A swarm of dozens of small earthquakes shaking a sparsely populated part of northwestern Arizona is entering its fourth week.
The Arizona Geologic Survey says the swarm in a remote area south of Littlefield near the Arizona-Nevada line extended Sunday and Monday with 10 small quakes, ranging from magnitude 0.9 to magnitude 3.7.
The Mohave County Sheriff's Office says it has no reports of injury or damage.
The Arizona Geologic Survey says the magnitude 3.7 quake Sunday evening was the largest of the swarm and was felt in Littlefield and in Mesquite, Nevada.
The swarm began March 28 and is occurring along the boundary between the Colorado Plateau and another region with active faults, the Basin and Range Province.