CHIANG MAI’S Irrigation Bureau 1 said this northern province’s two dams remained stable after a 4.1 magnitude earthquake with a very shallow depth of 2 kilometres hit Mae Khue subdistrict of Doi Saket district at 4.36 a.m. this morning (Oct. 20), Sanook.com said.
Mae Kuang Udom Thara Dam in Doi Saket district experienced peak ground acceleration of 0.15 g, with the impact being 16.38 percent.
Mae Ngat Somboon Chon Dam in the Mae Taeng district measured the peak ground acceleration at 0.0101854 g, affecting 4.123 percent of the structure.
Both dams are in stable and strong normal condition.
The Earthquake Observation Division of the Thai Meteorological Department also reported that an earthquake of 3.7 magnitude and depth of 3 kilometres struck Mae Pan subdistrict, Long district, Phrae province at 1.39 a.m. and milder ones measuring 2.9 on the Richter scale hit Ban Pin subdistrict at 4.50 a.m. and magnitude of 2 shook Huai O subdistrict at 5.32 a.m., both in Long district of this province.
The Office of Mineral Resources, District 1, Lampang, which in charge of the 17 northern provinces, said the cause of the quakes is the Mae Chan Fault which passes Mae Tha district of Lampang and Mae On district in Chiang Mai in an eastward curve and is 61 kilometres long.
Statistics show that this fault generated very strong earthquake measuring 5.1 on the Richter scale in 2006 with the epicentre being Mae Rim district and vibrations felt over in a wide area.
Earthquake Surveillance Division I was informed that tremors were felt in Mueang, San Kamphaeng, San Sai, Mae Rim and Doi Saket districts of Chiang Mai province; Mueang and Ban Thi districts of Lamphun province; Dok Khamtai district of Phayao province; and some parts of Hang Chat district of Lampang Province.
People in many Chiang Mai districts got frightened by the tremors of this quake that lasted about three seconds with even single-storey houses swaying. No aftershocks were reported.
Netizens quickly shared video clips of the quake which they said was quite strong. Residents in the area mentioned that they had never experienced this strong a quake that even shook houses before.
Mae Kuang Udom Thara Dam. Photo: Matichon
(This report has been updated to give details of earthquakes in Phrae province.)
Watch video clip of the impact of the predawn quake in Chiang Mai: