Seismic Signature of Rain and Wind Inferred From Seismic Data

Abstract

Seismic stations are increasingly used to monitor river activity and to quantify sediment transport during flood events. In tropical regions, cyclone‐induced floods are often associated with heavy rain and strong wind episodes, generating complex seismic records involving the simultaneous signature of water, sediment, rainfall and wind. Hence, seismic characterization of rain and wind is then required to better decipher each process and improve our understanding of the river seismic signature. In this study, we investigate experimentally the seismic response of rain and wind using data recorded by geophones deployed in various soil types and at different burial depth (BD), co‐located with various meteorological instruments. Our results show that the power spectral density (PSD) of the seismic noise intensifies at a frequency between 60 and 500 Hz for rain and 5 and 500 Hz for wind, in the presence of rain precipitation as low as 0.025 mm/min and/or wind speed ≥3 m/s. PSD analysis indicates that the seismic signal associated with rain decreases with the BD with a value of ∼2–5 dB in a depth difference of 10 cm. We also observe that each soil type has its own seismic signature. The 4‐min root mean square correlation between the seismic signal amplitude and the rain precipitation suggests that they best correlate with Pearson coefficient >0.90 at BD of 30 cm. The transfer function between the precipitation rate (or kinetic energy) and the seismic signal amplitude shows that the signal recorded by the geophone can be used as a robust proxy for these parameters.

High-resolution precipitation monitoring with a dense seismic nodal array

“…2 b). This finding aligns with previous studies indicating that elevated seismic PSD appears above 50–80 Hz 21 – 23 .

Figure 2 Seismic precipitation signals.

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“…Recent advancements in understanding seismic precipitation signals 21 – 23 provide an alternative to counter these weaknesses of existing precipitation monitoring approaches by measuring seismic waves. Seismic precipitation signals are generated when raindrops impact the ground and excite waves, at frequencies typically above 50 Hz 21 – 23 for nearby raindrop impacts. Hence, unlike remotely-sensed radar measurements, the seismic intensity serves as a direct sampling of surface precipitation similar to rain gauges with high temporal resolution.…”

“…Hence, unlike remotely-sensed radar measurements, the seismic intensity serves as a direct sampling of surface precipitation similar to rain gauges with high temporal resolution. Meanwhile, compared to traditional tipping-bucket rain gauges, the seismic intensity is dependent on the weight and speed of each raindrop in addition to the overall precipitation rate 21 – 23 , making it sensitive to precipitation type and hydrometeor (e.g., droplet) size, and thus could potentially be used to detect hail. Because a single seismic station is sensitive only to raindrops that fall within ~ 10 m of it 21 , a seismic array is required to monitor regional rainfall patterns.…”

“…These nodal stations have a sampling rate of 500 Hz, and were buried in ~ 18 cm-deep holes with ~ 3 cm soil cover 26 . Such shallow burial depths enable detection of rainfall signals 23 . Compared to broadband seismometers, these seismic nodes can only record high frequency vertical vibrations but are much cheaper, with a cost comparable to a tipping-bucket rain gauge.…”

Monitoring storm evolution using a high-density seismic network

“…In the last decade environmental seismology has emerged as an active research field, based on the use of the vibrations generated by different processes, and recorded at seismic stations to monitor to some detail their activity. This approach has been used to study a large variety of processes, many of them related to hydrology and meteorology sciences, as Antarctica ice cover 5 , glaciers 6 , river floods 7 , mountain snowmelt 8 , groundwater variations 9 , rain 10 , wind 11 and thunders 12 . This range of phenomena can be extended to topics related within astronomy and astrophysics, as the monitoring of auroras, electromagnetic storms or bolides entering the atmosphere [12][13][14] and also to the biological sciences, using seismic data to detect marine mammal vocalizations 15 or to investigate the use of vibrations as a communication tool by the elephants 16,17 .…”