Mohorovičić's observation was that "Seismic waves travelled at varying speeds." This observation led to the identification of the Mohorovičić discontinuity (or Moho), which marks the boundary between the Earth's crust and the underlying mantle, where seismic wave speeds change significantly.
What was Mohorovičić's observation?(1 point)
Responses
Seismic waves travelled at constant speeds.
Seismic waves travelled at constant speeds.
Seismic waves penetrated all Earth's layers.
Seismic waves penetrated all Earth's layers.
Seismic waves could not go through the brittle crust.
Seismic waves could not go through the brittle crust.
Seismic waves travelled at varying speeds.
3 answers
Responses
cross-cutting relationships
cross-cutting relationships
original angularity
original angularity
superposition
superposition
original horizontality
original horizontality
radiometric dating
radiometric dating
angular relationships
The three methods of relative aging of rocks from the options provided are:
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Cross-cutting relationships - This principle states that a geologic feature that cuts another is younger than the feature it cuts.
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Superposition - In an undisturbed sequence of rocks, the oldest rocks are at the bottom, and the younger rocks are at the top.
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Original horizontality - This principle states that layers of sediment are originally deposited horizontally under the action of gravity.
Radiometric dating is a method of absolute dating, not relative aging, and "angular relationships" is not a recognized method of relative dating in the same sense as the others listed.
So the correct answers are: cross-cutting relationships, superposition, and original horizontality.