Design and Calibration of an Affordable Seismic Monitoring System

Abstract

This paper presents the design, calibration, and
validation of a low-cost seismic monitoring system using an
ADXL335 Micro-Electro-Mechanical Systems (MEMS)
accelerometer, ADS1115 16-bit Analog-to-Digital Converter
(ADC), Raspberry Pi 4 Model B, and Long Range (LoRa)
SX1278 transceiver. A standardized one-dimensional shake
table, which simulates controlled ground motion, was used to
calibrate the system, providing a safe and repeatable
environment for evaluating the system. The monitoring system
was validated using the 2010 Chile (M8.8) and 2015 Gorkha
(M7.3) aftershock records, achieving Pearson correlation
coefficients of 0.8911 and 0.9010, respectively. A 4th-order
Butterworth bandpass filter (0.1–2.0 Hz) reduced out-of-band
noise, while LoRa communication achieved 100% packet
delivery with Received Signal Strength Indicator (RSSI) values
between −31 and −34 dBm at 10m distance. Costing under 20
USD per node, the proposed system provides an affordable and
scalable solution for dense seismic monitoring in earthquakeprone
developing regions.