Question 71 (1 point)
deep-ocean trenches mark the sites where lithospheric plates are subducting back into the mantle.
question 71 options:
true
false
question 72 (1 point)
clastic particles in a sedimentary breccia are rounded and are about the same size as fine-grained sand.
question 72 options:
true
false
question 73 (1 point)
the first sign of a tsunami's approach is a rapid retreat of water from the shoreline.
question 73 options:
true
false
question 74 (1 point)
you are monitoring a seismograph in seattle. one morning, your instrument records an earthquake approximately 2000 km away. from that information, can you determine where the earthquake occurred?
question 74 options:
yes, because seismographs can indicate direction as well as distance.
no, because seismographs can't pick up earthquakes from that far away.
yes. you could take the distance and match it up with known fault lines to find the epicenter.
no, because you would need information from more than one seismograph to plot the epicenter.

Answer 71: True

Answer 72: False

Answer 73: True

Answer 74: No, because you need information from more than one seismograph to plot the epicenter

Explanation:

Answer 71:

When a plate is subducting under another it forms a trench in the limit between the plates, because the one that is subducting takes the extern part of the other toward the Earth's interior.

Answer 72:

A sedimentary breccia has angular clastic particles and is bad sorted, that means that the grains have different sizes . It's related to low transport and high energy environments and it's not related with water, because water use to form rounded clasts.

Answer 73:

A tsunami is like a big wave in the sea that's prapagated from the original point to the shoreline. Here is important to remember that the amount of water is not changing, so, to generate a big wave is necessary to take the disponible water and for that reason, when the wave is growing seaward, the water in the shoreline retraets rapidly to form the big wave that then will be coming to the coast.

Answer 74:

The process to determine the epicenter of a seism is called triangulation, and it needs 3 different seismographs to work. It consists in drawing a circle whose center is the seismograph localization and the radius is the approximate distance of the earthquake recorded by the instrument. After having drawed the three circles, we will have a common zone between them with a triangle form and that's the localization of the epicenter.

answer: s     se x

explanation: