Why is there a chain of earthquake epicenters cutting across Guatemala and continuing eastward south of Cuba

What are advantages and disadvantages of taking troops out of siria?

Which of the layers of the earth has the following three characteristics? i. it is made of molten rock. ii. it has currents that are constantly moving. iii. earth’s plates float on top of its currents.

Some gamma ray bursts are hypothesized to come from mergers of neutron stars or black holes. if this hypothesis is correct, what else should we in principle be able to detect from such mergers? a. gravitiational waves b. x-ray bursts c. significant disruption of gas thousands of light-years away in the surrounding galaxy d. an "afterglow" of bright visible light, lasting for weeks