RAPID EMPLACEMENT OF A MIDOCEAN RIDGE LAVA FLOW ON THE EAST PACIFIC RISE AT 9-DEGREES 46'-51'N

In April, 1991, during a submersible diving expedition to the East Pac ific Rise (EPR) crest at 9 degrees 46'-51'N, a new volcanic eruption o n the sea floor was discovered. Here, we report results from numerical modeling of that eruption, which indicate that similar to 4 x 10(6)-6 x 10(6) m(3) of lava was emplaced in similar to 1-2 h, with an averag e eruption rate of similar to 10(3)-10(6) m(3) s(-1) - comparable to r ates observed in Hawaii at Kilauea's East Rift Zone. If the rapid empl acement of the 1991 EPR lava and its short eruption duration are typic al of volcanic events at fast-spreading mid-ocean ridge crests, these characteristics have broad implications for our ability to detect, mon itor and understand the evolution of magmatic and volcanic processes w ithin the axial zone.