Strong and shallow M6.4 earthquake hits Assam, India

A strong and shallow earthquake registered by India's National Center for Seismology as M6.4 hit Assam, India at 02:21 UTC (07:56 LT) on April 28, 2021. The agency is reporting a depth of 17 km (10.5 miles). The USGS is reporting M6.0 at a depth of 34 km (21 miles), EMSC M6.1 at a depth of 40 km (24.8 miles).

The epicenter was located about 9.7 km (6 miles) NNW of Dhekiajuli (population 21 271), 24 km (15 miles) WSW of Rangapara (population 18 739), 33 km (21 miles) E of Udalguri (population 15 935), and 35 km (22 miles) N of Dhing, India.

There are about 10 410 000 people living within 100 km (62 miles).

According to the USGS, 427 000 people are estimated to have felt very strong shaking, 3 637 000 strong, 5 055 000 moderate, and 26 766 000 light.

The USGS issued an orange alert for shaking-related fatalities and economic losses. Significant casualties and damage are likely and the disaster is potentially widespread. Past orange alerts have required a regional or national level response.

Estimated economic losses are less than 1% of GDP of India.

Overall, the population in this region resides in structures that are vulnerable to earthquake shaking, though resistant structures exist. The predominant vulnerable building types are adobe blocks with wood and rubble/field stone masonry construction.

Recent earthquakes in this area have caused secondary hazards such as landslides that might have contributed to losses.

The quake shocked residents and forced them to run out of their homes.

Some buildings have been damaged but there were no immediate reports of casualties.

Several aftershocks were reported by 05:00 UTC, including M4.7, M4.0, M3.6, and M3.2.

A multi-storied building in Nagaon tilted on the adjacent structure, triggering panic, the India Today reports. Healthcare facilities such as Dispur Hospital, Apollo Clinic, Down Town Hospital and Excelcare Hospital were also damages.

Dozens of homes, apartment buildings and shopping malls across the state also developed cracks.

Many vehicles were damaged after concrete blocks fell on them due to the jolts.

Many people suffered minor injuries while running out in panic as the first quake struck.

Later in the day, authorities said two people died of shock.

Estimated population exposure to earthquake shaking

Selected cities exposed

Regional seismicity

Featured image credit: TW/SAM, Google