February 29, 1928 - Helena ,MT - M 5½±
The 1928 Helena, Montana earthquake had no reported injuries or damage. The shaking startled people throughout the city of Helena and was more noticeable on upper floors of buildings with two or more stories above ground. The shaking was severe enough to disrupt a trial in one city courthouse. Without taking time to formally adjourn the proceedings, the judge and others fled the courtroom as the shaking began.
The earthquake was reported felt in areas southeast of Helena including: Trident, Three Forks, Manhattan, Logan, Lombard, and Sixteen-Mile Canyon. White Sulphur Springs, to the east of Helena, also reported earthquake shaking.
There were reports of shaken buildings, windows rattling, furniture moving, and goods being shaken from shelves.
For additional information about this earthquake:
Earthquake Summary Newspaper Articles
Intermountain Seismic Belt Historical Earthquake Project
- 1945 Flathead Lake, MT M5.5
- 1952 Bigfork, MT M5.5
- 1935 Helena, MT (series) M6¼
- 1929 Lombard, MT M 5.6
- 1925 Clarkston Valley, MT M 6¾
- 1959 Hebgen Lake, MT M 7.5
- 1975 Yellowstone National Park , WY M 6.1
- 1947 Virginia City, MT M 6¼
- 1945 Central Idaho M 6.0
- 1944 Central Idaho M 6.1
- 1983 Borah Peak, ID (series) M 7.3