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SUMMARY We examine and model analogue recordings from 6 early mechanical seismographs for the 1910 June 16 earthquake at Adra, Southern Spain. Modern standard, time‐domain analysis techniques were applied to the historical data to estimate the source parameters of the event: The regional sparse network data were inverted for the deviatoric seismic moment tensor. The best moment tensor solution corresponds to a M0= 1.50 · 1018 Nm, MW 6.1 oblique strike‐slip event at 16 km depth. Our preferred faulting solution is: strike 122°, dip 80°, rake −137°, in very good agreement with available neo‐ and seismotectonic data. The source time function of this earthquake was estimated by deconvolving recordings of a MW 5.5 aftershock that occurred the same day. The time function indicates a total rupture time of 4.5 s, corresponding to estimates for mainshock rupture length of 12 km, and stress drop of 29 bar.

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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 9 10 -1 to 3.8 9 10 7 J, the source radii from 4 to 110 m, the apparent stress from 6.2 9 10 2 to 1.1 9 10 6 Pa, energy ratio (E s /E p ) from 1.2 to 126, and apparent volume from 1.8 9 10 3 to 1.1 9 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.

Kiirunavaara (Kiruna) iron ore mine owned by LKAB (Sweden) is one of the largest underground mines. Mining started in 1898 as an open pit mine. In mid-1950, the mine started a transition to underground mining and passed to only underground mining in 1962. More substantial problems with seismicity started in 2007-2008 when the deepest mining level was 907 m (ca. 670 m below surface). By 2016, the mining production is at 1,022-1,079 m Level (ca. 785-845 m below surface). More than one billion tonnes of ore have been extracted since the beginning of mining. The average yearly production in recent years is 28 million tonnes. By 2016 the mine has the largest underground seismic system in the world with 204 operational geophones. The number of the sensors (geophones with natural frequencies of 4.5, 14, and a few of 30 Hz) changed with the increasing of production depth. The major stages with seismic system upgrades are: