Iwaki City Earthquake Map

Introduction

Overview of the Great East Japan Earthquake

On March 11th, 2011, a destructive natural disaster known as the Great East Japan Earthquake occurred. A magnitude 9.1 earthquake occurred at the Pacific Sanriku offshore (Map 1) and the main disaster hit a northeastern part of Japan at 14:46 Tokyo time. Soon after the earthquake, a tsunami of around 40 m maximum height and 10 km maximum interior spilled onto the coastline. It ended up both destroying and swiping a broad swath of coastal land.

As a result of the earthquake-tsunami combination, the Fukushima-Daiichi nuclear power plant exploded and caused a nuclear crisis with severe long-term impacts to the surrounding areas. The Great East Japan Earthquake resulted in the following: a) the destruction of over 270,000 buildings; b) over 400,000 people being evacuated; and c) over 20,000 casualties.

Usually, in case of natural disasters, local or regional governments will response and lead the situation. However, since the scale of disaster was extremely huge and destructive, regional governments could not function at the Great East Japan Earthquake event. It took a longer time to grasp the whole damaging situation because the affected area was too large to be observed by helicopters or planes, and many roads were destroyed that created a lot of isolated areas. The damaged area was about 500km north to south and 200km east to west.

Location	38.297 °N 142.373 °E
Magnitude	9.1
Depth	29 km
Origin Time	3/11/2011 2:46:24 PM (GMT +9)
Max Tsunami	40 m High, 10 km Interior
Casualties	20,000 +
Building Damage	270,000 +
Evacuee Population	400,000 +

Table 1. Main Shock Summary

Study Area: Iwaki

Overview of the Iwaki City

Iwaki City, Fukushima which is located 200 km north of Tokyo was affected by the earthquake and tsunami. However, the city accepts evacuees from the “difficult-to-return-zone” which is within 30km from the nuclear power plant.
Iwaki City is...

1,232 ㎢ large and has more than 30,000 people.
Located 30 km south from Fukushima Daiichi Nuclear Power Plant (Map 2).
Facing the Pacific Ocean on east side, and the coastline is about 60 km long.
Accepting 20,000 evacuees from “difficult-to-return-zone”.

Damage in Iwaki City

Below is the summary of the main shock damage in the Iwaki City.

Shake Lasted more than 3 minutes.
Scale was 6 Lower*.
The highest tsunami was 8.57 m in Toyoma neighborhood (Map 2).
Overall, 64 people lost their lives* (Table 2).
Water infrastructure took a month to recover.
Many Iwaki citizens chose to evacuate from Iwaki by themselves due to fear of invisible radiation.

*See table 2 for human and building damage in Iwaki.
*Read about earthquake scaling.
Iwaki had a harder time obtaining relief supplies and volunteers than other affected areas due to the radiation rumor.

Loss of Lives
Number of Direct Death	293
Number of Related Death	134
Number of Missing People Reported As Death	37
Total Number of Death	464

Number of Damaged Residential Buildings
Complete Destruction	7,902
Large Scale Destruction	9,253
Half Destruction	33,146
Partial Destruction	40,879
Total Number of Damaged Buildings	91,180

Table 2. Human and Building Damage

Damage and Recovery

This map introduces some of the damages and recovery of the disaster in Iwaki. Each point contains 2 images that shows the aftermath of the disaster and the recovery (by 2016).

Photo Credit: Iwaki City, Hiroko Ishikawa, Fukushima Prefecture EMAC, Ken Midorikawa, Dai Suzuki, JGSDF 8th Infantry Regiment, Takayuki Saito, Board of Education, Koichi Hosokawa, Fukushima Prefecture EMAC, Iwaki Construction Office, Tokuji Watanabe
*Jump to the actual web map

Population In Iwaki

Temporary Houses

The map shows the temporary houses in Iwaki City.
The Graph 1 shows the Population Change living in the temporary housing communities based on where the evacuees are from.
Graph 1

Graph 1

Hirono, Naraha, Kawauchi, and Tomioka were eliminated from the “difficult-to-return zone”.
2464 people changed their addresses to Iwaki from the areas listed in the graph.
Some elderly population from the areas which were eliminated from “difficult-to-return zone” returned.
Iwaki citizens living in temporary houses are mainly the population who lost their houses by tsunami.

Population Change

Iwaki is divided into 13 districts. Taira, Onahama, Uchigo are urban areas.

Population Change from 2010-2013

Hisanohama has a higher population declining rate. Why is that?

It is located 30 km from the nuclear power plant.
Residential area was wiped out by tsunami and fire. (Check the map in Damage and Recovery section.)

Overall, the population is declining even when Iwaki accepted evacuees from other towns. Why is that?

People who evacuated to Iwaki kept their old addresses, so their number is not reflected to the census.
Many Iwaki citizens chose to evacuate outside of Iwaki by themselves.

Map 3

Population Change from 2013-2016

From 2013-2016, population is increasing in urban area. Because....

Some of the Iwaki citizens returned.
Nuclear power plant workers moved to Iwaki and commute from Iwaki.
Many evacuees from outside changed their addresses to Iwaki and became Iwaki citizens.

(*Kawamae, Miwa, Tono, and Tabito are naturally decreasing.)

Map 4

About

I am a graduate student in University of Minnesota - Twin Cities in the Master in Geographic Information Science (GIS) program. I currently hold a Bachelor of Arts Degree from the University of Minnesota - Duluth in GIS with minor in Geography.

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