Question

an older machine that detects seismic waves is known as a _____.
a seismogram
b seismometer
c seismograph

Explanation:

• A seismogram is the recorded data/chart of seismic waves, not the machine.
• A seismometer is the modern, sensitive sensor component for detecting seismic waves.
• A seismograph is the older, full machine system that detects and records seismic waves.

Answer:

c. seismograph