PRE-ASSESSMENT

When two tectonic plates collide, the oceanic crust usually subducts beneath the continental crust because it is

• denser than continental crust

• less dense than continental crust

• thicker than continental crust

• thinner than continental crust

If you will visit a place in the Pacific known to be along converging plates, which of these should you not expect to see?

• active volcanoes

• mountain ranges

• rift valleys

• volcanic islands

You are an oceanographer and want to map the ocean floor on the east coast of the Philippines. As you do your study, you noticed that there is a portion of the ocean floor which is relatively much deeper than the rest. What most likely is that deeper part?

• linear sea

• oceanic ridge

• rift valley

• trench

What do you expect to find at a mid-ocean ridge?

• relatively young rocks

• reverse fault

• thick accumulation of sediments

• very ancient rocks

Crustal Plate A is moving away from Crustal Plate B. What is the expected average rate of change in position between A and B?

• a few centimeters per year

• a few meters per month

• a few millimeters per century

• a few millimeters per day

Which plate boundary is formed between the Philippine Plate and the Eurasian Plate?

• convergent

• divergent

• reverse fault

• transform fault

Which of these is false true about crustal plates

• have the same thickness everywhere

• include the crust and upper mantle

• thickest in the mountain region

• vary in thickness

Which of these is not true about the Philippine Islands?

• Most are part of the Philippine Mobile Belt except for Palawan, Mindoro, and Zamboanga

• formed because of the convergence of the Philippine Plate and the Pacific Plate

• Originated geologically in an oceanic-oceanic convergence

• Some are products of subduction process

You were provided with data showing the arrival time of the P and S waves recorded from three seismic stations. Which of these can you possibly determine?

• the damage at the focus

• the distance to the earthquake

• the intensity of the earthquake

• the location of the epicenter

From the seismogram, the distance to the epicenter can be determined by measuring

• the arrival time of surface wave

• the difference in the arrival times of the P and S waves

• the ratio of the amplitude of the largest P and S waves

• the speed of the surface wave