It uses special instruments to detect and measure changes in electromagnetic field due to magma activity.

a. Radioactivity
b. Seismic monitoring
c. Geophysical technique
d. Carbon dating​


Sagot :

Answer:

A.radioactivit

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Answer:

c. Geophysical technique

Explanation:

geophysical technique uses special instruments to measure changes in electromagnetic field due to magma activty, it also measure physical phenomena of the earth such as gravity, magnetism, elastic waves, electrical and electromagnetic waves.