Mount St. Helens 1980: Earthquake, Blast and Lahars Quiz

Test ten sourced facts about the 1980 Mount St. Helens eruption, landslide, lateral blast and volcano hazards.

Choose one answer per question. There’s no timer. You can skip a question; unanswered questions count as incorrect.

QUESTION 01On which date did the catastrophic Mount St. Helens eruption occur?

May 18, 1980June 18, 1981March 27, 1979August 20, 1980

QUESTION 02Which state contains Mount St. Helens?

OregonWashingtonCaliforniaIdaho

QUESTION 03What magnitude earthquake accompanied the collapse at about 8:32 a.m.?

7.96.65.13.0

QUESTION 04Which side of Mount St. Helens collapsed in the 1980 debris avalanche?

Eastern ridgeSouthern summitWestern craterNorthern flank

QUESTION 05What is the name for magma intruded within a volcano before reaching the surface?

CryptodomeCaldera lakeGlacier tongueRiver delta

QUESTION 06What made the 1980 initial blast particularly unusual?

It happened underwaterIt blasted sidewaysIt consisted entirely of lavaIt had no volcanic ash

QUESTION 07Which river valley received much of the enormous debris avalanche?

Colorado River valleyMississippi valleyNorth Fork Toutle River valleyHudson River valley

QUESTION 08What term describes destructive volcanic mudflows that follow valleys?

TsunamisTrade windsFirn fieldsLahars

QUESTION 09Which type of instrument helps scientists detect earthquakes around volcanoes?

SeismometerRain gauge onlyTide tableThermometer only

QUESTION 10What later happened inside the Mount St. Helens crater after the 1980 eruption?

A coral reef formedLava domes grewA major city was builtThe volcano became a glacier-free plain

Keep your curiosity going.