Subterranean rumbling is a phenomenon in which the ground vibrates and makes sounds due to an

earthquake An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...

. During earthquakes or

volcanic eruptions A volcanic eruption occurs when material is expelled from a volcanic vent or fissure. Several types of volcanic eruptions have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior h ...

, the ground vibrates, sometimes creating short-period seismic wave motion (

ground motion Ground motion is the movement of the Earth’s surface from earthquakes or explosions. Ground motion is produced by seismic waves that are generated by sudden slip on a fault or sudden pressure at the explosive source and travel through the Eart ...

) that reaches the air and becomes sounds (

sound waves In physics, sound is a vibration that propagates as an acoustic wave through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the br ...

), and low sounds can be heard. Tokuji Utsu『地震学第3版』P.308 This often occurs during shallow-focus earthquakes and

earthquake swarms In seismology, an earthquake swarm is a sequence of seismic events occurring in a local area within a relatively short period. The time span used to define a swarm varies, but may be days, months, or years. Such an energy release is different fr ...

. Even microearthquakes that produce noticeable tremors can sometimes produce rumbling. Hard ground tends to amplify rumbling. In earthquake-prone

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

rumbling is frequently observed near Mt. Tsukuba in

Ibaraki Prefecture is a Prefectures of Japan, prefecture of Japan located in the Kantō region of Honshu. Ibaraki Prefecture has a population of 2,828,086 (1 July 2023) and has a geographic area of . Ibaraki Prefecture borders Fukushima Prefecture to the north, ...

. This is believed to be due to local exposure of

basement rocks In geology, basement and crystalline basement are crystalline rocks lying above the mantle and beneath all other rocks and sediments. They are sometimes exposed at the surface, but often they are buried under miles of rock and sediment. The baseme ...

. During the 1965 Matsushiro earthquake swarm, a remarkable subterranean rumbling was observed.

References

{{Seismology-stub Sound Seismology