Real-time coverage of earthquake event — 17 km SW of Kōya, Japan — Pandita Data.
🌍 OPEN LIVE 3D EARTHQUAKE MAPA magnitude 5.7 earthquake struck 17 km southwest of Kōya, Japan on May 2, 2026 at 09:28 UTC, centred at a depth of 59.1 km. The US Geological Survey issued a GREEN PAGER alert, indicating minimal structural damage and few casualties are expected. Thirty-one people reported feeling the tremor across the Wakayama and Nara prefectures. No tsunami warning was issued. This intermediate-depth rupture occurred within the Philippine Plate subduction zone, a region historically prone to frequent seismic activity.
Japan sits atop one of Earth's most seismically active zones—the convergence of the Pacific, Eurasian, and Philippine Plates. The Kōya region lies in a complex intraslab stress field where the Philippine Plate descends beneath the Eurasian Plate at roughly 4–6 cm per year. At 59.1 km depth, this earthquake occurred within the subducting slab itself, not at the plate interface. These intraslab events—ruptures within the descending lithosphere—are distinct from megathrust earthquakes and typically cause less destructive surface shaking, though they can be widely felt across Japan due to efficient wave propagation through the rigid oceanic crust.
This M5.7 rupture released approximately 1.0 × 1018 joules of seismic energy—equivalent to roughly 240 tons of TNT. The intermediate depth substantially reduces expected ground acceleration at the surface compared to a shallow rupture of identical magnitude. Shallow earthquakes (0–30 km) tend to generate stronger, higher-frequency shaking near the epicentre; intermediate-depth events (30–100 km) radiate energy more efficiently over large distances but with diminished peak ground acceleration in near-field zones.
Shallow ruptures (0–30 km): Stronger near-field shaking, complex fault geometry, high damage potential locally. Intermediate ruptures (30–100 km): Wider felt area, lower near-field peak ground acceleration (PGA typically <0.3g for M5.7), reduced tsunami risk. This event's 59 km depth explains why it was widely felt across multiple prefectures with minimal structural threat.
Kōya and surrounding Wakayama Prefecture are home to ~900,000 residents. Modern seismic building codes in Japan (enforced nationwide post-1981) are among the world's most stringent, with structures engineered to withstand M6.0+ events. This M5.7 at intermediate depth posed negligible risk to building stock. The PAGER GREEN alert reflects zero expected fatalities and no economic losses. Historically, the Wakayama-Nara region experiences intraslab seismicity regularly; the 2004 Kii Peninsula earthquake (M7.4, 40 km depth) proved that even larger intermediate-depth ruptures cause minimal surface damage despite being widely felt.
Use Pandita Data's real-time 3D earthquake simulation to visualize seismic wave propagation from this Kōya rupture and understand how intermediate-depth energy radiates through the Philippine Plate slab.