Explore the vast range of titles available.

Back analysis for evaluation of the merits of the short-term seismic hazard indicators (precursors) used in the mines and their potential application for early warning was carried out for fourteen seismic events that potentially caused damage in Kiirunavaara Mine, Sweden, selected according to our designed criteria. Five short-term hazard indicators: Seismic Activity Rate (SAR), Cumulative Seismic Moment (CSM), Energy Index (EI), Cumulative Apparent Volume (CAV) and Seismic Apparent Stress Frequency (ASF) were tested. The behaviour of the indicators was studied using the parameters of all seismic events within a sphere around the hypocenter location of the analyzed seismic source within one month before the main (damaging) event. The size of the sphere equals the estimated radius of the analyzed seismic source (area of inelastic deformation). mXrap software (Australian Centre for Geomechanics) was used for data visualization, manipulation, analysis and extraction. The results from the main analysis showed a good agreement between the expected and actual behaviour of the SAR, CSM and CAV indicators. In overall, CSM and CAV ranked the highest positive/expected behaviour followed by SAR (Table 3). The EI and ASF ranked lowest and showed to be sensitive to the number of events within the source sphere. The rate of false warnings and missed warnings was also investigated for the 25 days-long period before the damaging events. A similar trend was observed as for the main analysed event. The results from this study can be used for further improvement of the short-term hazard estimations and early warning system in deep underground mines.

In geophysical inverse problems, the distribution of physical properties in an Earth model is inferred from a set of measured data. A necessary step is to select data that are best suited to the problem at hand. This step is performed ahead of solving the inverse problem, generally on the basis of expert knowledge. However, expert‐opinion can introduce bias based on pre‐conceptions. Here we apply a trans‐dimensional algorithm to automatically weigh data on the basis of how consistent they are with the fundamental hypotheses made to solve the inverse problem. We demonstrate this approach by inverting arrival times for the location of a seismic source in an elastic half‐space, assuming a point‐source and uniform weights in concentric shells. The key advantage is that the data do no longer need to be selected by an expert, but they are assigned varying weights during the inversion procedure. Plain Language Summary In the Big data era, automated approaches to data evaluation are needed for two main reasons: to be able to process a large amount of data in a limited time, and to avoid bias introduced by data analysists. In this study we present a novel approach to data analysis, where the data themselves measure their consistency with our hypotheses. The approach is applied to earthquake location in mines, where millions of seismic events occur every year, and automatic processing of seismic data is mandatory. We demonstrate that our approach outperforms standard ones when almost nothing is known about the data and their measurement errors. Key Points We develop a novel approach for automatic weighting of data in geophysical inverse problems, based on a trans‐dimensional algorithm We apply the novel approach to seismic event location in mines, obtaining consistent results compared to a more standard method Our approach outperforms standard seismic monitoring approaches, when limited information are available on local seismic structure

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 ).

An amendment to this paper has been published and can be accessed via a link at the top of the paper.An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Aftershock series of even comparatively small seismic events can pose a risk to the mining operation or the personnel in deep underground mines as the main shocks and some of the aftershocks can cause damage in the rock mass. Stochastic modeling was applied in this study for the analysis of the temporal evolution of aftershock occurrence probability during a M1.85 aftershock sequence in Kiirunavaara Mine, Sweden. The Restricted Epidemic-Type Aftershock Sequence (RETAS) model was chosen for estimation of the aftershock occurrence probability. This model considers all events with magnitude above the magnitude of completeness M0 and has the advantage of including the Modified Omori Formula (MOF) model and Epidemic-Type Aftershock Sequence (ETAS) model as its end versions, considering also all intermediate models. The model was applied sequentially to data samples covering cumulative periods of time, starting from the first 2 h after the main event and increasing them by 2 h until the period covered the entire 72-h sequence. For each sample, the best-fit RETAS version was identified and the probability of a M ≥ 0.5 aftershock for every next 2 h was determined through Monte Carlo simulation. The feasibility of the resulting probability evolution for suspension and re-starting of the mining operations was discussed together with possible prospects for future development of the methodology.

Forty-six mining-induced seismic events with moment magnitude between −1.2 and 2.1 that possibly caused damage were studied. The events occurred between 2008 and 2013 at mining level 850–1350 m in the Kiirunavaara Mine (Sweden). Hypocenter locations were refined using from 6 to 130 sensors at distances of up to 1400 m. The source parameters of the events were re-estimated using spectral analysis with a standard Brune model (slope −2). The radiated energy for the studied events varied from 4.7 × 10 −1 to 3.8 × 10 7 J, the source radii from 4 to 110 m, the apparent stress from 6.2 × 10 2 to 1.1 × 10 6 Pa, energy ratio ( E s / E p ) from 1.2 to 126, and apparent volume from 1.8 × 10 3 to 1.1 × 10 7 m 3 . 90% of the events were located in the footwall, close to the ore contact. The events were classified as shear/fault slip (FS) or non-shear (NS) based on the E s / E p ratio (>10 or <10). Out of 46 events 15 events were classified as NS located almost in the whole range between 840 and 1360 m, including many events below the production. The rest 31 FS events were concentrated mostly around the production levels and slightly below them. The relationships between some source parameters and seismic moment/moment magnitude showed dependence on the type of the source mechanism. The energy and the apparent stress were found to be three times larger for FS events than for NS events.

Using original seismograph records and bulletin data we re-determined theorigin time, location, seismic moment (M^sub 0^) and magnitudes(M^sub S^ and M^sub w^) for four earthquakes in the beginning of the20th century. These are two strong earthquakes April 4, 1904 nearKrupnik, Bulgaria (M^sub w^ = 6.8, M^sub S^ = 7.2 respectively), the April 231909 earthquake near Benavente, Portugal (M^sub S^ = 6.3), and the June14, 1913 earthquake near Gorna Orjahovitza, Bulgaria (M^sub S^ = 6.3).Twenty-nine traces from original records have been analysed, a largenumber of original station bulletins have been consulted and a consistentmethodology for analysing these early 20th century instrumentalinformation is presented.In spite of a thorough effort in re-assembling and quality control of theoriginal data, large inaccuracies remain in the improved instrumentalepicentre locations and origin times. The seismic moment estimates weobtained (2.3 10^sup 18^ ≤ M^sub 0^ ≤ 3.9 10^sup 19^Nm) are the first ever determined for these events. The magnitudeestimates (6.3 ≤ M^sub S^ ≤ 7.2 and 6.2 ≤ M^sub w^≤ 7.0) are robust and systematically lower than most of previousestimates for all earthquakes (Gutenberg and Richter, 1954; Christoskovand Grigorova, 1968; Karnik, 1969). For the largest Krupnik event ourestimates agree with those of Abe and Noguchi (1983b) and Pacheco andSykes (1992). The studied earthquakes all occur in moderately seismicactive regions, therefore our results may have significant consequences forhazard estimates in those regions.[PUBLICATION ABSTRACT]