INTRODUCTION TO EARTH SCIENCE
ESCI 121
Analyzing Earthquake Focus Maps Dr. Sanders
1) With your large group, arrange the maps into clusters based on the distribution
patterns of earthquake foci. Don’t forget to consider location as well as depth of
focus! If there is disagreement as to where a particular map should go, put the
disputed maps into their own cluster. Note that some maps might be in a “cluster” of
one.
2) Split into groups of four students each, and assign the following duties:
Coordinator (1 student): Keep the group on task, ensure that the work is
complete before the deadline, put all the work together, and hand it in by
the deadline.
Sticky-Note Arranger (1 student): Write the name of each mapped area on
a sticky note, and put them on sheets of paper to show how the group
arranged the clusters (one cluster per page).
Mapper(s) (1 or 2 students): Find and plot the location of each mapped area
on a map of the world. If there are two mappers, one should determine
the relationship of each location to plate boundaries (if any) and report it to
the analysts.
Analysts (all students in the group): Discuss this step with your group
members before writing your answer. Each analyst should choose one
page with a cluster of sticky-notes, and, writing on that page, explain the
pattern of earthquake foci.
Don’t forget to explain the pattern of focal depths in addition to
locations!
Consider the relationship to plate boundaries.
Use diagrams if you think they will help your explanation.
If there are any anomalies in the cluster, for example, a map that
seems similar to the others in most ways to the others in the
cluster, but might exhibit some differences, explain what you think
causes the anomaly.
Some clusters may not be easy to characterize or explain. Discuss these
with the group, and come up with hypotheses that could explain them.