Unit 3: Earth movements - Practice Quiz

1 What is folding in geomorphology?

2 Which type of stress commonly causes folding?

3 What is an upward-arching fold called?

4 What is a downward-curving fold called?

5 Fold mountains are mainly formed by the folding of rock layers due to:

6 What is a fault?

7 Which stress pulls rocks apart and commonly produces normal faults?

8 A fault caused mainly by rocks sliding past each other horizontally is called a:

9 What is a block of land that is uplifted between two faults called?

10 What is a down-dropped block of land between two faults called?

11 What is an earthquake?

12 The point inside Earth where an earthquake begins is called the:

13 What is the point on Earth's surface directly above the focus called?

14 Which instrument records earthquake vibrations?

15 Most earthquakes occur along:

16 What is a volcano?

17 Molten rock beneath Earth's surface is called:

18 Molten rock that reaches Earth's surface is called:

19 The bowl-shaped depression at the top of many volcanoes is called a:

20 Which material is commonly released during a volcanic eruption?

21 A rock layer is bent upward so that the limbs dip away from the center. Which fold has formed?

22 A sequence of sedimentary rocks has the oldest beds exposed in the center of a circular fold. Which structure is most likely present?

23 Which tectonic force most directly produces folding when rocks are subjected to prolonged horizontal compression?

24 A fold has one short, steep limb and one long, gentle limb. Which classification best describes it?

25 If intense compression causes both limbs of a fold to dip in nearly the same direction, which fold type is indicated?

26 A rock block above an inclined fault plane moves downward relative to the block below it. What type of fault is this?

27 Two crustal blocks move horizontally past one another with little vertical displacement. Which fault is most likely involved?

28 A region contains a raised central block bounded by two roughly parallel normal faults. Which landform has probably developed?

29 Which combination of stress and fault movement is most consistent with a reverse fault?

30 A long, down-dropped block forms between two normal faults in a region undergoing crustal stretching. What is this feature called?

31 An earthquake's focus lies km below the surface, while its epicenter is directly above it. What does the epicenter represent?

32 A station records the P-wave at 10:00:00 and the S-wave at 10:00:40. What does the time difference mainly indicate?

33 Which observation would provide the strongest evidence that an earthquake occurred along a shallow fault?

34 Why can an earthquake of moderate magnitude cause more damage in a densely populated city than a stronger earthquake in a remote area?

35 An earthquake occurs beneath the ocean and suddenly displaces the seafloor upward. Which hazard is most likely to follow?

36 A volcano has broad, gently sloping sides built mainly from fluid basaltic lava. Which type is most likely?

37 Why are composite volcanoes generally more explosive than shield volcanoes?

38 A volcano produces ash, pumice, and a high column of eruptive material. Which eruption style is most consistent with these observations?

39 Which setting most commonly produces a chain of volcanoes on the overriding plate above a subducting oceanic plate?

40 A volcanic hazard map shows valleys extending from a steep volcano as high-risk zones. Which hazard is most likely being emphasized?

41 A sedimentary sequence contains upright anticlines and synclines whose axial planes dip consistently eastward. The fold limbs are unequal, and the western limb is steeper. Which interpretation is most defensible?

42 On a geological map, beds dip outward from a central area, and the strata become progressively older toward the center. Which structure and erosion history best explain the pattern?

43 A fold has an axial-plane orientation of and a hinge plunging toward . Which description is most appropriate?

44 In a fold belt, cleavage is axial-planar, mineral lineations parallel the fold hinges, and stretching lineations plunge down the dip of the cleavage. What deformation history is most likely?

45 A fold pair has interlimb angles of in one area and in another, with the same fold trend. Which classification change occurs across the area?

46 A fault plane dips east. The hanging wall moved upward and eastward relative to the footwall. Which fault type and stress regime are indicated?

47 A river is offset 2.4 km dextrally by a fault. Its valley contains four abandoned channels, each formed during a separate period of incision. What can be inferred most cautiously?

48 A seismic section shows a fault that terminates upward within a sedimentary package, while the beds thicken toward the fault and progressively onlap its footwall. Which interpretation is strongest?

49 A fault has a rake of measured from the strike direction. The hanging wall moves m along the fault, and the fault strikes north-south. What is the approximate vertical component of displacement?

50 Two faults intersect: Fault A has a steep dip and normal displacement, while Fault B has a shallow dip and reverse displacement. Offset markers show that A cuts B. Which event sequence is supported?

51 Two earthquakes have identical rupture areas and stress drops, but one has twice the average slip. Which conclusion is most justified?

52 A station records a wave at 10:00:00 and an wave at 10:00:40. If the assumed - and -wave speeds are km/s and km/s, respectively, what is the approximate epicentral distance?

53 A shallow earthquake occurs beneath a soft, water-saturated alluvial basin. Which combination best explains why damage may exceed that predicted from magnitude alone?

54 After a major earthquake, the number of aftershocks decreases approximately according to the modified Omori relation. If the elapsed time is increased from day to days, what does the relation primarily predict?

55 A coastal earthquake has a -wave first motion pattern showing compression in quadrants aligned northeast-southwest and dilatation in the perpendicular quadrants. What can be determined most reliably?

56 A volcano produces highly viscous, silica-rich magma with abundant dissolved gas and eruptions dominated by ash columns and pyroclastic flows. Which setting and magma behavior are most consistent?

57 A stratovolcano shows increasing seismicity, ground inflation, rising volcanic gas emissions, and a shift from sulfur dioxide toward carbon dioxide dominance. What is the most cautious interpretation?

58 A lava flow advances at m/min and has a front km from a settlement. If the rate remains constant, approximately how long is available before arrival?

59 A volcano's eruption column collapses because the mass eruption rate exceeds the atmosphere's ability to support the column. Which hazard is consequently enhanced?

60 A shield volcano has a broad profile, low-angle slopes, and repeated extensive flows with low silica content. Which process most directly explains its morphology?