Exploring the application of Characteristic Functions on DAS data and their influence in event detection performance.

• DOI: 10.5194/egusphere-egu24-10893
• Publication Date: 2024-03-08T20:55:33Z
• Authors: Sonja Gaviano; Giacomo Rapagnani; Davide Pecci; Juan Porras; Estelle Rebel; Francesco Grigoli
• Keywords: Event data

Distributed Acoustic Sensing (DAS) has emerged as a powerful tool in seismological applications, transforming fiber-optic cables into dense arrays of geophones that can continuously sample seismic wavefields across several kilometers. DAS data acquisition presents versatile approach, utilizing either ad hoc installations with specific or leveraging existing telecommunication optical fiber-network infrastructure. Its adaptability makes particularly advantageous for monitoring logistically challenging environments like volcanoes offshore areas, where traditional seismometers may face limitations.   Conventional techniques struggle to effectively process due its unique characteristics—typically, are sampled at 1 m spacing frequencies exceeding kHz. As result, this technology provides detailed mapping the wavefield length fiber, and it also generates significant amount compared sparse seismometer installations. In order efficiently analyze these data, we introduced HECTOR, waveform-based detection method designed specifically (Porras et al. 2024). study, investigate capabilities HECTOR following preprocessing using various characteristic functions (CF). We explore non-negative functions, including Short Term Average Long (STALTA), Energy, Envelope, whose peculiarity is preserve noise. Conversely, zero-mean such derivative (STALTA derivative), Kurtosis, Kurtosis enhance signals mitigate Our objective assess HECTOR's performance when analyzing preprocessed raw data. To validate our findings, initially test detector on synthetic These simulations encompass diverse fiber geometries, source configurations, locations. Subsequently, apply algorithm real collected two distinct scenarios. The first scenario involves FORGE experiment situated Utah, US, which entails borehole installation km deployed above geothermal reservoir characterized by induced activity. second 90 horizontal Pyrenees region. area natural earthquake activity magnitudes (2.01≥ML≥0.02), alongside anthropic events quarry blasts.  evaluation focuses quantifying enhancement application CFs Through comprehensive exploration, aim advance understanding processing, demonstrating efficacy scenarios.  would thank TotalEnergies sharing set us well Febus Optic providing interrogator used acquisition. References:  A Semblance-based Microseismic Event Detector Data. Porras, D. Pecci, G. Bocchini, S. Gaviano, M. De Solda, K. Tuinstra, F. Lanza, A. Tognarelli, E. Stucchi, Grigoli. Geophysical Journal International (GJI) 2024 (Accepted)