seismograph
Concise Oxford English Dictionary © 2008 Oxford University Press:
seismograph /ˈsʌɪzmə(ʊ)grɑːf/
▶noun an instrument that measures and records details of earthquakes, such as force and duration.
– derivatives
seismographic adjective,
seismographical adjective.
seismographic adjective,
seismographical adjective.
'seismograph' also found in these Oxford entries:

