In tectonic and volcanic regions earthquake swarms and seismic sequences are frequently characterized by complex temporal evolution, and a delayed occurrence of the largest magnitude earthquakes. The complex evolution of such seismic sequences is generally considered to derive from transient forcing where fluids play a major role causing slow-slip and creeping events, and – at volcanoes – stresses due to magma migration (i.e. dike intrusion and pressurization of the magma plumbing system). Yet, the mechanisms of fluid-rock interaction, leading to changes of the rheological properties of faults, and of the fracture mechanics, are still far beyond a full understanding. Therefore, it is fundamental to develop and implement innovative methodologies and technologies or to apply multi-disciplinary approaches for a multi-parametric crustal imaging aimed at tracking fluid movements and/or pore fluid-pressure diffusion within the seismogenic crust, and to integrate the results with the analysis of spatio-temporal and size characteristics of earthquake occurrence. The two approaches complement each other improving, on one hand, our understanding of crustal properties and, on the other hand, help constraining the degree of involvement of fluids by the analysis of the earthquake statistics.
This session aims at putting together studies of swarms and complex seismic sequences modulated by aseismic transient forcing as well as field studies, numerical modeling, theoretical and experimental investigation on the detection and tracking of crustal fluids in tectonic, volcanic and industrial contexts. Contributions from multi-disciplinary studies of fluid geochemistry, surface ground deformation and space-time variations of electrical and seismic crustal properties are also welcome, as well as laboratory and numerical modeling simulating the mechanical condition yielding to fluid-driven swarm-like and complex seismic sequences.

Crustal faults are complex natural systems whose physical and chemical properties change with time over several scales. Tracking the evolution of a fault system toward the generation of a large earthquake requires thus a multi-disciplinary approach, that involves the analysis and modelling of seismological, geodetic, geochemical and other geophysical observations. To understand the fault behaviour, near-fault observatories have been deployed in Europe and worldwide, as dense, innovative infrastructures that monitor the underlying Earth crust providing state-of-the-art, high-resolution multidisciplinary time series.

This session promotes contributions aimed at characterizing physical and chemical processes related to the fault evolution through cross-disciplinary analysis and modelling of near fault observations. We encourage the submission of works that investigate faulting processes such as earthquake preparation, nucleation and triggering processes, aseismic transients and forcing mechanisms such as creeping that may influence further rupture development, diffusive processes associated to fluid migration and fluid-rock interaction, accurate location and characterization of the micro-seismicity to constrain space-time-magnitude patterns and other tectonic transients that may affect fault tectonics.

Numerous cases of induced/triggered seismicity have been reported in the last decades, directly or indirectly related to anthropogenic activity for the geo-resources exploration. Induced earthquakes felt by local population can often negatively affect public perception of geo-energies and may lead to the cancellation of important projects. Furthermore, large earthquakes may jeopardize wellbore stability and damage surface infrastructure. Thus, monitoring and modeling processes leading to fault reactivation, (seismic or aseismic) are critical to develop effective and reliable forecasting methodologies during deep underground exploitation. The complex interaction between injected fluids, subsurface geology, stress interactions, and resulting induced seismicity requires an interdisciplinary approach that accounts for coupled thermo-hydro-mechanical-chemical processes to understand the triggering mechanisms.
In this session, we invite contributions from research aimed at investigating the interaction of the above processes during exploitation of underground resources, including hydrocarbon extraction, wastewater disposal, geothermal-energy exploitation, hydraulic fracturing, gas storage and production, mining, and reservoir impoundment for hydro-energy. We particularly encourage novel contributions based on laboratory and underground near-fault experiments, numerical modeling, the spatio-temporal relationship between seismic properties, injection/extraction parameters, and/or geology, and fieldwork. Contributions covering both theoretical and experimental aspects of induced and triggered seismicity at multiple spatial and temporal scales are welcome.

Seismology is fundamental for monitoring and investigating volcanic systems.
Volcanoes are complex systems comprising both time-varying processes and structural heterogeneity. This combination of wide-ranging complex processes, extreme geomechanical heterogeneity, frequently rapid changes in time, leads to challenges in interpreting seismic observations in terms of physical processes at depth. In addition, the link between the variety of physical processes beneath volcanoes and their seismic response (or lack of) is often poorly understood, making it difficult to develop a detailed understanding of the physical processes at work in volcanic systems.
To address these challenges, this session aims to bring together seismologists, volcano and geothermal seismologists, and wave propagation and source modellers working on different aspects of volcano seismology including but not limited to: (i) seismicity catalogues (statistics & spatio-temporal evolution of seismicity), (ii) innovative methods for source locations (iii) source inversions (iv) seismic wave propagation & scattering, (v) small scale deformation studies, (vi) new developments in volcano imagery, (vii) time-lapse studies – including the use of noise, multiplets and high-rate GPS. Studies on geothermal systems in volcanic environments are also welcome.
By considering interrelationships between these complementary seismological areas, we aim to develop a coherent picture of the latest advances, successful applications and outstanding challenges in volcano seismology.

Public information:
SCHEDULE

16:15 Start of the session
Introduction

16:20 Guardo et al.: “Space-weighted seismic attenuation multi-frequency tomography at Deception Island volcano (Antartica)” (EGU2020-9986)

16:25 Eibl et al.: “Rotational sensor on a volcano: New insights from Etna, Italy” (EGU2020-18862)

16:30 Gabrielli et al.: “Geomorphological controls on seismic recordings in volcanic areas” (EGU2020-511)

16:35 Metaxian et al.: “Towards real-time monitoring with a seismic antenna at Merapi volcano” (EGU2020-19068)

16:40 Falcin et al.: “Automatic classification of seismo-volcanic signals at La Soufrière of Guadeloupe” (EGU2020-10234)

16:45 Lamb et al.: “Identifying icequakes at ice-covered volcanoes in Southern Chile” (EGU2020-851)

16:50 Battaglia et al.: “Discriminating icequakes from volcanic seismicity at Cotopaxi volcano (Ecuador) “ (EGU2020-11749)

16:55 Garza-Giron et al.: “Hidden earthquakes unveil the dynamic evolution of a large-scale explosive eruption “ (EGU2020-14124)

17:00 Shapiro et al.: "Degassing of volatile-reach basaltic magmas: source of deep long period volcanic earthquakes" (EGU2020-8251)

17:05 Cesca et al.: “The seismic sound of deep volcanic processes”, (EGU2020-6813)

17:10 Sadeghi and Suzuki: “The 11 November 2018 Mayotte event was observed at the Iranian Broadband seismic stations” (EGU2020-9767)

17:15 Ikegaya and Yamamoto: “Spatio-temporal characteristics and focal mechanisms of deep low-frequency earthquakes beneath Zao volcano, Japan”, (EGU2020-12533)

17:20 Möllhoff et al.: “Recent microseismicity observed at Hekla volcano and first velocity inversion results” (EGU2020-18954)

17:25 Bjarnasson et al. (presenting Revathy Parameswaran): “Interseismic stress field variations in Hjalli-Ölfus, SW Iceland” (EGU2020-8521)

17:30 Eibl et al.: “Seismic Eruption Catalog of Strokkur Geyser, Iceland“ (EGU2020-16535)

17:35 Thorbjarnardóttir et al.: “The Great Geysir and tectonic interactions in South Iceland”, (EGU2020-16388)

17:40 Nooshiri et al.: “Source mechanisms of seismic events during the 2018 eruption of Sierra Negra Volcano (Galapagos) determined by using polarization properties of complete (near-field and far-field) body waves”, (EGU2020-11297)

17:45 Longobardi,et al.: “Multiplet Based Time Lapse Velocity Changes Prior to the 2018 Eruption of Sierra Negra Volcano, Galapagos Island Observed with Coda Wave Interferometry” (EGU2020-18213)

17:50 Ka Lok Li et al.: “Different mechanisms of the pre- and co-eruptive tremor during the 2018 eruption at Sierra Negra volcano, Galapagos” (EGU2020-18975)

17:55 Dehghanniri and Jellinek: “An Experimental Study of Volcanic Tremor Driven by Magma Wagging” (EGU2020-11365)



FORMAT OF THE SESSION: Each author will present her/his work by highlighting the main points (ideally copy/paste). Please do it in a short summary. This will be followed by questions and discussion. The length of the individual slot (including questions) is 5 minutes.

Over the past few years, major technological advances allowed to significantly increase both the spatial coverage and frequency bandwidth of multi-disciplinary observations at active volcanoes. Networks of instruments for the quantitative measurement of many parameters now permit an unprecedented, multi-parameter vision of the surface manifestations of mass transport beneath volcanoes. Furthermore, new models and processing techniques have led to innovative paradigms for inverting observational data to image the structures and interpret the dynamics of volcanoes. Within this context, this session aims at bringing together a multidisciplinary audience to discuss the most recent innovations in volcano imaging and monitoring, and to present observations, methods and models that increase our understanding of volcanic processes.
We welcome contributions (1) related to methodological and instrumental advances in geophysical, geological and geochemical imaging of volcanoes, and (2) to explore new knowledge provided by these studies on the internal structure and physical processes of volcanic systems.
We invite contributors from all geophysical, geological and geochemical disciplines such as seismology, electromagnetics, geoelectrics, gravimetry, magnetics, muon tomography, volatile measurements and analysis; from in-situ monitoring networks to high resolution remote sensing and innovative processing methods, applied to volcanic systems ranging from near-surface hydrothermal activity to magmatic processes at depth.

Subduction zones are arguably the most important geological features of our planet, where plates plunge into the deep, metamorphic reactions take place, large earthquakes happen and melting induces volcanism and creation of continental crust. None of these processes would be possible without the cycling of volatiles, and this session aims to explore their role in convergent margins. Questions to address include the following. Do Atlantic and Pacific subduction zones cycle volatiles in different ways? What dynamic or chemical roles are played by subducted fracture zones and plate bending faults? How do fluids and melts interact with the mantle wedge and overlying lithosphere? Why do some of the Earth’s largest mineral resources form in subduction settings? We aim to bring together geodynamicists, geochemists, petrologists, seismologists, mineral and rock physicists, and structural geologists to understand how plate hydration/slab dynamics/dehydration, and subsequent mantle wedge melting/fluid percolation, and ultimately melt segregation/accumulation lead to the diverse range of phenomena observed at convergence zones around the globe.

Includes Augustus Love Medal by Harro Schmeling
Invited Speaker: Nestor Cerpa (University of Montpellier, France)

Geophysical data demonstrate elevated seismic activity in subduction zones. Here dehydration and fluid pressure cycling as a function of increasing compaction and metamorphic grade are closely linked to deformation over a multitude of spatial and time scales. The highly anisotropic and initially fluid saturated marine sediments and altered oceanic crust dehydrate, while being incorporated into the accretionary wedge and subducted under the upper plate. Under high tectonic stresses, fluid overpressure eventually results in mechanical instabilities, promoting either hydrofracturing or ductile failure giving way for fluids to circulate. Collection of these fluids at the micron-scale and propagation along pathways up to the deca-kilometre scale are probably in charge for phenomena such as episodic tremor and slow slip. Increasing evidence from geophysical and seismic studies suggest that accumulation of slow slip events and fluids may even trigger devastating high-energy megathrust earthquakes. Quantitative understanding about (i) the release of fluids from their host rocks, (ii) the effect of localisation of both fluid flow and deformation and (iii) their effect on seismic activity are therefore crucial to understand the complex feedback processes. This system can only be fully understood by a close collaboration between experts from structural geology, metamorphic petrology and geophysics. In this interdisciplinary session, we therefore invite contributions from natural, experimental- and numerical modelling-based studies focussing on both exhumed (paleo) and active subduction zones.

With an increasing demand for low-carbon energy solutions, the need of geothermal resources utilization is accelerating. Geothermal energy can be extracted from various, often complex geological settings, e.g. fractured crystalline rock, magmatic systems or sedimentary basins. Current advancements also target unconventional systems (e.g., Enhanced Geothermal Systems, super-hot, pressurized and co-produced, super-critical systems) besides conventional hydrothermal systems. Optimizing investments leads to the development of associated resources such as lithium, rare earths and hydrogen. This requires a joint effort for monitoring, understanding and modelling geological systems that are specific to each resource.
A sustainable use of geothermal resources requires advanced understanding of the properties of the entire system during exploration as well as monitoring, including geophysical properties, thermo-/petro-physical conditions, fluid composition; structural and hydrological features; and engineering challenges. Challenges faced are, among others, exploration of blind systems, reservoir stimulation, induced seismicity or related to multiphase fluid and scaling processes.

The integration of analogue field studies with real-life production data, from industrial as well as research sites, and their organization and the combination with numerical models, are a hot topic worldwide. With this session we aim to gather field, laboratory and numerical experts who focus their research on geothermal sites, to stimulate discussion in this multi-disciplinary applied research field. We seek for contributions from all disciplines, ranging from field data acquirements and analysis to laboratory experiments, e.g. geophysical surveys or geochemical experiments, and from the management and organization of information to numerical models as well as from (hydro)geologists, geochemists, (geo)physicists, surface and subsurface engineers.