QuakeIndex

Fault · Alaska

Yaga syncline (Chugach-St. Elias fold and thrust belt)

15 kmlong (9 mi), as mapped
1–5 mm/yrhow fast it slips
< 130,000 yearssince it last broke the surface
1quakes of M2.5+ within 10 km since 2016

In plain English

The two sides move 1 to 5 mm a year — 10 to 50 cm (4 to 20 inches) every century.

Its most recent surface rupture is younger than 130,000 years.

The largest earthquake recorded near it was M 6.9 in 1899 (The 1899 Yakutat Bay, Alaska Earthquakes (Strong Aftershock)) — about 710,000 times the energy of an M3.0, the size people start to feel. It released about 340 kilotons of TNT.

This week vs. its last ten years

Too quiet to rank: fewer than half a year's worth of weeks with any M1.5+ quake within 5 km, in ten years. A single quake here would read as "unusual", so we do not score it.

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

Denali faultPamplona faultChaix Hills fault (Chugach-St. Elias fold and thrust belt)Kosakuts fault (Chugach-St. Elias fold and thrust belt)Hope Creek fault (Chugach-St. Elias fold and thrust belt)Coal Glacier fault (Chugach-St. Elias fold and thrust belt)Malaspina fault (Chugach-St. Elias fold and thrust belt)White River syncline (Chugach-St. Elias fold and thrust belt)Yakataga anticline (Chugach-St. Elias fold and thrust belt)Miller Creek fault (Chugach-St. Elias fold and thrust belt)Sullivan fault (Chugach-St. Elias fold and thrust belt) M 6.9 · 1899 · The 1899 Yakutat Bay, Alaska Earthquakes (Strong Aftershock)
The Yaga syncline (Chugach-St. Elias fold and thrust belt) as mapped at the surface (glowing), with the other mapped faults nearby, 1 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 6.9 The 1899 Yakutat Bay, Alaska Earthquakes (Strong Aftershock)
    September 4, 1899 · epicentre 17 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 2.5 135 km WNW of Yakutat, Alaska
    2022-08-23 · 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.