TY - JOUR
T1 - Temporal variations of the fractal properties of seismicity in the western part of the north anatolian fault zone
T2 - Possible artifacts due to improvements in station coverage
AU - Öncel, A. O.
AU - Alptekin, null
AU - Main, I.
PY - 1995/1/1
Y1 - 1995/1/1
N2 - Seismically-active fault zones are complex natural systems exhibiting scale-invariant or fractal correlation between earthquakes in space and time, and a power-law scaling of fault length or earthquake source dimension consistent with the exponent b of the Gutenberg-Richter frequency-magnitude relation. The fractal dimension of seismicity is a measure of the degree of both the heterogeneity of the process (whether fixed or self-generated) and the clustering of seismic activity. Temporal variations of the b-value and the two-point fractal (correlation) dimension Dc have been related to the preparation process for natural earthquakes and rock fracture in the laboratory. These statistical scaling properties of seismicity may therefore have the potential at least to be sensitive ' short-term predictors of major earthquakes. The North Anatolian Fault Zone (NAFZ) is a seismically active dextral strike slip fault zone which forms the northern boundary of the westward moving Anatolian plate. It is splayed into three branches at about 31°E and continues westward toward the northern Aegean sea. In this study, we investigate the temporal variation of Dc and the Gutenberg-Richter b-value for seismicity in the western part of the NAFZ (including the northern Aegean sea) for earthquakes of Ms ≥ 4.5 occurring in the period between 1900 and 1992. b ranges from 0.6-1.6 and Dc from 0.6 to 1.4. The b-value is found to be weakly negatively correlated with Dc (r=-0.56). However the (log of) event rate N is positively correlated with b. with a similar degree of statistical significance (r=0.42), and negatively correlated with Dc (r=-0.48). Since N increases dramatically with improved station coverage since 1970, the observed negative correlation between b and Dc is therefore more likely to be due to this effect than any underlying physical process in this case. We present this as an example of how man-made artifacts of recording can have similar statistical effects to underlying processes.
AB - Seismically-active fault zones are complex natural systems exhibiting scale-invariant or fractal correlation between earthquakes in space and time, and a power-law scaling of fault length or earthquake source dimension consistent with the exponent b of the Gutenberg-Richter frequency-magnitude relation. The fractal dimension of seismicity is a measure of the degree of both the heterogeneity of the process (whether fixed or self-generated) and the clustering of seismic activity. Temporal variations of the b-value and the two-point fractal (correlation) dimension Dc have been related to the preparation process for natural earthquakes and rock fracture in the laboratory. These statistical scaling properties of seismicity may therefore have the potential at least to be sensitive ' short-term predictors of major earthquakes. The North Anatolian Fault Zone (NAFZ) is a seismically active dextral strike slip fault zone which forms the northern boundary of the westward moving Anatolian plate. It is splayed into three branches at about 31°E and continues westward toward the northern Aegean sea. In this study, we investigate the temporal variation of Dc and the Gutenberg-Richter b-value for seismicity in the western part of the NAFZ (including the northern Aegean sea) for earthquakes of Ms ≥ 4.5 occurring in the period between 1900 and 1992. b ranges from 0.6-1.6 and Dc from 0.6 to 1.4. The b-value is found to be weakly negatively correlated with Dc (r=-0.56). However the (log of) event rate N is positively correlated with b. with a similar degree of statistical significance (r=0.42), and negatively correlated with Dc (r=-0.48). Since N increases dramatically with improved station coverage since 1970, the observed negative correlation between b and Dc is therefore more likely to be due to this effect than any underlying physical process in this case. We present this as an example of how man-made artifacts of recording can have similar statistical effects to underlying processes.
UR - http://www.scopus.com/inward/record.url?scp=84984399934&partnerID=8YFLogxK
U2 - 10.5194/npg-2-147-1995
DO - 10.5194/npg-2-147-1995
M3 - Article
AN - SCOPUS:84984399934
SN - 1023-5809
VL - 2
SP - 147
EP - 157
JO - Nonlinear Processes in Geophysics
JF - Nonlinear Processes in Geophysics
IS - 3-4
ER -