
ALT Waveform comparison between the seismometer and the DAS. Top panel shows seismometer data in acceleration and bottom panel shows DAS data in strain rate. Blue circles indicate the peak ground acceleration (PGA) and the peak strain rate (PSR) measured within the first 3 second window of the P wave.

ALT Spectral characteristics of MFFI earthquake signals in cluster A. Each colored curve is the median power spectral density (PSD) of the cluster A events grouped within one magnitude bin, so the input is a whole bin and the output is its bin‐median PSD. These bin‐median PSDs are compared against the background PPSD (heat map), which represents the statistical distribution of the total ambient background spectra—earthquake, anthropogenic, and instrumental contributions combined—recorded over the full two‐month deployment. The earthquake energy concentrates in the 3–15 Hertz band (highlighted in orange), clearly decoupling from the background.



























