Authorities in Japan have warned that a second, potentially larger tsunami could strike following a powerful 7.5-magnitude earthquake off the country’s north-east coast.

The Japan Meteorological Agency said further seismic activity of a similar scale could occur over the coming week, noting that such warnings are standard after major earthquakes. Officials are also urging vigilance for landslides and additional aftershocks.

Residents in affected areas have been told to remain alert and stay inland until all tsunami advisories are lifted. Minoru Kihara reinforced the message, advising people not to return to coastal zones prematurely.

Initial reports indicate that around 100 households have been left without power, while some services on the Shinkansen have been temporarily suspended as a precaution.

Japan is one of the most seismically active countries in the world, accounting for more than 10% of earthquakes of magnitude six or higher globally. On average, the country experiences a magnitude-seven quake roughly once every 16 months.

The warning comes with the memory of the devastating 2011 Tohoku earthquake and tsunami still fresh. That magnitude 9.0 quake triggered a massive tsunami that killed more than 18,000 people and led to a nuclear disaster in Fukushima Prefecture.

Officials say lessons from that disaster have shaped current emergency responses, with stronger emphasis on rapid evacuation and public compliance with warnings. Residents are being urged to move to higher ground immediately if further alerts are issued, as tsunami waves can arrive in multiple surges and increase in size after the initial impact.

Global oil prices dropped sharply after Iran announced that the Strait of Hormuz would be “completely open” to commercial vessels for the remainder of the ceasefire.

The price of Brent crude fell to around $88 per barrel, down from above $98 earlier in the day, reflecting a rapid easing of supply concerns that had gripped global markets for weeks.

Iranian Foreign Minister Abbas Araghchi confirmed the development, stating that all commercial shipping would be allowed to pass freely through the strategic waterway during the ceasefire period.

The Strait of Hormuz, a narrow channel connecting the Gulf to the Arabian Sea, is one of the world’s most critical energy corridors, typically handling about one-fifth of global oil and liquefied natural gas shipments.

Markets reacted swiftly to the announcement. Major U.S. stock indices rallied in early trading, with the S&P 500 rising by 0.8%, while the Nasdaq Composite and the Dow Jones Industrial Average each gained more than 1%.

European markets also posted strong gains, with France’s CAC 40 and Germany’s DAX both climbing over 2%, while the UK’s FTSE 100 rose by around 0.5%.

The reopening follows weeks of disruption after the Strait was effectively closed amid escalating conflict involving Iran, the United States, and Israel. The shutdown had significantly reduced global oil and gas supplies, pushing prices above $100 per barrel and peaking at over $119 in March.

Before the conflict began, Brent crude had been trading below $70 per barrel, underscoring the scale of the price surge triggered by the الأزمة.

The spike in energy prices had ripple effects across the global economy, driving up petrol and diesel costs, increasing pressure on airlines due to rising jet fuel prices, and raising concerns over food inflation. The Strait is also a key route for fertiliser exports, with roughly a third of critical fertiliser chemicals passing through it.

However, there are early signs of relief. In the UK, fuel prices have begun to ease slightly, marking the first decline since the conflict began, though costs remain significantly higher than pre-war levels.

The Strait of Hormuz has been declared “completely open” to commercial shipping for the duration of the ceasefire, according to Iran, offering a potential easing of global energy supply concerns.

In a follow-up statement, U.S. President Donald Trump confirmed that the waterway is “COMPLETELY OPEN AND READY FOR BUSINESS,” but stressed that a U.S. naval blockade targeting Iran would remain in place.

“THE NAVAL BLOCKADE WILL REMAIN IN FULL FORCE AND EFFECT AS IT PERTAINS TO IRAN, ONLY, UNTIL SUCH TIME AS OUR TRANSACTION WITH IRAN IS 100% COMPLETE,” Trump said, adding that negotiations were close to being finalised.

The development signals a partial de-escalation in tensions, though the continued U.S. naval presence underscores the fragile nature of the ceasefire and ongoing diplomatic process.

Reacting to the announcement, UK Prime Minister Keir Starmer welcomed Iran’s decision but cautioned that any reopening must be sustained and credible.

He said international leaders had united behind a clear message that the strait should remain open without tolls or restrictions, emphasising the need for stability in global shipping routes.

Starmer also called for the swift resumption of maritime traffic to help mitigate the economic shock caused by weeks of disruption.

In a further sign of coordinated international action, he announced that the United Kingdom and France would lead a multinational mission aimed at safeguarding freedom of navigation in the region once conditions allow.

The mission, described as “strictly peaceful and defensive,” is expected to involve around a dozen countries. A planning conference is scheduled to take place in London next week to coordinate contributions and operational details.

“Our citizens need to see a return to peace and stability,” Starmer said, highlighting the broader global stakes tied to the security of the vital shipping route.