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A new method is introduced to determine the top and bottom depth of a vertical line using gravity anomalies. For this, gravity at a distance x from the origin and horizontal derivative at that point are utilized. A numerical value is obtained dividing the gravity at point x by horizontal derivative. Then a new equation is obtained dividing the theoretical gravity equation by the derivative equation. In that equation, assigning various values to the depth and length of vertical line, several new numerical values are obtained. Among these values, a curve is obtained for the one that is closest to the first value from attending the depth and length values. The intersection point of these curves obtained by repeating this procedure several times for different points x yield the real depth and length values of the line. The method is tested on two synthetics and field examples. Successful results are obtained in both applications.

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In this study, using the aftershocks that occurred after the March 02, 2017 Adıyaman-Samsat Earthquake (Ml = 5.7) statistical analyzes of b-value and aftershock decay parameter p-value were performed. 1345 aftershocks compiled from the catalogs of the Kandilli Observatory and Earthquake Research Institute (KOERI) and the Disaster & Emergency Management Authority (AFAD) were homogenized according to the local magnitude Ml. Afterwards, the completeness magnitude Mc=1.6 was obtained with the moving time window approach and using maximum likelihood method, b-value was calculated as 0.768±0.03 for the whole region. This value is close to the expected 1 for b for tectonic earthquakes and is consistent with the Gutenberg-Richter relation. With modified Omori's Law p=0.91±0.05, c=0.041±0.030 and K=25.6±3.21 were calculated for the entire region. The p-value, which is thought to be related to crustal heterogeneity, heat flux and tectonic deformation, is less than 1, reflecting the relatively slow aftershock decay rate. Regional variation maps of b-and p-parameters were prepared by taking 450 earthquakes at each node point with 0.01 O x 0.01 O grid interval. The b-value was high in the northeast-southwest line of the March 02, 2017 (Ml=5.7) earthquake and low in the south-southeast of this earthquake. Besides the low b-value, the occurrence of the 24 April 2018 (Ml=5.4) earthquake in the region may foreshadow the increase in regional stress. Examining the regional variation of the p-value, the high p-value is in the north-northeast of the Adıyaman-Samsat earthquake and is almost consistent with the deformation region on the InSAR map given in literature.