Integrating MEMS Accelerometers and Broadband Seismometers: Challenges and Opportunities in Modern Seismology

Seismology has seen growing interest in MEMS accelerometers — Micro-Electro-Mechanical Systems sensors — as an alternative or complement to traditional broadband seismometers. MEMS win on cost, size, and deployment flexibility, but they trade away performance at the low-frequency end. This article looks at how the two technologies can be integrated rather than pitted against each other.

Where MEMS shine

MEMS accelerometers have advanced remarkably, with some models showing excellent long-term stability and sensitivity suitable for gravimetry and seismology [1]. Because they’re cheap and small, you can deploy many of them — giving high spatial resolution, especially for higher-frequency phenomena, which makes them ideal for dense array deployments in local and regional studies [2].

Where broadband still wins

MEMS accelerometers still struggle to record long-period seismic waves. Broadband seismometers remain crucial for capturing low-frequency signals — the signals essential for global seismology and for imaging deep Earth structure [3]. Capturing those long-period waves doesn’t demand extremely dense station coverage, which is why broadband instruments fit their current role in sparse global networks.

The bandwidth and sensitivity gap

The primary challenge in replacing broadband seismometers with MEMS is bandwidth and sensitivity. Some MEMS accelerometers reach noise levels as low as 1.5 μg/√Hz [4], yet still fall short of high-end broadband instruments at low frequencies — a gap that matters most for phenomena like Earth tides or long-period surface waves. That said, the gap is narrowing: recent MEMS accelerometers report a dynamic range up to 110 dB and frequency responses extending from DC (0 Hz) to over 1000 Hz [5].

The hybrid future

Combining a backbone of high-quality broadband stations with dense arrays of MEMS sensors could leverage the strengths of both: unprecedented spatial resolution for local and regional studies and the ability to capture global-scale, long-period phenomena. Realizing that vision needs progress on a few fronts — data-fusion algorithms to combine heterogeneous sensor types, continued improvement of MEMS to extend their usable frequency range, and new deployment strategies for mixed-sensor networks.

Recap

Without scrolling up — can you state the tradeoff and the resolution?

• MEMS: cheap, small, dense, great at high frequency — but weak at long period.
• Broadband: sensitive, wide bandwidth, great at low frequency — but costly and sparse.
• Hybrid: a broadband backbone plus dense MEMS infill, tied together by data fusion — the likely future of seismic instrumentation.

MEMS can’t yet fully replace broadband seismometers for long-period and global seismology, but as a complement they promise more comprehensive, higher-resolution insight into Earth’s dynamics.

References

1. Field Tests of a Portable MEMS Gravimeter — Middlemiss et al., 2017, Sensors, 17(11), 2571.
2. Seismic Sensors Based on MEMS Technology: Advances and Perspectives — D'Alessandro et al., 2019, Sensors. (DOI not verified; listed for reference.)
3. Principles of Broadband Seismometry — Ackerley, 2015, Encyclopedia of Earthquake Engineering, Springer.
4. Ultra-low-noise MEMS accelerometer — SkyMEMS product page (manufacturer specification).
5. An Ultra-Low-Noise MEMS Accelerometer for Seismology (QuietSeis) — Guerineau & Fougerat, EGU General Assembly 2018 (conference presentation; no DOI).