sentence2_structure: Seismologists<>measured<>the intensity of an earthquake with the mercalli scale<>originally
sentence1: Two earthquakes, one measuring 4.3 on the Richter scale, struck eastern Taiwan early Tuesday, but there were no reports of casualties or damage, government seismologists said.
sentence2: Seismologists originally measured the intensity of an earthquake with the mercalli scale.
question: How did seismologists originally measure the intensity of an earthquake?