Dive and Discover : Expedition 3 : Daily Updates

Morning saw RV Melville steaming at 12.5 knots through glassy seas on a balmy day in the tropical Pacific. We have been spotting sea turtles often, and in between turtle sightings, we disturbed schools of flying fish with the bow wave of the ship, sending them skimming over the blue water in all directions. Did you know that flying fish do not actually fly? They use their caudal (tail) fin to propel themselves into the air, and then they spread the large pectoral fins on their sides to help them glide through the air. We are looking forward to seeing lots of marine life in the next few weeks, and catching more fish for dinner. We had the Mahi Mahi that Dave Grimes caught yesterday for dinner tonight. Thanks Dave!

We have made lots of progress in processing the sonar data we collected in the last few days using special computer programs that Gregg Kurras and Paul Johnson brought from their lab at the University of Hawaii. Mike, Dan, Gregg and Paul spent part of the afternoon discussing how they will put all the rock data, towed digital camera images, and Alvin observations from the previous cruises to the 9°N area together with the DSL-120 sonar data.

Unlike land geologists who can walk over the rocks and see how different rock types match up with different characteristics of the terrain, marine geologists have to piece together information collected by a variety of methods. On this cruise, we have been relying on remote sensing instruments, like sonar systems or camera sleds, to tell us about the physical characteristics of the terrain. We now have to put this information together with precisely located samples and images, like those we have collected using Alvin on past cruises, to understand the seafloor geology and the different volcanic features that are present. In this way, we will be able to identify where recent eruptions of lava have occurred on the East Pacific Rise crest between 9°-10°N latitude.

At 0800 hours local time (the same as 08:00 a.m. Central Time), RV Melville was 218 nautical miles away from where we will start our detailed survey of the 3° 20’N site on the East Pacific Rise crest. Our speed was 12.5 knots (nautical miles per hour). As I write this journal, at 2130 hours local time, we are about 55 nautical miles from the site. We are now traveling at a speed of 12.2 knots. Can you estimate what time tomorrow morning we will arrive at the site? I will post the exact time of arrival in the Daily Journal tomorrow.