Seismic activity and crustal deformation are indicative of underlying plate tectonic and/or volcanic processes. Their connectedness is often non-linear and non-sequential. Seismic activity can result in crustal deformation in a tectonically or volcanically active region, while deformation arising from these forces can harness seismic potency. In isolation, seismic and geodetic (GNSS, InSAR) analysis potentially run the risk of delivering partial inferences, especially in compound geodynamic settings. Evidently, independently obtained results from seismic and geodetic observations are heavily reliant on the data type, methodology, model assumptions, and error estimations. In recent times, there have been several measures to jointly employ seismic and geodetic data to understand complex processes in aforementioned settings. Such studies have made significant contributions to modern and reliable data analysis practices. Therefore, this session aims to explore ongoing research that works towards arriving at comprehensive results from both ends of the spectrum; seismicity, a form of fast deformation, and its relationship with the slower geodetically measured deformation.

The current session invites presentation of research that simultaneously incorporates seismic and geodetic (GNSS, InSAR) techniques to investigate any given tectonic and/or volcanic setting. The study may include analyses of selected earthquakes and related deformation, comparison studies between seismic and geodetic data analysis, volcanic deformation and associated seismicity, and seismic cycle monitoring based on both seismology and geodesy. We also encourage studies using models (analytical or numerical) linking geodetic and seismic research, such as stress-strain models in volcanic and tectonic areas.

Invited Abstract:
Using Seismic and Geodetic Observations in a Simultaneous Kinematic Model of the 2019 Ridgecrest, California Earthquakes
Dara Goldberg1, Diego Melgar1, Valerie Sahakian1, Amanda Thomas1, Xiaohua Xu2, Brendan Crowell3, and Jianghui Geng4
1Department of Earth Sciences, University of Oregon, Eugene, Oregon, United States of America
2Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America
3Department of Earth and Space Sciences, University of Washington, Seattle, Washington, United States of America
4Wuhan University, Wuhan, China

The largest earthquakes globally occur along plate boundaries, producing intense shaking and associated secondary hazards over broad regions. In the past few years, there have been significant improvements in the quantity and quality of geodetic, seismological, and geological observations of the slow accumulation and rapid release of strain at these plate boundaries. At the same time, improvements in modeling techniques are providing new insights into the geodynamic processes controlling the occurrence of major earthquakes. With these advances, it is now becoming possible to address outstanding issues about both seismic and aseismic deformation at plate boundaries, such as time-variable locking and unlocking of the plate interface, the extent and role of slow slip events, the links between earthquake cycles and permanent deformation, and the behavior of complete cycles revealed by paleo-seismic and paleo-geodetic observations.

We invite contributions that investigate the spectrum of deformation occurring throughout the earthquake cycle at plate boundaries, from aseismic to seismic and across a variety of spatial and temporal scales. Submissions that utilize improved remote and field observational capabilities, developments in data analysis, or innovations in analog and numerical modeling to advance the understanding of the underlying physical processes are encouraged.

Public information:
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We will begin our session by allowing 5-10 minutes for participants to look through the displays and prepare some discussion points. After this, we will go through all of the presenting author, and have each author briefly introduce their research. Audience participants will then have a few minutes to ask questions and make comments. Depending on the number of displays, we will be more or less strict on timing, but we are aiming for 5-10 minutes per author. Finally, after all authors have presented, we will turn the comments to open discussion. Talk to you soon!

Earthquake mechanics is controlled by a spectrum of processes covering a wide range of length scales, from tens of kilometres down to few nanometres. While the geometry of the fault/fracture network and its physical properties control the global stress distribution and the propagation/arrest of the seismic rupture, earthquake nucleation and fault weakening is governed by frictional processes occurring within extremely localized sub-planar slipping zones. The co-seismic rheology of the slipping zones themselves depends on deformation mechanisms and dissipative processes active at the scale of the grain or asperity. The study of such complex multiscale systems requires an interdisciplinary approach spanning from structural geology to seismology, geophysics, petrology, rupture modelling and experimental rock deformation. In this session we aim to convene contributions dealing with different aspects of earthquake mechanics at various depths and scales such as:

· the thermo-hydro-mechanical processes associated with co-seismic fault weakening based on rock deformation experiments, numerical simulations and microstructural studies of fault rocks;
· the study of natural and experimental fault rocks to investigate the nucleation mechanisms of intermediate and deep earthquakes in comparison to their shallow counterparts;
· the elastic, frictional and transport properties of fault rocks from the field (geophysical and hydrogeological data) to the laboratory scale (petrophysical and rock deformation studies);
· the internal architecture of seismogenic fault zones from field structural survey and geophysical investigations;
· the modeling of earthquake ruptures, off-fault dynamic stress fields and long-term mechanical evolution of realistic fault networks;
· the earthquake source energy budget and partitioning between fracture, friction and elastic wave radiation from seismological, theoretical and field observations.
· the interplay between fault geometry and earthquake rupture characteristics from seismological, geodetic, remote sensed or field observations;

We particularly welcome novel observations or innovative approaches to the study of earthquake faulting. Contributions from early career scientists are solicited.

Tectonic faults accommodate plate motion through various styles of seismic and aseismic slip spanning a wide range of spatiotemporal scales. Understanding the mechanics and interplay between seismic rupture and aseismic slip is central to seismotectonics as it determines the seismic potential of faults. In particular, unraveling the underlying physics controlling these styles of deformation bears a great deal in earthquakes hazards mitigation especially in highly urbanized regions.
In partnership with the AGU Tectonophysics section, we invite contributions from observational, experimental, geological and theoretical studies that explore the diversity and interplay among seismic and aseismic slip phenomena in various tectonic settings, including the following questions: (1) How does the nature of creeping faults change with the style of faulting, loading rate, and other factors? (2) Are different slip behaviors well separated in space, or can the same fault areas experience different failure modes? (3) Is there a systematic spatial or temporal relation between different types of slip?

Invited speakers:
- Chris Marone, Penn State. "Fault healing plays a key role in creating the spectrum of tectonic faulting styles from seismic to aseismic slip "

- Adriano Gualandi, Caltech. "Towards Slow Earthquakes Forecasting"

The broad scale tectonics of the Eastern Mediterranean are dominated by the interaction of the Nubian and Arabian plates with the Eurasian plate. This complex tectonic frame exhibit almost all type of plate boundary conditions such as continental convergence and extension, oceanic subduction, and continental transform. The evolution and present deformation are constrained by diverse geological, geophysical, and geodetic observations and have been explained by different hypotheses, such as (a) tectonic escape system caused by the post-collisional convergence of Eurasian and Arabian plates creating forces at its boundaries with gravitational potential differences of the Anatolian high plateau (b) asthenospheric flow dragging the circular flow of lithosphere from the Levant to Anatolia in the east and the Aegean in the west, (c) slab pull of the Hellenic subduction, (d) mantle upwelling underneath Afar and with the large-scale flow associated with a whole mantle, Tethyan convection cell, (e) or combinations of these mechanisms for the Eastern Mediterranean. Naturally, this tectonic setting generates frequent earthquakes with large magnitudes (M > 7), forming a natural laboratory on understanding the crustal deformation, and crust-mantle interactions for various disciplines of active tectonics.
Multi-disciplinary studies, especially within the last three decades, have made significant contributions to our understanding of the processes on the crustal deformation, and interaction of the mantle with the crustal processes of this region. With this session, we aim to bring together the recent findings of these studies, thus we welcome/invite contributions from a wide range of disciplines including, but not limited to, neotectonics, seismology, tectonic geodesy (e.g. GNSS, InSAR), paleoseismology, tectonic geomorphology, remote sensing, structural geology and geodynamic modelling, which geographically cover the Eastern Mediterranean region, including Anatolia-Aegean Block, Caucasus, Iran, Middle East and Greece.

Invited talks:
- Jonathan Weiss - Measuring Anatolian plate velocity and strain with InSAR: Implications for fault-locking, seismic hazard, and crustal dynamics.
- Pierre Henry - Contrasting seismogenic behaviors on the North Anatolian Fault in the Sea of Marmara

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.

Since 2004, there have been a number of large subduction earthquakes whose unexpected rupture features contributed to the generation of devastating tsunamis. The impact that these events have had on human society highlights the need to improve our knowledge of the key mechanisms behind their origin. Advances in these areas have led to progress in our understanding of the most important parameters affecting tsunamigenesis.

With increasing geophysical data, new descriptions of faulting and rupture complexity are being hypothesized (e.g., spatial and temporal seismic rupture heterogeneity, fault roughness, geometry and sediment type, interseismic coupling, etc.). Rock physicists have proposed new constitutive laws and parameters based on a new generation of laboratory experiments, which simulate close to natural seismic deformation conditions on natural fault samples. In addition, advances in numerical modelling now allow scientists to test how new geophysical observations, e.g. ocean drilling projects and laboratory analyses, influence subduction zone processes over a range of temporal and spatial scales (i.e., geodynamic, seismic cycling, earthquake rupture, wave propagation modelling).

In light of these advances, this session has a twofold mission: i) to integrate recent results from different fields to foster a comprehensive understanding of the key parameters controlling the physics of large subduction earthquakes over a range of spatial and temporal scales; ii) to identify how tsunami hazard analysis can benefit from using a multi-disciplinary approach.

We invite abstracts that enhance interdisciplinary collaboration and integrate observations, rock physics experiments, analog- and numerical modeling, and tsunami hazard.

The Mediterranean region spanning from the Betic Cordillera and the Alboran Sea to the Levantine and Dead Seas is the most tectonically active region of Europe. Over the last decades several moderate to large magnitude earthquakes affected the Mediterranean regions often causing substantial economical and sometimes human losses. The scientific community is developing a better understanding of the crustal processes that may drive seismic sequences thanks to denser and higher quality geophysical networks, multidisciplinary experiments and rapid field deployments in the aftermath of a mainshock. This allowed increasingly larger and more accurate datasets that can be exploited to improve the knowledge of crustal seismogenic processes. Over the years, this effort lead to the identification of seismic gaps, the production of seismic hazard maps and, not least, the characterization of seismogenic structures. Yet, each seismic sequence seems to be strongly affected by the local tectonics and by the interplay of crustal processes.

In this session we welcome contributions aimed at a better understanding of recent seismic sequences that may help improving our still fragmentary knowledge of earthquake nucleation processes. We are interested in new results from earthquakes that occurred both in front-arc and back-arc regions along the convergence zones between Africa and Europe, in the Apennines and other Mediterranean regions and their comparison with major historical earthquakes. This includes geophysical experiments, analyses of recent seismic sequences, and multidisciplinary studies focusing on the identification, characterisation and monitoring of seismic gaps. We also encourage analyses of fluid-driven seismic sequences and offshore campaigns characterizing key regional faults.

Typical practice for seismic hazard assessment (SHA) in stable continental regions (SCRs) uses a global-analogues approach to amalgamate seismicity data from SCRs globally. This approach is premised on all SCR crust sharing the same seismogenic potential. Is this approach valid? How can we better define seismogenic analogues in low strain regions? Are earthquake recurrence and long-term slip rates meaningful concepts in these settings for the purpose of seismic hazard analysis?
This session seeks to integrate paleoseismic, geomorphic, geodetic, geophysical and seismological datasets to provide insight into the earthquake cycle in low-strain regions. It will draw upon recent advances in high-resolution topography, geochronology, satellite geodesy techniques, subsurface imaging techniques, longer seismological records, high-density geophysical networks and unprecedented computational power to explore the driving mechanisms for earthquakes in low-strain settings. A comparison of the range of seismic behavior as a function of the different geodynamic attributes of these settings (e.g., crustal age, structure, stress, geology, antecedent
tectonics (inheritance); evolving boundary conditions; Quaternary processes (glaciation), etc), may provide a means to better refine and constrain the types of features or active processes that warrant treatment as analogues for seismic hazard assessment. We welcome contributions that (1) present new observations that place constraints on earthquake occurrence in low-strain regions, (2) explore patterns of stable or temporally varying earthquake recurrence, and (3) provide insight into the mechanisms that control earthquakes in regions of slow deformation via observation and/or
modeling.

Public information:
The session will be hosted both on Zoom and on the EGU text-based chat.

Schedule :
- 10:45-11:15 : Zoom session (see link below) - Presentations only (no questions and answers, this will take place in the chat), presenters are invited to share their screen
- 11:15-12:30 : EGU chat session - questions and answers for all presenters

------------------------------------- Zoom session link ------------------------------------
Join from PC, Mac, Linux, iOS or Android: https://videoconf-colibri.zoom.us/j/98788480483
Or iPhone one-tap: 308810988,98788480483# or 211202618,98788480483#
Or Telephone:
Dial: +351 308 810 988 (Portugal Toll) or +351 211 202 618 (Portugal Toll)
Meeting ID: 987 8848 0483
International numbers available: https://videoconf-colibri.zoom.us/u/adNZCcmlD1
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The Zoom session will start with a 10 minute presentation by Eulalia Gracia for a solicited talk. It will be followed by 6 3-minute long presentations.
Then, we will switch to the text-based chat for questions and answers ; 5 minutes for each presentation. Each presentation will be introduced by the conveners.

The schedule is given below.

ZOOM (10:45-11:15) -
10:45-10:55 E. Gracia Earthquake crisis unveils the growth of an incipient continental fault system
10:55-10:58 J. Ritz The Mw4.9 Le Teil surface-rupturing earthquake in southern France: New insight on seismic hazard assessment in stable continental regions
10:58-11:01 A. Vallage Full characterization of the ML 5.4 2019/11/11 Le Teil earthquake in France based on a multi-technology approach
11:01-11:04 T. King The 2016 Mw 6.1 Petermann Ranges earthquake rupture, Australia: another “one-off” stable continental region earthquake
11:04-11:07 C.-H. Tsai Palaeo-earthquake magnitudes on the Dzhungarian fault, N. Tien shan, and implications for the rupture processes of intraplate strike-slip faults
11:07-11:10 C. Daxer Quantitative paleoseismology in Carinthia, Eastern Alps: Calibrating the lacustrine sedimentary record with historical earthquake data
11:10-11:13 M. Moorkamp Integrated geophysical analysis of the April 2017 Moiyabana intra-plate earthquake, Botswana

TEXT-BASED EGU CHAT (11:15-12:30)
11:15-11:20 E. Gracia Earthquake crisis unveils the growth of an incipient continental fault system
11:20-11:25 O. Olesen Large magnitude earthquakes of late Holocene age in the Precambrian of Finnmark, Northern Norway
11:25-11:30 J. Ritz The Mw4.9 Le Teil surface-rupturing earthquake in southern France: New insight on seismic hazard assessment in stable continental regions
11:30-11:35 A. Vallage Full characterization of the ML 5.4 2019/11/11 Le Teil earthquake in France based on a multi-technology approach
11:35-11:40 T. King The 2016 Mw 6.1 Petermann Ranges earthquake rupture, Australia: another “one-off” stable continental region earthquake
11:40-11:45 C.-H. Tsai Palaeo-earthquake magnitudes on the Dzhungarian fault, N. Tien shan, and implications for the rupture processes of intraplate strike-slip faults
11:45-11:50 H. Choi What if a larger earthquake would occur at the causative fault of the Gyeongju earthquake with ML 5.8 on September 11, 2016 in South Korea?
11:50-11:55 J. Kley Seismotectonic regions for Germany - Concept and results
11:55-12:00 D. Clark Neotectonic constraint on models of strain localisation within Australian Stable Continental Region (SCR) crust
12:05-12:10 C. Daxer Quantitative paleoseismology in Carinthia, Eastern Alps: Calibrating the lacustrine sedimentary record with historical earthquake data
12:10:12:15 R. Minetto High-resolution catalog of the the Maurienne Swarm (French Alps) based on template matching and double-different relocation
12:15-12:20 M. Moorkamp Integrated geophysical analysis of the April 2017 Moiyabana intra-plate earthquake, Botswana
12:20-12:25 C. Reyes-Carmona Evidence of recent activity in the Camorro Fault (Central Betics, Southern Spain)

12:25-12:30 - Additional questions and time for discussion

The study of active tectonic structures in offshore areas has been hampered by the scarcity of direct observations and by the limited resolution of indirect data. Nevertheless, in the last years, the development of new geophysical instrumentation and the acquisition of high-resolution bathymetric and active and passive seismic data (i.e., chirp, parametric sounder, multichannel profiles or OBS information) has allowed making major advances in the study of active faults in offshore areas. These new data have become fundamental not only to identify and describe active tectonic structures but also to characterize their Quaternary activity and seismogenic potential. Together with these developments, our understanding of marine active tectonics and our knowledge about their associated hazards have also improved.
The aim of this session is to compile studies which focus on the use of geophysical data to identify and characterize offshore active structures (i.e., faults and folds), their seismogenic and tsunamigenic potential and possibly related features such as submarine landslides, and to estimate the related hazards. Studies can be focused at regional or local scale and the session includes but is not limited to, the following topics:
- Active faulting identification and description and/or 3D modeling.
- Contribution of seismicity analysis to the seismotectonic characterization of offshore areas.
- Seismogenic characterization of active structures and estimation of their tsunamigenic potential.
- Active tectonics processes related to landslides triggering.
- Contribution of marine active tectonic study to the hazard assessment.

The study of active faults and deformation of the Earth's surface has made, and continues to make, significant contributions to our understanding of earthquakes and the assessment of seismic related hazard. Active faulting may form and deform the Earth's surface so that records are documented in young sediments and in the landscape. Field studies of recent earthquake ruptures help to constrain earthquake source parameters and to identify previously unknown active structures. The insights gleaned from recent earthquakes can be applied to study past earthquakes. Paleoseismology and related disciplines such as paleogeodesy and paleotsunami investigations still are the primary tools to establish earthquake records that are long enough to determine recurrence intervals and long-term deformation rates for active faults. Multidisciplinary data sets accumulated over the years have brought unprecedented constraints on the size and timing of past earthquakes and allow deciphering shorter-term variations in fault slip rates or seismic activity rates, as well as the interaction of single faults within fault systems. This wide range of methods leads to a wide range of uncertainties in the definition of what is an active fault, which parameters are entered in fault databases, which consequently conditions the strategy used to transfer earthquake-fault data into fault models suitable for probabilistic SHA. Which uncertainty can be quantified by geologists and how can it be made easily accessible for proper usage in hazard computation is a fundamental question that the FAULT2SHA ESC working group (www.fault2sha.net) is attempting to tackle.
This FAULT2SHA session aims to spark a discussion between field earthquake geologists, crustal deformation modellers and fault modellers/seismic hazard practitioners around fault-related uncertainty issues and their inclusion in fault-based PSHA. We welcome contributions describing and critically discussing approaches used to study active faults as well as presentations discussing existing efforts on how fault-related information is translated into dedicated databases of primary surface information and then into 3D fault models. We particularly encourage contributions related to local studies of fault systems where specific issues could be debated on either fault data collection aspects, databases questions and/or fault hazard modelling