General Plan - Moreno Valley

CHAPTER 6 – SAFETYThe Richter Scale is a logarithmic scalewhere an increase of 1.0 on the scalerepresents an increase of 10 in the amplitudeof the recorded wave, and an increase ofabout 32 in the energy release. Thus, a 6.0magnitude earthquake releases 32 times asmuch energy as a 5.0 magnitude event. Anearthquake along the San Jacinto fault with amagnitude of 7 or more is likely to causeextensive damage. The Uniform BuildingCode requires new construction to bereinforced and braced to resist earthquakeforces, but would not provide 100 percentdamage protection from a major earthquakein close proximity to Moreno Valley. Thebuilding code requirements have increasedover time. As such, older structures aregenerally more susceptible to earthquakedamage than newer structures.Secondary seismic hazards that may betriggered by an earthquake includeliquefaction, land settlement, landslides, andseiches. Liquefaction is not considered to bea local hazard since groundwater levels inMoreno Valley are far below the surface. Ashallow water table is necessary forliquefaction to occur. There are isolatedinstances of collapsible soils. Soil engineersroutinely evaluate the potential for landsettlement when conducting foundationinvestigations.Loose rocks might roll down mountain slopesduring strong ground shaking, specifically thegranitic boulders on the mountains located atthe northern and southern margins of thestudy area. There is some potential forlandslides in the Badlands because theslopes are steep and the underlying geologicmaterial is poorly consolidated.Seiching is water movement caused byground shaking. Seiching may present ahazard during an earthquake at PoormanReservoir, Sunnymead Lake, and LakePerris if the seiching in conjunction withground shaking resulted in dam failure. Damrupture could endanger inhabitants andproperty within the path of the resulting flowMORENO VALLEY GENERAL PLANof water. Specific dam failure hazards arediscussed in the Flood Hazards section ofthe General Plan. Water storage tanks arealso susceptible to seiching. However, watertanks are designed to safely detain anddirect the flow of water in the event of failureor leakage.6.6 AIR QUALITY6.6.1 BackgroundAir pollution is a serious local, national andglobal problem. It is a health hazard.Cancer, lung damage, asthma and otherrespiratory ailments have been linked to airpollution. Air pollution also damages plantsand property and obscures views. Twoprimary factors influence air quality: theclimate and the amount of pollutants emittedinto the air.The Moreno Valley study area is locatednear the eastern edge of the South CoastAir Basin. This Basin includes most of thecounties of Los Angeles and Orange, aswell as the western portions of Riversideand San Bernardino Counties. The SouthCoast Air Basin has a Mediterraneanclimate with hot, dry summers and mild,moist winters. Occasional periods of strongSanta Ana winds and winter storms interruptthe otherwise mild weather pattern. MorenoValley has an annual average meantemperature for January and July of 51 and76 degrees Fahrenheit, respectively. Themaximum summer temperature reachesmore than 100 degrees Fahrenheit.Wind has an important effect on air quality.Low wind speeds and the mountainsbordering the South Coast Air Basin limit thedispersal of air pollutants. The daytimewinds typically originate off the coast andcarry significant amounts of industrial andautomobile air pollutants from the denselyurbanized western portion to the easternportion of the air basin. This influx ofpollution from the western part of the airPage 6-19 July 11, 2006