Seismic scream precedes volcanic eruptions

The transcript describes the events leading up to a 2009 volcanic eruption. It details a series of tremors occurring two kilometers below the crater, which escalated into a swarm of 1,600 drumbeat earthquakes in the 10 hours before the eruption. The frequency and occurrence of these tremors increased, culminating in a continuous scream that peaked 30 seconds before the eruption.

What was detected two kilometers below the crater prior to the 2009 eruption?

• A landslide

• A gas emission

• A series of tremors

• A lava flow

How many drumbeat earthquakes were recorded in the 10 hours before the eruption?

• 1,600

• 1,000

• 2,600

• 2,000

What happened to the frequency of the tremors as the eruption approached?

• They decreased

• They stopped

• They remained constant

• They increased

What did the tremors eventually blur into before the eruption?

• A gentle hum

• A continuous scream

• A loud bang

• A silent pause

How long before the eruption did the noise peak?

• 40 seconds

• 30 seconds

• 10 seconds

• 20 seconds