The earth has been shaking in California and Alaska.

A moderate but shallow quake hit Central California at 12:55 a.m. today (September 11).

At a depth of only four kilometres (two miles), the U.S. Geological Survey initially measured it as a 4.0-magnitude quake before being upgraded to a 4.2-magnitude quake.

The epicentre was located 12 kilometres (seven miles) southwest of Keeler, California, and 18 kilometres (11 miles) southeast of Lone Pine, California.

Meanwhile, seismic activity has been taking place near Anchorage, Alaska, with two notable quakes occurring in the past few days.

The most recent one took place at 5:58 a.m. local time (6:58 a.m. Vancouver time) today (September 11).

Initially assessed as a 4.6-magnitude quake based on preliminary measurements, it was later reassessed as a 4.3-magnitude quake.

This one was deep-set, at a depth of 105 kilometres (65 miles).

The epicentre was located 58 kilometres (36 miles) southwest of Skwentna, Alaska, and 132 kilometres (82 miles) northwest of Anchorage.

Previously, another quake had taken place at 6 p.m. local time (7 p.m. Vancouver time) on September 9 and was much closer to Anchorage.

Although it was originally reported as a 4.2-magnitude quake, it was re-evaluated as a 4.0-magnitude quake

At a depth of 18 kilometres (11 miles), the epicentre was six kilometres (four miles) north of Point MacKenzie, Alaska, and 22 kilometres (14 miles) north of Anchorage.