| M'sila, Algeria earthquake, Dec. 3, 1885 | 1 |
| Magna, Utah earthquake, March 18, 2020 | 1 |
| Managua, Nicaragua earthquake, Dec. 23, 1972 | 310 |
| Managua, Nicaragua earthquake, Mar. 31, 1931 | 1 |
| Manila, Philippines earthquake, June 3, 1863 | 6 |
| Marlborough, New Zealand earthquake, Oct. 15, 1848 | 2 |
| Matsushiro Swarm, Japan Aug. 3, 1965-1967 | 3 |
| Maule, Chile earthquake, Feb. 27, 2010 | 32 |
| Mendoza, Argentina earthquake, March 20, 1861 | 1 |
| Messina, Sicily earthquake, Dec. 28, 1908 | 15 |
| Messina, Sicily earthquake, Feb. 5, 1783 | 2 |
| Mexico City, Mexico earthquake, July 28, 1957 | 152 |
| Mexico City, Mexico earthquake, Sept. 19, 1985 | 127 |
| Mikawa, Japan earthquake, Jan. 13, 1945 | 1 |
| Mindanao, Philippines earthquake, August 16, 1976 | 1 |
| Mino-Owari, Japan earthquake, Oct. 28, 1891 | 34 |
| Mitylene, Greece earthquake, Mar 8, 1867 | 2 |
| Miyagi-ken, Japan earthquake, June 12, 1978 | 17 |
| Monte Vulture, Italy earthquake, Aug. 14, 1851 | 2 |
| Montenegro (Yugoslavia) earthquake, April 15, 1979 | 7 |
| Mor, Hungary earthquake, Jan. 24, 1810 | 4 |
| Morgan Hill, California earthquake, April 24, 1984 | 11 |
| Mount Bandai (Japan) eruption, July 15, 1888 | 4 |
| Mount Etna (Sicily) eruption, 1669 | 2 |
| Mount Etna (Sicily) eruption, March 22-24, 1883 | 1 |
| Mount Fuji (Japan) eruption, Dec. 16 and 31, 1707 | 1 |
| Mount Pacaya (Guatemala) eruption, July 1775 | 3 |
| Mount St. Helens, Washington eruption, May 18, 1980 | 37 |
| Mount Tambora (Sumbawa Is., Indonesia) eruption, April 11, 1815 | 1 |
| Mugello (Tuscany), Italy earthquake, June 13, 1542 | 2 |
| Murchison, New Zealand earthquake, June 17, 1929 | 9 |
| Murcia, Spain earthquake, Mar. 21, 1829 | 2 |