marine diatoms provide biostratigraphic evidence for tsunami
inundation at Bradley Lake, a small freshwater lake on the
south-central Oregon coast. During the past 7,200 years, fine-
grained lacustrine deposits in the deep axis of the lake were
disturbed 17 times by the erosion and emplacement of coarse-
grained gyttja and, in some cases, sand. By identifying diatoms
in closely spaced core samples, we determined that 13 of the 17
events (termed ìdisturbance eventsî) record prehistoric tsunamis
in Bradley Lake. We consider the evidence strong for 11 events,
based on numbers and diversity of marine taxa: De1, De2, De4,
De5, De6, De7, De8, De11, De12, De13, and De17. The evidence is
less compelling for an additional 2 events (De9 and De10),
although tsunami inundation is likely. Finally, we identified 4
events (De3, De14, De15 and De16) in which there were no marine
diatoms to support tsunami inundation, although stratigraphic
data shows that the lake bottom was disturbed. Freshwater
diatoms dominate throughout th