Far-field earthquake information from single-station waveforms: The 2026 M_W6.8 Kumamoto earthquake

On July 28, 2026, at 15:27:15.512 Beijing Time (07:27:15.512 UTC), an M_W6.8 earthquake occurred in the Kumamoto region of Japan. This study reviewed one operational run of a prototype system using three-component waveforms from Global Seismographic Network station IU.MAJO. The deployed DiTing model component processed the continuous waveform stream, identified the P-wave onset, produced preliminary event parameters, and recorded the completion of the server-side MQTT push. IU.MAJO is located approximately 808.7 km from the USGS catalog epicenter, with a forward azimuth of 55.9° from the epicenter to the station. The system P-wave first-arrival pick at 07:29:03.595 UTC occurred 108.1 s after the cataloged origin time and 1.9 s after the theoretical P-wave first arrival predicted by iasp91; This difference arises from the theoretical arrival rather than an error relative to the manual pick. The estimated system magnitude was M6.86, a numerical difference of 0.06 from the M_W6.8 provided by the USGS. The server-side MQTT push was completed 57.9 s after the P-wave pick and 166.0 s after the catalog origin time. The estimated origin time was 80.1 s later than the observed, and the reported location was approximately 982.1 km from the catalog epicenter, demonstrating substantial limitations in the preliminary single-station time and location estimates. However, the results only document one run for a specific event, station, and data condition. They do not constitute a statistical validation of the model performance or conventional near-source public earthquake early warning systems.