Real-time coverage of earthquake event — 93 km NNE of Hihifo, Tonga — Pandita Data.
🌍 OPEN LIVE 3D EARTHQUAKE MAPA magnitude 6.1 earthquake struck 93 km north-northeast of Hihifo, Tonga at 17:34 UTC on April 19, 2026, with a focal depth of 36 kilometers. The U.S. Geological Survey classified the event as GREEN on the PAGER (Prompt Assessment of Global Earthquakes for Response) scale, indicating minimal expected fatalities and economic losses across the region. No tsunami warning was issued by the Pacific Tsunami Warning Center. The moderate magnitude and intermediate depth place this event in Tonga's typical seismic signature—powerful enough to be felt widely but not catastrophic in isolation.
Tonga sits at one of Earth's most seismically active boundaries: the Tonga-Kermadec subduction zone, where the Pacific Plate descends beneath the Australian Plate at a rate of approximately 240 mm per year—one of the fastest subduction rates on the planet. This April 2026 event occurred within the upper-plate rupture zone, where stress accumulation from plate convergence is routinely released through shallow and intermediate-depth earthquakes. Tonga experiences dozens of magnitude 5+ events annually. The volcanic arc running through the islands (including Ambrym, Tafahi, and Kao) exists directly above this subduction interface, making the region simultaneously volcanically and seismically hazardous.
At 36 km depth, this earthquake represents a shallow-intermediate rupture—deep enough to avoid the most severe surface shaking but shallow enough to generate significant regional motion. The rupture released approximately 2.5 × 1017 joules of energy, equivalent to roughly 60 kilotons of TNT. Shallow earthquakes (0–35 km) typically produce stronger ground acceleration over shorter distances, while deeper events distribute energy over wider areas with less intensity. This rupture geometry, combined with the Pacific Plate's oblique descent angle, likely produced predominantly thrust-type motion along the subduction interface.
36 km Depth (Intermediate): Shallow enough to generate felt reports across Tonga and nearby island groups; deep enough to reduce maximum ground acceleration at the surface. Peak ground acceleration at epicenter estimated 0.10–0.15 g (gravitational acceleration). Tsunami generation unlikely at this depth unless significant seafloor displacement occurs at shallower levels.
Hihifo, on Niuatoputapu Island (northernmost inhabited island in Tonga), sits approximately 93 km south of the epicenter. Residents in Nuku'alofa, the capital on Tongatapu (~280 km away), would have felt weak to moderate shaking. The 13 felt reports logged reflect the sparse population distribution across Tonga's widely dispersed archipelago. Tongan infrastructure—predominantly low-rise residential and government buildings constructed to cyclone standards rather than seismic codes—sustained no reported damage. The 2022 Hunga Tonga–Hunga Ha'apai submarine volcanic eruption fundamentally altered regional tsunami preparedness protocols; however, this earthquake's moderate magnitude and depth presented minimal tsunami risk.
Pandita Data's 3D earthquake simulation powered by live USGS data visualizes subduction zone rupture mechanics, showing how the Pacific Plate's descent generates stress and how magnitude scales with depth and fault geometry. By exploring this event on our platform, you can observe the epicenter location, depth cross-section, focal mechanism, and seismic wave propagation patterns that explain why Tonga experiences frequent, powerful earthquakes and why volcanic activity is intrinsically linked to plate tectonics in this region.