Earthquakes occur with great spatio-temporal variability, which emerges from the complex interactions between them. Significant progress is being made towards understanding spatio-temporal correlations, scaling laws and clustering, and the emergence of seismicity patterns. New models being developed in statistical seismology have direct implications for time-dependent seismic hazard assessment and probabilistic earthquake forecasting. In addition, the increasing amount of earthquake data available on local to global scales provides new opportunities for model testing.


This session focuses both on recent insights on the physical processes responsible for the distribution of earthquakes in space and time, and on new models and techniques for quantifying the seismotectonic process and its evolution. Particular emphasis will be placed on:
- physical and statistical models of earthquake occurrence;
- analysis of earthquake clustering;
- spatio-temporal properties of earthquake statistics;
- quantitative testing of earthquake occurrence models;
- implications for time-dependent hazard assessment;
- methods for earthquake forecasting;
- data analyses and requirements for model testing.

Confirmed solicited speaker: Danijel Schorlemmer (GFZ - German Research Center for Geosciences, Potsdam, Germany)

From the real-time integration of multi-parametric observations is expected the major contribution to the development of operational t-DASH systems suitable for supporting decision makers with continuously updated seismic hazard scenarios. A very preliminary step in this direction is the identification of those parameters (seismological, chemical, physical, biological, etc.) whose space-time dynamics and/or anomalous variability can be, to some extent, associated with the complex process of preparation of major earthquakes.
This session wants then to encourage studies devoted to demonstrate the added value of the introduction of specific, observations and/or data analysis methods within the t-DASH and StEF perspectives. Therefore studies based on long-term data analyses, including different conditions of seismic activity, are particularly encouraged. Similarly welcome will be the presentation of infrastructures devoted to maintain and further develop our present observational capabilities of earthquake related phenomena also contributing in this way to build a global multi-parametric Earthquakes Observing System (EQuOS) to complement the existing GEOSS initiative.
To this aim this session is not addressed just to seismology and natural hazards scientists but also to geologist, atmospheric sciences and electromagnetism researchers, whose collaboration is particular important for fully understand mechanisms of earthquake preparation and their possible relation with other measurable quantities. For this reason all contributions devoted to the description of genetic models of earthquake’s precursory phenomena are equally welcome. Every 2 years selected papers presented in thsi session will be proposed for publication in a dedicated Special Issue of an international (ISI) scientific journal.

Our capability to provide timely and reliable seismic risk estimates is an essential element towards building a resilient society, through informed decision for risk management. The scientific base of the process of seismic risk mitigation includes various seismic hazard models, developed at different time scales and by different methods, as well as the use of information as complete and reliable as possible about past seismicity.
Some recent large earthquakes caused extensive damage in areas where some models indicated low seismic hazard, leading to an increased demand for criteria to objectively assess how well seismic hazard models are performing. This session aims to tackle theoretical and implementation issues, which are essential for the development of effective mitigation strategies and include:
⇒ methods for comparison of seismic hazard models and their performance evaluation;
⇒ hazard and risk assessment of extreme seismic events;
⇒ long-term evidences about past great earthquakes (including unconventional seismological observations, such as impact on caves, ancient constructions and other deformations evidences);
⇒ earthquake hazard assessment in terms of macro-seismic intensity;
⇒ seismic risk estimation at different time and space scale.
In particular, the session will address concepts, problems, and approaches in assessing hazard related to the earthquakes that “may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage” (according to UNISDR terminology). The session will include discussions of the pros and cons of deterministic, neo-deterministic, probabilistic, and intensity-based seismic hazard assessments. The latter is of special importance for Europe because of the available large historical information on macro-seismic intensities.
We invite contributions related to: hazard and risk assessment methods and their performance in applications; critical observations and constraints for seismic hazard assessment; verification methods that are suitable to quantify seismic hazard estimates and that can be applied to limited and/or heterogeneous observations (ranging from recent records of ground shaking parameters to past intensity data); seismic hazard and risk monitoring and modeling; and risk communication and mitigation.
The session will provide an opportunity to discuss best practices and share experience gained with different testing methods, including their application in different fields. We hope to highlight both the existing gaps and future research directions that could strengthen the procedures for testing and comparing performance of seismic hazard models.

Seismic techniques are becoming widely used to detect and quantitatively characterise a wide variety of natural processes occurring at the Earth’s surface. These processes include mass movements such as landslides, rock falls, debris flows and lahars; glacial phenomena such as icequakes, glacier calving/serac falls, glacier melt and supra- to sub-glacial hydrology; snow avalanches; water storage and water dynamics phenomena such as water table changes, river flow turbulence and fluvial sediment transport. Where other methods often provide limited spatial and temporal coverage, seismic observations allow recovering sequences of events with high temporal resolution and over large areas. These observational capabilities allow establishing connections with meteorological drivers, and give unprecedented insights on the underlying physics of the various Earth’s surface processes as well as on their interactions (chains of events). These capabilities are also of first interest for real time hazards monitoring and early warning purposes. In particular, seismic monitoring techniques can provide relevant information on the dynamics of flows and unstable slopes, and thus allow for the identification of precursory patterns of hazardous events and timely warning.

This session aims at bringing together scientists who use seismic methods to study Earth surface dynamics. We invite contributions from the field of geomorphology, cryospheric sciences, seismology, natural hazards, volcanology, soil system sciences and hydrology. Theoretical, field based and experimental approaches are highly welcome.

Hydraulic stimulation is a well-operation that aims at enhancing fluid flow at depth. It is applied to exploit unconventional hydrocarbon reservoirs with low permeability and deep geothermal resources. Induced earthquakes frequently accompany the injection of fluids into boreholes potentially leading to damage to infrastructure at the surface and thus generally raising public concern. Damage caused by such events have already terminated Enhanced Geothermal Energy projects in South Korea and Switzerland. Hence, finding safe stimulation methods is critical for future use and public acceptance of geothermal energy projects and potential other forms of energy extraction from the underground. A range of stimulation techniques have been developed to increase the permeability of low-permeable reservoirs, however, our understanding of the processes involved in the formation of hydrofracs and hydroshears and the effectiveness of these operations regarding flow enhancement are still rather limited. A series of successful mine-back experiments have been performed in a range of underground laboratories in Europe. For this session, we invite presentations covering the full range of rock mechanics experiments, underground laboratory testing, and field-scale operations aiming at improving the fundamental understanding of stimulation operations.

Numerical modeling of earthquakes provides new approaches to apprehend the physics of earthquake rupture and the seismic cycle, seismic wave propagation, fault zone evolution and seismic hazard assessment.
Recent advances in numerical algorithms and increasing computational power enable unforeseen precision and multi-physics components in physics-based earthquake simulation but also pose challenges in terms of fully exploiting modern supercomputing infrastructure, realistic parameterization of simulation ingredients and the analysis of large synthetic datasets.
This session aims to bring together modelers and data analysts interested in the physics and computational aspects of earthquake phenomena. We welcome studies focusing on all aspects of the physics of various earthquakes - from slow slip events, fault mechanics and rupture dynamics, to wave propagation and ground motion analysis, to the seismic cycle and inter seismic deformation - and studies which further the state-of-the art in the related computational and numerical aspects.
We further encourage studies linking earthquake source processes to rock mechanics and the laboratory scale.

This session covers the broad field of earthquake source processes, and includes the topics of observing the surface deformation caused by earthquakes, imaging the rupture kinematics and simulating earthquake dynamics using numerical methods, to develop a deeper understanding of earthquake source physics. We also invite presentation that link novel field observations and laboratory experiments to earthquake dynamics, and studies on earthquake scaling properties. Of particular interest are innovative studies on quantifying the uncertainties in earthquake source-parameter estimation.
Within this framework our session also provides a forum to discuss case studies of field observation, kinematic and dynamic source modeling of recent significant earthquakes.

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 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 progess in our understanding of the most important parameters affecting tsunamigenesis. For example, unexpectedly large slip was observed during the 2011 Tohoku-Oki earthquake, leading to re-investigations of the geology of other subduction zones and the conditions that can lead to large slip at the trench.

In general, the large amount of geophysical data recorded at present has led to new descriptions of faulting and rupture complexity (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. Analog modellers now have apparati that simulate multiple seismic cycles with unprecedented realism. These represent a valuable tool for investigating how various boundary conditions (e.g., frictional segmentation, interplate roughness) influence the seismic behavior of subduction megathrusts. In addition, advances in numerical modelling now allow scientists to test how new geophysical observations, e.g. from 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 individuate how the 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.

Recent catastrophic earthquakes have highlighted the importance of advancing seismic hazard models over a wide range of time frames, for example to support more reliable building codes and to track the short-term evolution of seismic sequences. Over the past years, the exponential growth of ground-motion data, short- and long-term forecasting models, hazard model test results, new engineering needs, and progress in research on earthquake predictability and ground-motion processes are creating a strong motivation for the exploration and incorporation of new concepts and methods into the next generation of probabilistic forecasts, both for long-term probabilistic seismic hazard assessment (PSHA), and operational earthquake forecasting. Owing to the important societal impact, any forecasting model has to be scientifically reliable. Prospective modeling is the best way of testing alternate hypotheses and models, and hence advancing our scientific understanding of the processes involved. Pragmatically, prospective testing provides an essential scientific contribution to improving the capacity to manage seismic hazard and risk in a wide range of forecasting time windows, for a broad range of stakeholders, including vulnerable societies. The development of such new and innovative long- and short-term forecasting/hazard models is a necessary but insufficient step: major advances in forecasting and hazard assessment require a solid testing phase that allows for model evaluation and quantifies any increase in forecasting skill over a benchmark model. 

We solicit contributions related to new developments in all aspects of long- and short-term seismic hazard and earthquake forecasting models:
   • Definition of earthquake sources and determination of activity rates and their uncertainty, including assessment of earthquake datasets, calibration of magnitude scales, representation of seismogenic sources and their geological constraints, and the emerging roles of strain and simulation-based earthquake-rupture forecasts.
   • Development of innovative earthquake forecasting models with forecast horizons of days to decades.
   • Estimation of strong ground motions and their uncertainty, development of new ground-motion models, assessment of site effects, the consideration of new parameters to characterize the intensity of shaking, and potential insights and uses of physics-based simulations of ground shaking. 
   • Testing and evaluation of hazard and earthquake forecasting models including statistical tests of 
activity rates, earthquake occurrence, calibration of ground-motion models, hazard-model parameterization and implementation, sensitivity analyses of key parameters and results, as well as the development of innovative testing procedures.
   • Case studies of PSHA from Europe and around the globe. 
   • Model building processes and related uncertainties, formal elicitation of expert opinion and its consequences for the levels of knowledge or belief, and comprehensive treatment of aleatory and epistemic uncertainties.
   • Contributions related to the ongoing update of the Harmonized European Seismic Hazard model and the emerging EPOS infrastructure on hazard and risk.
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The use of fibre technologies for geophysical applications is expanding since few years. The design of highly sensitive sensors, such as rotational seismometers or strainmeters is one approach. In addition, initiatives such as SMART cables systems aim at piggy-backing environmental sensors onto submarine repeater units in order to improve sensor coverage across the oceans The use the fibre itself as a distribution of sensors for temperature or strain distributed sensing is an alternative. The vast majority of all telecommunications data (99%) transit through submarine and land-based fibre-optic cables. As the need for larger bandwidth and more rapid transmission has increased, so do the global networks of cables encircling the Earth. They now cover even remote regions of most continents and oceans. There have been significant advances in cable design and manufacturing technology, as well as cable deployment procedures. In very recent years there have been significant breakthroughs, applying techniques developed to interrogate the cables at very high precision over very large distances. For example, laser reflectometry using DAS (Distributed Acoustic Sensing) on both dedicated experimental and commercial fiber optic cables onshore and in submarine environment have successfully detected a variety of seismic sources (including ambient noise (microseism), local and teleseismic earthquakes, volcanic events, etc.). Other laser reflectometry techniques have long been used for monitoring of large-scale engineering infrastructures (dams, tunnels, bridges, pipelines, boreholes, etc.) and recently have been applied to natural hazard studies on land (monitoring of landslides or karst sinkholes) and have broader applications to the study of faults for instance. We welcome contributions that involve the application of fiber-optic cables or sensors in seismology, geodesy, geophysics, natural hazards, etc. from the laboratory to large-scale field tests.
We are delighted to have an Invited Speaker: Giuseppe Marra

Induced and triggered seismicity are common phenomena associated with sub-surface exploration and remote seismic events, respectively, and have been related to hydrocarbon extraction, hydraulic fracturing, geothermal exploitation, open-pit crater formation and underground mining operations, CO2 sequestration, and filling of new water reservoirs. Public awareness and concern of induced seismicity has become ubiquitous in locations where subsurface exploration and storage is carried out in close proximity to communities. Of particular concerns are massive fluid injections for hydro-fracturing to increase subsurface permeability as well as long-term injection in disposal wells. These concerns have led to regulations to passively monitor induced seismicity and consequently to a wealth of continuous seismic data. In contrast to the increase in data volume, our understanding of the relationship between exploitation techniques and induced seismicity as well as earthquake-earthquake interactions is still limited. New processing methods to analyze data and quantitative models to improve our understanding of the causal relationship between exploitation and seismicity have been developped. The current session is intended to provide a platform to present the latest research, field studies, theoretical and modelling aspects as well as methods for seismic hazard analysis related to induced and triggered seismicity. Topics to be presented include spatio-temporal variations of physical parameters in reservoirs and natural environments including stress and pressure changes, spatial-temporal patterns of seismicity, source mechanisms of micro- or larger-scale seismicity, mechanisms for induced events and seismic interaction, as well as, fracture-induced anisotropy. Contributions are sought from fundamental and applied research covering the fields of oil and gas operations including hydro-fracturing, geothermal exploitation particularly related to enhanced geothermal systems, open pit and underground mining, CO2 storage, and other fields such as volcano-seismology where induced and triggered seismic activity is observed.

Many new high quality and high resolution geophysical and geological data had been acquired in the past years that need to be updated, re-analysed and re-interpreted in the light of our present knowledge in subductions processes. Moreover it is needed to better clarify the temporal and spatial evolution of those processes in order to much precise our geodynamic ideas of mountain building, subduction, transition of collision to subduction, or transition of subduction to collision.
Among other global places, the zone from Japan, Taiwan to the Philippines is a key area to study such subduction/collision transition due to the rapid convergence between Eurasian and Philippine Sea plates. There are geodynamic inversion of the east dipping Manila oceanic subduction, that evolves northward, first, into a Continental Subduction (also called Collision) onshore Taiwan, then secondly, east of Taiwan, into the north dipping Ryukyu arc/continent subduction. Due to the so rapid Plates shortening rate (10cm.y-1), those active Oceanic to Continental Subductions processes in Taiwan creates 1/8 of the annual seismicity in the World !
There are other places in the World active or not, that should also be taken into careful consideration in order to reveal and lead us to better understand new tectonic processes (e.g.: Alpes, Pyrénées, Cascades and so on).
To conclude in this EGU session, we aim to update the existing geodynamic state of the art of the oceanic to continental subductions processes after so numerous data that had been collected recently and all the works that had been done on this subject. Therefore this EGU Session should help us to much better understand the tectonics related to plate, plate collision and the transition between the subduction and collision.

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 not only constraining earthquake source parameters but also the identification of 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. Based on the this rich, but very heterogeneous knowledge of seismogenic faults, a variety of approaches have been developed to tranfer earthquake-fault geology into fault models suitable for probabilistic SHA. This session thus aims at linking field geologists, crustal deformation modellers, fault modellers, and seismic hazard practitioners.

In this session, we welcome contributions describing and critically discussing different approaches to study active faults. We are particularly interested in studies applying new and innovative methodological or multidisciplinary approaches. We hope to assemble a broad program bringing together studies dealing with on-land, lake or offshore environments, and applying a variety of methods such as traditional paleoseismic trenching, high-resolution coring, geophysical imaging, tectonic geomorphology, and remote sensing, as well as the application of earthquake geology in seismic hazard assessments. In addition, we encourage contributors describing how to translate fault data or catalogue data into fault models for SHA , and how to account for faults or catalogue issues.

Our first-order understanding of earthquake cycles is limited by our ability to detect and interpret natural phenomena or their relict signatures on faults. However, such observations allow us to define fundamental hypotheses that can be tested by way of experiments and models, ultimately yielding deeper insights into mechanics of faulting in nature. Inter-, co-, and post-seismic deformation can be documented geodetically, but the sparseness of the data and its large spatial and temporal variability do not sufficiently resolve their driving mechanisms. Laboratory experiments under controlled conditions can narrow down the possibilities, while numerical modelling helps extrapolating these results back to natural conditions. Thus, integrated approaches to bridge long-term tectonics and the earthquake cycle that combine observation, interpretation, experimentation, and finally, physical or numerical modelling, are key for our understanding of the deformation behaviour of complex fault systems.

This session seeks contributions toward an integrated perspective on the earthquake cycle that span a wide range of observations, methodologies, and modelling over a variety of spatial and temporal scales. Presentations can cover brittle and ductile deformation, from microstructures to mantle rheology and with applications to earthquake mechanics, geodynamics, geodesy, geohazards, and more. Specific questions include: How do long-term crustal and lithospheric deformation affect short-term seismicity and earthquake cycle behaviour? What is the long-term topographic signature of the earthquake? What are the relative contributions of rheology and geometry for seismic and aseismic slip? What are the roles of on- and off-fault deformation in shaping the landscape and partitioning seismic and aseismic energy dissipation? We welcome submissions by early-career scientists in particular.

— Invited speaker: Luc L Lavier, Jackson School of Geosciences | The University of Texas at Austin

Earthquakes that occur within regions of slow lithospheric deformation (low-strain regions) are inherently difficult to study. The long interval between earthquakes, coupled with natural and anthropogenic modification, limit preservation of paleoearthquakes in the landscape. Low deformation rates push the limits of modern geodetic observation techniques. The short instrumental record challenges extrapolation of small earthquake recurrence based on modern seismological measurement to characterize the probability of larger, more damaging earthquakes. Characterizing the earthquake cycle in low-strain settings is further compounded by temporal clustering of earthquakes, punctuated by long periods of quiescence (e.g. non-steady recurrence intervals). However, earthquakes in slowly deforming regions can reach high magnitudes and pose significant risk to populations.

This session seeks to integrate paleoseismic, geomorphic, geodetic, geophysical, and seismologic datasets to provide a comprehensive understanding of the earthquake cycle in low-strain regions. This session 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. 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.