Question

on april 20, 2002, an earthquake struck northern new york state near the adirondack region. although it was a moderate - magnitude event, it was widely felt across the state. seismologists recorded the earthquake as magnitude 5.1 on the richter scale, meaning instruments detected a moderate release of energy. however, the intensity—how strongly the shaking was felt by people and how structures responded—varied widely across new york.
to report intensity, scientists use the modified mercalli intensity (mmi) scale, which is based on observations of damage, human perception of shaking, and effects on the environment, rather than on instrument measurements. the scale ranges from i (not felt) to xii (total destruction).
below are the reported modified mercalli intensities for the april 20, 2002 earthquake in five new york cities:
city mmi
albany, ny iv
binghamton, ny iii - iv
plattsburgh, ny vi
rochester, ny ii
syracuse, ny iii

1. of the five cities, identify which city experienced the strongest ground shaking.
2. state one reason why plattsburgh, ny experienced a higher modified mercalli intensity than syracuse, ny during the april 20, 2002 earthquake. answer in terms of geography or spatial scale from the epicenter.
3. explain why the april 20th earthquake had only one richter magnitude but multiple modified mercalli intensity values across ny state.
4. the modified mercalli scale uses roman numerals to describe the intensity of the earthquake. explain why scientists cannot use this scale to determine the earthquakes total energy released.

Explanation:

1. The Modified Mercalli Intensity (MMI) Scale is used to report intensity. The higher the MMI value, the stronger the ground shaking. Among the given cities, Plattsburgh, NY has the highest MMI value (VI).
2. The closer a location is to the epicenter of an earthquake, the stronger the shaking (higher MMI). Plattsburgh, NY was closer to the epicenter than Syracuse, NY.
3. The Richter magnitude measures the total energy released by an earthquake (a single value based on instrument - measured seismic waves). The MMI is based on observations of damage, human perception, and environmental effects. These factors (e.g., distance from epicenter, local geology, building construction) vary across different locations in NY state, leading to multiple MMI values.
4. The MMI scale is qualitative (based on observations like damage, human perception) and not directly related to the physical measurement of energy. It does not have a consistent mathematical relationship with energy release. The Richter scale, on the other hand, is a logarithmic scale based on seismic wave amplitude (related to energy).

Answer:

1. Plattsburgh, NY
2. Plattsburgh, NY was closer to the epicenter.
3. Richter magnitude measures energy (instrument - based, single value), MMI is based on variable local factors (damage, perception, environment).
4. MMI is qualitative (observation - based) and not directly related to energy measurement (Richter is energy - related, logarithmic).