At 18:03hrs UTC, a magnitude M6.5 earthquake shook the Earth near the Bouvet Islands. The focal depth was ~15kms, about 118 pol deg away, and occurred near a triple junction plate boundary (see map below). WHY DIDN’T station E1TX record this event (assuming all wave phases)? Hypothesis: the epicenter (blue dot) was ~118 pol deg was in the P-wave shadow zone – epicentral distances 104 to 140 degrees from the recording station. If we examine the seismogram closely, it’s possible to interpret a PS wave phase, however no other confident interpretations have been made by the station’s operator.
QUESTION: Are “missing” wave phases not recorded? did not arrive at location? does it matter?