Very-Long-Period Tremors from Ice-Covered Canadian Arctic Islands

Abstract Continuous seismic waveform records capture persistent vibrations driven by long-lasting, nontectonic, and nonvolcanic processes at Earth’s surface. Characterizing these signals enables seismic networks to function as remote sensors of environmental processes involving fluids, interactions between ocean and solid Earth, and glacial activities. Long-term broadband seismometer records may contain additional surface-generated seismic signals that remain unrecognized or lack systematic characterization. This study identified a new class of 43 s period monochromatic tremors in the northern Canadian Arctic. Cross-spectral analysis across station pairs demonstrates that these tremors last for hours and propagate globally as surface waves. The tremor events occurred predominantly in winter, when ice covered the entire surface around the source area with a thickness of 1–4 m. Sea-ice thickness from satellite data, the force spectrum of tremor, and the dominant period together support ocean–ice–solid-Earth coupling as a plausible excitation mechanism for the monochromatic tremors from the Arctic region. Beyond documenting a new tremor class, our findings highlight that broadband seismic stations can monitor cryosphere–ocean processes through the solid Earth.