Earth's 26-Second Pulse
Every 26 seconds, a faint tremor ripples out from the Gulf of Guinea. Seismologists have known about it for 60 years, and still argue about the cause.
What was reported
In the early 1960s, geologist Jack Oliver noticed a faint, regular 'pulse' on seismometers, repeating every 26 seconds. In 1962 he published a paper suggesting it came from somewhere in the Atlantic.
Later researchers traced it to the Bight of Bonny, in the Gulf of Guinea off the coast of West Africa. It is too weak to feel, but seismometers on several continents pick it up, and it has continued for decades.
Explanations offered
One leading idea is that ocean waves strike the continental shelf in a way that sets up a regular vibration in the Earth's crust. Another links it to volcanic activity near the island of São Tomé. Neither explanation has been confirmed, and similar pulses are not known anywhere else.
- When
- Detected since the early 1960s
- Where
- Gulf of Guinea, off West Africa
- Witnesses
- Seismometers around the world
- Status
- Unexplained
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