### Hawaiian-Emperor Seamount Chain The Hawaiian-Emperor seamount chain is a trail of volc… — ACT

### Hawaiian-Emperor Seamount Chain

The Hawaiian-Emperor seamount chain is a trail of volcanoes on the Pacific Plate. Two hypotheses discuss the origin of these volcanoes.

Hypothesis 1 (Stationary Plume)
A stationary mantle plume under the Pacific Plate supplies magma. As the plate moves northwestward at a constant rate, new volcanoes form directly over the plume. Volcanoes that have moved away from the plume become inactive. This hypothesis predicts that the age of the seamounts increases linearly with distance from the active hotspot ( $0\text{ km}$ at Hawaii).

Hypothesis 2 (Lithospheric Stress)
Volcanism occurs along pre-existing fractures in the plate. The fractures open due to tectonic stress changes at plate boundaries. Volcanic activity can occur simultaneously along a fracture zone, and the age of volcanic centers is determined by when stress reactivation occurred, resulting in clustered or non-linear ages along the chain.

Researchers measured the age and distance from Hawaii of four seamounts in the chain, shown in the table below:

Seamount	Distance from Hawaii (km)	Measured Age (million years)
Seamount W	500	5.2
Seamount X	1,000	9.8
Seamount Y	1,500	15.1
Seamount Z	2,000	19.9

Which hypothesis is supported by this data, and why?

Hypothesis 1, because the age of the seamounts increases linearly with distance from Hawaii.Answer
B
Hypothesis 1, because the age of the seamounts is independent of their distance from Hawaii.
C
Hypothesis 2, because the age of the seamounts increases linearly with distance from Hawaii.
D
Hypothesis 2, because the age of the seamounts is independent of their distance from Hawaii.

Answer

Hypothesis 1, because the age of the seamounts increases linearly with distance from Hawaii.

The correct answer is supported because the data in the table shows that as the distance from Hawaii increases (from

500\text{ km}

2,000\text{ km}

), the measured age of the seamounts increases steadily and linearly (from

5.2

19.9\text{ million years}

). This direct linear relationship directly aligns with the prediction of Hypothesis 1, which states that volcanic age increases linearly with distance from the active hotspot.

Step-by-Step Solution

Analyze the predictions made by each hypothesis regarding seamount ages and distances.

Hypothesis 1 predicts a linear increase in age with distance from the active hotspot. Hypothesis 2 predicts non-linear, clustered, or independent ages along the chain.

This establishes the predicted patterns for each viewpoint to compare with the data.

Examine the data table to identify the relationship between the distance from Hawaii and the measured age of the seamounts.

As the distance increases from

500\text{ km}

2,000\text{ km}

, the age increases from

5.2\text{ million years}

19.9\text{ million years}

. This is a steady, linear increase.

This extracts the empirical trend shown by the measurements.

Align the identified data trend with the correct hypothesis.

The linear increase observed in the data matches the linear prediction of Hypothesis 1 and contradicts the non-linear prediction of Hypothesis 2.

This determines which viewpoint is supported by the data.

Key Concept

Aligning Data and Predictions with Viewpoints

Estimated Time:1m 0s

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