A 4.5-magnitude earthquake shook six northern provinces early yesterday morning, prompting calls from experts for an inspection of older buildings.
The Thai Meteorological Department (TMD) reported the quake was detected five kilometres underground in tambon Phai Lom of Phitsanulok's Bang Krathum district at 12.17am.
People in Phitsanulok and the adjacent provinces of Phichit and Kamphaeng Phet reportedly felt the tremor.
Others in Nakhon Sawan province in the lower North and the northeastern province of Loei also felt it, according to the TMD.
There were reports of cracks at Wat Rat Chang Khwan in Muang district of Phichit. The Buddhist temple stands about 7km from the epicentre of the earthquake.
The Department of Mineral Resources (DMR) attributed the quake to the movement of a hidden fault line that had not been active for about a century.
The earthquake was at a relatively shallow depth and was felt in Phitsanulok, Phichit, Kamphaeng Phet, Nakhon Sawan, Loei, as well as Phetchabun, said the department.
No aftershocks or casualties were reported.
A crisis centre was set up to monitor the aftermath of the quake in Bang Krathum district on the provincial governor's order. Officials were immediately sent to inspect any damage to buildings and temples and give counselling to worried residents.
In neighbouring Uttaradit, the Sirikit dam, the closest major dam to the quake's epicentre, was found not to have been impacted, according to the authorities.
TMD director-general, Chomparee Chompurat, said yesterday it took the department 17 minutes to convey essential information about the quake to related agencies such as the Electricity Generating Authority of Thailand (Egat), which supervises operations at the Sirikit dam, and the Highways Department.
The TMD was working with the DMR to follow up on a post-quake damage assessment. Locals were also bracing for possible aftershocks.
So far, 144 residents were reported to have been adversely impacted by the quake.
Meanwhile, Amorn Pimanmas, president of the Thailand Structural Engineers Association and an earthquake emergency mitigation researcher, said buildings, particularly those that are two years or older, are regularly inspected to test their ability to withstand earthquakes.
Yesterday's quake, although medium-sized, was felt far and wide because it was located relatively close to the ground surface.
In 2021, the Department of Public Works and Town & Country Planning decreed that new buildings must be quake-tolerant. The ministerial regulation comes with strict building requirements on structural strength reinforcements.
Under the regulation, some provinces were given a quake-risk rating. Phichit, however, was not one of them.
Mr Amorn said any buildings constructed prior to 2021, as well as temples and historical structures, were not designed to resist tremors.