Mining, water-reservoir impoundment, underground gas storage, geothermal energy exploitation and hydrocarbon extraction have the potential to cause rock deformation and earthquakes, which may be hazardous for people, infrastructure and the environment. Restricted access to data constitutes a barrier to assessing and mitigating the associated hazards. Thematic Core Service Anthropogenic Hazards (TCS AH) of the European Plate Observing System (EPOS) provides a novel e-research infrastructure. The core of this infrastructure, the IS-EPOS Platform (tcs.ah-epos.eu) connected to international data storage nodes offers open access to large grouped datasets (here termed episodes), comprising geoscientific and associated data from industrial activity along with a large set of embedded applications for their efficient data processing, analysis and visualization. The novel team-working features of the IS-EPOS Platform facilitate collaborative and interdisciplinary scientific research, public understanding of science, citizen science applications, knowledge dissemination, data-informed policy-making and the teaching of anthropogenic hazards related to georesource exploitation. TCS AH is one of 10 thematic core services forming EPOS, a solid earth science European Research Infrastructure Consortium (ERIC) (www.epos-ip.org).

Summary. Seismicity accompanying mining exploitation results from changes in the stress field in the rock mass near the mining excavations caused by human acti

Underground fluid injections result in rock mass fracturing. The associated environmental hazards in a significant part stem from a possibility for linking these fractures. The resultant crevices may allow for an undesired and hazardous fluid migration. We studied the fracture linking problem on data from a part of The Geysers geothermal field in California, USA. We parameterized seismic events by the distance between hypocenter and injecting well, by the angle between the position vector of hypocentre and the maximum horizontal stress direction and by the angle of rotation required to turn the event’s double-couple mechanism into the prevailing in this area faults’ orientation. To make these parameters comparable, we transformed them to equivalent dimensions. Based on distances between events in the transformed parameter space, we divided the seismic events into clusters. The percentage of potentially linked fractures in clusters was greater at low than at high injection rate.

Seismicity induced by geo-engineering operations may be hazardous for people, infrastructure and the environment. The crucial information for assessing induced seismic hazards and related risks is knowledge of the time-dependent strength of rocks and the deformation due to fluid injection. Our studies of seismic and injection data from a geothermal field indicate that pressurized injections lead to rock fracturing at stress levels below the rock toughness, i.e., subcritical fracture growth. We provide a relation between the rate of this subcritical fracture growth and the injection rate. Based on this relation, we estimate the maximum subcritical magnitude. We hypothesize that subcritical fracture growth may be controlled by the amount of stress asymmetry, i.e., the relative values of the principal stresses. We discuss the conditions under which the subcritical fracturing regime can transform to a critical state and critical rupture may occur. We present the possibility of using these results in the operational reservoir to manage seismic hazards.

A series of six seismic events that occurred in one panel of Rudna copper-ore mine in Poland is studied. Although the events had comparable magnitudes, from 3.0 to 3.7, their ground effects were very diverse. Comparing the accelerations observed at various locations with their estimates from ground motion prediction equation the events split into three distinct pairs. The first pair ground effects exceed considerably the estimates at most of observation points, the second pair effects are abnormally high at short epicentral distances, whereas the third pair effects are much less than the estimates at most of observation points. The similarities in ground effects correlate with the fault mechanisms similarities. The first two pairs’ events, whose ground effects were strong, exhibit thrust faulting and the third pair events, which caused unexpectedly low ground motion exhibit normal faulting mechanisms. The paired events have also similar apparent stress values. These stress values of the two events of very weak ground effects are distinctly lower than the values of other four events. All events demonstrate dominating non-double-couple components in the overall mechanisms. A kinematic source analysis indicates that these events have extended rather than point sources, and five of them have distinct directivity effects. A static stress transfer analysis signifies interrelations between these events. The rupture of all events started in areas of Coulomb failure function increase due to the cumulative effect of previous events. Linking results of the ground effects, source, rupture and interaction analyses tentative geodynamic conclusions are formulated. The untypical and diverse ground effects of the studied events result likely from the events’ complexity expressed by tensile source mechanisms, finite sources, directivity of ruptures and nearly horizontal rupture planes. The above features seem to be implied by a superposition of coseismic alterations of stress field and stress changes due to mining. One cannot, therefore, exclude the possibility of other cases of significant deviations from the expected ground motion amplitudes, due to specific geodynamics in another parts of the mine. An analysis like that done within this work can allow, however, foreseeing such extreme surface impacts.

Deep underground water injections induce seismicity. When the seismic fractures coalesce into far‐reaching pathways for fluid migration, the migrating fluid may reach preexisting faults and, by decreasing fault strength, can trigger major seismic events. We assume that the potential for building such pathways depends on closeness of hypocenters, similarity of fracture planes orientations, and closeness of radii taking off from the injection point, on which events locate. We define this potential as the average distance between seismic events in the space of parameters quantifying the above conditions. We show that in the studied case from The Geysers geothermal field, this potential is highly correlated with injection rate. When the overall level of injection rate is high, the higher the injection rate is, the more the potential for building far‐reaching pathways for fluid migration is reduced.