Typhoon approaching local government HP "I can not see"

Typhoon approaching local government HP "I can't see" November 6, 7:17

In the last month when Typhoon No.19 caused a record heavy rain, local governments reported disaster prevention information through websites, but when NHK analyzed posts to SNS, it was at least 11 from Kanto to Tohoku at that time. It turned out that it was difficult to connect the homepage in 53 municipalities in all prefectures.

Last month's Typhoon No. 19 was a record heavy rain with a special heavy rain warning in a wide area of ​​eastern Japan, and many local governments provided information on evacuation and river levels through the local government website.

In this regard, NHK uses a system called “DISANANA” that analyzes Twitter posts in the event of a disaster operated by the National Institute of Information and Communications Technology to examine posts from 12th to 14th of the month when Typhoon 19 approached. It was.

As a result, posts indicating that local government websites are difficult to connect, such as “Cannot see homepage” or “Server is down”, were sent from Tokyo, Saitama Prefecture, Nagano Prefecture, etc. I found that it climbed to 53 cities in at least 11 prefectures in the Tohoku region.

Many of these areas were included in areas where special warnings were issued.

At that time, many local governments provided information on disaster prevention from their websites, which is thought to be due to the concentration of access.

Prof. Takamichi Saito of Meiji University, who is familiar with information systems, said, “During disasters, the provision of information through websites is becoming very important. Also need to participate and create a reliable system. "

Mayor Setagaya disseminates information on Twitter

In Setagaya Ward, Tokyo, the homepage of the ward is no longer connected, so the director of Setagaya Ward, Hosaka Exhibition Director, sent information using Twitter.

Mr. Hosaka usually uses Twitter personally and has 83,000 followers called followers.

At that time, the mayor's Twitter said that the sound of the disaster prevention administrative radio could not be heard or that the homepage was not connected and the hazard map could not be seen. It was that I posted it by taking a picture of the hazard map or taking a picture of the hazard map.

In addition, many residents asked for information on river levels, shelter locations, etc., and Mayor Hosaka said, “The information was sent with care not to differ from official information. “It is indispensable for residents to seek detailed information about themselves in real time.The transmission on the homepage is indispensable, and we want to quickly build a system that can be surely transmitted even in the event of a disaster based on the lessons learned. I was talking.

Local government response

The capacity of the internet connection to connect to the homepage is limited, and if communication exceeding the assumption is concentrated, communication will overflow and connection will become impossible.

A blogger who is familiar with information security research organizations under the name of “piyokango”, who is familiar with information security, measured the communication speed of a page that posted disaster information on Tokyo on the 12th of the month when a typhoon was approaching. As a result, the communication speed dropped rapidly from the early morning of the 12th of last month, and it was almost zero around 8am.

In fact, the homepage of the city was almost unconnected for about 14 hours until around 10pm.

In Setagaya Ward, Tokyo, 270,000 accesses were concentrated on the 1st of last month, nearly 40 times the normal, making it difficult to connect to the homepage from around 11:00 am.

Ward removed videos and images with large communication capacity from the homepage, switched to a disaster homepage that displays only text information, or switched to an emergency server, but it was difficult to connect until around 6pm It is that.

Shigeko Yamato, Director of Public Relations Division, Setagaya Ward, said, “I have a countermeasure for the disaster, but I have a countermeasure for the disaster. I want to make use of my lessons.

On the other hand, in Adachi-ku, Tokyo, the past fireworks display and the experience of concentrated access to the homepage during Typhoon No. 15 in September, the typhoon No. 19 before the typhoon approached 10 am Sometimes, the homepage was switched to a disaster with only text information.

Also, even if the load was concentrated on one server by distributing the servers, it was possible to prevent the situation where the homepage could not be connected because the system for securing the connection was used.

Analyzing the country

According to the Ministry of Internal Affairs and Communications, after the Great East Japan Earthquake, maintenance has been promoted so that the internal system does not break down at the time of the disaster, but there are no manuals etc. specified for measures when communication is concentrated on the homepage is.

In response to the fact that this typhoon No. 19 made it difficult for local governments to connect to the homepage, the Ministry of Internal Affairs and Communications is conducting a survey on the correspondence of local governments in each region, so how can the connection of the homepage be interrupted in the event of a disaster? However, I want to analyze successful cases and introduce improvement measures and countermeasures.