HILO, Hawai'i — Scientists say the pair of moderate earthquakes off the Big Island over the past week do not signal that a larger earthquake is coming soon, but should serve as a reminder that the island is overdue for one.

"The natural question people have now is, does that mean we're getting set for a big one?" said Stuart Koyanagi, seismologist with the U.S. Geological Survey's Hawaiian Volcano Observatory. "There's no way we can tell that."

Big Island residents were jolted by a magnitude-5.2 earthquake Sunday morning centered 17 miles southeast of South Point. That temblor came just two days after a 5.2 quake was recorded 49 miles north of Hilo, which was the largest earthquake recorded in Hawai'i in six years.

There isn't much scientists can read into those earthquakes, in part because both occurred in areas where scientists do not have many instruments to collect data. They don't know what caused them, and while stronger earthquakes have been known to trigger seismicity elsewhere, there is no indication that that is what happened last week.

"The typical pattern for earthquakes, just generally, they tend to cluster," Koyanagi said. "They don't happen randomly."

On the other hand "the bottom line is that we haven't had a (magnitude) 6 in quite a while," he said. "Even before these 5.2 earthquakes occurred, we've been waiting for a large earthquake to happen for over 15 years now."

Koyanagi said the last magnitude-6 or greater earthquake was on June 25, 1989, beneath Kilauea's south flank. Before that, the island experienced magnitude-6 or greater earthquakes in 1983, 1975, 1973 and 1962, he said.

The 1975 earthquake was a magnitude-7.2 quake that generated a tsunami and killed two people.