Srinagar, July 30 -- A massive 8.8-magnitude undersea earthquake rocked Russia's Far East early Wednesday, triggering tsunami waves up to 4 metres high and setting off alarms across the Pacific-from Japan to the US and several island nations.

The quake struck just off the Kamchatka Peninsula, near the coastal city of Petropavlovsk-Kamchatsky, at a shallow depth of 19.3 km. Initially recorded as 8.0 by the US Geological Survey (USGS), the tremor was later upgraded to 8.8.

Authorities in Russia reported building damage and activated emergency protocols. No major injuries or deaths have been confirmed yet. Coastal areas including the Kuril Islands and Japan's Hokkaido have experienced wave impacts. Japan's Meteorological Agency warned that...