Evaluation of the Grillo sensor, a low-cost accelerometer for IoT-based Real-time seismology

Micro-Electro-Mechanical (MEMS) accelerometers are useful for real-time seismology due to their ability to record strong, unsaturated seismic signals. Recent advances in MEMS technologies enable design of instruments with improved capabilities that also allow recording of small signals. As a result, MEMS can be useful across a broad dynamic range and for both major earthquakes and smaller magnitude events. Leveraging improved capabilities from off-the-shelf components, we demonstrate a new, low-cost MEMS-based accelerometer that provides an optimal tradeoff between instrument cost and performance. This article analyzes the instrument's performance in a regional network deployed in southern Mexico over a period of 3+ years for the purpose of earthquake early warning. We discuss the self-noise level, dynamic range, and useful resolution, and compare these parameters to other MEMS-based instruments. Besides the sensor evaluation, we present a large, openly available dataset of strong motion data that comprises continuous ground motion records from 24 instruments since 2017.