Earthquake Intensity from
Historical Accounts
BACKGROUND
The measure of shaking and damage from an earthquake is called "seismic intensity." In
general, the intensity decreases with increasing distance from the earthquake. Since 1931,
the USGS has been assigning intensities to earthquakes in the United States on the basis
of the Modified Mercalli Intensity (MMI) scale. Typically, this is done by collecting
responses to a postal questionnaire that is sent to each post office near the earthquake,
and to a sparser sample of post offices with increasing distance from the earthquake. Now
these questionnaires are filled out on the internet. For historical earthquakes, newspaper
archives are often used to gather the information needed to assign an intensity.
Figure 1. Felt intensity map for Dec 16, 1811 New Madrid earthquake of approximate
magnitude 7.2
GOALS
In this activity you will learn how the Modified Mercalli Intensity Scale is used to
measure the size of earthquakes from observations when seismometers are not available
and apply it to verbal accounts of earthquake experiences.
OBJECTIVES
In this experiment, you will
• Read written accounts of earthquakes.
• Determine their maximum intensity from the Modified Mercalli Intensity chart.
• Compare the distance over which earthquakes are felt.
MATERIALS
Modified Mercalli Intensity Scale
Historical accounts of seismicity
PROCEDURE
1. Read the description of the levels of shaking that are included in the Modified
Mercalli Intensity scale.
2. Read the article from the Chillicothe Fredonian newspaper describing the Dec 16,
1811 earthquake.
3. Write down from this account the phrases that are useful for determining the
intensity for the author’s location in Asheville NC.
4. Assign an intensity for the location of Asheville.
5. Write down the phrases that are useful for determining the intensity for the city of
Knoxville.
6. Assign an intensity for the location of Knoxville.
7. Read the article from the Evansville Courier & Press article describing the June
18, 2002 earthquake
8. Write down the phrases that are useful for determining the intensity for the city of
Evansville.
9. Assign an intensity for the location of Evansville.
DATA
Article from the newspaper Chillicothe Fredonian, Chillicothe, Ohio, 2/19/1812
Article from the newspaper Evansville Courier & Press, Evansville, IN, June 19, 2002
Table 1 Earthquake Data Set
Date Time Latitude Longitude Magnitude Location
12/16/1811 08:15 35.6 N 90.4 W 7.7 New Madrid Area
06/18/2002 12:37 37.98 N 87.78 W 4.6 Evansville, IN
PROCESSING THE DATA
1. What is the maximum intensity that was felt in Asheville from the Dec 16, 1811
earthquake based on the newspaper article?
2. What is the maximum intensity felt in Knoxville from the same article?
3. What is the maximum intensity felt near New Madrid, from the map in figure 1?
4. Is the maximum intensity greater in Knoxville or Asheville? Is Knoxville or Asheville
closer to the location where the New Madrid earthquake occurred? Describe the
relation between distance from the earthquake and felt intensity.
5. How well does the intensity that you deduced for Asheville, NC, agree with what is
shown on the map in figure 1?
6. What is the maximum intensity that was felt in Evansville from the June 18, 2002
earthquake based on the newspaper article?
7. Compare the two earthquakes in 2002 and 1811. Which one has the highest
magnitude from Table 1? Which one has the highest maximum intensity near their
epicenters?
8. Summarize the results of your investigation.
EXTENSIONS
1. You can look at maps of intensities from for recent earthquakes at the web site:
http://pasadena.wr.usgs.gov/shake/cus/archives.html
CREDITS
This activity contains material reproduced from the following web sites:
Sue Hough, USGS, information page on the New Madrid earthquake:
http://pasadena.wr.usgs.gov/office/hough/NewMadrid.html
REFERENCES AND FURTHER INFORMATION
News report of the June 18, 2002 earthquake near Evansville, IN:
URL: http://www.courierpress.com/ecp/news/article/0,1626,ECP_734_1216972,00.html
News report of the Dec 16, 1811 earthquake near New Madrid, MO
http://pasadena.wr.usgs.gov/office/hough/NewMadrid.html
The Modified Mercalli Intensity Scale:
Richter, C.F., 1958. Elementary Seismology. W.H. Freeman and Company, San
Francisco, pp. 135-149; 650-653.
MODIFIED MERCALLI INTENSITY SCALE
MMI Description
Value
I Not felt. Marginal and long period effects of large earthquakes.
II Felt by persons at rest, on upper floors, or favorably placed.
III Felt indoors. Hanging objects swing. Vibration like passing of light trucks.
Duration estimated. May not be recognized as an earthquake.
IV Hanging objects swing. Windows, dishes, doors rattle.Vibration like passing
of heavy trucks; or sensation of a jolt like a heavy ball striking the walls.
Standing motor cars rock. Glasses clink. Crockery clashes. In the upper range
of IV, wooden walls and frame creak.
V Pictures move. Felt outdoors; direction estimated. Sleepers wakened. Liquids
disturbed, some spilled. Small unstable objects displaced or upset. Doors swing,
close, open. Shutters, pictures move. Pendulum clocks stop, start, change rate.
VI Objects Fall. Felt by all. Many frightened and run outdoors. Persons walk
unsteadily. Windows, dishes, glassware broken. Knickknacks, books, etc., off
shelves. Pictures off walls. Furniture moved or overturned. Weak plaster and
masonry D cracked. Small bells ring (church, school). Trees, bushes shaken
(visibly or heard to rustle).
VII Nonstructural Damage. Difficult to stand. Noitced by drivers of motor cars.
Hanging objects quiver. Furniture broken. Damage to masonry D, including
cracks. Weak chimneys broken at roof line. Fall of plaster, loose bricks, stones,
tiles, cornices (also unbraced parapets and architectural ornaments. Some
cracks in masonry C. Waves on ponds; water turbid with mud. Small slides and
caving in along sand or gravel banks. Large bells ring. Concrete irrigation
ditches damaged.
VIII Moderate Damage. Steering of motor cars affected. Damage to masonry C;
partial collapse. Some damage to masonry B. none to masonry A. Fall of stucco
and some masonry walls. Twisting, fall of chimneys, factory stacks,
monuments, towers, elevated tanks. Frame houses moved on foundations if not
bolted down; Loose panel walls thrown out. Decayed piling broken off.
Branches broken from trees. Changes in flow or temperature of springs and
wells. Cracks in wet ground and on steep slopes.
IX Heavy Damage. General panic. Masonry D destroyed; masonry C heavily
damaged, sometimes with complete collapse; masonry B seriously damaged.
(General damage to foundations.) Frame structures if not bolted, shifted off
foundations. Frames racked. Serious damage to reservoirs. Underground pipes
broken. Conspicuous cracks in ground. In alluvial areas sand and mud ejected,
earthquake fountains, sand craters.
X Extreme Damage. Most masonry and frame structures destroyed with their
foundations. Some well-built wooden structures and bridges destroyed. Serious
damage to dams, dikes, embankments. Large landslides. Water thrown on
banks of canals, rivers, lakes, etc. Sand and mud shifted horizontally on
beaches and flat land. Rails bent slightly.
XI Rails bent greatly. Underground pipelies completely out of service.
XII Damage nearly total. Large rock masses displaced. Lines of sight and level
distorted. Objects thrown into the air.
Masonry A: Good workmanship, mortar, and design; reinforced, especially laterally, and
bound together by using steel, concrete, etc.; designed to resist lateral forces.
Masonry B: Good workmanship and mortar; reinforced, but not designed in detail to
resist lateral forces.
Masonry C: Ordinary workmanship and mortar; no extreme weaknesses like failing to tie
in at corners, but neither reinforced nor designed against horizontal forces.
Masonry D: Weak materials, such as adobe; poor mortar; low standards of workmanship;
weak horizontally.
From the newspaper Chillicothe Fredonian, Chillicothe, Ohio, 2/19/1812
(letter dated 12/19/1811 from Asheville, NC)
Gentlemen,--I take the liberty to transmit the following account of an earthquake which
happened on the night between the 15th and 16th inst.
For several nights previous, the Aurora Borealis brilliantly illuminated the sky with its
trembling corruscations; the late appearance of a splendid comet, and the blood-like color
of the sun for several days, had alarmed a great many superstitious people. They talked of
war; and when the news of Governor Harrison's dear-bought victory arrived, it brought to
their recollection all those appearances which are still believed (as these are now) to have
been the awful precursors of that bloody war by which we gained our independence.
On Monday morning, about one o'clock, the inhabitants were roused from their peaceful
slumbers by a dreadful sound: some waggoners who were up the time it began, said it
resembled, but was louder, than if 100 waggons were driven at full speed down the
mountain. This gave us considerable alarm: the timid took to prayer, expecting every
moment (as they say) to hear the sound of the last trumpet. The more courageous
ventured to open their doors to discover what occasioned the noise. A sudden trembling
of the earth caused fresh terror and alarm, from which we had not time to recover when
we felt a violent shock which lasted about 3 minutes and was attended with a hollow
rumbling noise, and ended with a dreadful crash leaving behind a strong sulphurous
stench.
For the remainder of the night, all was still and calm, but was spent by us in trembling
anxiety. When the wished for morning came, we were happy to find no lives were lost,
but while some of us were in the street, congratulating each other on our happy escape,
we were again alarmed by a much louder noise than any we had heard before. It was
quickly followed by a more violent shock, which gave the earth an undulating motion
resembling the waves of the sea. Two of those who were standing with me, were thrown
off their feet, the rest of us with difficulty kept from falling, while two or three cows that
were near us were unable to stand, and testified their fear by their loud bellowing, which
with the cries of the women and children, and the terror that was depicted in the
countenances of the men, presented a scene of terror I am uanble to describe.
It is somewhat strange that its effects were more violent in the vallies than on the
mountains: a tan yard, in a valley near this place, had several vats displaced--the edges of
some were raised 3 feet above their former level, and others were moved partly round,
and left in a zig-zag manner. It would far exceed the bounds of this letter to describe all
of the phenomena produced by this awful convulsion of nature: rocks moved, hills shook,
houses shattered, &c.
A wonderful change has taken place in the manners of the people. I believe so many
fervent prayers never were put up in this place as were on that fearful night and morning.
I think what has been done may be termed a revival in religion.
I have just seen a gentleman from Knoxville, who passed Sunday night with Mr. Nelson
at the warm springs: from his account his situation was more
terrifying than ours. For several hours previous to the shock, a
most tremendous noise was heard from the neighboring mountains.
At intervals it was quiet, but would begin with so much violence, that each repetition was
believed to be the last groan of expiring nature. The shock at that place did but little
damage, except to a few huts that were built near the springs for the accomodation of
invalids. The fulminating of the mountains was accompanied with flashes of fire seen
issuing from their sides. Each flash ended with a snap, or crack, like that which is heard
on discharging an electric battery, but 1000 times as loud. This induced him to believe
that the earthquake was caused by the electric fluid.
In the morning it was observed that a large stream of warm water (temperature Fah. 142
degrees) issued from a fissure in a rock on the side of the mountain, which had been
opened the preceding night. While they were examining it, another shock was felt which
lasted two minutes. Although perfectly calm, the tops of the trees appeared to be greatly
agitated, the earth shook violently, and the water of the warm springs, at that time
overflowed by French Broad River, was thrown up several times to the height of 30 or 40
feet.
Several masses of stone were loosed from their ancient beds and precipitated from the
summits and sides of the mountains. One in particular, well known to western travelers
by the name of the Painted Rock, was torn from its base and fell across the road that leads
from hence to Knoxville: it has completely shut up the passage for wagons. A great many
people who were moving westwardly, are in a pittable situation at this inclement season,
being unable to proceed until a new road is made round the rock (no easy task): in this
they are cheerfully assisted by their neighbors.
I have been for three months in those dreary regions, examing a mine of Cobalt. The ore
is rich: it abounds with arsenic. In May we intend to calcine the orre and prepare it for
exportation, or perhaps manufacture it into smalt. The mine is within a few miles of
Mackeysville.
John C. Edwards
From the Evansville Courier & Press, Evansville, IN, June 19, 2002
“Did you feel that? Moderate earthquake rumbles through Tri-State”
By Sarah Paff and Ryan Reynolds, Courier & Press staff writers
The earthquake that rattled the Tri-State hit home for hundreds of thousands of people,
but especially those whose back yards were the home to the epicenter of Tuesday's quake.
Data from the U.S. Geological Survey initially pinpointed the epicenter almost directly
beneath a pond located in northwest German Township - and the middle of William and
Sue Mayville's back yard at Hillview Drive near No. 3 School Road.
Sue Mayville said she was watching the soap opera "Days of Our Lives" when her house
began to shake. "At first I didn't know what it was," she said. "With all of this terrorist
stuff, you're just not sure."
Initial confusion was a common theme around Evansville and surrounding towns after the
magnitude 5.0 earthquake. The temblor struck at 12:37 p.m., was felt for a few seconds
and left behind very little damage. The quake's epicenter was eventually established nine
miles northwest of Evansville and six miles west-southwest of Darmstadt, Ind.
The Mayvilles know that for sure. Sue Mayville panicked, but since the quake only lasted
a few seconds, William Mayville was able to quickly allay his wife's fears. "My husband
was Mr. Cool," Sue Mayville said. Spices fell off their shelves and pictures fell off the
walls, but Sue Mayville said they didn't sustain any major damage.
Other residents on Hillview Drive found minor problems in their houses, though they
weren't there to experience the action. Jaymi Hohler, a neighbor of the Mayvilles, was
working at Integra Bank when the quake hit. The vibrations especially concerned her
since her office is almost on the top floor of the bank building. She didn't realize that the
epicenter was so close to her house until she got home from work to find news crews
waiting. "That must be why all the pictures fell off my walls," Hohler said.
Like hundreds of thousands of other Tri-Staters, Larry Caplan was caught off guard by
Tuesday's midday tremor, just not enough to lose his sense of humor about the situation.
"The fact that (it) seems to be centered on my office is purely coincidental," said Caplan,
an extension educator who works near Darmstadt. "I was not in my office at the time, and
I don't want to hear any fat jokes." Taking the shaking with a smile, Caplan checked
everything around his home and office, found minimal damage - a potted cactus rolled
off a window sill - and went on about his business.
Sherman Greer, the director of Evansville-Vanderburgh Emergency Management
Agency, said one of the first tasks he faced was sorting rumors out from facts.
"Immediately into this, the thing we had to deal with was a lot of rumors about damage in
Evansville," he said. "We had to get a handle on rumor control immediately," Greer said.
Indiana State Police had called the emergency management office about reports of broken
glass throughout Downtown Evansville and fallen chimneys in
houses around town.
Greer said one caller even reported that Mount Vernon, Ind., had been completely
devastated in the quake. Though that wasn't the case, there was no shortage of personal
tales, which dominated conversations at offices, restaurants and supper tables.
Paul Doss, chairman of the Department of Geology at the University of Southern Indiana,
believed immediately it was an earthquake. But he then glanced out his office window on
campus and saw workers on a new science and education building who appeared to be
totally unfazed by the jolt. "The workers didn't seem to bat an eye. They didn't stop at all
and didn't change their behavior any," he said. He began accessing data on the Internet
from earthquake recorders and quickly was able to confirm his belief that it was, indeed,
an earthquake.
It was the largest quake to rumble through the Tri-State since 1987, when a magnitude
5.0 temblor struck near Lawrenceville, Ill. The strongest earthquake to occur in the last
100 years in the Wabash Valley region happened on Nov. 9, 1968, in south-central
Illinois. It had a magnitude of 5.4 and was felt in 23 states.
This one will be memorable enough, many Tri-Staters said. Tuesday's quake was felt at
least 250 miles away - as far north as South Bend, Ind., and as far south as Memphis,
Tenn. It also was felt in much of Illinois, Kentucky, Ohio, Tennessee and in a portion of
Missouri.
"There was a lot of swaying and merchandise moving, but no real damage to the building.
Just a few scared folks," said John Tarrants, assistant manager at Wal-Mart on the West
Side. "We lost a few things but considering how hard it hit we were lucky."
With no major damage reported by area law enforcement beyond a few shattered
windows and cracked house foundations, excitement was limited to brief business
evacuations.
An exception was at the GE Plastics plant in Mount Vernon., where more than 700 first-
shift employees were sent home for the day after the earthquake. Second- and third-shift
employees reported to work as normal. There were no reports of injuries or damage at the
plant, but officials wanted to do "a fine point-by-point check," said Kimberly Derk,
communications manager. She said the plant also wanted to give employees an
opportunity to make sure their homes were undamaged.
In Downtown Evansville, damage to businesses was slight. Frances Wolf, owner of
Fran's Hope Chest, a Main Street antique shop, said the quake was the strongest she had
ever experienced. She feared the worst for the fragile items in her store, but after her
initial inspection, she found only one damaged bowl.
One block away at the Jungle Restaurant on Main Street, cigar boxes fell from their
overhead nesting spaces and glasses rattled on hanging racks. None were broken. "I've
never felt the ground shake under my feet like that," said server Jenny Thomas.
People from the Old National Bank building on Fourth and Main streets had a "self-
directed evacuation," according to Paige McFarland, spokeswoman for Old National
Bank. She said employees chose to wait on nearby sidewalks while emergency personnel
inspected the facility for dangerous conditions, including gas leaks
and electrical problems. The earthquake didn't cause major
problems in the building, McFarland said.
Still, pictures were crooked and televisions were displaced throughout the building, said
Jodie Cantrell, a NatCity Investments Inc. employee. Her office is located in the Old
National building. "I felt a tremor, heard a loud bang, and it almost felt like there was a
decompression," Cantrell said. She remembered that doorways are safe during
earthquakes, so she immediately took shelter there before evacuating.
Residents felt effects of the earthquake both indoors and out. James J. Mockford Jr. was
washing windows at Denning & Tillman Tillman, an optometry office at 605 Main
Street, when he felt the quake. Mockford said he noticed the ground moving and
buildings rumbling. "This one seemed like it was right underneath me," he said.
The quake interrupted a Rotary Club luncheon speech in Evansville by Indiana Secretary
of State candidate John Fernandez. "This was definitely my most interesting Rotary
speech," said Fernandez, the current mayor of Bloomington, Ind. "I heard this city
rocked, but this is ridiculous."
City Councilwoman Angela Koehler-Walden caught a lucky break - or lack thereof -
when the rumble came to her home near North Park. A crystal vase fell from a wooden
shelf but did not break. But when Koehler-Walden opened a closet a little later, a box -
loosened by the quake - fell and hit her in the head. She's OK.