Possible Clues:

• Instrument for registering earthquakes
• Recorder of earth movement that’s wrecked gophers’ aims
• Instrument that measures current pollution described by new phrase
• Earthquake detector
• What's set to shake recording angel, involving one dirty cloud?
• Tremor detector
• Earthquake recorder
• Earthquake measuring instrument
• One records shocking experiences with exceptional heroism (gasp!)
• What detects such tremors as grip homes in a quake