The pulse appears every 26 seconds, is from People imperceptible, but so strong that it is recorded with sensitive seismological devices around the globe. For almost 038 years this natural phenomenon has puzzled researchers around the world.

John Ertle “Jack” Oliver, born 26. September 1923 in Massillon, (Ohio), died January 5th 2011 in Ithaca (New York) has made a name for itself primarily with research into plate tectonics.

For the first time on a larger scale, the seismological phenomenon at the beginning of the 1960 years examined. The American geologist John Ertle “Jack” Oliver published 1961 in the seismological journal Bulletin of the Seismological Society of America ( BSSA) the article “A Worldwide Storm of Microseims With Periods Of About 27 Seconds “by presenting the results of his research on microquakes.

Microquakes in the 26 – Second interval The Quakes appeared in an interval between on average 18 and 27 seconds and Oliver located the epicenter in the Gulf of Guinea. Overall, the earthquakes between June 6th and 7th 1961 were researched and in 16 from 18 Research stations measured across the globe. He compared the strongest rash with the explosion of about 600 tons of TNT. The strength fluctuated with time; Oliver also found out that the impulse was strongest in the winter months of the southern hemisphere.

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First of all, microquakes are nothing special. In Germany, the earth shakes in this way almost every day without anyone outside of seismological research being aware of it. The corona crisis even improves research, as the exit restrictions reduce the everyday sources of interference that these earthquakes otherwise easily overlay.

Earthquakes as a monitor of the soil condition The findings are helpful for geological research – liquids and gases can be responsible for the stress conditions in moist rock . Therefore, more information about the nature of the rock can be gained from the measured microquakes.

The difference is precisely the periodicity. And that makes it so difficult for researchers to locate the source of this phenomenon. And Jack Oliver was limited by the technical possibilities of his time; he could therefore only speculate.

Hypotheses between wave impact and magnetic activity The main hypothesis was that the microquakes were caused by waves hitting the coast in the Gulf of Guinea. A second assumption that magnetic activity under the South Atlantic caused the quakes.

The Gulf of Guinea in the Atlantic Ocean, with the coastal area of ​​West Africa. According to the measurements of various researchers, the point of origin of the microquake lies in the Bay of Bonny, a little to the right above the center of the picture. In August 2006 an article was published in the journal Geophysical Research Letters in which the researchers found the place of origin for the pulse (0, 038 Hz) more precisely. The microquakes were detected in Bonny Bay, in the Gulf of Guinea as well as in the Antipodean Pacific region east of Papaua New Guinea.

New findings from the Chinese research team A Chinese research team published 2011 in the Geophysical Journal International another specialist article on the phenomenon. They discovered a second periodic pulse (0, 27 Hz). While they assume the Sao Tome volcano as the source as the origin for the known impulse due to the local proximity, the possible cause of the newly discovered source remains in the dark. The researchers suspect volcanic activity there too.

Be that as it may – the origin of this fascinating natural phenomenon is not certain. Thus the research question remains exciting; where – another original theory is provided by geek comic author Randall Munroe in his xkcd comic “26 – Second Pulse “. Microquake as the pulse of a giant – the research remains exciting! (mawi)