← Back to Sessions

Apparent Large Seismic Velocity Variations Across the East Anatolian Fault, Turkiye

Description: 

We use aftershocks of the 6 February 2023 Mw 7.8 and Mw 7.6 Kahramanmaras (Turkiye) earthquake sequence that were and data recorded on nodal seismometers to develop 2D tomographic Vp and Vs models of the upper 12 km of the crust across the East Anatolian Fault (EAF) near Malatya, Turkiye. Nodal seismometers were deployed along an ~8-km-long, N-S-oriented profile, centered on the EAF, with nominal 0.5-km spacing. We used eight aftershocks (M2.1 to M2.9) that were aligned with the nodal array, and we developed velocity models using first-arrival P- and S-waves and local-network-based hypocenters. The resulting models show wide-ranging velocities (Vp = 5 to 7.5 km/s; Vs = 3.1 to 4.7 km/s) across the EAF in the upper 12 km of the crust, with higher velocities (Vp ~6 km/s to 7.5 km/s; Vs = 3.6 km/s to 4.7 km/s) north of the EAF and lower velocities (Vp ~5 km/s to 5.5 km/s; Vs ~3.1 km/s to 3.5 km/s) south of the EAF. Vp/Vs ratios are highest (1.8) directly beneath the fault at 7 to 11 km depth. Such large velocity variations make it difficult to accurately locate earthquakes using the network’s regional 1D velocity model. In addition, our velocity models are affected by the local network-determined hypocenters. As a result, we develop more detailed velocity models and earthquake locations using a combination of regional nodal seismometer data and network data.

Session: Innovative Applications of Seismic Nodal Technology for Hazard Mitigation and Earth System Monitoring [Poster]

Type: Poster

Date: 4/15/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Rufus

Student Presenter: No

Invited Presentation: 

Poster Number: 10

Authors