Long-term seismic hazard
Probability estimates for a major earthquake in the coming decades, based on seismological research — regions with the highest known risk
Precise short-term earthquake prediction (exactly when it will happen) does not exist — that's a fundamental scientific limit, not something this site is missing. Below are official and scientific long-term (decades-scale) probability estimates for a major quake in a region, based on seismic history and accumulated tectonic strain. Scientists periodically revise these figures — the numbers here are approximate, as of the cited study's publication.
Sea of Marmara / Istanbul, Turkey1 — highestSeismologists rate the probability of an M7+ quake in the Sea of Marmara within a few decades as among the highest in the world; the fault segment beneath Istanbul hasn't ruptured in over 250 years.
- East Anatolian Fault, Turkey1 — highest
Source of the February 2023 Kahramanmaraş disaster (M7.8). The fault remains tectonically active along its length, with continued risk of large repeat events.
- North Anatolian Fault, Turkey1 — highest
One of the most studied faults in the world — a sequence of major earthquakes progressively ruptured along it through the 20th century, including İzmit 1999 (M7.6).
San Andreas Fault, California, USA1 — highestUSGS (UCERF3) estimates the probability of an M6.7+ quake in the San Francisco Bay Area in the coming decades at over 70%.
Nankai Trough, Japan1 — highestJapan's government research committee rates the probability of an M8-9 megathrust quake in the coming decades as very high — a central focus of the national disaster-preparedness system.
- Cascadia Subduction Zone, USA/Canada2 — very high
A potential M8-9 megathrust quake in the coming decades — the region hasn't experienced one since 1700, and accumulated strain is significant.
Sunda Megathrust, Indonesia1 — highestAfter the 2004 disaster (M9.1), individual segments of the megathrust along Sumatra remain tectonically stressed and are considered by researchers to be undischarged 'seismic gaps'.
Chilean coast2 — very highOne of the most seismically active regions on the planet — site of the strongest earthquake ever recorded (M9.5, 1960). Major quakes occur regularly.
Tehran, Iran2 — very highThe capital sits near several active faults; researchers have repeatedly flagged the long interval since the last major rupture as an elevated-risk factor.
Himalayan front, Nepal2 — very highLong 'seismic gaps' have been identified along the Himalayan front — segments that haven't ruptured in a major quake for a very long time, which researchers consider a sign of accumulated risk.