A 4.9 quake under Chamoli shakes Delhi-NCR at 10:23 pm, with no damage count yet

A magnitude 4.9 earthquake struck Uttarakhand's Chamoli district at 10:23 pm on Tuesday and was felt across Delhi-NCR, Himachal Pradesh, Punjab and Haryana. The National Centre for Seismology, the nodal agency, placed the hypocentre 13 km below the surface and about 22 km from Khadun Laga Gawali, in the Gairsain area of Chamoli. By midnight the agency had not reported deaths, injuries or collapsed buildings. Residents in Delhi described a short shake rather than a long roll. A revised magnitude, once more stations report, often moves by a tenth or two. The preliminary figure is the one the NCS put out on Tuesday night.

The NCS runs more than 170 seismic stations. A 4.9 at 13 km is a moderate crustal event. At that depth and size, strong shaking is usually limited to a few tens of kilometres from the epicentre, while lighter tremors travel much further through the Indo-Gangetic sediments under Delhi. That pattern matches what was reported: a clear jolt in Chamoli and a noticeable rattle in the capital, without a damage bulletin. India Today noted that researchers will need the focal mechanism, a refined depth and a tighter epicentre before they can tie Tuesday's shock to a named fault. Many earlier Uttarakhand quakes have clustered near the Main Central Thrust, the fault that carries the High Himalaya over the Lesser Himalaya. Proximity is not the same as a published attribution, and the NCS has not issued one.

Chamoli already has a date in the national catalogue. On 29 March 1999 a magnitude 6.8 earthquake in the same district killed about 100 people and damaged houses across Garhwal. The 20 October 1991 Uttarkashi earthquake, also magnitude 6.8, killed several hundred and wrecked villages along the Bhagirathi. Tuesday's 4.9 is not in that class. Each whole step on the magnitude scale is about thirty times the energy, so the gap between 4.9 and 6.8 is several hundred times. What the two older shocks do explain is why a late-night alert from Chamoli still empties stairwells in Delhi. The city sits on a deep sedimentary basin that amplifies distant Himalayan waves, and it has not had a near-field damaging quake in living memory. The hazard planners cite is a future Himalayan rupture, not a repeat of Tuesday's number.

Gairsain is the summer capital of Uttarakhand, chosen in part because it sits closer to the hill districts than Dehradun. A 4.9 under that belt is a local event for the secretariat as well as for the villages around Khadun Laga Gawali. State authorities had not, by the first NCS note, ordered school closures or posted a structural survey. Those steps usually follow a damage report. None had been filed when the preliminary magnitude was released. The district administration's morning round of panchayat offices is the check that would turn a felt event into a casualty list. As of the NCS bulletin, that list did not exist.

The useful figure for anyone who felt the shake is the one the NCS already published: 4.9, 13 km down, 10:23 pm, 22 km from a named village in Gairsain. If the revision stays under 5, and if the morning damage survey from Chamoli is empty, Tuesday night will sit in the catalogue as a felt event rather than a disaster. The older dates, 1991 and 1999, are the reason the phones still light up when the number comes from this district. They are also the reason a 4.9 should be reported with its depth and its distance from a village, not as a prelude.