The earthquake did not arrive without warning. Ten days earlier, on July 20, a magnitude 7.4 foreshock had struck the same region, a tremor powerful enough to be a major earthquake in its own right. When the 8.8 mainshock followed on July 30, seismologists recognized the earlier event for what it was: a preliminary fracture along the same megathrust boundary that had been building stress since the last great rupture in 1952. The mainshock was followed by a punishing aftershock sequence, including events of magnitude 6.9, 7.4, and 7.8. Parts of the southern Kamchatka Peninsula shifted southeast by a measurable distance, according to the Geophysical Service of the Russian Academy of Sciences. The ground had moved, and it kept moving.

The Pacific Tsunami Warning Center issued alerts for hazardous waves along the coasts of Russia and Japan within minutes. What made this event distinctive was the scale of the global response. In Japan, 900,000 people across 133 municipalities were advised to evacuate. Sendai Airport closed its runways. Rail services across eastern Japan were suspended. Workers at the Fukushima Daiichi Nuclear Power Plant were ordered to evacuate, and a scheduled release of treated radioactive water into the ocean was halted. Taiwan activated its Central Emergency Operation Center for the first time for a tsunami event, placing 23 rescue aircraft and 14 naval vessels on standby. The Philippines issued advisories for 22 provinces. Indonesia, China, and South Korea issued warnings. Across the Pacific, New Zealand warned of unpredictable surges around its entire coast. Tonga and Fiji ordered evacuations. The entire U.S. West Coast was placed under alert, from Alaska to California.

The tsunami struck Severo-Kurilsk in the Kuril Islands first, with inundation reaching roughly 600 meters inland. On Shumshu Island, waves reached a maximum run-up height in Baikovo and flooded far inland. Waves were recorded along Khalaktyrsky Beach on the Kamchatka mainland. In Japan, tsunamis were observed in 22 of the country's 47 prefectures. Waves struck Hokkaido, Hachijo-jima, and were even measured in Harumi, Tokyo. In Hawaii, Kahului and Hilo recorded measurable waves, and Haleiwa was struck by a surge that registered 4 feet above normal sea level. The wave traveled the full breadth of the Pacific: La Push, Washington, recorded waves, as did Seattle. Along the Chilean coast, wave heights exceeded normal levels at multiple beaches. The Galapagos Islands recorded a tsunami. It was a demonstration of the Pacific Ocean's capacity to transmit energy across its entire 15,000-kilometer width.

In Kamchatka, roughly 1,400 homes were damaged. The facade of a kindergarten in Petropavlovsk-Kamchatsky partially collapsed, and cracks formed in medical and social service buildings. At Yelizovo Airport, a terminal ceiling collapsed, injuring a woman. Power outages and mobile phone failures rippled across the region. At Rybachy, a nuclear submarine base in Avacha Bay, satellite images showed at least one pier damaged by the tsunami. In Severo-Kurilsk, every one of the town's 106 apartment buildings was damaged and more than 90 percent of chimneys toppled. The port was inundated, with a fish processing plant swept away. Yet no one died from the earthquake or tsunami in Russia. Kremlin spokesman Dmitry Peskov attributed this to robust construction and local preparedness. Severo-Kurilsk itself offered a grim precedent for that preparedness: the town had been largely destroyed by a tsunami in 1952 and rebuilt on higher ground, leaving only the port exposed. In Japan, 21 people were injured while evacuating, and one woman died relocating her car to higher ground. In the United States, $1 million in property damage occurred in Crescent City, California. Around 2,700 people were evacuated across the affected Russian territories.

In the days following the earthquake, seven Kamchatka volcanoes erupted, a cascade that the Institute of Volcanology and Seismology said had not occurred on the peninsula in nearly three centuries. On August 3, Krasheninnikov volcano generated an eruption plume in what was its first recorded eruption since human observations began. The eruptions were not directly caused by the earthquake in the simple mechanical sense, but the seismic disturbance appears to have destabilized volcanic systems that were already approaching activity. The coincidence of a great earthquake and a multi-volcano eruption event underscored what Kamchatka's geography has always implied: this is one of the most geologically active places on the planet, where the forces shaping the Earth's surface operate not in geological time but in human time, on scales that demand attention.