According to volcanologists from the Russian Academy of Sciences, the Shivelutch volcano began erupting shortly after a strong 7.0 magnitude earthquake struck off the east coast of Kamchatka early Sunday.

They warned that another, even more violent earthquake could be imminent.

The Academy’s Institute of Volcanology and Seismology has released a video showing the ash cloud over Shiveluch.

It extended over 490 kilometers east and southeast of the volcano.

The Ebeko volcano on the Kuril Islands also caused ash emissions 2.5 kilometers high, the institute said.

It was not explicitly stated whether the eruptions were triggered by the earthquake.

A Code Red ash cloud warning briefly put all aircraft in the region on alert, the Kamchatka Volcanic Eruption Response Team reported.

A separate report by the official Tass news agency said on Sunday that there were no disruptions to commercial air traffic and no damage to aviation infrastructure.

The tremors in the region could be the prelude to an even stronger earthquake in southeastern Kamchatka, Russian scientists warned.

The Institute of Volcanology said a possible second quake could occur “within 24 hours,” with a magnitude of nearly 9.0.

There were no initial reports of injuries from Sunday’s earthquake, according to Russian emergency officials. The earthquake struck six kilometers below the seabed and its epicenter was 108 kilometers southeast of the nearest city.

Russian news agencies reported the strongest earthquakes “in a long time,” citing residents of Petropavlovsk-Kamchatsky, a port city of more than 181,000 people located across from a bay with a major Russian submarine base.

On November 4, 1952, a magnitude 9.0 earthquake caused damage in Kamchatka but no fatalities, although it triggered 9.1-meter-high waves in Hawaii.