M 7.4 Earthquake — 97 felt reports
100 km ENE of Miyako, Japan — 97 people reported feeling this earthquake — CDI 5.8 (Moderate)
Geographic Context
This earthquake event occurred near Miyako (approximately 100 km away) in Japan, situated along the Pacific Ring of Fire, one of the most seismically active zones on Earth.
Event Assessment
This event is a major earthquake registering magnitude 7.4, classified as a "major" event on the Richter scale capable of causing widespread damage. Calamity.live has classified it as "critical" severity with a severity value of 88.80000000000001. The computed Calamity Score is 40 out of 100, reflecting a moderate-impact event. The primary scoring components are: intensity (68), cascading (48), historical (34). Data for this event was sourced from usgs_dyfi, one of the 250 scientific monitoring sources aggregated by Calamity.live.
Regional Monitoring Context
Japan has a documented history of earthquake events. Seismic monitoring in the region draws on data from multiple agencies including USGS, EMSC, and regional networks. Understanding local seismicity helps emergency management agencies plan for potential future events and assess building code adequacy. Earthquake hazard in any region depends on fault proximity, soil conditions, and building vulnerability — factors that can vary significantly even within a single metropolitan area.
Cascade Risk Analysis
This event may trigger secondary hazards through cascade effects. Cascade detection is an automated process that evaluates how primary disasters can trigger secondary events — for example, earthquakes triggering landslides, or volcanic eruptions causing lahars and pyroclastic flows. These secondary hazards can sometimes pose a greater threat than the initial event, particularly in mountainous terrain or densely populated areas.
Event Data
| Type | Earthquake |
| Severity | critical |
| Severity Value | 88.80000000000001 |
| Calamity Score | 40 / 100 |
| Confidence | 70% |
| Coordinates | 39.9532, 143.0462 |
| Nearest City | Miyako (100 km) |
| Impact Tier | minor |
| Timestamp | 2026-04-20T07:53:00.185Z |
| Source | https://earthquake.usgs.gov/earthquakes/eventpage/us6000sri7/dyfi |
Score Breakdown
Technical Details
| Mag | 7.4 |
| Depth | 35 |
| Felt | 97 |
| Cdi | 5.8 |
| CdiDescription | Moderate |
| Mmi | 6.212 |
| Alert | green |
| Sig | 899 |
| Tsunami | true |
| Place | 100 km ENE of Miyako, Japan |
| Types | ,dyfi,finite-fault,general-text,ground-failure,impact-link,losspager,moment-tensor,origin,phase-data,shakemap, |
| Usgs Shakemap Mag | 7.4 |
| Usgs Shakemap Depth | 35 |
| Usgs Shakemap Mmi | 6.212 |
| Usgs Shakemap MmiDescription | Strong |
| Usgs Shakemap Felt | 97 |
| Usgs Shakemap Alert | green |
| Usgs Shakemap Sig | 899 |
| Usgs Shakemap Tsunami | true |
| Usgs Shakemap Place | 100 km ENE of Miyako, Japan |
Cascade Risks
Safety Information
If you feel shaking: Drop, Cover, and Hold On. Move away from windows, heavy objects, and exterior walls. After shaking stops, check for injuries and structural damage. Be prepared for aftershocks, which can occur minutes to months after the mainshock. Follow instructions from local emergency management authorities.
This data is aggregated algorithmically from scientific sources. Not a replacement for official emergency warnings.
Calamity.live data shows a earthquake event with CalamityScore 40/100, near Miyako (Japan), based on data from usgs_dyfi. Source: Calamity.live, a platform aggregating real-time data from 197 scientific monitoring sources.