A record of the seismic activity observed on September 11, 1973 was found by graduate of the Department of Geophysics (DGF) of the University of Chile and researcher at the Advanced Center for Mining Technology (AMTC), Sergio León Ríos.
The seismologist and postdoctoral researcher at AMTC found the seismograms from the day of the 1973 civil-military coup while searching old documents in the DGF camps for an initiative to save cultural heritage, together with University of Chile professor Raúl Madariaga.
“We found a package marked “Santiago 1973.” We were surprised and of course opened it to see what was inside. What we then discovered were many recordings from a seismological station in Santiago,” said León Ríos.
When asked about the seismic activity of September 11th 50 years ago, the DGF graduate replied that the observation of the traces was not conclusive. “There are some unusual signs, but there is not enough certainty to link them to the La Moneda bombing. In general, you could say that this is masked by the noise of the city,” he explained.
On this last point, the researcher added that changes in the seismic pulse of the city were being observed. “Seismographs are very sensitive. During the Covid-19 pandemic, it was already observed how seismic noise decreased worldwide thanks to data from sensors installed in various cities. We could say that it was the same in this case, even if the instruments at that time were a little louder,” said the seismologist.
His colleague, academician of the Department of Geophysics at the University of Chile and former deputy director of the National Seismological Center (CSN), Mario Pardo, agreed with this assessment, adding that “the sensors that recorded the seismic activity were transient.” ‘ and were installed in a small underground at Calle Blanco Encalada 2085, where the Seismological Service of the time operated.”
Asked about the significance of this discovery, León Ríos explained that these seismograms “are of invaluable historical value because they reveal the records that were stored in warehouses until today.”
“For a seismologist and scientist like me, it is exciting to see how traces can tell stories. In addition, access to documents like these, especially now that it has been 50 years since the coup, allows us to carry out a memory exercise and provide more background information on this gray period of our history from a different angle and from a different perspective,” he assured.
Today, the seismograms from September 1973 are being digitized and secured with three objectives. The first is to ensure that they are stored in a digital archive of the F. Montessus de Ballore Library of the Geophysics Department of the University of Chile, for which it initially has the support of librarian Marcela Pérez. Secondly, it is intended to serve as a source of information for a later article that will appreciate the seismological and historical value of the seismograms found. The third would be aimed at scientific dissemination.
“The idea is to make this discovery public,” said Sergio León Ríos, announcing that he does not rule out the possibility of working within the Faculty of Physical and Mathematical Sciences or the University of Chile.
