earthquake vs shock

earthquake and shock both are nouns.

Word	Noun	Adjective	Verb	Adverb
earthquake	Yes	No	No	No
shock	Yes	No	Yes	No

As nouns, shock is a hyponym of earthquake; that is, shock is a word with a more specific, narrower meaning than earthquake:

earthquake: shaking and vibration at the surface of the earth resulting from underground movement along a fault plane or from volcanic activity
shock: an instance of agitation of the earth's crust

Other hyponyms of earthquake include seismic disturbance, earth tremor, microseism, tremor, seaquake, submarine earthquake.

earthquake (noun)	shock (noun)
shaking and vibration at the surface of the earth resulting from underground movement along a fault plane or from volcanic activity	a reflex response to the passage of electric current through the body
a disturbance that is extremely disruptive	the violent interaction of individuals or groups entering into combat
	a mechanical damper; absorbs energy of sudden impulses
	an instance of agitation of the earth's crust
	an unpleasant or disappointing surprise
	a sudden jarring impact
	the feeling of distress and disbelief that you have when something bad happens accidentally
	a pile of sheaves of grain set on end in a field to dry; stalks of Indian corn set up in a field
	a bushy thick mass (especially hair)
	(pathology) bodily collapse or near collapse caused by inadequate oxygen delivery to the cells; characterized by reduced cardiac output and rapid heartbeat and circulatory insufficiency and pallor

earthquake (verb)	shock (verb)
	inflict a trauma upon
	subject to electrical shocks
	collect or gather into shocks
	collide violently
	strike with horror or terror
	surprise greatly; knock someone's socks off
	strike with disgust or revulsion