graphic has been studied extensively because its regional variations reflect geological structure: values around 1 Hz show close correlation with tectonic seismicity. We analyze graphic in South Korea by applying the source pair/receiver pair (sprp) method to 39 Korean earthquakes and 32 far-regional earthquakes. We obtain nearly 1500 source-receiver pairs with the combined difference of epicentral distance, D, ranging from 16 to 657 km. Seismograms are filtered by using an eight-pole bandpass Butterworth filter with five-center frequencies. 0.375, 0.75, 1.5, 3, and 6 Hz. The obtained graphic for all frequencies are less than 0.002, which is a reasonable value for a seismically inactive region. In spite of the short range of D, the results of the sprp method show reliable values, especially at 1.5 and 3 Hz.

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