On the Kola peninsula one of the strongest seismic events (MS 4.2)
in recent years occurred on 17 August 1999. The event was located
in the Lovozero Massif close to the city of Revda and the Umbozero
mining site. The Revda event was recorded with a temporary broadband
network in Finnmark (Masi region), northern Norway. Based on high-quality
three-component seismic data from this network we analyzed the event
by full waveform modeling using a frequency-wavenumber method. We
systematically varied the source depth, the size and orientation
of the fault plane, and the crustal velocity model and compared the
resulting synthetic seismograms with the observed data. The spectra
could be matched quite well with synthetics for a circular fault
plane of radius 1.6 km, an effective stress drop of 4.5 MPa, and
a seismic moment of 6.0 x 10^15 Nm. The source depth was estimated
to be about 5 km. The fault-plane solution is mainly characterized
by a reverse focal mechanism with strike 240 deg, dip 60 deg, and
rake 70 deg, consistent with first motions observed at 28 Fennoscandian
stations. The distinct dispersion of the observed data could be explained
by introducing a relatively strong shear-wave velocity gradient in
the uppermost crust.We think that the Revda event may have been influenced,
possibly even triggered, by the presence of the mine. The Lovozero
Massif has a distinct block structure with a northeast-southwest-oriented
fault system and a conjugated system in the north-west-southeast
direction associated and consistent with the regional north-northwest
compressional tectonic stress field. Long-term mining can redistribute
stress and initiate ruptures along favorably oriented faults, and
to this end our fault-plane solution is in agreement with an event
on the major Alluaiv fault of the northeast-southwest-oriented system.
Local inspections revealed that a rockburst occurred in a part of
the mine that was abandoned 10-20 years ago. This rockburst has also
a reverse fault mechanism, but with a shear plane striking perpendicular
to our solution. We therefore consider the observed rockburst as
a secondary effect. 10.1785/0120020015
%0 Journal Article
%1 roth_bungum:2003
%A Roth, M.
%A Bungum, H.
%D 2003
%I Seismological Society of America
%J Bulletin of the Seismological Society of America
%K geophysics seismology
%N 4
%P 1559--1572
%R 10.1785/0120020015
%T Waveform modeling of the 17 August 1999 Kola Peninsula earthquake
%U http://dx.doi.org/10.1785/0120020015
%V 93
%X On the Kola peninsula one of the strongest seismic events (MS 4.2)
in recent years occurred on 17 August 1999. The event was located
in the Lovozero Massif close to the city of Revda and the Umbozero
mining site. The Revda event was recorded with a temporary broadband
network in Finnmark (Masi region), northern Norway. Based on high-quality
three-component seismic data from this network we analyzed the event
by full waveform modeling using a frequency-wavenumber method. We
systematically varied the source depth, the size and orientation
of the fault plane, and the crustal velocity model and compared the
resulting synthetic seismograms with the observed data. The spectra
could be matched quite well with synthetics for a circular fault
plane of radius 1.6 km, an effective stress drop of 4.5 MPa, and
a seismic moment of 6.0 x 10^15 Nm. The source depth was estimated
to be about 5 km. The fault-plane solution is mainly characterized
by a reverse focal mechanism with strike 240 deg, dip 60 deg, and
rake 70 deg, consistent with first motions observed at 28 Fennoscandian
stations. The distinct dispersion of the observed data could be explained
by introducing a relatively strong shear-wave velocity gradient in
the uppermost crust.We think that the Revda event may have been influenced,
possibly even triggered, by the presence of the mine. The Lovozero
Massif has a distinct block structure with a northeast-southwest-oriented
fault system and a conjugated system in the north-west-southeast
direction associated and consistent with the regional north-northwest
compressional tectonic stress field. Long-term mining can redistribute
stress and initiate ruptures along favorably oriented faults, and
to this end our fault-plane solution is in agreement with an event
on the major Alluaiv fault of the northeast-southwest-oriented system.
Local inspections revealed that a rockburst occurred in a part of
the mine that was abandoned 10-20 years ago. This rockburst has also
a reverse fault mechanism, but with a shear plane striking perpendicular
to our solution. We therefore consider the observed rockburst as
a secondary effect. 10.1785/0120020015
@article{roth_bungum:2003,
abstract = {On the Kola peninsula one of the strongest seismic events (MS 4.2)
in recent years occurred on 17 August 1999. The event was located
in the Lovozero Massif close to the city of Revda and the Umbozero
mining site. The Revda event was recorded with a temporary broadband
network in Finnmark (Masi region), northern Norway. Based on high-quality
three-component seismic data from this network we analyzed the event
by full waveform modeling using a frequency-wavenumber method. We
systematically varied the source depth, the size and orientation
of the fault plane, and the crustal velocity model and compared the
resulting synthetic seismograms with the observed data. The spectra
could be matched quite well with synthetics for a circular fault
plane of radius 1.6 km, an effective stress drop of 4.5 MPa, and
a seismic moment of 6.0 x 10^15 Nm. The source depth was estimated
to be about 5 km. The fault-plane solution is mainly characterized
by a reverse focal mechanism with strike 240 deg, dip 60 deg, and
rake 70 deg, consistent with first motions observed at 28 Fennoscandian
stations. The distinct dispersion of the observed data could be explained
by introducing a relatively strong shear-wave velocity gradient in
the uppermost crust.We think that the Revda event may have been influenced,
possibly even triggered, by the presence of the mine. The Lovozero
Massif has a distinct block structure with a northeast-southwest-oriented
fault system and a conjugated system in the north-west-southeast
direction associated and consistent with the regional north-northwest
compressional tectonic stress field. Long-term mining can redistribute
stress and initiate ruptures along favorably oriented faults, and
to this end our fault-plane solution is in agreement with an event
on the major Alluaiv fault of the northeast-southwest-oriented system.
Local inspections revealed that a rockburst occurred in a part of
the mine that was abandoned 10-20 years ago. This rockburst has also
a reverse fault mechanism, but with a shear plane striking perpendicular
to our solution. We therefore consider the observed rockburst as
a secondary effect. 10.1785/0120020015},
added-at = {2012-09-01T13:08:21.000+0200},
author = {Roth, M. and Bungum, H.},
biburl = {https://www.bibsonomy.org/bibtex/2014cec511fce4d5136da21b4e2cb634a/nilsma},
day = 01,
doi = {10.1785/0120020015},
interhash = {385f605193f63342df5e5afc8fd4eeab},
intrahash = {014cec511fce4d5136da21b4e2cb634a},
issn = {1943-3573},
journal = {Bulletin of the Seismological Society of America},
keywords = {geophysics seismology},
month = aug,
number = 4,
pages = {1559--1572},
publisher = {Seismological Society of America},
timestamp = {2021-02-09T13:26:17.000+0100},
title = {Waveform modeling of the 17 August 1999 Kola Peninsula earthquake},
url = {http://dx.doi.org/10.1785/0120020015},
volume = 93,
year = 2003
}