QuakeIndex

Fault · Washington

Olympia structure

89 kmlong (55 mi), as mapped
not measuredhow fast it slips
< 15,000 yearssince it last broke the surface
3quakes of M2.5+ within 10 km since 2016

In plain English

Its most recent surface rupture is younger than 15,000 years.

The largest earthquake recorded near it was M 6.7 in 1949 (4 km WNW of Roy, Washington) — about 350,000 times the energy of an M3.0, the size people start to feel. It released about 170 kilotons of TNT.

This week vs. its last ten years

0/100

quiet

0 quakes of M1.5+ within 5 km of the trace in the last 7 days — busier than 0% of weeks since 2016. A normal week: 0–0.

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

Seattle faultSouthern Whidbey Island faultTacoma faultSaddle Mountain faults M 6.7 · 1949 · 4 km WNW of Roy, Washington
The Olympia structure as mapped at the surface (glowing), with the other mapped faults nearby, 3 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 6.7 4 km WNW of Roy, Washington
    April 13, 1949 · epicentre 12 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 3.2 3 km W of Skokomish, Washington
    2021-06-22 · 5 km from the trace
  2. M 3.8 3 km WSW of Skokomish, Washington
    2021-06-12 · 4 km from the trace
  3. M 2.8 8 km SW of Skokomish, Washington
    2019-02-15 · 1 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.