| UTC time | 2020-05-15 11:03:27 |
|---|---|
| ISC event | 618259420 |
| USGS-ANSS | ComCat |
| Local date | May 15, 2020 |
| Local time | 4:03 a.m.PT |
| Magnitude | 6.5Mw |
| Depth | 2.7 km (1.7 mi) |
| Epicenter | 38°10′08″N117°51′00″W / 38.169°N 117.850°W /38.169; -117.850 |
| Fault | Walker Lane Seismic Zone |
| Type | Strike-slip |
| Areas affected | Nevada |
| Max. intensity | MMI VIII (Severe)[1] |
| Aftershocks | 23,314+ (As of September 22, 2021)[2] |
| Casualties | 0 |
On May 15, 2020, at 4:03:27 local time, a magnitude 6.5 earthquake struck ~35 miles (56 km) west ofTonopah,Nevada in theMonte Cristo Range near theCalifornia-Nevada border.[3] It was Nevada's largestearthquake in 66 years.[4][5]
Southwestern Nevada lies within a complex zone of distributed faulting known as theWalker Lane, which carries up to a quarter of the motion of theNorth American plate relative to thePacific plate.[3] It extends from theGarlock Fault in the southeast along the northeastern flank of theSierra Nevada, running parallel to the California–Nevada boundary. The central Walker Lane is characterized by a zone of west–east trending left-lateral strike-slip faults that link northwest–southeast trending dominantly right-lateral strike-slip faults.[6]
The earthquake had a magnitude of 6.5 ML and ahypocentral depth of only 2.8 km (1.7 mi). Shaking was felt throughout California and Nevada, with some reports from as far asSan Francisco,Los Angeles, andSalt Lake City.[7][8] The estimated maximum intensity of shaking was rated as VIII (Severe) on theModified Mercalli intensity scale. The magnitude was initially reported as M 6.4, but was upgraded about 1 hour later byUSGS to its current figure.[9] More than 22,300 people reported feeling the earthquake.[3]
Thefocal mechanism of the earthquake suggests either left-lateralstrike-slip faulting on a west–east trending fault or right-lateral faulting on a north–south trending fault.[10] The distribution of aftershocks supports the first of these options.[11] The earthquake lies close to the projected eastward continuation of the Candelaria fault, which is known to have beenactive during theQuaternary period.[12] It also lies close to the northern end of the north–south trending Eastern Columbus Salt Marsh fault.[13]
Within the first 5 hours proceeding the main shock, there were 6aftershocks measuring magnitude 4.5 or higher, the highest being a 5.1.[14]
On November 13, at 1:13 a.m. local time, a magnitude 5.3 aftershock took place. It is the largest aftershock of the sequence.[15]
Since the earthquake occurred in a remote and relatively uninhabited area, few people were exposed to severe shaking, hence no casualties occurred.[8][16][17] The earthquake crackedU.S. Route 95 betweenReno andLas Vegas, causing it to be temporarily closed. The highway was reopened 10 hours after repair operations. Several post-earthquake field reconnaissance teams documented surface fault expressions, rock falls, subsidence features, and other geologic and geotechnical effects in theColumbus Salt Marsh to the west of U.S. Route 95 and surrounding areas.[18][19] In Tonopah, displaced items, broken windows, cracked asphalt, masonry, and drywall were reported.[20][21][22]
