Earthquakes in New York State
Introduction:
Although many people do not consider New York a “quake” state, it has had the third highest earthquake activity of the states east of the Mississippi River. The question that is always asked is “When and where will the next earthquake take place?” The data for New York State used in this investigation goes back to 1737 and includes data for 16 major earthquakes. In recent years, an earthquake of magnitude 3.5 to 4.0 occurs, on average every 3 years somewhere in New York State.
The likelihood that an earthquake of a certain intensity will occur at a given location and time is known as the earthquake hazard. The hazard determination is largely dependent on geologic factors and seismic history. Seismic risk is a further determination in which population density, architecture, and disaster preparedness are considered. The seismic risk anywhere in New York State is greater today that it was 100 years ago because the population is many times greater. The effects of an earthquake are determined not only by its intensity, but also by the population of the area and the local geology. Seismologists have concluded that the soil conditions along the collapsed section of the Nimitz Freeway in Oakland, California, were a factor in the 1989 Loma Prieta Earthquake (the World Series quake). Ground motions produced during earthquakes often determine the extent of structural damage and related injuries and fatalities.
An earthquake registering a magnitude of 6.0 occurring in New York State would cause greater damage than an earthquake of similar magnitude on the West Coast. The older, more brittle rocks of the East Coast transmit seismic energy more efficiently, with the effect of earthquakes being felt over larger areas. Figure 3 (on your Report Sheet) shows the area affected by the largest earthquake ever recorded in New York State. The isolines (lines of equal intensity) drawn to show intensity levels are based on the experiences of people who felt the effects of the September 5, 1944 earthquake. See figure 2 for a description of the intensity levels I-VIII.
There is still much to be learned about earthquake mechanisms, especially those causing the stronger earthquakes. Although New York State is in a region of lower seismic hazard than California or Alaska there is a considerable seismic risk for many who live in this state. See Figure 1 for the seismic risk areas in the United States.
Objectives: When you have completed this investigation, you should be able to:
1. Describe the seismic hazard and risk situation in New York State.
2. Identify where earthquakes have occurred in New York State.
Materials: Colored Pencils
Ruler
Procedure:
1. Find the map of New York State in your Report Sheet. Using a regular lead pencil, draw in (very lightly) the North latitude lines for 410, 420, 430, 440and 450. Also, draw in (very lightly) the West longitude lines for 730, 740, 750, 760, 770, 780and 790.
2. Figure 3 in this procedure booklet shows the information on the locations of major earthquakes in New York State between 1737 and 1983. n the Report Sheet, the New York State Structure – Seismic Patterns map shows the location of faults and fractures in the bedrock of the state. The Adirondacks, the Hudson Highlands and the Clarendon-Linden fault system of western New York are among the larger, better known fault systems.
Plot the earthquakes listed in Figure 3 on the New York Structure – Seismic Patterns map. Use the key below the map for showing the Maximum Modified Mercalli Intensity. Use a different colored pencil for each symbol in the key. Use all solid circles, but use a different color for I0 Values VIII, VII, VI, V and IV.
3. On the Cornwall Massena Earthquake map on the Report Sheet, color each intensity value area a different color. Shade in very lightly so you can still read the map.
4. Answer the questions on the Report Sheet using the information provided in the following diagrams.
Figure 1: Seismic Risks Areas in the Continental United States
Figure 2: Modified Mercalli Scale
Date
/Locality
/ Latitude (North) /Longitude
(West) / I0 /M
Dec. 18, 1737 / New York City / 40.60 / 73.80 / VI / 5.0Mar. 12, 1853 / Lowville / 43.70 / 75.50 / VI / 4.8
Dec. 18, 1867 / Canton / 44.05 / 75.15 / VI / 4.8
Dec. 11, 1874 / Irvington / 41.00 / 73.90 / VI / 4.8
August 10, 1884 / Rockaway Beach / 40.59 / 73.84 / VI / 5.3
May 28, 1897 / Plattsburgh / 44.50 / 73.50 / VI
Mar. 18, 1928 / Saranac Lake / 44.50 / 74.30 / VI / 4.5
Aug. 12, 1929 / Attica / 42.84 / 78.24 / VII / 5.2
Apr. 20, 1931 / Warrensburg / 43.50 / 73.80 / VI / 4.5
Apr. 15, 1934 / Dannemora / 44.70 / 73.80 / VI / 4.5
Sep. 5, 1944 / Massena / 45.00 / 74.85 / VIII / 6.0
Sep. 9, 1944 / Massena / 45.00 / 74.85 / V / 4.0
Jan 1, 1966 / Attica / 42.84 / 78.23 / VI / 4.6
Jun. 13, 1967 / Attica / 42.84 / 78.23 / V / 4.4
Oct. 7, 1983 / Goodnow / 43.97 / 74.25 / VI / 5.1
I0 = Maximum Modified Mercalli Intensity
M = Magnitude (Richter Scale)
Figure 3: Major Earthquakes across New York State
Figure 4: Location and Magnitude of Earthquakes in the northeastern United States and Canada from 1075 to 1987.