Bight of Biafra

The Bight of Biafra (officially Bight of Bonny, in Nigeria) is a bight off the West African coast, in the easternmost part of the Gulf of Guinea.
Geography.
The Bight of Biafra, or Mafra (named after the town Mafra in southern Portugal), between Capes Formosa and Lopez, is the most eastern part of the Gulf of Guinea; it contains the islands Bioko [Equatorial Guinea], São Tomé and Príncipe. The name Biafra – as indicating the country – fell into disuse in the later part of the 19th century 
A 1710 map indicates that the region known as "Biafra" (Biafra) was located in present-day Cameroon.
The Bight of Biafra extends east from the River Delta of the Niger in the north until it reaches Cape Lopez in Gabon. Besides the Niger River, other rivers reaching the bay are the Cross River, Calabar River, Ndian, Wouri, Sanaga, Nyong River, Ntem, Mbia, Mbini, Muni and Komo River.
The main islands in the Bay are Bioko and Príncipe; other important islands are Ilhéu Bom Bom, Ilhéu Caroço, Elobey Grande and Elobey Chico. Countries located at the Bight of Bonny are Nigeria (eastern coast), Cameroon, Equatorial Guinea (Bioko Island and Río Muni), and Gabon (northern coast). The internationally unrecognized self-declared state of Ambazonia also borders the Bight of Biafra.
History.
Travel via the Bight of Biafra is estimated to account for 13% (1.6 million) of the total number of enslaved people exported from the Western African coast. The Bight of Benin to the west is estimated to account for 17% while Central Africa to the south is estimated to account for up to 48%.
By the middle of the eighteenth century, Bonny had emerged as the major slave trading port on the Bight of Biafra outpacing the earlier dominant slave ports at Elem Kalabari (also known then as New Calabar) and Old Calabar. These 3 ports together accounted for over 90% of the slave trade emanating from the Bight of Biafra.
Between 1525 and 1859, Britain accounted for over two-thirds of slaves exported from the Bight of Biafra to the New World.
In 1777, Portugal transferred control of Fernando Po and Annobón to Spanish suzerainty thus introducing Spain into the early colonial history of the Bight of Biafra.
In 1807, the United Kingdom made illegal the international trade in slaves, and the Royal Navy was deployed to forcibly prevent slavers from the United States, France, Spain, Portugal, Holland, West Africa and Arabia from plying their trade.
On 30 June 1849, Britain established its military influence over the Bight of Biafra by building a naval base and consulate on the island of Fernando Po, under the authority of the British Consuls of the Bight of Benin:
On 6 August 1861, the Bight of Biafra and the neighboring Bight of Benin (under its own British consuls) became a united British consulate, again under British consuls:
In 1967, the Eastern Region of Nigeria seceded from the Nigerian State and adopted the name of its coastline, the adjoining Bight of Biafra, becoming the newly independent Republic of Biafra. This independence was short-lived as the new state lost the ensuing Nigerian Civil War. In 1975, by decree, the Nigerian government changed the name of the Bight of Biafra to the Bight of Bonny.
Pulsations.
In 1962, Jack Oliver, a geologist at Columbia University, first noticed the earth had a "pulse" also known in geology lingo as a "microseism." This discovery was put on the shelves and re-examined briefly in 1980 by Gary Holcomb and then fully examined in 2005 by graduate student Greg Benson at the University of Colorado.
Later results revealed that the earth pulses every 26 seconds, but nobody is exactly sure why. Theories range from waves hitting the continental shelf to volcanic activity.
By using triangulation, they were able to locate the source of the pulse in the Bight of Bonny.