Hokkaidō earthquake 2018

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Hokkaidō earthquake 2018
2018 Hokkaidō earthquake (Hokkaidō Prefecture)
Bullseye1.svg
date September 5, 2018 UTC
Time 18:07:58 UTC
intensity IX  on the MM scale
Magnitude 6.6  M W
depth 35 km
epicenter 42 ° 41 '10 "  N , 141 ° 55' 44"  E Coordinates: 42 ° 41 '10 "  N , 141 ° 55' 44"  E
country Japan
dead 43


The Hokkaido earthquake occurred on September 6, 2018 at 03:08 local time in southern Hokkaido in the sub-prefecture Iburi , Japan .

course

Main quake

At 3:08 a.m. local time, the earth shook with a strength of 6.6 M w on the moment magnitude scale . The epicenter of the earthquake was near Tomakomai , with a focus depth of 35 kilometers. The Japan Meteorological Agency (JMA) registered a magnitude of 6.7 M jma and a maximum intensity of 7 on the JMA scale . The tremors caused by the earthquake were felt strongly in Aomori Prefecture as well as in Hokkaidō .

Geophysical, geological and climatic environment

At the location of the Hokkaidō earthquake, the Pacific plate moves at a rate of about 87 mm per year in relation to the North American plate towards the northwest and collides with the North American , Eurasian and Philippine plates along the West Pacific subduction zone , which leads to frequent earthquakes .

According to the results of the Earthquake Research Committee , which was set up by the government organization Headquarters for Earthquake Research Promotion ( 地震 調査 研究 推進 本部 ), the earthquake was not associated with the Ishikari fault zone (more precisely: Ishikari-teichi-toen fault zone). Instead, it is more of a intraplate earthquakes of deferment -type (ger .: reverse fault-type ) have acted, in which therefore a hanging wall bedrock along the surface of a tectonic fold to a Lying was pushed bedrock. This fault, which was responsible for the earthquake, was therefore a different fault zone in which the blocks moved up to around 30 km in a north-south direction. The southern central part of Hokkaidō Prefecture near the epicenter is prone to building pressures due to tension from the east and west that is believed to cause earthquakes like the 2018 Hokkaidō earthquake. The same area had already experienced earthquakes with a magnitude of 5 to 6 in the past.

The massive quake triggered landslides in an area of ​​around 20 km by 20 km in the hinterland of the city of Atsuma . This area consists of Neogene sedimentary rocks underground and is largely covered with layers of pumice stone in the size of lapilli (1.5 m grain size ) from the Tarumae volcano (樽前 山). Soil layers close to the surface, which cover low to medium mountain ranges, are in alternation with the pumice stone and volcanic ash . The surface geology in the area around the epicenter of the earthquake has a total thickness of about 4 to 5 m. Experts blamed the high occurrence of loose volcanic soil on Hokkaidō for the island's particular susceptibility to landslides.

Just one day before the earthquake, the mighty Typhoon Jebi (Typhoon 21 of the year 2018 in Japan), which was regarded as the strongest typhoon in Japan for 25 years and claimed 14 lives nationwide, caused heavy rainfall in the region of the earthquake on Hokkaidō, which loosened the soil on the hills and mountains of Hokkaidō. According to JMA, the accumulated rainfall in the last 3 days before the earthquake (September 3rd to 5th) had reached almost 100mm.

Seismic intensity

In the Shikanuma district (鹿 沼) of the city of Atsuma, the quake reached the maximum seismic intensity of 7 on the JMA scale . It was the first earthquake in Hokkaido Prefecture to have a level 7 intensity. It was also the first earthquake in Japan with such a high intensity since the Kumamoto earthquake in 2016 , the sixth earthquake for which a level 7 intensity was recorded in the history of Japan.

Locations with a seismic intensity level 5 or more on the JMA scale
Shindo (intensity) prefecture Place names
7th Hokkaidō Atsuma
6+ Abira , Mukawa
6- Sapporo - Higashi-ku , Chitose , Hidaka , Biratori
5+ Sapporo - Kiyota-ku , - Shiroishi-ku , - Teine-ku , - Kita-ku , Tomakomai, Ebetsu , Mikasa , Eniwa , Naganuma , Shinhidaka , Niikappu
5- Sapporo - Atsubetsu-ku , - Toyohira-ku , - Nishi-ku , Hakodate , Muroran , Iwamizawa , Noboribetsu , Date , Kitahiroshima , Ishikari , Shinshinotsu , Nanporo , Yuni , Kuriyama , Shiraoi

Aftershocks

Aftershocks

By the end of March 2019 there had been 344 subsequent earthquakes with an intensity of 1 or higher (1 earthquake with an intensity of 6, 2 earthquakes with an intensity of 5, 21 earthquakes with an intensity of 4, 38 earthquakes with an intensity of 3, 89 earthquakes with an intensity of 2 and 193 earthquakes with an intensity of 1).

Effects

There were 227 sediment disasters (all in Hokkaidō prefecture), including 133 fractures in rock faces (111 in Atsuma and 3 in Mukawa) and 94 debris avalanches (90 in Atsuma Town).

Victim

Dead and missing

According to the fire and disaster control authority (FDMA), the quake killed 43 people (36 of them in Atsuma, three in Sapporo, two in Tomakomai and one each in Mukawa and Shinhidaka).

The main cause of death was sediment disasters (including landslides and debris avalanches ). In particular, a large landslide on the hill in the city of Atsuma resulted in many deaths and serious and minor injuries. According to reports, 36 people had been killed in landslides (with a total of 41 fatalities from the earthquake).

Around 40,000 emergency services with evacuation vehicles, helicopters and search dogs were used to search for victims. The last person reported missing was found on September 10th.

Injured

48 people were seriously injured in the quake and 734 others were slightly injured.

Evacuations

10 emergency shelters were opened in Hokkaidō Prefecture , to which up to 17,000 people were evacuated . After a month, the number of evacuees had dropped below 500. In Atsuma, the emergency shelters were closed on December 6, 2018. The last emergency shelter in the prefecture was closed on December 21, 2018 in Mukawa.

Damage

Ground surface in northern Atsuma Town before 2018 earthquake.jpg
Ground surface in northern Atsuma Town after 2018 earthquake.jpg
Land cover in North Atsuma before (above: aerial photo taken before 2015) and after (below: aerial photo from September 6, 2018) the quake.
Building damage

415 residential buildings were completely (192 in Atsuma, 92 in Abira, 84 in Sapporo, 26 in Mukawa, 17 in Kitahiroshima, 2 in Hidaka and 1 each in Ebetsu and Chitose) and a further 1,346 partially (530 in Sapporo, 332 in Abira, 278 in Atsuma, 110 in Mukawa, 52 in Hidaka, 17 in Ebetsu, 18 in Kitahiroshima, 3 in Biratori, 2 in Yuni and 1 each in Chitose, Noboribetsu, Hakodate and Tomakomai). Another 8,607 residential buildings were damaged.

The number of non-residential buildings affected was 2,260 (1,181 in Atsuma, 888 in Abira, 157 in Mukawa, 27 in Sapporo, 6 in Ebetsu and 1 in Biratori).

Landslides

The tremendous tremor triggered landslides in an area of ​​about 400 square kilometers in the hinterland of the small town of Atsuma, the place with the most victims, and destroyed houses at the foot of the slopes there.

Subsidence

The earthquake caused many water pipe breaks and subsidence . Dozens of houses were damaged, particularly in Kiyota-ku and other residential areas of the hill zone in southeast Sapporo.

Soil liquefaction

The Satozuka district in Kiyota-ku had been reclaimed by filling a valley with volcanic sand. Since the water table was high due to Typhoon Jebi, the earthquake vibrations liquefied the ground to below the water table, so that finally ground water in lower-lying places emerged and the houses in the area were badly damaged.

Fires

Fires broke out in an oil industrial complex in Muroran City and in the Tomato-Atsuma thermal power station . Both fires were put out on the same morning without any deaths occurring.

Power supply

Two of the three units (units 2 and 4) of the large Tomatō-Atsuma thermal power station, which accounts for around 40% of the electricity produced in Hokkaidō Prefecture, switched off automatically immediately after the earthquake. The third unit (unit 1) was later shut down due to damage to the boiler tube and pressure drop. The failure of electricity generation in the Tomatō-Atsuma thermal power station and the failure of hydropower plants due to interruptions in power lines meant that the remaining electricity generation could no longer cover consumption requirements by far. It came first, the entire coverage area of Hokkaido comprehensive major blackout (Engl. Blackout ). Around 3 million households in Hokkaidō Prefecture (or 5.3 million residents) were without power due to this power outage. A planned emergency power supply from the main island failed due to the failure of an inverter , which was supposed to feed the direct current supplied by the heartland as alternating current into the power grid of Hokkaidō.

There were major disruptions in medical facilities. Power outages affected 349 hospitals in Hokkaido Prefecture. Patients who needed medical ventilators or dialysis treatments therefore had to be transferred from these hospitals to others. 34 so-called disaster hospitals (around the clock responsible for the emergency provision of first aid medication) in the areas with power failure were able to switch to internal power generation and continue their medical service because their emergency power generators have a capacity of 60% of the normal power source and they also had fuel for three days of electricity supply.

The cooling of the old fuel in the cooling pond of the decommissioned nuclear power plant Tomari had to be supplied with emergency generators.

It took about 45 hours to restore power to almost all areas. Two days after the quake, 20,000 households were still without electricity. On September 11, 2018, the power supply was restored in all areas (with the exception of those inaccessible by landslides).

Traffic and transportation

Landslides triggered by the quake made some roads impassable and others were damaged by soil liquefaction .

In many areas, the traffic lights failed because of the power outages, which also affected long-distance truck transport. In various areas of Hokkaidō Prefecture, and particularly in the urban areas including Sapporos, this resulted in a shortage of essential goods such as food, everyday items and petroleum fuels. Freight train traffic in the prefecture also ceased immediately after the earthquake, which in turn affected the delivery of agricultural products such as potatoes and onions, which were just in peak season. The government responded by making trucking available as an alternative to delivery.

At New Chitose Airport , all flights were canceled on September 6, immediately after the earthquake. As a result, many foreign tourists got stuck in the urban area of ​​Sapporo. If they could not find accommodation, they were forced to spend a few nights in buildings belonging to the prefectural government or in underground passages in Sapporo. On the day after the earthquake, almost half of domestic flights resumed. After two days the international flights started running again.

The quake and the associated power outage also affected public transport: The Hokkaido Railway Company stopped train traffic on the island, as did the subways and trams in Sapporo. In the course of September 7th, most of the routes were resumed.

Water and gas supply

Broken water pipes and other reasons led to water outages , affecting up to 68,000 households in 44 communities.

In some hospitals the water supply failed, in some also the supply of medical gas. Many of these hospitals have had to stop accepting outpatients.

After about a month (on October 9, 2018), the water supply was restored in all areas by repairing the power supply and water pipes.

economy

The massive power outage caused by the earthquake led to significant economic losses. He forced many producers to temporarily close their factories. Some companies supplied products and components from the main Japanese island of Honshu by air or sea. There was a bottleneck in the milk supply across Japan, as the dairy industry in Hokkaidō prefecture, which normally accounts for around 50% of national production in Japan, was only able to produce a limited amount of milk due to the earthquake. On the one hand, the power failure disrupted the production processes (e.g. milking , cooling) of the raw milk (i.e. the raw material for drinking milk and butter ), and on the other hand, only two of the 39 milk factories in the prefecture were able to continue operations with their own electricity generation.

Web links

Commons : Hokkaidō Earthquake  - Collection of images, videos and audio files

Individual evidence

  1. ↑ M 6.6 - 27km E of Tomakomai, Japan. United States Geological Survey , accessed May 29, 2020 .
  2. ↑ a b Xiaoyi Shao, Siyuan Ma, Chong Xu, Pengfei Zhang, Boyu Wen, Yingying Tian, ​​Qing Zhou, Yulong Cui: Planet Image-Based Inventorying and Machine Learning-Based Susceptibility Mapping for the Landslides Triggered by the 2018 Mw6.6 Tomakomai , Japan Earthquake . In: Remote Sensing . tape 11 , no. 8 , 2019, pp. 978 ff ., doi : 10.3390 / rs11080978 (English). Published online April 24, 2019. License: Creative Commons Attribution 4.0 International (CC BY 4.0).
  3. ↑ a b c d e f g h i j k l m n o p q r s t u v w x White Paper on Disaster Management 2019 ( en , PDF; 21.7 MB) Cabinet Office Japan (内閣 府), Disaster Management in Japan. Pp. 22-33. Archived from the original on May 14, 2020. Retrieved May 14, 2020. Accessed via website: " White Paper on Disaster Management "
  4. ↑ a b c d e Hiromitsu Yamagishi, Fumiaki Yamazaki: Landslides by the 2018 Hokkaido Iburi-Tobu Earthquake on September 6 . In: Landslides . tape 15 , 2018, p. 2521-2524 , doi : 10.1007 / s10346-018-1092-z (English). Published online October 31, 2018. License: Creative Commons Attribution 4.0 International (CC BY 4.0).
  5. ↑ a b After the severe earthquake on Hokkaido, the death toll rises ( memento from September 8, 2018 on WebCite ) , nzz.ch, September 7, 2018, by Patrick Welter.
  6. ↑ 平 成 30 年 09 月 03 日 平 成 30 年 台風 第 21 号 に よ る 被害 及 び 消防 機関 等 の 対 応 状況 （第 10 報 R1.8.20） ( jp , PDF; 214 KB) 総 務 省 消防 庁 (Fire and Disaster Management Agency ). Pp. 1-3. August 20, 2019. Archived from the original on December 27, 2019. Retrieved on May 17, 2020. [10. Damage report on Typhoon 21/2018]. Access via website: " 平 成 30 年 災害 情報 一 覧 "
  7. ↑ White Paper on Disaster Management 2019 ( en , PDF; 21.7 MB) Cabinet Office Japan (内閣 府), Disaster Management in Japan. Pp. 17-21. Archived from the original on May 14, 2020. Retrieved May 14, 2020. Accessed via website: " White Paper on Disaster Management "
  8. ↑ Number of deaths after earthquake in Japan rises to 35 - the severe quake on the Japanese north island of Hokkaido claimed dozens of lives - and people are still missing ( memento from September 9, 2018 on WebCite ) , bernerzeitung.ch, September 9, 2018 .
  9. ↑ a b c d e 7 die, 30 missing after intensity-7 earthquake strikes Hokkaido ( Memento from September 8, 2018 on WebCite ) , The Asahi Shimbun, September 6, 2018.
  10. ↑ 震度データベース検索(地震別検索結果) ( Memento of 9 September 2018 Webcite ) ,気象庁(Japan Meteorological Agency) website Path:ホーム>各種データ·資料>震度データベース検索>震度データベース検索(地震別検索結果）.
  11. ↑ 平 成 30 年 北海道 胆 振 東部 地震 に よ る 被害 及 び 消防 機関 等 の 対 応 状況 （第 22 報 H30.9.12） ( Memento from September 12, 2018 on WebCite ) , 総 務 省 消防 庁 (Fire and Disaster Management Agency), 22. Damage report, September 12, 2018.
  12. ↑ a b 平 成 30 年 09 月 06 日 平 成 30 年 北海道 胆 振 東部 地震 に よ る 被害 及 び 消防 機関 等 の 対 応 状況 （第 35 報 R1.8.20） ( jp , PDF; 192 KB) 総 務 省 消防 庁 (Fire and Disaster Management Agency). Pp. 1-3. August 20, 2019. Archived from the original on May 16, 2020. Retrieved on May 16, 2020. [35. Damage report]. Access via website: " 平 成 30 年 災害 情報 一 覧 "
  13. ↑ a b c d Number of victims after earthquake in Japan rose to 30. In: ORF . September 8, 2018, accessed September 8, 2018 .
  14. ↑ a b c Death toll from Hokkaido quake reaches 41 as last missing found. In: Asahi Shimbun . September 11, 2018, accessed on September 11, 2018 .
  15. ↑ a b c 平 成 30 年 北海道 胆 振 東部 地震 に よ る 被害 及 び 消防 機関 等 の 対 応 状況 （第 33 報 H30.11.6） ( Memento from December 7, 2018 on WebCite ) , 総 務 省 消防 庁 (Fire and Disaster Management Agency) , 33rd damage report, November 6, 2018.
  16. ↑ a b c d e Hokkaido blackout partly due to power diversion failure; dialysis patients at risk. In: Mainichi Shimbun . September 7, 2018, accessed September 8, 2018 .
  17. ↑ Deaths and severe damage after earthquake in Japan. In: The press . September 6, 2018, accessed September 8, 2018 .
  18. ↑ a b Transportation services resume in quake hit Hokkaido. In: Asahi Shimbun . September 7, 2018, accessed September 8, 2018 .