Seismic tomography is a powerful tool for imaging the Earth’s interior and inferring its structure, composition, dynamics and evolution. Over the last decades, our images have sharpened, thanks to the growth of global and dense regional networks (on land and in the oceans), the extraction of new observables, advances in modelling techniques and increased computational power. We are now not only resolving unprecedented details on local and regional scales, but also moving towards whole-Earth tomography, including the inner core.

We welcome contributions on methods and applications of seismic tomography from the crust to the core and at scales from local to regional to global, including studies of new observables, developments in forward modelling and inversion techniques, innovative approaches to uncertainty quantification, and seismological and interdisciplinary efforts aimed at obtaining new insights into Earth's dynamics and evolution. While we welcome all studies aimed at constraining Earth structure, we particularly invite contributions that utilise passive sources.

This session will cover applied and theoretical aspects of geophysical imaging, modelling and inversion using both active- and passive-source seismic measurements as well as other geophysical techniques (e.g., gravimetry, magnetic and electromagnetic) to investigate the Earth’s crust and uppermost mantle. We invite contributions focused on methodological developments, theoretical aspects, and applications. Studies across the scales and disciplines are particularly welcome.

Among others, the session may cover the following topics:
- Active- and passive-source imaging using body- and surface-waves;
- Full waveform inversion developments and applications;
- Advancements and case studies in 2D and 3D active-source imaging;
- Interferometry and Marchenko imaging;
- Seismic attenuation and anisotropy;
- Developments and applications of multi-scale and multi-parameter inversion;
- Joint inversion of seismic and complementary geophysical data;
- Applications of new acquisition systems.

Geophysical imaging techniques such as seismic, (complex) electrical resistivity, electromagnetic, and ground-penetrating radar methods are widely used to characterize structures and processes in the shallow subsurface. Advances in experimental design, instrumentation, data acquisition, data processing, numerical modeling, and inversion constantly push the limits of spatial and temporal resolution. Despite these advances, the interpretation of geophysical images often remains ambiguous. Persistent challenges addressed in this session include optimal data acquisition strategies, (automated) data processing and error quantification, appropriate spatial and temporal regularization of model parameters, integration of prior information and non-geophysical measurements into the imaging process, joint inversion, Bayesian inference, as well as the quantitative interpretation of tomograms through suitable petrophysical relations.

In light of these topics, we invite submissions concerning a broad spectrum of near-surface geophysical imaging methods and applications at different spatial and temporal scales. Novel developments in the combination of complementary measurement methods and process-monitoring applications are particularly welcome.

Invited speaker: Frederick D. Day-Lewis (U.S. Geological Survey)

The aims of the session are (1) to discuss methodological and instrumental advances in geophysical 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 areas, such as seismology, electromagnetics/geoelectrics, gravimetry/magnetics, muon tomography, remote sensing, and other geophysical observations applied to volcanic systems ranging from near-surface hydrothermal activity to magmatic processes at depth.

This year's session is focused on the contribution of geophysical imaging to better understand volcanological processes. We particularly welcome studies where complementary imaging techniques, as well as multi-disciplinary datasets, are integrated to investigate subsurface hydrothermal and magmatic processes.

The past few years have seen an increase in the application of machine learning methods for seismic data analysis. This is due to the increased adoption and visibility of freely available and easy-to-use machine learning toolkits, faster computation, reduced cost of data storage, and the very large sets of continuous geophysical and laboratory experimental data. The combination of these factors means that now is the time to consider machine learning as one of the key strategies modeling tools in both improving routine data processing and for better understanding the underlying geophysical processes.

Already, significant progress has been made in seismic waveform detection and classification of seismic waves for automatic onset picking. Such advances are allowing us to vastly speed up and improve the accuracy of previously laborious processing flows. In other notable recent applications, waveforms and ground motions, from both laboratory and natural datasets, are being used to understand the precursory physics of sudden- and slow-slip and to predict aftershock locations within supervised learning frameworks.

In this session, we will see machine learning focussed presentations covering topics such as seismic waveform processing, earthquake cataloging, earthquake classification, and earthquake cycle behavior from numerical and laboratory experiments.

In particular we would like to highlight invited talks from
Beroza et al.: Earthquake Monitoring with Deep Learning
Hulbert et al.: Probing Fault Physics Applying Machine Learning
De Hoop et al.: Unsupervised learning for identification of seismic signals
and
Kriegerowski et al.: Deep learning for localizing and detecting earthquake swarm activity based on full waveforms: Chances, challenges and questions

Many mantle structures have recently been observed by seismologists including the lithosphere-asthenosphere boundary (LAB), a possible transition near ~1000 km depth, small scale heterogeneities in the transition zone and in the lowermost mantle (ULVZ, D"), plumes, stagnating slabs, mantle anisotropy... However their origin is still unclear and geodynamical modelling can help propose plausible scenarios. Furthermore, geodynamic models and tomographic images often investigate different physical parameters, and propose views of the mantle at separate scales. Combining information from both fields is therefore necessary to understand and link mantle processes across scales. We encourage every contribution that can feed the dialogue between seismologists and geodynamicists.

Sollicited speakers: Harriet C.P Lau (Harvard University), Manuele Faccenda (University of Padova)

Dynamic processes shape the Earth and other planets throughout their history. Processes and lifetimes of magma oceans establish the initial conditions on the development of rocky planets and their early atmospheres. The dynamics of the mantle, the composition and mineral physics shape the present-day observable structure of the Earth's mantle and planetary bodies visible through seismic observations.
This session aims to provide a multidisciplinary view on the processes and structures of the Earth and planets. We welcome contributions that address the structure, dynamics, composition and evolution of their mantle, and their interactions with the outer layers, on temporal scales ranging from the present day to billions of years, and on spatial scales ranging from microscopic mineralogical samples, kilometer-size seismic structures to global planetary models.

Dynamic processes shape the Earth and other planets throughout their history. Processes and lifetimes of magma oceans establish the initial conditions on the development of rocky planets and their early atmospheres. The dynamics of the mantle, the composition and mineral physics shape the present-day observable structure of the Earth's mantle and planetary bodies visible through seismic observations.
This session aims to provide a multidisciplinary view on the processes and structures of the Earth and planets. We welcome contributions that address the structure, dynamics, composition and evolution of their mantle, and their interactions with the outer layers, on temporal scales ranging from the present day to billions of years, and on spatial scales ranging from microscopic mineralogical samples, kilometer-size seismic structures to global planetary models.

The processes of the Earth deformation can be revealed by means of diverse methods of investigations. The seasonal distribution of surface loading, the earthquake cycle, volcanic processes (eruptions, dike intrusions, induced seismic activity), near surface motions (landslides, induced and natural superficial subsidence/collapse).
Recently, major earthquakes in Sumatra (2004, Mw 9.2), Maule (2010, Mw 8.8), Haiti (2010, Mw 7.1) and Tohoku (2011, Mw 9.0) have exposed the impact of such events and the need for better understanding of Earth deformation processes. These events illustrate the geodynamic complexities that include subduction zones and giant earthquakes, continental faults and depth versus surface deformation, the seismic cycle and seismotectonics of active zones, magmatism processes and crustal deformation. The observation techniques, methods and data analysis need the Earth observation systems and reference frames that include remote sensing and surface and satellite gravity observations
This session is conducted in the frame of the WEGENER consortium*) and we seek submissions that emphasize multidisciplinary studies of Earth deformation using geodetic techniques (GPS, InSAR, LiDAR, space/air/terrestrial gravity, ground-based geodetic observations), complementary tectonic and geophysical observations, and modeling approaches focusing on the European-Mediterranean and Northern African regions. We also welcome contributions discussing the realization and outcomes of Supersites in the frame of the GEO initiative, as well as fundamental studies of natural and induced physical phenomena, strategies to develop early warning and rapid response systems.
*) The World Earthquake GEodesy Network for Environmental Hazard Research (Sub-commission 3.5 of IAG commission 3, namely Tectonics and Earthquake Geodesy)

Mantle upwellings are an important component of the Earth’s convective system that can cause volcanism and anomalies in surface topography. Upwellings can rise from thermal boundary layers as hot “mantle plumes”. Alternatively, they can be the response to upper-mantle convective flow, subduction, or rifting. Clearly, different mechanisms sustain mantle upwellings of various temperature, vigour and composition, causing characteristic signals that can potentially be imaged using geophysical data, as well as expressed in the geochemistry and petrology of related magmatism.

This session invites contributions that focus on mantle upwellings from geophysics, geochemistry, and modelling perspectives. Our aim is to bring together constraints from multiple disciplines to understand the origin and dynamics of mantle upwellings, as well as their potential to trigger mantle melting, create volcanism, generate ore deposits, and build dynamic topography.

Subduction drives plate tectonics, generates the major proportion of subaerial volcanism, forms continents, and entrains surface material back to the deep Earth. Therefore, it is arguably the most important geodynamical phenomenon on Earth and the major driver of global geochemical cycles. Seismological data show a fascinating range in shapes of subducting slabs. Arc volcanism illustrates the complexity of geochemical and petrological phenomena associated with subduction. Surface topography provides insight in the orogenic processes related to subduction and continental collision.

Numerical and laboratory modelling studies have successfully built our understanding of many aspects of the geodynamics of subduction zones. Detailed geochemical studies, investigating compositional variation within and between volcanic arcs, provide further insights into systematic chemical processes at the slab surface and within the mantle wedge, providing constraints on thermal structures and material transport within subduction zones. However, with different technical and methodological approaches, model set-ups, inputs and material properties, and in some cases conflicting conclusions between chemical and physical models, a consistent picture of the controlling parameters of subduction-zone processes has so far not emerged.

This session aims to follow subducting lithosphere on its journey from the surface down into the Earth's mantle, and to understand the driving processes for deformation and magmatism in the over-riding plate. We aim to address topics such as: subduction initiation and dynamics; changes in mineral breakdown processes at the slab surface; the formation and migration of fluids and melts at the slab surface; primary melt generation in the wedge; subduction-related magmatism; controls on the position and width of the volcanic arc; subduction-induced seismicity; mantle wedge processes; the fate of subducted crust, sediments and volatiles; the importance of subducting seamounts, LIPs, and ridges; links between near-surface processes and slab dynamics and with regional tectonic evolution; slab delamination and break-off; the effect of subduction on mantle flow; and imaging subduction zone processes.

With this session, we aim to form an integrated picture of the subduction process, and invite contributions from a wide range of disciplines, such as geodynamics, modelling, geochemistry, petrology, volcanology and seismology, to discuss subduction zone dynamics at all scales from the surface to the lower mantle, or in applications to natural laboratories.

The lithosphere, the outermost shell of the Earth, constitutes the upper thermal boundary layer of mantle convection. It is well established that its properties play a central role in the development of solid Earth dynamics. Through its properties the lithosphere also provides a primary source of thermal and chemical anomalies for mantle convection when it is injected in the mantle as subducting slabs. Here, the subduction of cold and dense oceanic lithosphere into the underlying mantle acts as the major driving force of plate motion, and as a key component of the water and carbon cycles throughout the Earth. At the global scale, some of these lithosphere heterogeneities include rheological stratifications, sutures, fracture zones, and lateral and vertical variations in temperature and composition. These exist at various scales and play a major role in determining subduction dynamics and the degree of lithosphere-mantle decoupling. Deciphering the interaction of the lithosphere with the underlying asthenosphere and deeper mantle is critical to understanding the secular evolution of the Earth system and to reconcile models with natural observations. This session aims to highlight recent advances in constraining the scales and amplitudes of heterogeneities in the lithosphere as well as their dynamic role. We welcome multidisciplinary contributions. Some key areas of interest are lithospheric structure and morphology, subduction kinematics and dynamics, slab-mantle interaction and slab deformation, active margin tectonics and subduction-induced seismicity.

We invite, in particular multidisciplinary, contributions which focus on the structure and evolution of the continental crust and upper mantle and on the nature of mantle discontinuities. The latter include, but are not limited to, the mid-lithosphere discontinuity (MLD), the lithosphere-asthenosphere boundary (LAB), and the mantle transition zone, as imaged by various seismological techniques and interpreted within interdisciplinary approaches. Papers with focus on the structure of the crust and the nature of the Moho are also welcome. Methodologically, the contributions will include studies based on seismic, thermal, gravity, petrological, and/or electro-magnetic data interpretations.
Confirmed invited speaker: Arwen Deuss on Upper Mantle Doscontinuities

Many regions of the Earth, from crust to core, exhibit anisotropic fabrics which can reveal much about geodynamic processes in the subsurface. These fabrics can exist at a variety of scales, from crystallographic orientations to regional structure alignments. In the past few decades, a tremendous body of multidisciplinary research has been dedicated to characterizing anisotropy in the solid Earth and understanding its geodynamical implications. This has included work in fields such as: (1) geophysics, to make in situ observations and construct models of anisotropic properties at a range of depths; (2) mineral physics, to explain the cause of some of these observations; and (3) numerical modelling, to relate the inferred fabrics to regional stress and flow regimes and, thus, geodynamic processes in the Earth. The study of anisotropy in the Solid Earth encompasses topics so diverse that it often appears fragmented according to regions of interest, e.g., the upper or lower crust, oceanic lithosphere, continental lithosphere, cratons, subduction zones, D'', or the inner core. The aim of this session is to bring together scientists working on different aspects of anisotropy to provide a comprehensive overview of the field. We encourage contributions from all disciplines of the earth sciences (including mineral physics, seismology, magnetotellurics, geodynamic modelling) focused on anisotropy at all scales and depths within the Earth.

Our understanding of Earth's inner and outer core is progressing at a rapid pace thanks to cross-fertilization between a number of observational, theoretical and experimental disciplines.

Improved seismic observations continue to provide better images of the core and prompt refinements in structural and geodynamic models. Mineral physics provides constraints for dynamic, structural, and thermodynamic models. The heat budget of the core, paleomagnetic observations, and models promote the exploration of new dynamo mechanisms. Geomagnetic observations from both ground and satellite, along with magneto-hydrodynamic experiments, provide additional insight to our ever expanding view of Earth's core.

This session welcomes contributions from all disciplines, as well as interdisciplinary efforts, on attempts to proceed towards an integrated, self-consistent picture of core structure, dynamics and history, and to understand its overwhelming complexity.

The Alpine-Himalayan orogenic belt is one of the largest and most prominent suture zones on Earth. The belt ranges from the Mediterranean in the west to Indonesia in the east. It results from the subduction and closing of different branches of the Tethyan Oceanic Realm and the subsequent collision of the African, Arabian and Indian continental plates with Eurasia. Its long-lasting geological record of complex interactions among major and smaller plates, featuring the presence of subduction zones at different evolutionary stages, has progressively grown as a comprehensive test site to investigate fundamental plate tectonics and geodynamic processes with multi-disciplinary studies. Advances in a variety of geophysical and geological fields provide a rich and growing set of constraints on the crust-lithosphere and mantle structure, as well as tectonics and geodynamic evolution of the entire mountain belt

We welcome contributions presenting new insights and observations derived from different perspectives like geology (stratigraphy, petrology, geochronology, geochemistry, tectonics and geomorphology), geophysics (seismicity, seismic imaging, seismic anisotropy, gravity), geodesy (GPS, InSAR), modelling (numerical and analogue), risk assessment (earthquake, volcanism), as well as from multi-disciplinary studies.

Keynote Presentations:
-Insights into the transitions in the Banda Arc-Australian continental collision from seismic imaging of deep slab structures by Meghan Miller (Australian National University)
-Active tectonics of Iran and the South Caspian: from earthquakes to
mountain-building by Richard Walker(Oxford University)