Complex sentence: Barcena's only historic eruption began around 8:30 AM on August 1 1952 from the El Boquerón vent, rapidly covering the entire island in ash and pumice up to 10 ft (3 m) high.
Split into simpler sentences: Barcena's only historic eruption began around 8:30 AM on August 1 1952 from the El Boquerón vent. Soon the entire island was covered in ash and pumice up to 10 ft (3 m) high.