Moment Tensor Solution and Physical Parameters of Selected Recent Seismic Events at Rudna Copper Mine

2011 ◽  
pp. 11-19 ◽  
Author(s):  
Grzegorz Lizurek ◽  
Paweł Wiejacz
Keyword(s):  
Moment Tensor ◽  
Physical Parameters ◽  
Seismic Events ◽  
Copper Mine ◽  
Moment Tensor Solution

scholarly journals The 30 June 2017 North Sea Earthquake: Location, Characteristics, and Context

2020 ◽  
Vol 110 (2) ◽  
pp. 937-952
Author(s):  
Annie E. Jerkins ◽  
Hasbi Ash Shiddiqi ◽  
Tormod Kværna ◽  
Steven J. Gibbons ◽  
Johannes Schweitzer ◽  
...  
Keyword(s):  
North Sea ◽  
Moment Tensor ◽  
P Wave ◽  
Double Difference ◽  
High Signal ◽  
Seismic Events ◽  
S Wave ◽  
Surface Reflection ◽  
Moment Tensor Solution ◽  
Seismicity Pattern

ABSTRACT The Mw 4.5 southern Viking graben earthquake on 30 June 2017 was one of the largest seismic events in the Norwegian part of the North Sea during the last century. It was well recorded on surrounding broadband seismic stations at regional distances, and it generated high signal-to-noise ratio teleseismic P arrivals at up to 90° with good azimuthal coverage. Here, the teleseismic signals provide a unique opportunity to constrain the event hypocenter. Depth phases are visible globally and indicate a surface reflection in the P-wave coda some 4 s after the initial P arrival, giving a much better depth constraint than regional S-P time differences provide. Moment tensor inversion results in a reverse thrust faulting mechanism. The fit between synthetic and observed surface waves at regional distances is improved by including a sedimentary layer. Synthetic teleseismic waveforms generated based on the moment tensor solution, and a near-source 1D velocity model indicates a depth of 7 km. Correlation detectors using the S-wave coda from the main event were run on almost 30 yr of continuous multichannel seismic data searching for repeating signals. In addition to a magnitude 1.9 aftershock 33 min later, and a few magnitude ∼1 events in the following days, a magnitude 2.5 earthquake on 13 November 2016 was the only event found to match the 30 June 2017 event well. Using double-difference techniques, we find that the two largest events are located within 1 km of the main event. We present a Bayesloc probabilistic multiple event location including the 30 June event and all additional seismic events in the region well recorded on the regional networks. The Bayesloc relocation gave a more consistent seismicity pattern and moved several of the events more toward the west. The results of this study are also discussed within the regional seismotectonic frame of reference.

Regional Earthquake Magnitude Conversion Relations for the Himalayan Seismic Belt

2020 ◽  
Vol 91 (6) ◽  
pp. 3195-3207
Author(s):  
Rajiv Kumar ◽  
Ram Bichar Singh Yadav ◽  
Silvia Castellaro
Keyword(s):  
Moment Tensor ◽  
Earthquake Magnitude ◽  
Seismic Belt ◽  
Centroid Moment Tensor ◽  
Moment Tensor Solution ◽  
Magnitude Conversion ◽  
Magnitude Scales ◽  
Regression Relations ◽  
Regional Earthquake ◽  
Earthquake Magnitude Conversion

Abstract We present regional earthquake magnitude conversion relations among different magnitude scales (Mw, Ms, mb, ML, and MD) for the Himalayan seismic belt developed from data of local, regional, and international seismological agencies (International Seismological Centre [ISC], National Earthquake Information Centre [NEIC], Global Centroid Moment Tensor Solution [CMT], International Data Centre [IDC], China Earthquake Administration [BJI], and National Centre for Seismology [NDI]). The intra- (within the same magnitude scale) and inter- (with different magnitude scales) magnitude regression relations have been established using the general orthogonal regression and orthogonal distance regression techniques. Results show that the intra-magnitude relations for Mw, Ms, and mb reported by the Global CMT, ISC, and NEIC exhibit 1:1 relationships, whereas ML reported by the IDC, BJI, and NDI deviates from this relationship. The IDC underestimates Ms and mb compared with the ISC, NEIC, and Global CMT; this may be due to different measurement procedures adopted by the IDC agency. The inter-magnitude relations are established between Mw,Global CMT and Ms, mb, and ML reported by the ISC, NEIC, IDC, and NDI, and compared with the previously developed regional and global regression relations. The duration (MD) and local (ML) magnitudes reported by NDI exhibit a 1:1 relationship. The derived magnitude regression relations are expected to support the homogenization of the earthquake catalogs and to improve seismic hazard assessment in this region.

Neogene and active brittle deformation on Amorgos Island (Greece)

2020 ◽  
Author(s):  
Jan Behrmann ◽  
Jakob Schneider ◽  
Benjamin Zitzow
Keyword(s):  
Moment Tensor ◽  
Spatial Relationship ◽  
Shear Zones ◽  
Fault System ◽  
Normal Faults ◽  
Small Scale ◽  
Past Century ◽  
Fault Plane Solutions ◽  
Moment Tensor Solution ◽  
Late Neogene

<p>Amorgos is the south-eastern outpost of the Cyclades Islands in the Aegean Sea, which forms part of the Neogene-Quaternary zone of crustal and lithospheric N-S upper plate extension northward of the Hellenic subduction zone and deep sea trench. Apart from subduction-related earthquakes further south, the southern Aegean is affected by frequent earthquakes sourced in the upper plate. The twin earthquakes of 9 July 1956, followed by a strong tsunami, were the strongest events of this kind in the past Century. Hypocenters are related to a NE-SW oriented normal fault bounding the Amorgos-Santorini Graben System. There are questions in the literature regarding the seismic source and fault plane solutions, especially the contribution of a transcurrent faulting component.</p><p>We have analyzed the kinematics of brittle faults exposed on Amorgos Island itself that could be related to Neogene and active extensional and/or transcurrent deformation. Seismic slip often occurs on previously existing faults. Thus, their orientations and kinematics may help shed light on the structure of seismic sources at depth. We present evidence for a complex history of faulting. Early normal detachment faults and shear zones overprint older (rare) reverse faults, and are themselves overprinted by several sets of dominantly dextral NE and SE trending strike slip faults. Youngest is a conjugate set of NE trending high-angle normal faults. These are especially frequent along the SE coast of the island, suggesting a clear spatial relationship with the 1956 rupture. They can be fitted to a moment tensor solution similar to the published solutions for the 1956 Amorgos earthquake. The kinematic solution for the population of early normal faults suggests that the whole of Amorgos Island may have experienced a 15° NNW tilt during later extension, which lets us suspect that the island could be a tilted block of a much larger fault system. Regarding long-term late Neogene to Quaternary kinematics, dextrally transtensive fault slip is required to fit the regional pattern of extensional deformation in the Aegean, and this is reflected by small-scale brittle faulting on Amorgos.</p>

Source Time Function of Seismic Events at Rudna Copper Mine, Poland

2002 ◽  
Vol 159 (1) ◽  
pp. 131-144 ◽  
Author(s):  
B. Domański ◽  
S. J. Gibowicz ◽  
P. Wiejacz
Keyword(s):  
Time Function ◽  
Seismic Events ◽  
Source Time Function ◽  
Copper Mine

scholarly journals Characterisation of fault plane and coseismic slip for the May 2, 2020, Mw 6.6 Cretan Passage earthquake from tide-gauge tsunami data and moment tensor solutions

2021 ◽  
Author(s):  
Enrico Baglione ◽  
Stefano Lorito ◽  
Alessio Piatanesi ◽  
Fabrizio Romano ◽  
Roberto Basili ◽  
...  
Keyword(s):  
Tide Gauge ◽  
Moment Tensor ◽  
Early Warning Systems ◽  
Thrust Fault ◽  
Coseismic Slip ◽  
Moment Tensor Solution ◽  
Crete Island ◽  
Tsunami Forecasting ◽  
Oblique Convergence ◽  
Splay Fault

Abstract. We present a source solution for the tsunami generated by the Mw 6.6 earthquake that occurred on May 2, 2020, about 807thinsp;km offshore south of Crete, in the Cretan Passage, on the shallow portion of the Hellenic Arc Subduction Zone (HASZ). The tide-gauges recorded this local tsunami on the southern coast of Crete island and Kasos island. We used these tsunami observations to constrain the geometry and orientation of the causative fault, the rupture mechanism and the slip amount. We first modelled an ensemble of synthetic tsunami waveforms at the tide-gauge locations, produced for a range of earthquake parameter values as constrained by some of the available moment tensor solutions. We allow for both a splay and a back-thrust fault, corresponding to the two nodal planes of the moment tensor solution. We then measured the misfit between the synthetic and the observed marigrams for each source parameter set. Our results identify the shallow steeply-dipping back-thrust fault as the one producing the lowest misfit to the tsunami data. However, a rupture on a lower angle fault, possibly a splay fault, with a sinistral component due to the oblique convergence on this segment of the HASZ, cannot be completely ruled out. This earthquake reminds us that the uncertainty regarding potential earthquake mechanisms at a specific location remains quite significant. In this case, for example, it is not possible to anticipate if the next event will be one occurring on the subduction interface, on a splay fault, or on a back-thrust which seems the most likely for the event under investigation. This circumstance bears important consequences because back-thrust and splay faults might enhance the tsunamigenic potential with respect to the subduction interface due to their steeper dip. Then, these results are relevant for tsunami forecasting both in the framework of the long-term hazard assessment and of the early warning systems.

Sign in / Sign up

Export Citation Format

Share Document