Oestreicher

Rift obliquity is known to be very frequent at divergent plate boundaries and shear components in the opening of fissures have been detected through seismicity in the monitoring of recent rifting events. However, the field structural evidence of obliquity in active rifts for Holocene events is still poorly studied, despite its relevance at both the lithospheric and upper-crust scales. We performed extensive high resolution UAV surveys on Holocene terrains in four areas along the active rift in the Northern Volcanic Zone of Iceland, to map structures and morphotectonic features in detail. We did a kinematic analysis and found an increase of the obliquity from N to S. We further discuss the origins of this obliquity and suggest that the combination of inherited structures reactivation, magmatic intrusions, and topography influence on the propagation of both fractures and magma intrusions can have an impact on the mismatch between rift opening direction and the far-field strain. We conclude that obliquity can be inferred for Holocene rifting events from surface structural data. It is thus fundamental to take into account the existing structural pattern and its (re)activation history in active rift zones to avoid missing out on possible preferential structure reactivation, magma propagation ways, and eruption sites during the monitoring of ongoing rifting events.

Rift zone

East African Rift

10.1016/j.jvolgeores.2024.108072

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