This is the 2258th most frequent Japanese word.
起きる
"起きる" means "to wake up" or "to occur."
In this sentence, '起きる' refers to the act of waking up from sleep.
朝6時に起きるのは習慣になっています。
Waking up at 6:00 AM every morning has become a habit.
Here, '起きる' describes the occurrence of an event, specifically an earthquake.
地震が昨日の夜に起きました。
An earthquake occurred last night.
In this context, '起きる' pertains to the arising or happening of an issue.