Two "Tunguskas" in South America in the 1930's?

This article was printed in IMO's December 1995 edition of the WGN Journal.
It was written by Duncan Steel of the Anglo-Australian Observatory.

There is evidence that there were two massive bolide explosions which occurred over South America in the 1930's. One seems to have occurred over Amazonia, near the Brazil-Peru border, on August 13, 1930, whilst the other was over British Guyana on December 11, 1935. It is noted that these dates coincide with the peaks of the Perseids and the Geminids, although any association with those meteor showers is very tentative. The identification of such events is significant in particular in that they point to the need for re-assessment of the frequency of tunguska-type atmospheric detonations.

part 1: The Rio Curaca event

In 1989 an article by N.Vasilyev and G.V. Andreev in the IMO Journal (1) drew attention to a discussion, published in 1931 by L.A. Kulik (2), of a possible Brazilian counterpart to the Tunguska bolide explosion of 1908. The Brazilian event, which occurred on August 13, 1930, was described in the papal newspaper L'Osservatore Romano, the report being derived from Catholic missionaries working in Amazonia. That report, in Italian, was used as the basis of a front-page story in the London newspaper The Daily Herald (since closed down), which was published on March 6, 1931, and then seen by Kulik. (For the interested reader, a copy of the story is reprinted in the December 1995 Journal).

The locality of the explosion gives it it's name: The Rio Curaca event. This is close to the border between Brazil and Peru, at Latitude: 5 degrees South, Longitude: 71.5 degrees West.

Both of these newspaper stories were discussed in a recent paper by Bailey and co-workers (4), who provide an English translation of the story which appeared in L'Osservatore Romano. Since that paper should be accessible to many readers of WGN, I will not give an extensive account of it here. I will, however, just mention that although the eye-witness accounts give do cover the phenomena which one might expect to be produced by a massive bolide, there are some other interesting reported observation which would require some explanation. These include the following:

Bailey et al. also discuss the fact that the Rio Curaca event occurred on the day of the peak of the annual Perseid meteor shower, but conclude that this is likely to be purely a coincidence. The date is also close to august 10, on which day in 1972 a large bolide was filmed skipping through the upper atmosphere above western Wyoming and Montana, departing from the earth above Canada (4). Again, this may be merely a coincidence.

A brief discussion of the event is also given by R. Gorelli in august 1995 issue of Meteorite! magazine.

part 2 The Rupununi event

I now move on to the suspected explosion over British Guyana in 1935. The main source for information on this event is a story entitled Tornado or Meteor Crash? in the magazine The Sky (the forerunner of Sky and Telescope) of September 1939(5). A report from Serge A. Korff of the Bartol Research Foundation, Franklin Institute (Delaware, USA) was printed, he having been in the area--the Rupununi region of British Guyana--a couple of months later. The date of the explosion appears to have been December 11, 1935, at about 21h local time. I might note that this is near the date of the peak of the Geminid meteor shower, but yet again this may be merely a coincidence. The location is given as being near Lat: 2 deg 10min North, Long: 59 deg 10 min West, close to Marudi Mountain.

Korff's description suggested that the region of devastation might be greater than that involved in the Tunguska event itself. On his suggestion, a message was sent to William H. Holden, who in 1937 was in the general region with the Terry-Holden expedition of the American Museum of Natural History. That group hiked to the top of Marudi Mountain in 1937 November and reported seeing an area some miles across where the trees had been broken off about 25 feet above their bases, although regrowth over two years in this tropical jungle had made it difficult to define the area affected. Holden confirmed, on returning to New York, that he believed the devastation was due to an atmospheric explosion of cosmic origin. An explorer and author, Desmond Holdridge, also visited the region in the late 1930's and confirmed the suspicion that a comet or asteroid detonation was responsible.

Korff obtained several local reports, the best being from a Scottish gold miner, Godfrey Davidson, who reported having been woken by the explosion, with pots and pans being dislodged in his kitchen, and seeing a luminous residual trail in the sky. A short while later, whilst prospecting, he cam across a devastated region of the jungle he estimated to be about five by ten miles (8 by 16 kilometers), with the trees all seeming to have been pushed over.

Holden was unsure of the origin of the flattening of the forest, and pointed out that similar destruction can result from tornados. Holdridge, however, reported eye-witness accounts in accord with a large meteoroid/small asteroid entry, with a body passing overhead accompanied by a terrific roar (presumably electrophonic effects), later concussions, and the sky being lit up like daylight. A local aircraft operator, Art Williams, reported seeing an area of forest more than twnety miles (32 kilometers) in extent which had been destroyed, and he later stated that the shattered jungle was elongated rather than circular, as occurred at Tunguska and would be expected from the air blast caused by an object entering away from the vertical (the most likely entry angle for all cosmic projectiles is 45 degrees).

There is a report of the Guyanan event, largely derived from the account in The Sky, in the newsletter Meteor News for March 1974. Apparently as a result of that, the publishers (Karl and Wanda Simmons, of Callahan, Florida) had some correspondence with a Mr. F.A. Liems of Paramaribo, Surinam, concerning a possible crater/event at Wahyombo in that country; he gives the location as Lat: 5.25 deg North, Long: 56.05 deg West. The letters date from 1976; apparently Liems died in 1982. In 1990, as a result of Andreev's article in WGN about the Brazilian event, Wanda Simmons sent copies to him, and he kindly sent copies on to me. Various notes/maps/letters are included, but it is difficult to know what to make of them: my impression is that this concerns something that occurred some time ago, not in this century, and it's linkage with an incursion by an asteroid or comet is far from clear.


1) N. Vasilyev, G. Andreev, WGN 17:6, 1989, pp. 247-248.
2) L.A. Kulik, Priroda i Ljudi 13-14, 1931, p.6
3) M.E. Bailey, D.J.Markham, S. Massai, J.E. Scriven, The Observatory 115, 1995, pp. 250-253.
4) Sky and Telescope 44, 1972, pp. 269-272.
5) The Sky, September 1939, pp. 8-10 and p.24.

Below is the wording of the Newspaper article printed in The Daily Herald on March 6, 1931.