STRONG EARTHQUAKE JOLTS ALASKA

Associated Press ... breaking on the wire | October 23, 2002

[NYer]

PALMER, Alaska (AP) _ A strong earthquake struck deep underground near Denali National Park early Wednesday, rocking much of Alaska and waking people as far as 350 miles away, experts at the Alaska Tsunami Warning Center said. There were no immediate reports of widespread damage.

The quake, with a preliminary magnitude of 6.5, hit at 3:27 a.m., jarring residents in Fairbanks, 85 miles north of the epicenter, and in Anchorage, 170 miles to the southwest, seismologist Bruce Turner said. Telephone lines to the Denali National Park ranger station, about 27 miles from the epicenter, were dead. The observatory was deluged with calls about the quake, which occurred on an active fault about 25 miles beneath the surface, Turner said.

Outside Cantwell, a hamlet of about 200 people 36 miles from the epicenter, the quake roused owners and residents of the Backwoods Lodge. No one was hurt and damage appeared to be limited to ``some things falling off of the shelves,'' co-owner Kathie White said. ``Just a good shaker.''

The quake was too far from water to generate a tsunami, or seismic sea wave, but it was felt as far as 350 miles from the epicenter, Turner said. The magnitude of an earthquake reflects an analysis of seismic waves and the amount of earth slippage over the area of the fault. An earthquake of 6 can cause severe damage and a magnitude 7 quake is considered major and capable of widespread, heavy damage. The ``Good Friday'' earthquake in Alaska that left 131 people dead in 1964 measured 8.5 on the now-abandoned Richter scale _ 9.2 by the current measurement system _ and was centered in Prince William Sound near Anchorage.

AP-ES-10-23-02 0843EDT

[NYer]

Praying that all are well up there!

[randita]

There aren't a heck of a lot of people up that way--it's past prime tourist season as well. Probably just frightened a lot of grizzly bears and elk.

[ohioman]

I use to live up there and luckily this a sparsely populated, but beautiful area. Thank god it wasn't off the coast and like previous quakes in Alaska. The Good Friday Quake in '64 was the strongest EVER to hit North America, and the second strongest in recorded history at 9.2.

[xzins]

measured 8.5 on the now-abandoned Richter scale _ 9.2 by the current measurement system

Can someone explain this to me? When did Richter get abandoned? What's the new scale called and how is it used?

[SMEDLEYBUTLER]

Earthquake Location

Date-Time	2002 10 23 11:27:18 UTC
Location	63.62N 148.04W
Depth	10.0 kilometers
Magnitude	6.7
Region	CENTRAL ALASKA
Reference	30 miles (50 km) ENE of Cantwell, Alaska 35 miles (55 km) ESE of Healy, Alaska 85 miles (135 km) S of Fairbanks, Alaska 590 miles (945 km) NW of JUNEAU, Alaska
Source	USGS NEIC

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U.S. Department of the Interior, U.S. Geological Survey Privacy Statement || Disclaimer || FOIA || Accessibility USGS National Earthquake Information Center

Maintained by: M. Zirbes Feedback
Updated: Wednesday, 2002 October 23 06:26:04 MDT

URL: http://neic.usgs.gov/neis/bulletin/neic_kqaz_l.html

[Brad C.]

I am up here (Fairbanks)and it was a real roller. Haven't felt one like that in a long time. Really glad I wasn't down in the Cantwell or Healy area, it must have really rocked.

[MissAmericanPie]

bttt

[aardvark1]

I thought Congress passed a law against earthquakes in this area of Alaska.

[NYer]

I am up here (Fairbanks)and it was a real roller.

Are you all right? Please keep us posted on any aftershocks.

[Johnny Gage]

Bumping an Alaskan resident!

[jimtorr]

AP is wrong, as usual, when their ignorant stringers try to be technical.

While it's true that many geoligists no longer use the richter scale for analysis of events, it is still widely used for comparison purposes to earthquakes in the past. I think that earthquakes occuring more than perhaps 40 years ago don't have reliable measurments using the newer scales.

[Colonel Jim]

Im just outside of Anchorage getting ready for work, things seem OK at this point. No damage here, every thing is still on the shelves!

[Brad C.]

I am just fine, working night shift. The quake was a real roller, probably lasted about 10 seconds or so. All of the computer monitors we have were just wiggling around. Our electronic equipment racks (8' tall) were almost dancing in place.

[Lokibob]

Earthquake Severity

Richter         Earthquake
Magnitudes      Effects

Less than 3.5   Generally not felt, but recorded.

3.5-5.4         Often felt, but rarely causes damage.

Under 6.0       At most slight damage to well-designed buildings.
		Can cause major damage to poorly constructed buildings
		over small regions.

6.1-6.9         Can be destructive in areas up to about 100 kilometers
		across where people live.

7.0-7.9         Major earthquake. Can cause serious damage over larger areas.

8 or greater    Great earthquake. Can cause serious damage in areas several
		hundred kilometers across.

 

The Modified Mercalli Scale
of Earthquake Intensity

In seismology a scale of seismic intensity is a way of measuring or rating the effects of an earthquake at different sites. The Modified Mercalli Intensity Scale is commonly used in the United States by seismologists seeking information on the severity of earthquake effects. Intensity ratings are expressed as Roman numerals between I at the low end and XII at the high end.

The Intensity Scale differs from the Richter Magnitude Scale in that the effects of any one earthquake vary greatly from place to place, so there may be many Intensity values (e.g.: IV, VII) measured from one earthquake. Each earthquake, on the other hand, should have just one Magnitude, although the several methods of estimating it will yield slightly different values (e.g.: 6.1, 6.3).

Ratings of earthquake effects are based on the following relatively subjective scale of descriptions:

 

I'm not sure the Richter scale has been "abandoned" but here is the mercalli scale.

Modified Mercalli Intensity Scale

from FEMA

I. People do not feel any Earth movement.

II. A few people might notice movement if they are at rest and/or on the upper floors of tall buildings.

III. Many people indoors feel movement. Hanging objects swing back and forth. People outdoors might not realize that an earthquake is occurring.

IV. Most people indoors feel movement. Hanging objects swing. Dishes, windows, and doors rattle. The earthquake feels like a heavy truck hitting the walls. A few people outdoors may feel movement. Parked cars rock.

V. Almost everyone feels movement. Sleeping people are awakened. Doors swing open or close. Dishes are broken. Pictures on the wall move. Small objects move or are turned over. Trees might shake. Liquids might spill out of open containers.

VI. Everyone feels movement. People have trouble walking. Objects fall from shelves. Pictures fall off walls. Furniture moves. Plaster in walls might crack. Trees and bushes shake. Damage is slight in poorly built buildings. No structural damage.

VII. People have difficulty standing. Drivers feel their cars shaking. Some furniture breaks. Loose bricks fall from buildings. Damage is slight to moderate in well-built buildings; considerable in poorly built buildings.

VIII. Drivers have trouble steering. Houses that are not bolted down might shift on their foundations. Tall structures such as towers and chimneys might twist and fall. Well-built buildings suffer slight damage. Poorly built structures suffer severe damage. Tree branches break. Hillsides might crack if the ground is wet. Water levels in wells might change.

IX. Well-built buildings suffer considerable damage. Houses that are not bolted down move off their foundations. Some underground pipes are broken. The ground cracks. Reservoirs suffer serious damage.

X. Most buildings and their foundations are destroyed. Some bridges are destroyed. Dams are seriously damaged. Large landslides occur. Water is thrown on the banks of canals, rivers, lakes. The ground cracks in large areas. Railroad tracks are bent slightly.

XI. Most buildings collapse. Some bridges are destroyed. Large cracks appear in the ground. Underground pipelines are destroyed. Railroad tracks are badly bent.

XII. Almost everything is destroyed. Objects are thrown into the air. The ground moves in waves or ripples. Large amounts of rock may move.

As you can see from the list above, rating the Intensity of an earthquake's effects does not require any instrumental measurements. Thus seismologists can use newspaper accounts, diaries, and other historical records to make intensity ratings of past earthquakes, for which there are no instrumental recordings. Such research helps promote our understanding of the earthquake history of a region, and estimate future hazards.

[DoctorMichael]

........preliminary magnitude of 6.5..........

That'll rattle your teeth.

[Colonel Jim]

I havent noted any after shocks as yet!

[NotJustAnotherPrettyFace]

This is why no one can pay me enough to live anywhere near the Pacific "Ring of Fire". Imagine being not just woken up at 3:27am, but SHAKEN up at that hour. Ye gods!

[NotJustAnotherPrettyFace]

Brad C. is now singing "I Feel the Earth (pause) Move (pause) Under My Feet......." :-).

[68-69TonkinGulfYachtClub]

Saying a prayer that you are safe.

[Colonel Jim]

Very funny!