# Integrating fiber-optic seismic arrays into earthquake early warning systems with the dEPIC framework

## TL;DR

This paper introduces dEPIC, a new system that uses fiber-optic cables to detect earthquakes and improve early warning systems, especially in offshore areas.

## Contribution

The first operational DAS-integrated EEW framework, dEPIC, is introduced for real-time earthquake detection using fiber-optic seismic arrays.

## Key findings

- dEPIC accurately detected onshore and offshore earthquakes with sub-second processing time.
- The system's modular design supports future DAS deployments to enhance existing EEW systems.
- Tests showed dEPIC's ability to operate independently or alongside existing algorithms like ShakeAlert’s EPIC.

## Abstract

Distributed Acoustic Sensing (DAS) can enhance earthquake early warning (EEW) by transforming existing fiber-optic cables into dense seismic arrays, including in offshore areas with sparse instrumentation. We present dEPIC (DAS–Earthquake Point-source Integrated Code), the first operational DAS-integrated EEW framework, deployed on a submarine cable in Monterey Bay, California, and designed to operate independently or jointly with ShakeAlert’s EPIC algorithm. dEPIC combines GPU-accelerated machine-learning phase picking, grid-search location, and empirical magnitude estimation, with real-time quality metrics to suppress unstable solutions. In event replays and continuous data tests, dEPIC detected both onshore and offshore earthquakes accurately with sub-second processing time. The modular, edge-computing design enables adaptation to future DAS deployments to improve existing EEW systems like ShakeAlert.