1. Seismology Center, IAG, University of São Paulo, Rua do Matão 1226, 05508‐090 Sao Paulo, Brazil, marcelo.assumpcao@iag.usp.br
2. Seismological Observatory, University of Brasilia, 70910‐900 Brasilia, Brazil
3. Now at Federal University of Western Pará, IEG‐UFOPA, 68040‐255 Santarém, Brazil.
4. National Observatory, MCTI, Rua General José Cristino 77, 20921‐400 Rio de Janeiro, Brazil
5. Geophysics Department, Federal University of Rio Grande do Norte, Campus Universitário Lagoa Nova, 59078‐970 Natal, Brazil
6. CPRM ‐ Geological Survey of Brazil, SBN‐Q2, 70040‐704 Brasilia, Brazil