Aon initially expects the earthquake that struck Kumamoto Prefecture and the island of Kyushu in southern Japan on 28 July to result in relatively lower losses than the devastating 2016 Kumamoto earthquakes, which caused $53 billion in economic and $7.7 billion in insured losses.
In its Weekly Cat Report, the re/insurance broker said the powerful earthquake that struck southern Japan resulted in at least 35 fatalities and hundreds of injuries, while causing significant property and infrastructural damage across several prefectures.
The United States Geological Survey provided a summary of the event: “The July 28, 2026 M 6.8 earthquake south of Kumamoto, on the island of Kyushu in southwest Japan, occurred as the result of shallow strike‑slip faulting. Focal mechanisms indicate that the slip took place either on a left‑lateral fault striking northwest or on a right‑lateral fault striking northeast.
“Although the earthquake occurred several hundred kilometers northwest of the Ryukyu Trench, where the Philippine Sea plate begins its northwestward subduction beneath Japan and the Eurasia plate, the shallow depth and faulting style indicate that this event occurred on a crustal fault within the upper Eurasia plate. At this location, the Philippine Sea plate converges with the Eurasia plate toward the northwest at a rate of 58 mm per year.”
In the city of Uki and the town of Hikawa, the earthquake reached the highest intensity level of 7 on the Japan Meteorological Agency (JMA) seismic intensity scale, with intensities of 6 recorded in surrounding municipalities, including parts of Kumamoto City, Yatsushiro, Uto, Misato and Mashiki.
As of 31 July, at least 35 fatalities had been confirmed and hundreds of people were reported injured across the affected area, with the toll expected to evolve as rescue operations continue.
Nearly 50,000 households in Kumamoto Prefecture experienced power outages shortly after the earthquake, and over 100,000 customers remained without water two days after the event.
Rail services, including sections of the JR Kyushu network and some Shinkansen operations, were suspended pending safety inspections.
As of 30 July, authorities had yet to fully quantify the scale of property damage, but reports indicate widespread damage to residential and commercial buildings, alongside industrial facilities, in the worst-hit areas.
Humanitarian impacts are being compounded by severe summer heat. Daytime temperatures in the affected region have climbed to around 35°C (95°F), complicating rescue operations and conditions in evacuation shelters.
Approximately 400 to 450 evacuation centres have been opened across the region, housing several thousand displaced residents while power and water restoration continues.
While rescue operations and damage assessments continue and the risk of aftershocks persists, Aon said the event is likely to result in significant economic and insurance industry losses. The firm added that the full assessment of impacts will continue in the coming weeks.
