The first Brazilian seism was recorded in Brasília by the SAAS Array

The seism occurred on August 06^th, 1967, at 06h55min(a.m), and was felt within an area of approximately 16.000 km² (Picture 1). This seism was recorded by the SAAS array's E10 Station (Picture 2), which, by that time, had already been implemented. The Picture 3 shows the seism recordings with raw and filtered data.

It was about an land-tremor of a regular intensity, felt in the city of Rio de Janeiro /RJ and that, according to Assumpção et al. (1980), had its greatest intensity observed in some of São Gonçalo's neighborhoods, estimated to have been V MM, but one which could have been VI MM, causing cracks on the walls, something that was noticed in newspapers. The macroseismic data for this event are presented as follows:

 

Macroseismic data:

Ilha do Governador /RJ: It was more intense in Niterói, São Gonçalo and Ilha do Governador(6). The phenomenon was felt (4). Noise resembling a thunder and tremor; associated to a noisy bus passing by.

Niterói/RJ: Slight tremor of 3s in the morning and a shanty collapsed in the Morro dos Milagres. In some houses, pans on stoves were threw off onto the ground; window panes broke (5a e 5b). According to the National Observatory's astronomer, it would have occurred at 06h49min (Sc).

Shanty fell down in the Morros dos Milagres (2). It was more intense in Niterói, São Gonçalo and Governador's Island(6). By 03h00min(a.m). Some noises of “ mice prowling about on the roof” were heard,

São Gonçalo/ RJ: Slight land tremors yesterday overnight shattered many building's window panes (1) In the neighboorhoods of Boaçu, Gelo Branco, Covanca and Itauna some residences developed some cracks on the walls; a shanty fell down and a great number of buildings developed cracks (2). In São Gonçalo, Niterói and Ilha do Governador it was more intense, with broken window panes and furniture which had been slightly shaken by the trembling; In São Gonçalo cracks in residences (6). The tremor seems to have been stronger in this town; many houses with broken window panes (4). In São Gonçalo, in the Boaçu neighboorhood, houses with cracks on the walls;a milk jug was knocked over onto the stove; police station full of people in search of explanations (Sb). Cracks on the roof-tiles and on the walls of ten houses; tremor preceded by a strong flash (3).

Other localities: Tremor felt in Saturday's morning in Jacarepaguá, Grajaú, Olaria, Ilha do Governador, Lins de Vasconcelos, Paquetá, Magé and Niterói; it was felt simultaneously in Maciço Carioca and Serra do Mar (6). Slight tremors in Rio's State and many neighborhoods in Rio de Janeiro (1). It was felt in Petrópolis, Teresópolis, Nova Iguaçu and Magé (Sá and Sb).

 

Picture 1 – Rio de Janeiro Seism's macroseismic map, on August 6^th , 1967, which was felt the strongest in the neighborhoods of São Gonçalo/RJ. The star stands for the macroseismic epicenter and the broken line sets the limits for where the seism was felt.