Nicaragua’s tallest volcano belched an ash cloud on Saturday, sending hundreds of nearby residents scrambling to evacuate.

Reuters reported the 5,725-foot San Cristobal volcano, which is about 100 miles north of the capital Managua, sent ash nearly a mile into the atmosphere. Residents said they could hear explosions emanating from its crater.

Government spokeswoman Rosario Murillo told Reuters authorities were still assessing the strength of the volcano and as many as 20,000 people could be affected by the gas and ash.

San Cristobal has been active recently. In the mid-2008, when it expelled gas and rumbled with a series of small eruptions.

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Meanwhile, the Nicaragua Dispatch reported the nation's capital is preparing for a possible earthquake after Managua was hit by a series of 17 tremors ranging in magnitude from 2.3 to 3.7, according to the Nicaraguan Institute of Territorial Studies (INETER).