36 research outputs found
Earthquake source parameters and scaling relationships in Hungary (central Pannonian basin)
Abstract Fifty earthquakes that occurred in Hungary (central
part of the Pannonian basin) with local magnitude ML
ranging from 0.8 to 4.5 have been analyzed. The digital
seismograms used in this study were recorded by six permanent
broad-band stations and twenty short-period ones at
hypocentral distances between 10 and 327 km. The displacement
spectra for P- and SH-waves were analyzed according
to Brune’s source model. Observed spectra were corrected
for path-dependent attenuation effects using an independent
regional estimate of the quality factor QS. To correct spectra
for near-surface attenuation, the k parameterwas calculated,
obtaining it fromwaveforms recorded at short epicentral distances.
The values of the k parameter vary between 0.01 to
0.06 s with a mean of 0.03 s for P-waves and between 0.01
to 0.09 s with a mean of 0.04 s for SH-waves. After correction
for attenuation effects, spectral parameters (corner
frequency and low-frequency spectral level) were estimated
by a grid search algorithm. The obtained seismic moments
range from4.21×1011 to 3.41×1015 Nm (1.7≤Mw ≤4.3).
The source radii are between 125 and 1343 m. Stress drop
values vary between 0.14 and 32.4 bars with a logarithmic
mean of 2.59 bars (1 bar = 105 Pa). From the results, a linear
relationship between local andmomentmagnitudes has been
established. The obtained scaling relations show slight evidence
of self-similarity violation. However, due to the high
scatter of our data, the existence of self-similarity cannot be
excluded