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M 3.8 - 17.4 km (10.8 mi) SW of Ukiah, CA

Saturday, January 10, 2009 at 09:18:11 UTC
Location: 39.0°N 123.3°W  Depth: 5km
Alert version 3

Summary

[PDF | Additional Information]

Estimated Population Exposed to Earthquake Shaking

Est. Modified
Mercalli Intensity
Est. Population
Exposure (k = x1000)
Perceived ShakingPotential Structure Damage
ResistantVulnerable
X0ExtremeV. HeavyV. Heavy
IX0ViolentHeavyV. Heavy
VIII0SevereModerate/HeavyHeavy
VII0Very StrongModerateModerate/Heavy
VI0StrongLightModerate
V0ModerateV. LightLight
IV0LightNoneNone
II-III2kWeakNoneNone
I788k*Not FeltNoneNone
*Estimated exposure only includes population within the map area.

Population Exposure
 Population per ˜1 square km from Landscan 2005
Population Exposure
Selected City Exposure

MMICityPopulation
IUkiah15k
ITalmage1k
IHealdsburg11k
ISebastopol7k
ISanta Rosa155k
ISonoma9k
IClearlake14k
INapa77k
IPetaluma55k
IWindsor25k
IRohnert Park41k
Shaking Intensity
    MMI
Shakemap

Population exposure estimates are NOT a direct estimate of earthquake damage; comparable shaking will result in significantly lower losses in regions with well built structures than in regions with vulnerable structures. Overall, the population in this region resides in structures that are resistant to earthquake shaking, though some vulnerable structures exist.


 

PAGER results are generally available on the Internet within 30 minutes of the earthquake's occurrence. However, information on the extent of shaking will be uncertain in the minutes and hours following an earthquake and typically improves as additional sensor data and reported intensities are acquired and incorporated into models of the earthquake's source. Users of PAGER exposure estimates should account for uncertainty and always seek the most current PAGER release for any earthquake.

Maps

[Population | Shakemap]
Population Exposure

Map of MMI contours plotted over population per ˜1 square km (see gray scale bar on top of map). The regions of integer MMI values are separated by the thick contour lines and labeled with Roman numerals. The total population exposure to a given MMI value is obtained by summing the population between the thick contour lines. This total is shown in population exposure table.

Shakemap

Map of shaking intensity. This map shows the estimated MMI as a continuous color scale. The ground shaking estimates can be obtained from http://earthquake.usgs.gov/shakemap/nc/shake/51214975.

Exposure

Est. Modified
Mercalli Intensity
Est. Population
Exposure (k = x1000)
Perceived ShakingPotential Structure Damage
ResistantVulnerable
X0ExtremeV. HeavyV. Heavy
IX0ViolentHeavyV. Heavy
VIII0SevereModerate/HeavyHeavy
VII0Very StrongModerateModerate/Heavy
VI0StrongLightModerate
V0ModerateV. LightLight
IV0LightNoneNone
II-III2kWeakNoneNone
I788k*Not FeltNoneNone
*Estimated exposure only includes population within the map area.

Table showing population exposed to different estimated Modified Mercalli Intensity (MMI) levels and the possible damage at different intensity levels for resistant and vulnerable structures. MMI describes the severity of an earthquake in terms of its effect on humans and structures and is a rough measure of the amount of shaking at a given location. Unlike earthquake magnitude, intensity varies with distance from the fault, and is influenced by the depth of the earthquake and the types of soils in the shaken region. Population outside the map bounds are not included in the totals.

Cities

MMICityPopulation
IUkiah15k
ITalmage1k
IForestville2k
IGraton2k
ILower Lake2k
IClearlake Oaks2k
INice2k
IAngwin3k
IKelseyville3k
ILucerne2k
IGreen Valley1k
IGuerneville2k
ICobb1k
ICovelo1k
IMonte Rio1k
IMiddletown1k
IUpper Lake1k
IOccidental1k
ILaytonville1k
IYountville3k
IBodega Bay1k
ITemelec1k
IDeer Park1k
IEldridge1k
IWilliams3k
ISonoma9k
ISebastopol7k
IBoyes Hot Springs7k
IFort Bragg6k
IHealdsburg11k
IClearlake14k
INapa77k
IPetaluma55k
IRohnert Park41k
IWindsor25k
ICotati6k
ICloverdale6k
ICalistoga5k
IWillits5k
IHidden Valley Lake4k
IEl Verano4k
ILakeport5k
IRoseland5k
IOrland6k
IWillows6k
ISaint Helena6k
ISanta Rosa155k

Table of MMI estimates and populations for settlements falling within the map boundaries. The settlement name, location, and population are obtained from the freely-available GeoNames geographical database.


 

Details

Magnitude3.8
Max MMIIII
Date-TimeSaturday, January 10, 2009 at 09:18:11 UTC
Location39.032°N, 123.343°W
Depth4.9 km (3.0 miles)
Event IDNC51214975
Version3
Additional Information