Hawaiiearthquakestoday:liveseismicandvolcanicactivitymonitoring

Length

60 km

Max plausible

M7.7

Return period

~100 years for M7+ movement; ongoing slow creep

The Hilina Slump is a massive, seaward-creeping segment of Kīlauea's south flank covering roughly 5,000 km² and containing an estimated 20,000 km³ of material — one of the largest active landslide systems on Earth. Normal faulting along its headwall scarp has produced M7+ earthquakes in 1868 and 1975, and slow GPS-measured seaward motion of 6–10 cm/year continues today. A large-scale collapse of the Hilina Slump is considered the primary local-tsunami generation scenario for the Hawaiian Islands.

Max plausible

M7.0

Return period

~30–50 years for M6+

The Kaʻōiki Fault System occupies the saddle between Kīlauea and Mauna Loa on the Big Island, connecting and accommodating stress transfer between the two rift zone systems. It generated the M6.6 Kaʻōiki earthquake in 1983 and has produced multiple M6–6.5 events over the past century. Seismologists consider the Kaʻōiki zone capable of M6.5–7.0 ruptures that could simultaneously trigger rift zone intrusions in both volcanoes.

The Molokaʻi Fracture Zone is a major structural feature of the Pacific plate floor running east–west offshore north of the Hawaiian Islands, representing a fossil transform fault that offsets the Pacific plate fabric by hundreds of kilometres. Although no longer seismically active at the fracture itself, it affects the stress state of the lithosphere beneath the archipelago and creates heterogeneous rigidity that influences how seismic waves propagate across the island chain. Interaction between the fracture zone geometry and the hotspot's thermal swell influences long-term subsidence rates and tsunami wave-speed anomalies in the Hawaii region.

Max plausible

M5.0

The Pāhala seismic cluster is a persistent swarm of earthquakes occurring at depths of roughly 30 km beneath the Pāhala district on the Big Island's south coast, driven by continuous magmatic intrusion into the deep lithosphere from the Hawaiian hotspot. Unlike the shallow volcanic earthquakes near Kīlauea's surface, Pāhala events represent the deep plumbing that feeds both Kīlauea and Mauna Loa and have intensified measurably since 2015. The cluster rarely exceeds M5 but generates thousands of small events per year and is considered a proxy for the long-term magma supply rate to the island.

United States Geological Survey

National (USA)

Publishes earthquake magnitude, depth, and ShakeMap data for all Hawaii events via the ANSS ComCat catalog. Cross-references HVO volcanic seismicity.

Hawaiian Volcano Observatory

Hawaii (Big Island focus)

Operates the dense seismic network on the Big Island to monitor volcanic seismicity and eruption precursors. Issues eruption alert levels and volcanic earthquake summaries.

Pacific Tsunami Warning Center

Pacific Ocean basin

Issues Pacific-wide tsunami bulletins, watches, advisories, and warnings for earthquakes generating tsunamis across the Pacific Ocean basin. Headquartered at Ewa Beach, Hawaii.

National Tsunami Warning Center

US continental coasts and Alaska

Issues tsunami warnings for the US mainland coasts and Alaska. Cross-references PTWC Pacific-wide bulletins to ensure consistent messaging for US territories.

Hawaii Emergency Management Agency

State of Hawaii

Coordinates state-level emergency alerts, publishes tsunami evacuation zone maps for all islands, and manages evacuation routing and public shelter information.