The chain of powerful quakes that have rocked Kumamoto Prefecture and neighboring areas since Thursday has defied conventional wisdom built on past experience in this quake-prone country. The initial magnitude 6.5 earthquake that registered the maximum 7 on the Japanese seismic intensity scale Thursday night was followed by a much more powerful magnitude 7.3 temblor — equivalent to the 1995 quake that devastated Kobe in 1995 — in the wee hours of Saturday morning, which expanded the destruction to much broader areas. The number of quakes that hit the areas topped 500 as of Monday morning, including six that registered in the 6 range on the Japanese scale — each strong enough to wreak extensive damage.
The emergency rescue and support of survivors remains a top priority after the quakes claimed at least 42 lives and injured more than 1,000. More than 100,000 people were forced to evacuate their homes as of Monday since the quakes made them uninhabitable or they feared further destruction of their already-damaged properties by the aftershocks. Food supplies to evacuees and local shops remain scarce due to transportation disruptions. Hundreds of thousands of households have been left without water, gas and electricity for days.
The quakes demonstrate once again that natural disasters can hit at any time and anywhere in ways and scope that are beyond our imagination — just as the Great East Japan Earthquake and tsunami showed us five years ago. The Kumamoto quakes, which originated at a shallow depth of around 10 km, took place on active faults. The nation is estimated to have roughly 2,000 active faults. We can’t stop natural disasters from hitting us but we can still find ways to control the damage. We need to assess if the lessons of past disasters have helped contain damage in the Kumamoto quakes and explore what can be learned from the latest catastrophe.
Most of the powerful earthquakes on record in this country have been followed by aftershocks that continued for days but with declining seismic intensity and frequency. The Kumamoto quakes were unusual in that the biggest temblor had been preceded by the magnitude 6.5 quake two days earlier, and was then followed by powerful aftershocks in quick succession. Many houses that had been partially damaged in the Thursday quake in the town of Mashiki, near the epicenter, were destroyed by the Saturday temblor, whose seismic energy was 16 times stronger than the first one. It also defied past experience that the area of seismic activity widened with time — in a northeast direction toward neighboring Oita Prefecture. The Meteorological Agency said the seismic movements remained active across the affected areas on Monday.
About 400 houses and buildings have been destroyed and more than 1,200 others were seriously damaged. In Uto, Yatsushiro and Mashiki, all in Kumamoto Prefecture, municipal government functions were paralyzed because the city halls were damaged. Many public facilities designed to serve as shelters for the evacuees were rendered unusable.
Many of the people killed and injured in the Kumamoto quakes were crushed when their houses collapsed. Nearly 90 percent of the victims of the 1995 Great Hanshin Earthquake — which claimed more than 6,000 lives, were crushed when their wooden houses collapsed. Most had been built before the anti-quake standards were updated in the 1980s. Many of the houses destroyed by the Kumamoto quakes also appear to have been built under the old standards. Efforts since the 1995 disaster to make houses quake-resistant are making slow progress, with the ratio improving from 79 percent in 2008 to 82 percent in 2013, according to the land ministry. The advancement of such efforts will be key to limiting the destruction caused by future earthquakes.
The extensive damage to houses and the continuing aftershocks will likely force large numbers of residents in the quake-hit areas to remain evacuated for an extended period. Safe shelter and sufficient basic supplies such as food and water must be secured for them, but longer-term care, including psychological care to ease the stress and fear caused by the quakes and evacuation should also be provided.
In the 2004 quake that hit Niigata Prefecture, which was also marked by powerful aftershocks that continued for days, evacuation-related health issues claimed the lives of three-quarters of the victims. The tough life in evacuation can take an especially heavy toll on the health of the elderly in particular, as demonstrated by the 3/11 disasters. On Sunday, a 77-year-old woman who had been evacuated to a shelter in Aso, Kumamoto Prefecture died of acute heart failure that was possibly linked to the stress and fatigue from evacuation. Utmost care needs to be taken to provide elderly evacuees with both physical and psychological support.
By subscribing, you can help us get the story right.