Automatic target recognition based on cross-plot

Automatic target recognition that relies on rapid feature extraction of real-time target from photo-realistic imaging will enable efficient identification of target patterns. To achieve this objective, Cross-plots of binary patterns are explored as potential signatures for the observed target by high-speed capture of the crucial spatial features using minimal computational resources. Target recognition was implemented based on the proposed pattern recognition concept and tested rigorously for its precision and recall performance. We conclude that Cross-plotting is able to produce a digital fingerprint of a target that correlates efficiently and effectively to signatures of patterns having its identity in a target repository.Kelvin Kian Loong Wong and Derek Abbot

The major asperities of the 1999 M-w=7.4 Izmit earthquake defined by the microseismicity of the two decades before it

We compare the rupture location of the M-w 7.4 Izmit earthquake to the local seismic hazard estimated by the technique of mapping local recurrence time, T-L, based on the microseismicity. After correcting for a magnitude shift in 1990, the declustered earthquake catalogue, produced by the University of Istanbul for the Marmara Sea region, is homogeneous for M(d)greater than or equal to2.9 during 1983-1999. We mapped T-L in the area bounded by 40 degrees -41 degrees latitude and 27.6 degrees -30.5 degrees longitude. T-L is the probabilistic estimate of recurrence time, calculated from the a- and b-values of the frequency-magnitude relation of the seismicity within a radius of 20 km from every point on a grid with 5 km spacing. T-L varies strongly as a function of space, since a- and b-values also vary strongly. In our interpretation, the 5-20 pet cent of locations with the shortest recurrence times map major asperities. In the Marmara region, we mapped four anomalies of short T-L, together covering about 12 per cent of the total area. They are centered near 40.25 degrees /29.4 degrees, 40.8 degrees /28.3 degrees, 40.75 degrees /28.8 degrees and 40.7 degrees /29.8 degrees. The last two of these coincide with the western end of the rupture and the epicentre location of the Izmit earthquake, respectively. Thus, we suggest that the major asperity of this rupture and a point past which it could not propagate were mapped out by the background seismicity during the years before the event as locations that produced more large microearthquakes than average, and hence showed anomalously short T-L The T-L method does not contain information about when earthquakes are expected, and the absolute values of the recurrence time could be inaccurate. The method only specifies the most likely locations of main shocks. Since the method is new, it will have to be tested for many cases and in many areas before its reliability can be assessed

The Dinar earthquake (M-w = 6.2; October 1, 1995; Afyon-Turkey) and earthquake hazard of the Dinar-Civril fault

A moderately strong earthquake (M-w,, = 6.2) occurred in the town of Dinar at 17.57 UT on October 1, 1995, taking the lives of 90 people and damaging about 4500 buildings. Its epicenter is located near the Dinar-Civril fault and its focal mechanism is linked to a northeast-southwesterly tensional stress field arising from the interaction between the subducting African plate and the overriding Aegean-Anatolian plate in the eastern Mediterranean

Spatial variations of the fractal properties of seismicity in the Anatolian fault zones

The Anatolian fault zones are seismically active strike-slip fault zones transcending the Anatolian plate in E-W and N-S directions. We investigate the spatial variations of seismicity along these zones in an attempt to investigate fault complexity along strike, quantified by the Gutenberg-Richter b-value and the fractal (correlation) dimension of earthquake epicentres, using the maximum likelihood method and the correlation integral, respectively. The investigation covers instrumentally recorded earthquakes of magnitude M > 4.5 occurring between 1900 and 1992. We find systematic spatial variations which may be related to structural or mechanical variability along strike. In particular the large change in strike at the northern apex of the North Anatolian Fault Zone is associated with the highest correlation dimension and lowest b-value for seismicity this century. The correlation dimension and b-value show a negative correlation with respect to each other, similar to results reported in other regional studies of Japan and southern California. This statistical correlation is stronger when more objective seismic zoning is carried out (based on number of events) rather than more subjective seismotectonic zoning in common use in seismic hazard analysis

Temporal variations in the fractal properties of seismicity in the North Anatolian Fault Zone between 31 degrees E and 41 degrees E

We investigate the nature of temporal variations in the statistical properties of seismicity associated with the North Anatolian Fault Zone between longitudes 31 degrees-41 degrees E during the instrumental period 1900-1992. Temporal variations in the seismic b value and the fractal (correlation) dimension D-c of earthquake epicenters are examined for earthquakes of magnitude M(S) greater than or equal to 4.5, using sliding windows of 100 consecutive events. b varies temporally between 0.6 and 1.0, and D-c between 0.6 and 1.4, both representing significant fluctuations above the errors in measurement technique. A strong negative correlation (r = -0.85) is observed between b and D-c, consistent with previous observation of seismicity in Japan and southern California. Major events early in this century (M(S) greater than or equal to 7) are associated with low b and high D-c, respectively consistent with greater stress intensity and greater spatial clustering of epicenters-both implying a greater degree of stress concentration at this time