Source parameters of seismic events potentially associated with damage in block 33/34 of the Kiirunavaara mine (Sweden)     

Emilia Nordström  Savka Dineva  Erling Nordlund 《Acta Geophysica》2017,65(6):1229-1242

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 × 10⁷ J, the source radii from 4 to 110 m, the apparent stress from 6.2 × 10² to 1.1 × 10⁶ Pa, energy ratio (E _s/E _p) from 1.2 to 126, and apparent volume from 1.8 × 10³ to 1.1 × 10⁷ m³. 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.  相似文献   

On the applicability of the RETAS model for forecasting aftershock probability in underground mines (Kiirunavaara Mine,Sweden)     

Gospodinov  Dragomir  Dineva  Savka  Dahnér-Lindkvist  Christina 《Journal of Seismology》2022,26(5):1023-1037

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.

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Source parameters of the M_W= 6.1 1910 Adra earthquake (southern Spain)     

Daniel Stich  Josep Batlló  Jose Morales  Ramon Macià  Savka Dineva 《Geophysical Journal International》2003,155(2):539-546

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Crustal thickness and V_P/V_S variations in the Grenville orogen (Ontario, Canada) from analysis of teleseismic receiver functions     

David W. Eaton  Savka Dineva  Robert Mereu 《Tectonophysics》2006,420(1-2):223

We have developed a simple semblance-weighted stacking technique to estimate crustal thickness and average V_P/V_S ratio using teleseismic receiver functions. We have applied our method to data from 32 broadband seismograph stations that cover a 700 × 400 km² region of the Grenville orogen, a 1.2–0.98 Ga Himalayan-scale collisional belt in eastern North America. Our seismograph network partly overlaps with Lithoprobe and other crustal refraction surveys. In 8 out of 9 cases where a crustal-refraction profile passes within 30 km of a seismograph station, the two independent crustal thickness estimates agree to within 7%. Our regional crustal-thickness model, constructed using both teleseismic and refraction observations, ranges between 34.0 and 52.4 km. Crustal-thickness trends show a strong correlation with geological belts, but do not correlate with surface topography and are far in excess of relief required to maintain local isostatic equilibrium. The thickest crust (52.4 ± 1.7 km) was found at a station located within the 1.1 Ga mid-continent (failed) rift. The Central Gneiss Belt, which contains rocks exhumed from deep levels of the crust, is characterized by V_P/V_S ranging from 1.78 to 1.85. In other parts of the Grenville orogen, V_P/V_S is found to be generally less than 1.80. The thinnest crust (34.5–37.0 km) occurs northeast of the 0.7 Ga Ottawa–Bonnechere graben and correlates with areas of high intraplate seismicity.  相似文献