TOPICSThe Impact of the Great East Japan
Earthquake Disaster on Ship Movements

Port Planning Division, Port and Harbor Department
SEMA Motohiro, Researcher
ANDO Kazuya, Research Officer(Keywords) Great East Japan Earthquake Disaster, ship movements, AIS data, ship calling data

2. Impact on ship movements
Firstly, we used AIS data to glean general trends
in the impact on ship movements. Fig. 1 shows
year-on-year change in total monthly transits byships through the three main bays (Tokyo Bay, Ise
Bay and Osaka Bay), organized by ship type(January = 1.00). The year-on-year decline by purecar carriers after the disaster is particularly stark; thisis thought to result from reduced production offinished vehicles owing to the disaster. A sharp
decrease was seen even in general cargo ships inApril. Tankers, on the other hand, increased from
April onwards. This is thought to be because output
by refineries in western Japan was increased to fill
the gap caused by damage to refineries in Tokyo Bay
and on the Pacific coast of Tohoku due to thedisaster.
As well as this, we used ship calling data toascertain in greater detail the state of damaged ports(from Hachinohe to Kagoshima) as compared toports on the Japan Sea side (from the Japan Sea sideof Tohoku to the Hokuriku region). Fig. 2 shows theaggregated ship calling frequency of full containerships, bulk carriers and general cargo ships by month,
as well as trends in these.

対前年同月比(1月=1.0)

Year-on-year comparison by month (Jan. = 1.0)

1.4Full container ships
Bulk carriers●：フルコンテナ船□：バルクキャリア
Tankers
General cargo ships
Pure car carriers◇：一般貨物船▲：自動車専用船▼：タンカー

1.2
10.8
0.6Jan.
1月

Feb.
2月

Mar.
Apr.
3月
4月
2011
2011年

May
5月

Jun
6月

Figure 1. Year-on-year change in total monthlytransits through the three main bays
200
Ship callingfrequency
寄港回数1. Introduction
The Great East Japan Earthquake Disaster ofMarch 11th, 2011, caused immense damage to port
and harbor facilities, particularly in the Pacific coast
regions of eastern Japan. Moreover, the accidental
release of radioactive substances following a fire at
TEPCO’s Fukushima No. 1 nuclear power plant had
a major impact on the international cargo flow andship calling of Japan. We therefore organized AIS
data and LLI ship calling data to discover the impactof the disaster on ship movements.
Here, AIS data are data observed from signals(vessel name, positional information, etc.)
transmitted by the Automatic Identification System,
which ships above a certain scale are obliged tocarry.

Full container ships●：フルコンテナ船(damaged ports)（被災港湾）
Full container ships○：フルコンテナ船(Japan Sea ports)（日本海側港湾）
Bulk carriers (damaged■：バルクキャリアports)（被災港湾）
Bulk carriers (Japan Sea□：バルクキャリアports)（日本海側港湾）
General cargo ships◆：一般貨物船(damaged ports)（被災港湾）
General cargo ships◇：一般貨物船(Japan Sea ports)（日本海側港湾）150
100
500Jan.
1月

Feb.
2月

Mar.
3月
2011
2011年

Apr.
4月

Figure 2. Trends in ship calling frequency
This study confirmed that, while the ship calling
frequency in damaged ports decreased after thedisaster, it increased in Japan Sea ports, particularly
among full container ships, and that therefore theJapan Sea ports served as substitutes for thefunctions of damaged ports.
[Reference]
NILIM Technical Note No. 649
http://www.nilim.go.jp/lab/bcg/siryou/tnn/tnn0649.
htm