Author Archives: johnmichaelkendall

Until this cruise, my experience with seismology fieldwork had been entirely on land. The group at Bristol has deployed seismometers in some of the harshest conditions on Earth, including the Canadian Arctic and the Afar region of Ethiopia and Eritrea. Operating a seismometer at the bottom of the ocean presents a whole new set ofContinue reading “What’s inside an OBS”

The weather remains good, the sea is calm and we are about to cross the equator for the third time. We are steaming westward away from Africa and have some long transits between stations. Time to enjoy the sunsets and sunrises. But, this has also given us some time to start acquiring magnetic data. ElectromagneticContinue reading “Magnetic attractions at the equator”

If you have been to sea many times, packing is no doubt a fairly simple task and you seldom forget something. However, for many of us on DY-072, this is the first time on a scientific cruise. I am happy to have remembered all the cables and adaptors that I need, but brought too manyContinue reading “What to pack”

Over 12 days into the trip and instruments are being recovered fast and furiously. We are just finishing the densest of the 3 lines and at one point we were pulling in a station every 6 hours, working 24 hours around the clock. The transit from L20D to S19D marked half-way and we have crossed the equatorContinue reading “Mid-way”

Finally, after nearly 6 days of sailing we arrived at our first site – L39D – where we retrieved one of the Lamont ocean-bottom seismometers (OBS) and a Scripps ocean-bottom magnetotelluric (OBMT) instrument. We arrived on site at almost 17:00 and we finished at midnight. Much of this time was spent trying to communicate withContinue reading “Our first returned instruments”

The Royal Research Ship (RRS) Discovery is our home for the month. We are currently about 200 nautical miles off the coast of Sierra Leone and will arrive at our first site tomorrow afternoon. The weather has been good – calm seas and the temperature is climbing towards 30oC. The past 4 transit days haveContinue reading “The RRS Discovery”

Anyone who has done a gravity survey on land knows that this can be a labour of patience – a bit of wind or uneven terrain makes things difficult. So, even though gravimeters have been used on ships and planes routinely since the 60s, I am still impressed with this technology. The RRS Discovery isContinue reading “Seaboard gravimeter”

We are now firmly in the tropics and making good time to the first site. The wind is at our backs and the sea is still calm. The biggest issue has been problems with our satellite links, which has led to a lack of internet and inability to receive our email and the like. OneContinue reading “Time is money”

We are now underway. The ship left Tenerife at 9pm last night and we are heading down the west coast of Africa. Fortunately, the weather is good and we were rocked to sleep by a gentle swell as the RRS Discovery steamed towards the equator travelling at 12-13 knots. Safety is of paramount importance atContinue reading “Safety at sea”

Tectonic plates are jigsaw-like pieces of the thin rigid outer-shell of our planet, which move around colliding and sliding past each other. They are comprised of the crust and the outermost part of the mantle, and are somewhat simpler in nature beneath the oceanic parts than they are beneath the continental parts. Plates are aContinue reading “What is a plate?”