[mahy-kruh-sahy-zuh
m, -suhm] 
| a feeble, recurrent vibration of the ground recorded by seismographs and believed to be due to an earthquake or a storm at sea. |
| microseism (mī'krə-sī'zəm) Pronunciation Key
A faint Earth tremor, unrelated to earthquakes, caused by natural phenomena, such as winds and strong ocean waves. |