The sequence
Newest first.
- 3.3Guerrero, Mexico17 km SE of the mainshock2 weeks ago· 5.0 km deep
- 3.5Guerrero, Mexico32 km SSW of the mainshock2 weeks ago· 5.0 km deep
- 3.4Guerrero, Mexico31 km WSW of the mainshock3 weeks ago· 19.4 km deep
- 3.8Guerrero, Mexico33 km WNW of the mainshock3 weeks ago· 43.6 km deep
- 3.7Offshore Guerrero, Mexico48 km SSW of the mainshock3 weeks ago· 10.8 km deep
- 3.1Guerrero, Mexico11 km WSW of the mainshock3 weeks ago· 41.5 km deep
- 3.4Guerrero, Mexico30 km SSE of the mainshock3 weeks ago· 11.4 km deep
- 3.4Guerrero, Mexico32 km SSE of the mainshock4 weeks ago· 23.5 km deep
How the rupture zone is measured
An aftershock is a smaller earthquake triggered as the crust settles around the fault that ruptured. They cluster along that rupture, so the area worth searching scales with the size of the mainshock rather than being a fixed radius.
The 50 km zone above comes from the Wells & Coppersmith (1994) rupture-length relation, doubled because aftershocks routinely extend about one rupture length beyond each end of the fault, then floored at 50 km and capped at 400 km. Anything outside it is counted as separate regional seismicity, not part of this sequence.
Aftershocks are most frequent in the hours right after the mainshock and taper off over days to months. A quiet day does not mean the sequence has ended.
Data from USGS, EMSC and partner agencies. Magnitudes and locations are preliminary and may be revised.