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Show State Press FAMILIAR SIGHT. This foundation is one of the many that can be found on north Highland Drive in Cedar City as evidence of extensive damage identified as "hydrocompaction." Study reveals wide problem Efforts to seek out and make application ap-plication for available funds for a large section of the residential area of Cedar City was set in motion Monday at a special meeting of the Cedar City Council. Accpeted at the meeting was a Summary Report to Cedar City by B. N. Kaliser, State Engineering Geologist, Utah Geological and Mineral Survey, which indicated a broad ground surface subsidence due to the phenomenon of "hydrocompaction." "hydrocom-paction." Originally believed to be a problem isolated on the north section of . Highland Drive in the northeast sector of the community, the report, as presented by Mayor Kerry Jones indicated that ". .'. this phenomenon in Cedar City. . . appears to be relatively widespread. This latter fact is quite important," the report indicated," in-dicated," because it means that the damage to homes along Highland Drive is only indicative of a much wider problem." . Immediate action The Council took action to "im- mediately seek and make application for available funds for the citizens in j the Highland Drive Area. . .and authorized the mayor and city I manager to prepare application for any and all agencies for funds to make available emergency assistance for citizens who have suffered losses due to damage to their homes and property." A complete report from the engineering study, undertaken by the City through a grant from the Four Corners Regional Commission, is expected by the latter part of November. "At that time we expect that the problem will be more fully detailed identifying areas that could be effected ef-fected by the 'hydrocompaction' problem, Mayor Jones stated. Public Hearing Mayor Jones did commit to the many residents in attendance that upon receipt of the full report a public hearing would be held at .which time solutions to the problem will be discussed and a course of action determined. "We cannot say at this time," Mike Embley, City Manager said "just how extensive this problem is." Broadly and unofficially it was defined as a substantial area north of Coal Creek and east of Main Street. However, the final report will detail the.area more specifically. Concerns of residents who have already been forced to move, those who will, according to the report, be forced to move, and future plans were expressed at the meeting. The summary of the final report on the Ground Surface Subsidence Problem in Cedar City reads as follows: Method & Procedures During the summer of 1977 the Utah Geological & Mineral Survey with the aid of the Utah Department of Transportation drilled five exploration ex-ploration holes and conducted two long seismic traverses in Cedar City. Simultaneously extensive ground surface observation was done and interviewing of long time residents of Cedar City and other agency personnel per-sonnel was conducted. Undisturbed samples from the bore hole drilling operation, and builk samples from extensive augering along the geophysical lines were subjected to laboratory analysis and testing. All of the above information has been compiled, together with other data such as earthquake epicenters and groundwater withdrawal and water well data, and conclusions reached based on the whole information package. No single element of data lead to a readily apparent determination. deter-mination. Only now, after nine months of study, are answers forthcoming. for-thcoming. General Conclusions The major cause of the ground surface subsidence is due to the phenomenon of 'hydrocompaction' or the densification of the soil mass on application of water upon the surface of the ground or in the shallow subsurface sub-surface environment. Certain geologic materials are susceptible to this phenomenon and in Cedar City the occu ranee of these materials appears to be relatively widespread. This latter fact is quite important because it means that the damage to homes along Highland Drive is only indicative of a much wider problem. The role played by the major Hurricane Fault Zone is not altogether known. It may be no evidence that the distribution of damage seen today in a north-south strip through the City" is either within or in the immediate vicinity of the fault zone. Tectonic creep or very slow fault movement cannot be altogether dismissed as a possibility. The fault may also act as a linear band of void spaces into which overlying soil may move with the aid of gravity and water infiltration. Microsesmic events of magnitudes unfelt by man may help induce the latter type of soil movement. Impact of the Project Repercussions for Cedar City are relatively severe. Those homes existing in the damage zone cannot (continued on page 3) soil study (continued from page 1) economically be treated in any manner. Therefore, those homes will ultimately become so badly i distressed that they must be. "aban- v - (, ; , ,., dooed.. ,H may be .desirea hje, , tpone xt certain areas from residential single family dwellings or other structures. If susceptible areas are to be permitted per-mitted to develop then detailed geotechnical evaluations will need to be a requirement for each site in the future. It must be borne in mind that few geotechnical practitioners occur in the. State of Utah, none in Cedar I City and the city itself is presently without expertise in this technical field. The problem will not be an easy one for the city fathers to wrestle with, now or in the future. Consideration may be given, to a green belt or recreation belt where susceptible earth materials prohibit residential construction. Larger, structures with deeper foundations are another alternative for susceptible suscep-tible areas. In the case of the latter economics justifies through site exploration and individual foundation design, adding up to considerable dollar expenditure if necessary. With respect to single family residences an architectural firm has been engaged to offer whatever construction techniques might be of help to the individual homeowner, builder. These remarks will be in the final comprehensive report, but, as stated earlier, the only sure remedy for residences is to avoid susceptible areas. |