Crustal Shear-Wave Velocity Distribution beneath the Biga-Peninsula (North Aegean) and its Correlation with Seismotectonic b-value

<p class="MsoNormal" style="margin-bottom:0cm;text-align:justify;text-justify:inter-ideograph;text-indent:35.4pt"><span lang="EN-US" style="font-size:12.0pt;line-height:115%;font-family:&quot;Times New Roman&quot;,serif;letter-spacing:.2pt;mso-ansi-language:EN-US">In this study, we aimed to investigate the crustalstructure and the associated future seismic hazards in the Biga-Peninsula(North Aegean) using algorithms known as P-eceiver function inversion and theGutenberg-Richter power-law relation. Firstly, to calculate the shear wavevelocity models, we selected 11 three-component strong motion seismic stationsoperated by the Disaster and Emergency Management Authority with approximately680 local earthquakes. The local earthquakes of magnitude ≥ 4.0 were at epicentraldistances between 30 and 100 km. Secondly, to estimate the distribution of theGutenberg-Richter <i>b</i>-value, weprepared the earthquake catalog using the compilation from the BoğaziciUniversity Kandilli Observatory and Earthquake Research Institute. Thishomogeneous catalog spans </span><span lang="EN-US" style="font-size:12.0pt;line-height:115%;font-family:Symbol;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;letter-spacing:.2pt;mso-ansi-language:EN-US;mso-char-type:symbol;mso-symbol-font-family:Symbol">~</span><span lang="EN-US" style="font-size:12.0pt;line-height:115%;font-family:&quot;Times New Roman&quot;,serif;letter-spacing:.2pt;mso-ansi-language:EN-US">105.12 years, between 1919 and2025. The distribution of <i>b</i>-value isexamined in depth intervals of 5 km up to 20 km. Through this process, <i>b</i>-value variations at different depthsare analyzed. These depths include 0-5, 5-10, 10-15, and 15-20 km intervals. Todetermine the changes in <i>b</i>-value forthese depth intervals, earthquakes occurring at these depths are utilized. Inorder to perform the inversion of receiver functions, we implemented threecritical steps: LQT ray coordinate system rotation, time-domain deconvolution,and stacking with moveout time corrections. Subsequently, we executed theiterative inversion algorithm using a method similar to Simulated Annealing.Stacking the receiver functions inverted for 0 km depth allowed us to createthe velocity-depth models beneath the selected stations. According to theS-wave velocity models, the Moho discontinuity is calculated to be approximately32 km deep, the Conrad discontinuity is estimated at around 19 km, and a thicksedimentary layer is found between 1 and 2 km. The crustal velocities aredetermined to be high, and the earthquakes that occurred at crustal depthsalign with the shear wave velocity distribution. Additionally, small <i>b</i>-values (&lt;1.0) are observed aroundthe south and southeast regions at a depth of 15 km, including Edremit Gulf,Havran-Balya Fault Zone, and Balıkesir Fault. While big <i>b</i>-values (&gt;1.0) are observed around the north and northeastregions at a depth of 5 km to 10 km, including the Sinekçi Fault, Manyas FaultZone, and Gündoğan Fault. Thus, this alignment suggests that seismic activityfor the Biga-Peninsula may continue in the future.&nbsp;<o:p></o:p></span>