Exam #3 - All numbered questions are given equal weight in the multiple choice part.

Transcription

1 Exam #3 - All numbered questions are given equal weight in the multiple choice part. Multiple Choice Mark only one answer for each question. 1) On a global map of earthquakes, the locations of the earthquakes can be used to interpret A) The edges of the tectonic plate boundaries B) Ancient meteor impacts C) Heavily populated zones at high risk of tsunami 2) Which of the following lines of evidence did Wegener use to support his idea of continental drift? A) Fit of the shape of the continents B) Locations of past glaciations C) Distribution of equatorial climatic belts D) Distribution of fossils E) All of the above 3) How is the age of the ocean crust related to the distance from a mid-ocean ridge? A) the age is approximately constant until approaching the continental shelf where it is younger. B) the age gets younger gradually towards the continental shelf C) the age gets older as the distance from the ridge increases 4) How is the depth of the ocean floor related to the location of a mid-ocean ridge? A) the depth is approximately constant until approaching the continental shelf where it is shallower. B) the depth gets shallower gradually towards the continental shelf C) the depth gets deeper as the distance from the ridge increases. 5) What is the explanation of how the continents move apart? A) They spread apart as crust is created at mid-ocean ridges B) They floated through the oceanic crust C) They subduct beneath island arcs 6) The location of glacial moraines on South America, Africa, India and Australia were all once connected A) To Antarctica B) To North America 7) Where is the oceanic floor shallowest? A) The mid-ocean ridge B) 100 km from the mid-ocean ridge. 8) Which is older? A) The oceanic crust at the mid-ocean ridge B) The trench east of the Philippines. 9) Over the course of geologic history, has magnetic north always been at the current geographic north pole? A) Yes B) No

2 10) Marine magnetic anomalies are measurements of the strength of the magnetic field that are made from ships as they traverse the ocean floor. They vary because A) some volcanic rocks under the ship on the sea floor cooled during periods when the magnetic north pole was at the current geographic north pole and some rocks cooled when the magnetic north pole was at the current geographic south pole B) sometimes the ships cross over volcanic hot spots and the volcanoes cooled during a time when the magnetic north pole was at the current geographic south pole C) sometimes the magnetic field changes in strength because the earth s core rotates more slowly. 11) Marine magnetic anomalies are symmetric on either side of a mid-ocean ridge. This means that A) New crust is being formed at the mid-ocean ridge B) Oceanic crust 100 km to the west side of the ridge is the same age as oceanic crust 100 km to the east of the ridge C) All of the above. 12) Marine magnetic anomalies can be used to determine the age of oceanic crust A) Yes B) No 13) What do hotspot volcanoes on the ocean floor tell about plate tectonic motion? A) The direction of tectonic plate motion is from the oldest to the youngest island in the chain B) The direction of tectonic plate motion is from the youngest to the oldest island in the chain C) The direction of plate motion is perpendicular to the direction from the youngest to the oldest island in the chain. 14) If Midway Island is an ancient hot spot volcano 25 million years old and it is located 1500 km from another submarine volcano in the same island chain that is 43 million years old, then how fast is the tectonic plate moving over the hotspot? The correct answer is A km (43+25) x 10 years (43-25) million years A) B) C) (43 25) million yrs 1500km 1500km 15) 225 million years ago the continents were: A) further apart; B) one super continent; C) unable to move through the ocean floor; D) missing from the surface of the Earth; E) all at the bottom of the ocean. 16) The mantle is A) Solid B) liquid 17) Subduction zones are where oceanic crust is formed A) True B) False 18) The names of geological epochs such as Permian and Cretaceous are important because A) They tell us the relative age of different rocks B) They are associated with major events when species became extinct C) They describe major stages in the evolution of life on earth D) All of the above

3 Refer to the figure below to answer the following 6 questions 19) Point C is a A) Subduction zone B) mid-ocean ridge C) transform fault D) fracture zone 20) Point B is a A) Subduction zone B) mid-ocean ridge C) transform fault 21) Point C is an example of a A) Convergent plate boundary B) Divergent plate boundary C) Transform plate boundary D) Neophyte plate boundary 22) Point B is an example of a A) Convergent plate boundary B) Divergent plate boundary C) Transform plate boundary D) Neophyte plate boundary 23) What kind of earthquake fault would one expect to find at Point C? A) Thrust fault B) Normal fault C) Left-lateral strike-slip fault D) Right-lateral strike-slip fault 24) What kind of earthquake fault would one expect to find at Point B? A) Thrust fault B) Normal fault C) Left-lateral strike-slip fault D) Right-lateral strike-slip fault 25) Why is it important to know what kind of plate boundary is at a particular place? A) So a map of earthquake epicenters can be made B) So we know where the earth s crust is weak C) So we know what kind of earthquake to expect there 26) Earthquake hypocenters in a subduction zone when seen from the side indicate A) the location of the rigid slab of the tectonic plate that is subducting B) molten magma C) the oceanic fracture zone

4 Use the diagram below that shows the magnetic anomalies on the sea floor to answer the following two questions: A C B 27) Point A is a A) Subuction zone B) mid-ocean ridge C) strike slip fault D) convergent boundary 28) The crust at point C is older than the crust at point B A) True B) false 29) The deepest earthquakes in the world are found in A) Subduction zones B) mid-ocean ridges C) California 30) Which of the following are not found in the region of Tonga: A) a chain of islands B) a chain of underwater sea mounts C) a deep trench D) earthquakes E) normal faults 31) GPS is used to measure tectonic plate motion in the following way: A) GPS receivers are put on ships with sonar to measure the distance to the sea floor at the midocean ridge. This is done on both sides of the ridge and the distance is divided by the time it takes the sonar to travel to the sea floor to get the velocity of the two oceanic plates. B) GPS receivers are taken to two points on two different plates and their positions are calculated with an accuracy of 5mm, the distance between the two points is measured, then the points are remeasured several years later. The change in distance is divided by the time interval to calculate the relative velocity of the tectonic plates. 32) In a subduction zone environment, chains of volcanic islands are found A) parallel to the trench B) perpendicular to the trench 33) In a subduction zone environment, earthquake align A) parallel to the trench B) perpendicular to the trench Use the color handouts to answer the two questions below:

5 Use the figure at left to answer the following questions. A color version of the figure is provided in your packet. 34) What is the distance from the point at the end of the arrow marked Q to the closest dashed line? A) 200 km B) 300 km C) 400 km D 500 km 35) What type of plate boundary is shown by the black dashed line? A) Divergent plate boundary B) mid-ocean ridge C) continental rift D) All of the above E) Answers A and B 36) What is the name of the tectonic plate to the east of the dashed line? A) Nazca plate B) Cocos plate C) Juan de Fuca plate D) Pacific plate

6 37) How old is the oceanic crust at the center of the mid-ocean ridge here? A) 0 million years B) 6 million years C) 8 million years D) 10 million years 38) How old is the oceanic crust at point Q at the boundary between the green and blue magnetic anomalies? A) 0 million years B) 6 million years C) 8 million years D) 10 million years GPS has been used to measure the velocity of plate B relative to plate A in the figure below. Based on the velocity vectors for Plate B, answer the following three questions: 39) The figure on the left shows which directional type of plate boundary: A) convergent B) divergent C) transform 40) The figure in the center could have been measured at which type of plate boundary D) Ocean-ocean subduction like the Marianas Trench in the west pacific E) Continent-continent transform like the San Andreas Fault in California F) Continental rift like the east African rift 41) The figure at the right shows a tectonic environment where one could find a G) Thrust fault H) Strike slip fault I) Normal fault Use the color handouts to answer the two questions below: 42) The dark red regions in figure A show A) Young ocean crust B) Crust that has just been created at a mid-ocean ridge C) Divergent plate boundaries D) All of the above E) Answers A and B 43) What type of plate boundary is shown in the black rectangle in Figure A: A) Divergent plate boundary B) mid-ocean ridge C) continental rift D) All of the above E) Answers A and B

7 End of scan sheet multiple choice questions. Next questions are 2 points each. 44) Using the distance you found from the dashed line to point Q, what is the velocity that the plate on the west side of the ridge is moving away from the current location of the mid-ocean ridge? change in position velocity = = km m cm = 3 cm 6 change in time (10 0) 10 yr km m yr 45) What are the three directional types plate boundaries that indicate relative motion: Divergent, convergent, and transform 46) What are the two types of crustal material that are at the surface of tectonic plates: Oceanic and continental 47) What are seven types of plate boundaries (include variations of directional types and crustal types and other words that describe the environement (ie ocean-continent subduction; YAY! You get one for free) Ocean-ocean subduction and Ocean-continent subduction Continent-continent collision mid-ocean ridge continental rift oceanic fracture zone continental strike-slip fault 48) What are the three types of earthquake faults: Normal, thrust ( or reverse) and strike-slip For each figure in the color attachment, give all of the following information. If one item does not apply to the situation or you do not have the information to answer, then answer N/A. Figure A and B are provided for reference. Do not write on the color pages. Write your answers on the black photocopy and in the spaces below. 49) Figure C D) Names of the tectonic plates within the rectangular box: Eurasian and Philippines E) Relative direction of motion at the plate boundary in box: convergent F) Type of crust on each side of plate boundary within box: oceanic-oceanic G) Type of boundary in box: ocean-ocean subduction zone H) Name of overriding plate for each plate boundary: Philippines overriding in north, Eurasian overriding in south (either answer or both will count as correct) I) Type of earthquake fault expected: thrust J) Is volcanisim expected: yes

8 50) Figure D D) Names of the tectonic plates within the rectangular box: Indian plate, Eurasian plate E) Relative direction of motion at the plate boundary in box: convergent F) Type of crust on each side of plate boundary within box: continental continental G) Type of boundary in box: continent-continent collision H) Name of overriding plate: N/A (but historically Eurasian is actually overriding India so that answer is acceptable also) I) Type of earthquake fault expected: thrust J) Is volcanisim expected: no 51) Figure E D) Names of the tectonic plates within the rectangular box: Cocos plate, Caribbean plate E) Relative direction of motion at the plate boundary in box: convergent F) Type of crust on each side of plate boundary within box: Cocos oceanic, Caribbean continental (I will accept Caribbean as oceanic crust) G) Type of boundary in box: ocean-continent subduction (I will accept ocean-ocean subduction) H) Name of overriding plate: Caribbean I) Type of earthquake fault expected: thrust (or reverse) J) Is volcanisim expected: yes 52) Figure F D) Names of the tectonic plates within the rectangular box: North American, Eurasian E) Relative direction of motion at the plate boundary in box: divergent F) Type of crust on each side of plate boundary within box: oceanic-oceanic G) Type of boundary in box: mid-ocean ridge H) Name of overriding plate: N/A I) Type of earthquake fault expected: normal J) Is volcanisim expected: Yes 53) Figure G D) Names of the tectonic plates within the rectangular box: Nazca plate, South American plate E) Relative direction of motion at the plate boundary in box: convergent F) Type of crust on each side of plate boundary within box: Nazca oceanic, South American continental G) Type of boundary in box: ocean-continent subduction H) Name of overriding plate: South American plate

9 I) Type of earthquake fault expected: thrust (or reverse) J) Is volcanisim expected: Yes 54) Figure H D) Names of the tectonic plates within the rectangular box: Pacific plate, North American Plate E) Relative direction of motion at the plate boundary in box: transform F) Type of crust on each side of plate boundary within box: continental continental G) Type of boundary in box: continental strike-slip H) Name of overriding plate: N/A I) Type of earthquake fault expected: strike-slip J) Is volcanisim expected: No Do not do Figure I, or any others