Distributed Acoustic Sensing (DAS) is a promising technique to improve the rapid detection and characterization of earthquakes. Previous DAS studies mainly focus on the phase information but less on the amplitude information. In this study, we compile earthquake data from two DAS arrays in California, USA, and one submarine array in Sanriku, Japan. We develop a data-driven method to obtain the first scaling relation between DAS amplitude and earthquake magnitude. Our results reveal that the earthquake amplitudes recorded by DAS in different regions follow a similar scaling relation. The scaling relation can provide a rapid earthquake magnitude estimation and effectively avoid uncertainties caused by the conversion to ground motions. Our results show that the scaling relation appears transferable to new regions with calibrations. The scaling relation highlights the great potential of DAS in earthquake source characterization and early warning.

We develop a methodology to compile an objective tremor catalog by combining the envelope cross-correlation method with clustering, utilizing distinctive event features that can differentiate tectonic tremors from non-tremor events. This approach enables tremor extraction without subjective criteria, allowing for the detection of short-duration tremors overlooked in previous studies. The event features are depth, the mean amplitudes at high and low frequencies, the ratio of these two amplitudes, and event duration, which is defined as the minimum period within which 50 % of the seismic energy is concentrated. The application of this method for western Japan detects 1.7 times more tremors compared with previous studies, with durations of 0.3 to ~100 s. The events with short durations are considered to be low-frequency earthquakes. The relationship between seismic moment and the duration of the detected tremors adheres to the scaling law of slow earthquakes.