Glendale (PDF) - Hazard Mitigation Web Portal - State of California

Natural Hazards Mitigation PlanCity of Glendale, CaliforniaSection 2 – Community ProfileIn addition, many areas in the Los Angeles basin, including the city of Glendale, have sandysoils that are subject to liquefaction. The liquefaction-susceptible zones in the city of Glendaleare shown on Plate H-5 (Appendix H). These zones include the youthful sandy sediments ofVerdugo Wash and La Cañada Valley, along the Los Angeles River floodplain in the southwestpart of the city, and in the bottom of the smaller canyons emanating from the VerdugoMountains and the San Rafael Hills, such as Scholl and Sycamore canyons.The city of Glendale also has areas of slope instability potential. Evidence of past slope failuresare found throughout the mountain- and foothill-regions of the city. The crystalline bedrock ofthe San Gabriel Mountains, weakened by fracturing, shearing, and crushing along numerousfault zones, particularly near the range front, combined with the moderate to extremely steepslopes that have resulted from rapid uplift of the mountains, are important elements that createthe setting for the development of slope failures. Similar conditions are present in the VerdugoMountains and the San Rafael Hills, where rocks are highly weathered and slope gradients of 30degrees or steeper are common. Unfortunately, detailed maps showing previous sites ofsurficial slope failures, such as small landslides, slumps, soil slips, and rockfalls have not beencompiled or published for the Glendale area. However, an unpublished engineering geologyreport records several talus rockfalls on steep slopes and roadcuts in the Verdugo Mountains (R.T. Frankian & Associates, 1968). The common occurrence of rockfalls can also be inferred bythe abundant talus at the base of steep slopes and in canyons of the San Gabriel Mountains.Significantly, however, areas of gross instability such as large deep-seated landslides have notbeen mapped in the Glendale area, primarily because the highly fractured crystalline rocks thatunderlie the San Gabriel and Verdugo Mountains and the San Rafael Hills rarely fail as largecohesive units. All of the landslides mapped within city limits are relatively small in area, andlimited to the Verdugo Mountains and San Rafael Hills. The larger of these landslides areshown on Plates H-2 and H-11 (in Appendix H). The distribution of existing landslides in theGlendale area and vicinity was compiled from various publications, including Morton andStreitz, (1969), Crook et al. (1987), and Dibblee, (1989a, 1989b, 1991a, 1991b, 2002).Community HistoryGlendale has an ethnically diverse and rich cultural heritage that dates back to the 1700s. Thefirst known inhabitants of the Glendale area were the native Americans known as theGabrielinos. In 1784, Corporal Verdugo of the Spanish Army received permission to settle onthis land, and by 1798 he had received title to the land and was a full-time rancher and farmer.Over the next 90 years, Verdugo’s descendants divided and sold off the ranch. In 1884, the arearesidents decided to form a town and chose the name “Glendale.” The city of Glendale wasincorporated in 1906.Population and DemographicsAccording to the 2000 Census data, in the year 2000 the city of Glendale had a population of194,973. The city’s population steadily increased from 1940 through 1990 after a sharp increaseof about 50,000 between 1930 and 1940 (see Table 2.3 below). Although population growthcontinued in the 1990s, the city’s growth rate slowed to about 8 percent from 1990 to 2000 froman average of about 20 percent per decade for the previous 50 years. The California Departmentof Finance projects a continued 5 to 7 percent population increase per decade for the near futurein Glendale. This population is not evenly distributed throughout the city’s 30.7 square miles,but is rather concentrated in the lowland portions of the city, south of the Verdugo Mountains,and between the Verdugo Mountains to the south and the San Gabriel Mountains to the north.Over the years, Glendale has experienced in-fill development, increasing its population density.This creates greater service loads on the built infrastructure, including roads, water supply,sewer services and storm drains, and existing services.2006 PAGE 2 - 6