HILO, Hawai'i — An earthquake rattled the Big Island last night, but there were no immediate reports of injuries or structural damage.

"Earthquakes, hurricanes, what next?" Gene Karolyn said as she sat in a Starbucks coffee shop in Hilo.

The magnitude 5.4 earthquake happened at 7:38 p.m. and was centered nine miles south-southeast of Fern Forest, the U.S. Geological Service said. It did not generate a tsunami.

Hawai'i County official deEtte Fukamitsu said the Civil Defense office received no reports of damage. The quake did cause a small landslide, according to Tom Brown, a spokesman for Hawai'i County Civil Defense. Police said there were reports of rocks on the Hawai'i Belt Road along Route 19 from Hilo along the Hamakua Coast to Waimea, but no major roads were closed.

University of Hawai'i-Hilo professor Don Eads and his son, Hoku, were in the new University Classroom Building when they felt the tremor.

"The building shook so hard we thought it was going to fall down," Eads said in an e-mail to The Advertiser.

Six aftershocks, ranging from magnitude 3.2 to 1.9, were recorded within two hours of the initial strong earthquake and in the same general vicinity.

The Big Island has seen an increase in seismic activity since mid-June, when hundreds of small earthquakes suggested a significant movement of magma under Kilauea Volcano and prompted the rare closure of most of Hawai'i Volcanoes National Park.

Reach Mary Vorsino at mvorsino@honoluluadvertiser.com and Rod Ohira at rohira@honoluluadvertiser.com.