What happened in the Sanriku earthquake and when did it strike?
The Japan Meteorological Agency (JMA) reported a 7.5 magnitude earthquake off the Sanriku Coast on Monday, 20 April 2026, at 1653 hours local time, at a depth of 10 kilometres. The Sanriku earthquake prompted authorities to issue a tsunami warning for the coastal regions of Japan, with similar advisories for the Pacific coasts of Hokkaido and Aomori prefectures and for the Miyagi and Fukushima prefectures. Initial reports indicated no major structural damage or fatalities, although safety assessments were still under way and high-rise buildings in Tokyo were reported to have swayed noticeably. The first tsunami waves reached Iwate Prefecture, with up to 40 centimetres recorded at Miyako Port, and a tsunami was also observed roughly 50 kilometres off the coast of Aomori.
Which areas face the highest tsunami and evacuation risk?
Authorities cautioned that waves as high as three metres could reach parts of Iwate Prefecture and Hokkaido, and forecast waves of up to three metres along the Pacific coasts of both. Evacuation orders were issued in Hokkaido (Urakawa, Urahoro, Erimo, Samani, Shinhidaka, Taiki, Toyokoro, Niikappu, Hidaka and Hiroo), Aomori (Oirase, Oma, Kazamaura, Goshogawara, Hashikami, Hachinohe, Higashidori, Misawa, Mutsu and Rokkasho), Iwate (Miyako, Ofunato, Rikuzentakata, Kamaishi, Otsuchi, Hirono, Kuji, Yamada, Iwaizumi, Tanohata, Fudai and Noda), Miyagi (Ishinomaki, Iwanuma, Kesennuma, Shichigahama, Matsushima, Yamamoto, Rifu, Watari and parts of Sendai) and Fukushima (Iwaki and Naraha). The high-risk zones highlighted by datasurfr cover Hokkaido, Aomori, Iwate, Miyagi and Fukushima. Residents were urged to move to higher ground, and people in coastal areas should stay away from beaches, harbours and river mouths until an official all-clear is declared.
What are the transport, power and aftershock risks?
Transport services can be partially suspended as a safety precaution, including bullet trains, and datasurfr advises anticipating disruption to local train operations in affected areas. The Risk Flash specifically recommends avoiding non-essential travel between Tokyo and Aomori because of the suspension of bullet train services. Widespread power outages in coastal towns cannot be ruled out because transmission lines may have been damaged. Aftershocks can be expected across a wide arc of northern and eastern Japan, including Aomori, Iwate, Miyagi, Hokkaido, Akita, Yamagata, Fukushima, Ibaraki, Tochigi and Gunma prefectures and Tokyo. Because tsunami forecasts, evacuation orders and rail status can change quickly, the JMA website is the primary source for updates, and instructions from local authorities should always be followed.
What are the business continuity risks?
Based on early reports, the principal operational risks are temporary loss of access and utilities rather than structural damage. Facilities, harbours and staff in coastal Iwate, Miyagi, Aomori, Hokkaido and Fukushima may need to evacuate to higher ground or move inland at short notice, interrupting shifts, deliveries and maritime activity. Partial suspension of bullet trains and local rail can strand business travellers and delay staff movement between Tokyo and Aomori, while possible power outages in coastal towns may affect operations that depend on grid supply. Offices in Tokyo may need to check on staff after high-rise buildings swayed, and safety assessments of buildings and infrastructure remain ongoing. Aftershocks mean conditions can deteriorate or recovery can be delayed, so contingency plans should assume rolling disruption rather than a single event.
What should travellers and organisations do to prepare?
Travellers and organisations should follow all protocols issued by the authorities and monitor the JMA website for the latest updates. Anyone operating in coastal Japan should evacuate to higher ground or move further inland as a precaution, avoid beaches, harbours and river mouths until an official all-clear is declared, and relocate immediately to inland or elevated shelter areas as needed. Avoid non-essential travel between Tokyo and Aomori while bullet train services are suspended, and consider alternative transport where necessary. Organisations should account for staff and travellers in the affected prefectures, expect disruption to local train operations, and keep the emergency numbers below to hand. Further detail is available from MitKat’s business development team, whose contact appears in the full Risk Flash.
Frequently asked questions
How strong was the Sanriku earthquake and when did it happen?
The JMA reported a 7.5 magnitude earthquake off the Sanriku Coast on Monday, 20 April 2026, at 1653 hours local time, at a depth of 10 kilometres.
How high could the tsunami waves be?
Authorities cautioned that waves of up to three metres could reach parts of Iwate Prefecture and Hokkaido, while initial waves of up to 40 centimetres were recorded at Miyako Port in Iwate.
What are the emergency contact numbers in Japan?
Fire or medical emergencies: 119. Medical consultation: #7119. Maritime emergencies: 118. Disaster line: 171. Japan National Tourism Organization (JNTO): 050-3816-2787.
Download the full risk flash now
datasurfr’s Risk Flash on the 7.5 magnitude earthquake off the Sanriku Coast carries the event summary, the high-risk zone map, the full list of evacuation orders and the emergency contacts directory. Download the full risk flash now to brief your travel and continuity teams.
Filed under: APACRegional Risk Reviews
