   Fort Collins Denver  Fort Collins | |
| UTC time | 1882-11-08 19:30:00 |
|---|---|
| USGS-ANSS | ComCat |
| Local date | November 7, 1882 (1882-11-07) |
| Magnitude | Mfa 6.2, Mw 6.6±0.6 |
| Epicenter | 40°30′N105°30′W / 40.5°N 105.5°W /40.5; -105.5 |
| Areas affected | Northern Colorado United States |
| Max. intensity | MMI VII (Very strong) |
The1882 Fort Collins earthquake orFront Range earthquake measured Mw 6.6 and struck nearFort Collins,Colorado at 1:30 UTC on November 8, which was 18:30 on the November 7.[1] The earthquake occurred as the result of deformation within theFront Range and caused shaking as strong asModified Mercalli intensity (MMI) VII (Very Strong). Shaking was felt as far away asSalt Lake City,Utah andSalina,Kansas. An aftershock struck locally at 04:45 on November 8 and was felt as far asLaramie,Wyoming andMeeker, Colorado. It is the largest earthquake in Colorado's history.
The SouthernRocky Mountains are still actively growing due to theLaramide orogeny. TheFront Range accommodates some of this as a deformation front of the orogeny. Stresses in this region are generally northwest–southeast oriented. The causative fault of this specific earthquake is unknown, but other earthquakes such as the 1984 Wyoming earthquake struck at a depth of 20 km (12 mi).[2][3]
The Mw 6.6[a] earthquake struck at 01:30 on November 8 in UTC time, or 18:30 on November 7. The earthquake causedModified Mercalli intensity (MMI) VII (Very Strong) shaking in various localities near in theFront Range urban corridor and was felt over an area of 470,000 km2 (180,000 sq mi).[2] Due to the sparseness of the epicentral region, very little is known about where exactly the earthquake occurred.[2] An aftershock of magnitude 4.5 to 5.0 was also felt in the urban corridor.[5] This earthquake is the largest known to have occurred in the state of Colorado.[4]
At theUniversity of Colorado Boulder, plaster fell from the ceiling. InDenver, some bolts snapped and bent at an electric light plant. InLa Porte, a wooden house suffered cracking. At Thompson, a house's walls were severely cracked and the plaster on some walls came off. Glass windows broke inLaramie.[4]