A strong and shallow earthquake registered by India’s National Center for Seismology (NCS) as M6.2 hit Nepal at 09:21 UTC (15:06 local time) on October 3, 2023. The agency is reporting a depth of 5 km (3.1 miles). USGS and EMSC are reporting M5.7 at a depth of 10 km (6.2 miles).
According to the NCS, the quake was preceded by M4.6 and followed by M3.6, M3.1, M3.5, M4.3, M3.9 and M3.0 by 14:00 UTC.
The epicenter was located 38.7 km (24.1 miles) NE of Dipayal (population 23 416), 65.8 km (40.9 miles) ENE of Dadeldhurā (population 19 014), and 72.9 km (45.3 miles) ENE of Dārchulā (population 18 317), Sudurpashchim Pradesh, Nepal.
The area is seismically very active and associated with collisional tectonics where the Indian plate
subducts beneath the Eurasian Plate, NCS said.
The event was well recorded by more than 60 broadband seismic stations installed by the NCS. The analysis of seismic data shows that the events occurred on North Almora Thrust (NAT) which provides a very apt location for triggering the mainshock due to appreciable structural heterogeneity in and around the mainshock.
The preliminary fault plane solution derived from moment tensor inversion suggests a thrust fault. The earthquake was located 50 km (31 miles) NNE of the recent M6.3 earthquake on November 9, 2022.
Maximum Intensity of VI (MMI scale) was reported in the epicentral region.
The recorded earthquakes as per the EQ Catalogue of NCS reveal that the region is associated with moderate to large earthquakes with varying magnitudes in the last 13 years. In addition to the above, it is noteworthy that prior to the mainshock, there were three prominent events recorded on November 9, 2022 (M6.3), January 24, 2023 (M5.8) and February 22, 2023 (M4.4) occurred within 50 km3 (19 mi3) of today events which were also felt with slight to moderate intensity in Delhi-NCR and others neighboring states.
The occurrence of earthquakes in the region is attributed mainly to the tectonic settings of the Himalayas comprising Himalayan Frontal Thrust (HFT), Main Boundary Thrust (MBT), and Main Central Thrust (MCT) besides several local faults and geological demarcated lineaments.
6.3 and 5.3 magnitude #earthquakes rock #Nepal, leaving 11 #injured— Daryo | Central Asia & Afghanistan (@DaryoEng) October 3, 2023
While the #epicenters were situated in western #Nepal, the effects of the #quakes were #felt as far away as #NewDelhi, #India.
👉Details — https://t.co/vyddsdM7zJ#NepalEarthquake #EarthquakeNepal… pic.twitter.com/501gupnf43
According to the USGS PAGER, 1 000 people are estimated to have felt very strong shaking, 83 000 strong, and 158 000 moderate.
The USGS issued a Green alert for shaking-related fatalities and economic losses. There is a low likelihood of casualties and damage.
Overall, the population in this region resides in structures that are highly vulnerable to earthquake shaking, though some resistant structures exist. The predominant vulnerable building types are adobe block and unreinforced brick with mud construction.
Recent earthquakes in this area have caused secondary hazards such as landslides that might have contributed to losses.
The quakes injured at least 17 people, damaged homes and triggered a landslide in the district of Bajhang that blocked a major highway, officials reported. Some homes in Chainpur, a town in the district, collapsed.
The landslide blocked the road to the southern plains. A woman is missing after being engulfed by the landslide, police official Dipesh Chaudhary said.
Estimated population exposure to earthquake shaking
Selected cities exposed
Featured image credit: TW/SAM, Google
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