Crustal thickness beneath Rio de Janeiro, Brazil, from spectra of SH waves at station RDJ

Abstract

Amplitude and phase spectra of long period analog S wave records were used to estimate crustal thickness under Rio de Janeiro seismic station. Earthquakes with shallow focal depths (10-33 km) and epicentral distances varying from 83 to 88 degrees provided the best estimates of crustal thickness. Epicentral distance seems to be the most important parameter in getting adequate amplitude and phase spectra. The estimated crustal thickness under RDJ station is 32.9 ± 2.6 km. This value is compatible with an intraplate continent-ocean transition zone and with recent surface wave studies and crustal thickness determinations from receiver functions.

Keywords

• SH waves
• amplitude and phase spectra
• crustal thickness
• Rio de Janeiro
• S wave velocity
• southeastern Brazil