Direct Evidence of a Slow‐Slip Transient Modulating the Spatiotemporal and Frequency‐Magnitude Earthquake Distribution: Insights From the Armutlu Peninsula, Northwestern Turkey

Abstract

Earthquakes and slow‐slip events interact, however, detailed studies investigating their interplay are still limited. We generate the highest resolution microseismicity catalog to date for the northern Armutlu Peninsula in a ∼1‐year period to perform a detailed seismicity distribution analysis and correlate the results with a local, geodetically observed slow‐slip transient within the same period. Seismicity shows a transition of cluster‐type behavior from swarm‐like to burst‐like, accompanied by an increasing relative proportion of clustered (non‐Poissonian) relative to background (Poissonian) seismicity and gradually decreasing b‐value as the geodetically observed slow‐slip transient ends. The observed slow‐slip transient decay correlates with gradually increasing effective‐stress‐drop values. The observed correlation between the b‐value and geodetic transient highlights the influence of aseismic deformation on seismic deformation and the impact of slow‐slip transients on local seismic hazard.

WITHDRAWN: Geoelectric Structure of Yalova-termal Town Bymagnetotelluric Data, Northwestern Turkey

“…The NAF traces an old suture zone, the Intra-Pontide Suture Zone, that was occurred by collision of two continents during the Late Cretaceous (Şengör and Yılmaz, 1981;1997;Akbayram et al, 2013). The Armutlu PeninsulaBer has very dense and active seismicity (Bocchini et al, 2022, Pekşen et al, 2021, Kinscher et al, 2013. The peninsula located in the Eastern Marmara region is con ned by the northern and southern branches of the North Anatolian Fault (NAF) zone and is located at the western end of the rupture of the 1999 Izmit Earthquake (Mw = 7.4).…”

Sea Level Changes Affect Seismicity Rates in a Hydrothermal System Near Istanbul

“…To explore the relation between seismicity and sea level changes in the remaining three-month time period, we utilized an enhanced seismicity catalog for this region derived from a temporary seismic deployment in this area (SMARTNET network) containing up to 30 local stations (Bocchini et al, 2022a(Bocchini et al, , 2022bMartínez-Garzón et al, 2021; Figure 1b). We utilized both the entire catalog and a subset of it representing the background seismicity.…”

“…The aftershock sequence of the M W 4.3 event is shorter and the Omori fit is worse (Figure S7d in Supporting Information S1). We also utilized a declustered version of the SMARTNET catalog (Bocchini et al, 2022a) to cover the remaining time period (Figure S8 in Supporting Information S1). Utilizing these catalogs of background seismicity, the p-values from the Schuster test still allow to reject the null hypothesis at the defined significance level, except with the AI-derived catalog.…”

“…This time period includes a complex earthquake sequence that took place in the northern portion of the Armutlu Peninsula, with two M > 4 seismic events. The largest event, a M W 4.5 activated an onshore normal fault that hosted at least three periods of intense seismic activity over the following year (Bocchini, Martínez‐Garzón, et al., 2022; Martínez‐Garzón et al., 2021, see SMARTNET seismicity in Figure 1b). In this study, we generated enhanced seismicity catalogs using both AI‐based and template‐matching techniques, and compared the results with those from the standard catalogs.…”