2018 Hokkaido Eastern Iburi earthquake

2018 Hokkaido Eastern Iburi earthquake
2018 Hokkaido Eastern Iburi earthquake is located in Japan
2018 Hokkaido Eastern Iburi earthquake
UTC time2018-09-05 18:07:58
ISC event
Local date6 September 2018 (2018-09-06)
Local time3:08 a.m. JST
Magnitude6.6 Mw
Depth35.0 km (22 mi)
Epicenter42°40′16″N 141°55′59″E / 42°40′16″N 141°55′59″E / 42.671; 141.933
TypeIntraplate earthquake[1]
Max. intensityIX (Violent)
7 (X–XII (Extreme))
Largest: Mw 5.4 on 6 September (6:04 a.m. JST)[2]
Casualties41 dead, about 680 injuries[3]

An earthquake measuring 6.6 MW on the moment magnitude scale struck Iburi Subprefecture in southern Hokkaido, Japan, on 6 September 2018 at 3:08 a.m. Japan Standard Time. The earthquake's epicenter was near Tomakomai and occurred at a depth of 35.0 kilometres (21.7 mi). The Japan Meteorological Agency (JMA) registered a magnitude of 6.7 Mj and a maximum intensity of 7 on the shindo scale.[4]Shaking from the earthquake was felt strongly in Hokkaido and Aomori Prefecture.[5] The earthquake disrupted electrical service throughout Hokkaido, leaving 5.3 million residents without power. Forty-one people were confirmed dead and around six hundred and eighty were injured.[3] The event is officially known as Heisei san-jū-nen Hokkaidō Iburi tōbu jishin (平成30年北海道胆振東部地震, "Hokkaido Eastern Iburi Earthquake of Heisei 30").

Damage and effects

Number of households that had power restored (JST)[6]
Date Time Households % Ref
6 Sep 3:08 0 / 2,950,000 0%
16:00 329,000 12% [7]
7 Sep 3:00 964,000 33% [8]
9:00 1,455,000 49% [9]
12:00 1,513,000 51% [10]
8 Sep 4:00 2,928,000 99% [11]

The earthquake cut power to all 2.95 million households in Hokkaido. This was because the Hokkaido Electric Power Company's coal-fired power plant in Atsuma was heavily damaged by fires that broke out during the earthquake. The damage to the plant caused an imbalance in the supply and demand of electricity throughout Hokkaido; this resulted in the blackout.[12] By 6:30 p.m. JST on the day of the earthquake, power was restored to 340,000 households in Hokkaido.

All flights to New Chitose Airport were cancelled on the day of the quake. NHK World-Japan announced the airport resumed business at 11:00 a.m. JST the day after the quake. All public transport, including rail, subway, and bus services was shut down in Hokkaido due to the loss of electricity and damages.[13][14] Hospitals were forced to function on emergency backup power, due to the blackout. Many hospitals had to turn away emergency patients because of the outages.[15]

The earthquake caused many roads in Hokkaido to become impassable. Some roads were blocked by debris from landslides, others were destroyed by soil liquefaction as far away from the epicenter as Kiyota-ku, Sapporo.[12] Near the earthquake's epicenter in Atsuma, emergency services could not take emergency calls after the quake due to the heavy damage.[16]

The blackout had a severe impact on the farming and fishing industries in Hokkaido. The prefecture provides half of Japan's raw milk, but without power for refrigeration or operating the milking equipment, the cows could not be milked and the product was wasted. Other produce, such as onions and potatoes, could not be kept cool or shipped away due to the closure of the rail network.[17]