The Alaska Peninsula was rocked with not one but two volcano eruptions this week. The 8,261-foot Pavlof Volcano has been erupting periodically since May. On Thursday, its explosions of lava, steam, and ash were accompanied by those of the nearby 8,225-foot Veniaminof Volvano, which sent plumes of ash 12,000 feet into the sky, reports Reuters. Scientists say the two eruptions were unrelated, and neither has interfered with air traffic. But a local observatory says bursts of up to 20,000 feet or higher could still occur without notice, and airlines, which frequently fly 30,000 feet above on trips between Asia and North America, have been warned.