"Death Risk at 100cm"...Why an Unprecedented 32-Hour Tsunami Advisory Was Issued in Midsummer [Sunday Japan Culture]

This week, a tsunami warning was issued in Japan following an earthquake on the Kamchatka Peninsula in Russia. The earthquake had a magnitude of 8.8, making it a significant event, and the tsunami alert in Japan has been widely reported in South Korea as well. Although the tsunami advisory was lifted as of July 31, there are still many discussions in Japan regarding follow-up measures. Today, we introduce how the aftermath of the tsunami that shook the Japanese archipelago this week is unfolding.

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This tsunami was triggered by the earthquake that occurred on July 30 in Petropavlovsk, Kamchatka Peninsula. In Japan, confusion arose in many areas because the tsunami struck in the middle of summer and the evacuation order was not lifted until 32 hours after it was issued.

When a tsunami evacuation order is issued, residents must move to nearby high ground. Typically, people head outdoors to mountains or hills. The problem is that they have to wait outdoors until the alert is lifted, even in the heat of summer. There have been cases where people returned home, feeling reassured after the first tsunami had passed, only to fall victim to a second tsunami.

Tsunami broadcast footage from the 31st of last month. TBS.

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As a result, many evacuees?especially among the elderly?were hospitalized for heatstroke. In Iwate Prefecture, a man in his 90s was transported due to heatstroke, and in Sendai City, a woman in her 50s was hospitalized after showing symptoms of heatstroke during evacuation. Since tsunamis do not choose a season to strike, the evacuation itself is only the beginning; the real challenge is dealing with the weather conditions that follow.

After the tsunami advisory was lifted, Japanese media began to explain new summer evacuation guidelines. They recommend bringing a parasol when evacuating outdoors, creating shade with a mat, and cooling heat-sensitive areas like the neck or palms with water or ice. Disaster prevention experts have also suggested that, rather than insisting on "always move to higher ground," people should stay indoors if they are in a sufficiently high place, such as the third floor or above. There were also proposals to include car evacuation as an option in summer, in addition to walking to higher ground, since cars allow for air conditioning and phone charging.

The process of issuing the tsunami warning was as follows. At 8:37 a.m. on July 30, a tsunami advisory was issued. When it became clear that a major earthquake had occurred, the advisory was upgraded to a tsunami warning at 9:40 a.m. The tsunami warning was lifted at 8:45 p.m., but advisories remained in place in some areas. It was not until 4:30 p.m. the next day that all advisories were lifted. The fact that advisories remained in effect for more than 30 hours was considered highly unusual.

This was reportedly because it was extremely difficult to predict this particular tsunami. Between the Kamchatka Peninsula and the eastern side of the Japanese archipelago lies the "Hawaii-Emperor Seamount Chain," an undersea mountain range stretching 2,000 km from north to south. Tsunami waves generated by the Kamchatka earthquake are repeatedly reflected or intersect in this area.

Tsunami action chart announced to residents in Nanao City, Japan. It explains response measures according to the height. Nanao City official website.

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Therefore, it is very difficult for the meteorological agency to calculate and predict tsunami behavior. In the past, there were cases where tsunamis reflected off this undersea mountain range were not detected, making the calculations highly complex. As a result, the agency delayed lifting the advisories as much as possible to account for potential reflected waves.

Even after the tsunami advisory was lifted, high waves were observed in various parts of the country, such as 27 cm in Iwate Prefecture and 6 cm in Shizuoka. The longer a tsunami warning remains in effect, the more daily life is disrupted and losses increase. However, the meteorological agency cannot simply lift the warning prematurely, so they face a difficult dilemma.

In fact, Japan has a long history of frequent tsunami damage, with records dating back to before the Common Era. This is also why the word "tsunami," a Japanese term, is used internationally for seismic sea waves. In Japanese, "tsunami" is written as "津波": the first character refers to a port or ferry landing, and the second means wave. In other words, it describes abnormal waves surging into a harbor. Although this week's Kamchatka Peninsula earthquake occurred in Russia, not Japan, waves surged into Japanese ports, forcing coastal residents to evacuate.

Because tsunamis have frequently damaged or destroyed cultural sites in Japan, many local governments sponsor restoration projects. In areas like Iwate Prefecture, which suffered greatly from the Great East Japan Earthquake, universities collaborate on active research projects to study how to rescue and restore cultural assets in the event of a tsunami.

Did you know that the United Nations also established World Tsunami Awareness Day? The reason for this also originates in Japan. The lesson comes from the story known as "The Fire of Inamura (rice sheaves)." On November 5, 1854, in Wakayama Prefecture, a soy sauce brewer set fire to his own rice sheaves to guide people to higher ground when a tsunami suddenly struck. Afterwards, he led efforts to build seawalls in the village to prevent future tsunami damage. The story of "The Fire of Inamura" embodies the humanitarian spirit discovered during a natural disaster. To remember this lesson, the UN General Assembly unanimously designated November 5 as "World Tsunami Awareness Day" in 2015.

A graphic from Yahoo Japan warning that a tsunami height of just 20 to 30 cm can be threatening. It explains that even 20 cm is enough to make it difficult for an adult to walk. Yahoo Japan.

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When we think of tsunamis, we often recall the massive waves that engulfed everything during the Great East Japan Earthquake. However, even waves just 20 to 30 cm high can be dangerous. At 20 cm, it is difficult for an adult to walk; at 50 cm, you cannot stand without holding onto something. At 70 cm, even adults can be swept away, and at 100 cm, it becomes impossible to stand and the risk of death is high. This is why evacuation is advised as soon as a tsunami advisory is issued.

Since the Great East Japan Earthquake, Japan's disaster news coverage regarding tsunamis has become more advanced. When an evacuation order is issued, broadcasters interrupt all programming to deliver earthquake alerts. Announcers speak in strong, loud voices to urge evacuation. For those who are not fluent in Japanese, instructions to flee are written in hiragana without kanji. Information about earthquakes is provided in 15 languages, including English, Chinese, and Tagalog, to accommodate foreign travelers and workers.

Ulleungdo and Dokdo in South Korea were also within the impact zone of this tsunami. In fact, when a major earthquake occurs in Japan, South Korea can also suffer direct or indirect tsunami damage. Although tsunamis do not occur as frequently as in neighboring Japan, it is clear that some level of preparedness is necessary.

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