QuakeIndex

Fault · Hawaii

Koa'e fault system

19 kmlong (12 mi), as mapped
> 5 mm/yrhow fast it slips
last 150 yearssince it last broke the surface
13,206quakes of M2.5+ within 10 km since 2016

Updated , with the latest earthquake of M2.5 or more within 10 km of the trace: M 3.6, 12 km SW of Volcano, Hawaii.

In plain English

The two sides grind past each other faster than 5 mm a year — more than half a metre (20 inches) every century.

It has broken the ground surface within the last 150 years.

The largest earthquake recorded near it was M 7.9 in 1868 (The 1868 Great K`au, Hawaii Earthquake) — about 22,000,000 times the energy of an M3.0, the size people start to feel. It released about 11 megatons of TNT.

This week vs. its last ten years

8/100

quiet

2 quakes of M1.5+ within 5 km of the trace in the last 7 days — busier than 8% of weeks since 2016. A normal week: 3–16.

Computed from the USGS catalogue · a description of the past, not a forecast · method

Kilauea VolcanoMauna Loa VolcanoKa'oiki-Honu'apo fault systemHilina fault systemLo'ihi Seamount M 7.9 · 1868 · The 1868 Great K`au, Hawaii Earthquake M 7.0 · 1823 · Kilauea South Flank, Hawaii M 7.0 · 1868 · Ka`u District, Hawaii M 6.7 · 1908 · Island of Hawai`i, Hawaii M 6.6 · 1880 · Kaoiki area, Hawaii M 6.5 · 1841 · Kilauea South Flank, Hawaii
The Koa'e fault system as mapped at the surface (glowing), with the other mapped faults nearby, 400 of the M2.5+ earthquakes within 10 km of it since 2016 (dots) and the epicentres of the large historic earthquakes recorded near it (rings). Traces: USGS Quaternary Fault and Fold Database. Historic epicentres are estimates.

Every year since 2016

Earthquakes of M2.5+ with an epicentre within 10 km of the mapped trace. Near is not the same as on: some will have slipped on neighbouring faults.

The big ones recorded near it

  1. M 7.9 The 1868 Great K`au, Hawaii Earthquake
    April 3, 1868 · epicentre 24 km from the trace
  2. M 7.0 Kilauea South Flank, Hawaii
    June 2, 1823 · epicentre 20 km from the trace
  3. M 7.0 Ka`u District, Hawaii
    March 28, 1868 · epicentre 22 km from the trace
  4. M 6.7 Island of Hawai`i, Hawaii
    September 21, 1908 · epicentre 20 km from the trace
  5. M 6.6 Kaoiki area, Hawaii
    September 24, 1880 · epicentre 13 km from the trace
  6. M 6.5 Kilauea South Flank, Hawaii
    April 8, 1841 · epicentre 20 km from the trace
  7. M 5.5 13 km SSE of Volcano, Hawaii
    March 13, 2019 · epicentre 4 km from the trace
  8. M 5.4 6 km SW of Volcano, Hawaii
    June 1, 2018 · epicentre 4 km from the trace

Before 1973 from the USGS ComCat historical catalogue (within 25 km; epicentres of old earthquakes are estimates). Since 2016, M4+ within 10 km.

Most recent near it

  1. M 3.6 12 km SW of Volcano, Hawaii
    2026-10-05 · 1 km from the trace
  2. M 3.5 5 km WSW of Volcano, Hawaii
    2026-10-02 · 6 km from the trace
  3. M 2.5 4 km SW of Volcano, Hawaii
    2026-10-01 · 7 km from the trace
  4. M 3.4 5 km WSW of Volcano, Hawaii
    2026-10-01 · 6 km from the trace
  5. M 2.6 5 km SW of Volcano, Hawaii
    2026-10-01 · 5 km from the trace
  6. M 2.5 5 km SW of Volcano, Hawaii
    2026-10-01 · 6 km from the trace

Neighbouring faults

Fault trace, slip rate and age: USGS Quaternary Fault and Fold Database (public domain), simplified for the web. Earthquakes: USGS ComCat. QuakeIndex does not forecast earthquakes; a fault's history describes the past. For early warning use ShakeAlert.