Ask A Scientist Question and Answer PageThese are the questions submitted by students and answered by on-board scientists during Expedition 316 on the Chikyu December 20, 2007 - Feb. 6, 2008. To learn more, click here. And check back often to see when our next Ask-A-Scientist session will begin! Questions About the Chikyu and Drilling Questions about Earthquakes and Volcanoes and Rocks. . . Q: Are volcanoes and earthquakes related?
Humans see volcanoes and earthquakes as two different types of natural disasters but they often can be closely related. Both are part of the plate tectonic cycle. Volcanic eruptions or magma activities can trigger numerous earthquakes and micro-earthquakes (earthquakes of very small magnitudes), many of which are imperceptible to human beings but can be recorded by seismometers. In fact, scientists can monitor or predict the imminent eruption of a volcano based on the sharp changes in numbers of earthquakes recorded around the volcano. Just as volcanic activities can trigger earthquakes, theoretically earthquakes can alter the subsurface stress field and trigger volcanic eruptions as well. But these are rare scenarios because there are far fewer active volcanoes on the Earth today than the number of earthquake events that occur each day. --------------------------- Name of answerer: Chun-Feng Li When speaking of an earthquake, we need three basic parameters to quantify it. They are location, time, and magnitude. First of all, large earthquakes (magnitude > 7) are rare events. However, there are many localized active zones (i.e., subduction zones, oceanic ridges, fault zones) on the Earth where large earthquakes occur almost periodically. These zones are highly hazardous, and scientists have made large research efforts and have already gained a reasonably good understanding of them. If we know the recurrent time interval of large earthquakes on these zones and if we also know the time when the last large earthquake occurred, we can estimate the time period when the next large earthquake will occur. For example, in the part of the Nankai Trough area that we are studying, scientists have learned that the recurrence interval between two large earthquakes is about 100-200 years, and we also know the last large earthquake happened in 1944 and 1946 in this area. Therefore we estimate that there is a very high chance that the next large earthquake will occur in this area in this century. Although we may know the approximate time period when a large earthquake will occur in an earthquake active zone, we are yet unable to pinpoint the exact second or hour and the exact location of the next large earthquake. Our current understanding of earthquakes has not reached a level that can allow us to accurately predict future earthquakes. This is why we are making an international effort (the IODP NanTroSEIZE project) here drilling into the subduction zone along the Nankai Trough. --------------------------- Q: Are some of the other
workers your friends? Do have fun working with them? Name of answerer: Olivier
Fabbri
Well, when I arrived on the
ship, I only knew one French colleague from the group of 27 scientists (and
almost 150 total people) onboard. But I quickly became friends with most people
I am working with. In particular, I have found a good friend in an American
guy, and now we spend our free time discussing of course our work onboard and about
the science behind it, but also about politics, social matters, comparing ----------------------------------------- Q: How do you talk to other
people on the ship if you don't use the same language? Name of answerer: Olivier
Fabbri English is the official
language on the ship. So everybody tries and succeeds in communicating in
English. As a non-native English speaker (I am French), I have some difficulty
understanding what my
Dean Name of Answerer: Xixi Zhao
It was the 1960 Sreya Name of answerer: Xixi Zhao I think it is an old tradition that comes from Romance
languages—the word “ship” is always feminine. One source also suggests that “a
ship was nearer and dearer to the sailor than anyone except his mother."
So, what can be a better reason to call his ship “She?” Name of answerer: Arito Sakaguchi
Q: How is the gravity in the center of the Earth? Shin Name of answerer: Xixi Zhao It should be zero. The gravitational pull from every side is
exactly counteracted by that from the opposite side at the same time. Q: Has the size of the Earth been changing since a hundred million years ago?
Name of answerer: Xixi Zhao This is a controversial question.
Some scholars believe the Earth has been expanding and growing rapidly by
external accretion of cosmic dust and meteorites and internal expansion of the
core. Others suggest Earth’s surface has been shrinking due to movement of
plates (subduction) or climate changes. However, these changes are
so small that people standing on Earth’s surface cannot see them. Q: This is a weird question but, what are the bathrooms like?
Name of answerer: Xixi Zhao The Chikyu’s bathrooms are similar to the ones you can see in
hotels with two important exceptions. One is that we do not have a bathtub (for
that we use the Sauna and Jacuzzi room). The other is the vacuum toilet. The
vacuum toilet is similar to the ones used in commercial airliners. It makes a
huge noise but it uses very little water. Potentially it can flush in any
direction since a vacuum system does not use gravity to move water. The pipe
does not need to go downward, meaning that you can avoid cutting into the floor
to put in new toilets. Katie Name of answerer: David Goldsby
Thanks for asking! Name of answerer: Matt Knuth
There are a lot of sea gulls around the ship all the time. We
didn't see any until the start of January, but now it seems like there are more
every day. They mostly just fly around the ship, but occasionally they land on
the helideck. The only type of fish I have seen is the Mahi-mahi, which we can
see swimming around the front of the ship on clear days. When we were using the
submersible ROV at the first site, we could occasionally see smaller fish
through its camera. Q: Do you wash your clothes on the boat or do you wait until you
dock? Name of answerer: David Goldsby We wash our clothes on the boat - or, rather, someone from the
excellent housekeeping staff on the boat does our laundry for us. We just place
it in a bag outside our cabin door and usually it is back within a few hours,
clean and folded! Thanks for asking! Q: Are you allowed to wear your own clothes or do you have a uniform? Lina Name of answerer: David Goldsby We wear our own normal, everyday clothes with one exception - when
we walk in hazardous areas of the boat, which are mostly located outside of the
scientific labs. Then, in addition to our normal everyday clothes, we must wear
a kind of uniform, which we call “full PPE,” or Physical Protection Equipment.
This includes a hardhat, safety glasses, steel-toed boots, and coveralls. This
equipment helps insure that we don't get hurt while walking in more hazardous
areas of the boat. Also, once a week we have a fire drill, where we wear full
PPE plus a lifejacket. During the drill we gather (muster) at our muster
stations near the lifeboats, like we might do in a real emergency.Thanks for asking! Q: Can you use your cell phone to contact your family? Name of answerer: Matt Knuth
Q: Do you drill in the same exact place every time? Meryl Name of answerer: Katerina Petronotis
We actually have drilled in quite a few different places around
the world. For this expedition, we are drilling off the coast of Kyah Name of answerer: Arito Sakaguchi We each have our own cabin. It is not large, but very comfortable. There is a bed, a desk, a bathroom, and storage cabinets.
--------------------------------- Q: Why do you drill near Name of answerer: Arito Sakaguchi Large earthquakes
happen in a few areas around the world, where one tectonic plate is subducting
under another. Among them, the area around Name of answerer: Fumio Inagaki
The deep subsurface on the Earth had long been
believed to be a place where life could not exist, but recently a tremendous
number of microorganisms have been found in deep marine sediments. These
sub-seafloor organisms are very small, less than 0.001 mm in diameter. They are
very different types of microbes from terrestrial ones, however, you don't have
to worry about that. They grow extremely slowly, each generation thought to be
over 1,000 years. But their activities in the geologic timescale are thought to
play an important role our planet by cycling elements through the crust. The
sub-seafloor life and bioshere remain largely unknown, so that scientists are
now investigating them using samples taken by the Chikyu. Q: Why is the ship called Chikyu and does it mean something in English?
Name of Answerer: Xin Su
The ship’s name "Chikyu" means "Earth" in English.
Name of answerer: Xin Su
Yes.
Noah and Grace
One of our goals is that Chikyu must operate in a way that is friendly to the environment. We usually keep all garbage on board and off-load it either to a smaller boat every few days or when we reach port. It is our policy to minimize environmental impact. ----- Q: What do you have to study to do what you are doing? Daniel Another answerer: Arito Sakaguchi Various subjects such as geology, physics, chemistry,
biology and mathematics are very useful for this type of
work. However, your interest in nature is as important as
----- Q: Does your drilling have a negative effect on the ocean environment and sea life? Name of answerer: Kazuhiro Hayashi Our operation pays a lot of attention to the environmental impact
during drilling operations. We carefully
decide where to drill using an ROV (Remotely Operated Vehicle) to examine the
seafloor. Moreover, we use ocean
sediments to study how the oceans have behaved in the past and understand
Earth's environmental changes. Ocean
drilling science is very important for our future. I like the sea and the Earth and would like
to keep our blue planet safe, the same as you. Q: Do you go fishing for your food ? Do you have a freezer to keep it (the fish) in?
Thomas Nope, we don't fish for our food. In fact, there is no fishing allowed on Chikyu, since the fishing lures and line could get caught up in the giant thrusters underneath the boat that help Chikyu stay in position during drilling. As an avid fisherman, I was a bit disappointed to learn this, especially after I saw mahi mahi swimming alongside the boat! However, we have plenty of fresh seafood and vegetables every day for lunch and dinner, since we are close enough to land that we are regularly resupplied via a supply boat (see picture). In fact, we are close enough to Japan to see the coastline on a clear day. Thanks for asking! Another answerer: Rob Harris While it would be great fun to spend time fishing there are several reasons we don’t. The most important is that the lines might interfere with the ship’s equipment. Also, the freeboard of the ship (the distance between the water and the deck) is so large it would be tough to get a fish up, and finally we don’t have a lot of free time. Fortunately we have excellent cooks on board so we don’t have to worry about food, and they serve fish quite often. I suppose though that if you did show up at a meal with a fish, the cooks would prepare it for you. ----- Q: How big is the boat you are on? What is the biggest boat made for this?
Valley Girl Name of answerer: Matthew Knuth The Chikyu is one of the biggest drilling vessels at work around the world today. The ship is 210 meters long and 38 meters wide. The derrick stands at 112 meters above the waterline, which makes it the highest operating derrick in the world today. I believe the largest drillship in the world today is called the Stena Drill MAX. It is about 14 meters longer than the Chikyu and 4 meters wider. There are a few other ships planned that may end up being even larger, but they are really more like a cross between a normal drillship and an oil tanker. They are built large so that they can store a lot of oil once they have drilled a well. The Chikyu was designed primarily for research, so it has a lot more space for laboratories. Its massive size makes it extremely stable, even in some pretty rough seas. That is very important when we are trying to set up sensitive experiments. Q: Is there a captain of the ship? If so, who is he? What is his background?
Name: Bradley
Specialty: Paleomagnetism Country: China and USA
Yes, every vessel has a captain and the Chikyu is no exception. In fact, Chikyu has two captains. Why? Because Chikyu’s mission (Chikyu is Japanese for “Earth Discovery”) is to sample sediment layers deep under the world’s ocean floor, she stays at sea continuously for 5-7 months once she leaves port. Thus, Chikyu needs two captains who rotate every 4 weeks. They use a helicopter to get on the ship as boarding from a smaller boat could be dangerous.
The current Captain on duty is Mr. Yuji Onda. He
was born in Tokyo in 1957 and currently lives in
Yokohoma Japan with his wife and two children as well as a dog. He graduated from the The other Captain is Mr. Kazuo Ichiyama, also Japanese.
Q: What kind of food do you eat on board? How do you receive supplies? Name: Katie, Caroline Name of answerer: Uisdean Nicholson There is a whole mixture of food available, as the cooks come from all over the world. Obviously there are a lot of Japanese people on board, so once a week we get Sushi. But we also get curries, roast dinners, seafood, steaks, salad and plenty of ice cream. Fortunately they have a gym too. The food arrives about once a week on a supply boat from Japan.
----- Q: What is the oldest layer of rock that you have collected? Name: Daniel Name of answerer: Xixi Zhao The oldest rock layer we have drilled so far is
several million years old. We know that by studying the record of calcareous
nannofossils (tiny fossils found in the cores) and geomagnetic field directions
that were preserved when the rock layer was deposited. In the geologic time
scale, this age is within the early Pliocene period (the word Pliocene is from
the Greek word, pleion, meaning ‘more’). So far, we have drilled about 400 meters below the seafloor and have reached the so-called “Lower Pliocene,”several million years ago. In our second site, we plan to drill down to 1000 meters below the seafloor; we are now at around 400 meters and sediment samples indicate a younger age (around 1,000,000 years). Amongst the techniques we use to date the sediments, we look at two microfossil groups. The most useful and abundant in this area of the ocean are nannofossils, very tiny microorganisms (200 times smaller than a millimeter) with a calcareous shell. They are so tiny that we need a microscope with a high magnification (100 times) to see them. We also look at radiolarians that are also small organisms made of opal (a mineral similar to quartz). Their size can vary from 40 to 300 micrometers (3 to 25 times smaller than a millimeter). Radiolarians are much bigger than nannofossils but if you look at them without a microscope, they would appear like very small sand grains. Many species from both microorganism groups are still living in today’s oceans, but the living species are different from the species that were living a few million years ago. Through time, they have changed their shape, became extinct, or new species have appeared. Scientists have been working for decades throughout the ocean, looking at sediments from all ages to find out when a species has appeared and disappeared. They came up with charts indicating the time intervals where you find particular species of microfossils. Based on these charts and the species that are present or absent in the sediments, we can tell the age of the sediment. It is really useful to use several different species to date the sediments, because it is possible that one microfossil group is missing or we don’t find a good species to establish an age.
Stylatractus universus, a radiolarian species that became extinct a few hundred thousands years ago (magnification 400 times) --------- Q: How do you get oil from the bottom of the sea and what do you use to get
Name of Answerer: Dr. Liz Screaton Answer: In NanTroSEIZE (this set of expeditions), we are drilling to understand earthquakes. So during this expedition, we are getting cores from beneath the ocean floor in order to understand how rocks moving past each other create earthquakes. The ship we use is a lot like ships used to explore for oil. The difference is that we are drilling in a different geologic area. For oil exploration, it is good to look in areas where sediment with a lot of organic matter (former living things) has fallen to the bottom of the ocean and been buried quickly. To understand earthquakes, we are drilling in a subduction zone, where one of the Earth’s tectonic plates is sliding underneath another plate.
---------------------------------------
Name: Rock Lady Name of Answerer: Arito Sakaguchi
Answer: The submarine faults (zones where rocks are sliding past each other) that we are studying are very far from our homes on land. But these types of faults repeatedly cause large earthquakes. The earthquake energy released from plate subduction zones is over 85% of all earthquake energy in the shallow Earth's crust. Also, submarine faults cause “tsunamis;” tsunamis occur when the sudden movement along the fault lifts or drops part of the ocean floor, creating a large wave. These waves can cause serious disasters. Research on submarine faults is important for earthquake sciences and disaster prevention. The collection of cores from this submarine fault zone will give us clues so we can understand how earthquakes occur. ---------------------------------------------------- Q: How are earthquakes formed? How do earthquakes stop? Name of Answerer: Xixi Zhao Answer: Earthquakes occur as a result of a build up of pressure between colliding sections of the Earth's crust, called “plates.” These plates “float” on the mantle like rafts, with a typical speed of a few centimeters per year (about as fast as your fingernails grow). Where we are drilling now, one plate is sliding underneath another plate, in what is called a subduction zone. When the plates “stick” in spots, rather than smoothly sliding past each other, these spots can accumulate tremendous pressure which is released abruptly when the rocks finally break. This release of energy travels through the Earth's crust and causes the shaking that we feel during earthquakes. Earthquakes stop after all the stored energy is released, or the plates “stick” in another spot. --------------------------------------- Name: K. Money This is a great question! It stumped us, so David Goldsby checked on “Wikipedia.” Below is what he found. Name of Answerer: Dr. David L. Goldsby, Brown University
Answer: ------------------------------------------------------------------ Q: What is the main rock or mineral that you find while drilling in the ocean? Name of Answerer: Kitty Milliken Specialty and role: Sedimentologist; I work to describe the appearance and composition of the cores. Answer: --------------------------------------- Q: What special tools do you use? Answer: Of course, there are other instruments for the things that hand lenses can’t figure out. Right by the rock description table there are two very nice light microscopes. One allows you to look at small chunks of rock a bit more closely than a hand lens. The other is a microscope that shoots light through things. In order to get light through the rock we put a tiny piece of the rock in a drop of water on a glass slide so that it falls apart into its sand, silt, or clay particles. Next we use a special glue to stick on a glass cover slip. Now, the grains can be examined really close up----typically at magnifications of 200x to 400x. -------------------------------------------- Q: How deep is the water? Name: France Elisabeth Girault The sea floor is a bit like what you see on land. Mountains, valleys, hills and even volcanoes are typical landscapes that we can see down on the sea floor. The area where we are drilling during this expedition is located on a large slope between the continent and the deep ocean. At our first drilling site, the water was about 2630 meters deep; at our second site, the water will be around 3900 meters deep. An additional note from Matt Knuth (Specialty: Geophysicist; Role: Physical Properties; Nationality: U.S.)
The location where we are drilling today is about 3.8 kilometers below the surface of the ocean, or about two and a half miles. For scale, that is about ten Empire State Buildings stacked one on top of the other. And the hole itself will be about 800 meters deep. This means that the length of hollow pipe extending from the Chikyu to the drill bit at the bottom of the hole will be over three miles long! Q: What do you do once you find the minerals and rocks? What happens to the cores once they are drilled? ------------------------------------ Q: What is your favorite thing about being in the ocean on this expedition? What is the coolest part of being on the Chikyu?
My favorite thing about the expedition is the excitement of drilling into rocks that have never been seen before, including some active faults, and getting to use some really sophisticated tools to analyze them. ------------------------------------- Q: What did you do during the Christmas holiday? Name of Answerer: France Elisabeth Girault --------------------------------------- Q: What would happen if an earthquake occurred while you were drilling? --------------------------------------- Q: Will you cause an earthquake?
-------------------------
Name: Ian Name of answerer: Uisdean Nicholson Specialty: Sedimentology Country: Scotland There are 25 scientists working on the ship but many more people are needed to run the ship. There are about 150 people on board in total including the captain and crew, drillers, technicians, cooks, cleaners and many more. Half of the crew works during the day and the other half works at night, so the action never stops! Another answer: Name of answerer: Yujin Kitamura
The maximum capacity of the Chikyu is 150 persons. At this moment, we have 148 people onboard including 26 scientists, 40 marine crew, 42 drillers, 6 operation intendants, 20 laboratory technicians, and 14 others (third party engineers, publication assistant and so on). In most of the departments, we have a crew change every two weeks and they stay for four weeks, and so that the number of onboard personnel can change in some range. Only scientists stay for whole expedition period (two months in case of ongoing Exp. 316). -------------- Q: What is a typical day for you on board? What do
you miss most about being away from home? Name of answerer: Rob Harris
The things I miss most about being away from home are my family and riding my bicycle. | |
