GeoJournal 334 453-458 453 © 1994 (Aug) by Kluwer Academic Publishers Spatial and Temporal Variations of Sound in an Andean City: Cajamarca, Peru Kent, Robert B., Prof. Dr., University of Akron, Department of Geography and Planning, Akron, Ohio 44325-5005, USA ABSTRACT: This study provides a preliminary examination of the temporal and geographic variations of sound in Cajamarca, a provincial city in the Andes of northern Peru. Sound levels were sampled in four neighborhoods of the city each representing different land-use characteristics and hypothetically distinct environmental sound profiles. The sample sites included the central plaza, the business district, a residential neighborhood, and a small residential community on the urban periphery. Sound readings were taken each hour between 6 am and 12 pm on every day of the week. Sound profiles for each location for a weekday, a Saturday, and a Sunday are presented. Distinct decibel profiles emerge, both geographically and temporally. These changing sound patterns reflect the activities of the town's residents as they move between home, work, and social/recreational activities during the course of a week. Cajamarca's sound profiles are believed to be characteristic of other provincial cities throughout the Andean region. Introduction economic and administrative center in the northern Andean region, with a population between 75,000 and As a component of the urban milieu in developing 85,000. The city is typical of a whole range of intermediate- countries, the study of sound has received little scholarly sized urban centers characteristic of the Andes ranging attention. Brief studies documenting temporal and from Colombia, through Ecuador, Peru, Bolivia, and into geographical variations in sound levels have been northern Argentina. conducted in Bangalore, India (Noble et al. 1985) and in The study anticipates that the sound profiles for Guangzhou, China (Noble 1980). In a related vein traffic Cajamarca will mirror the daily patterns of human activity sound and human response to it has been documented in in the city. Specifically, it is anticipated that the weekday three residential neighborhoods representing different sound profiles should illustrate the characteristic pattern of socio-economic status in Trinidad, West Indies morning travel from home to work, a return home during (Underwood and Boodlal 1983). In Lima, Peru an the long midday meal break generally from 1 to 3 pm, and unpublished study has documented decibel levels along then the afternoon return to work and the early evening major arterial transport routes at peak traffic hours for 19 return home. Sound profiles for weekend days are different sites in 1970 and 1973 (Ugarte Chamorro 1977). expected to reveal distinct patterns. Considerable This paper aims to add to the limited body of knowledge on commercial activity does occur on Saturday mornings and the temporal and geographical characteristics of urban the town's principal market day is also on Saturdays, but sound in cities in the developing world. It reports on sound afternoons are characterized by a notable reduction in variations in Cajamarca, Peru. business activity and a corresponding reduction in Cajamarca is a medium-sized city in the Andes of pedestrian and vehicular traffic. Sundays are expected to northern Peru. It has been an important urban place since demonstrate considerably lower levels of sound than pre-Hispanic times, and it was here that the Spanish weekdays or Saturdays, especially during the morning conquistador, Pizarro captured and ransomed Atahuallpa, hours. But, as socializing and family visits are common on the Inca emperor, in 1533. Today, it is the department Sundays, decibel levels should be higher on Sunday capital of the Department of Cajamarca and is a major afternoons. 454 GeoJourna! 33.4/1994 CAJAMARCA / Meters 0 100 200 300 SOUND READING SITES 1. Plaza de Armas 2. Jr. Tarapaca (commercial area) 3. Jr. Cinco Esquinas (residential area) 4. Huambocancha barrio (peripheral residential area) Fig 1 Sound recording sites in Cajamarca, Peru Methodology in the southeast section of the city at the corner of Jr. (Jir6n) Cinco Esquinas and Jr. Leticia. Although this Sound readings were taken in four different areas of neighborhood is dominated by residential land-uses, a Cajamarca, each representing a distinct land-use type or small neighborhood grocery is located across the street category (Fig 1). One set of decibel readings were taken on from the sampling site, and a small bakery and small the town's central plaza, the plaza de armas. The central evangelical church are each located about one-half block plaza is situated at the geographic center of the city and from where the decibel readings were taken. Most represents the focus of much of the city's social and structures in this neighborhood are two-story construction. economic activity. Two churches front on the plaza, as do The decibel readings were recorded on the northwest several large restaurants, the town's principal hotel, the corner of the intersection. national telephone and telegraph exchange, the offices of A final set of sound readings were taken a peripheral the prefect and police forces, and number of commercial barrio (neighborhood), Huambocancha. It is located along shops. Considerable vehicle and foot traffic also pass the principal highway leading north out of the town toward through the plaza. Readings were taken in the northwest the provincial capitals of Bambamarca and Chota. It corner of the plaza. represents a mix of rural and urban characteristics. While A second set of readings were recorded along one of the the narrow strip along the highway is occupied by city's major commercial arteries, Jirdn Lima (Lima Street) residential structures and a few petty commercial at the intersection with Jir6n Tarapacfi. This intersection enterprises, land-uses behind this narrow margin are lies two blocks to the northwest oftheplaza de armas in an decided rural with small cultivated fields and grazing areas. area of concentrated commercial activity. Retail shops, Most residents, however, are employed or engaged in banks, small restaurants, and some offices are located urban related occupations. The decibel readings were along this street and in the vicinity of the sampling site. taken on the west side of the highway and on the north end Two- and three-story buildings dominate the street. The of the barrio. decibel readings here were taken on the southeast corner Sound readings were recorded at each of the four sites of the intersection. during June and July 1985. The instrument used to take the A third set of sound readings were taken in an readings was a GenRad 1565-B Sound-Level Meter. established residential neighborhood with modest homes Readings were taken for every day of the week and for GeoJournal 33.4/1994 455 every hour, usually at the top of the hour, between 6 am and WEEKDAY SOUND PROFILES 85 12 pm. Ten readings were taken for each hour at ten second Plaza de Armas (central plaza) intervals. Only one set of readings were taken for each hour 7~ at each site for each day. Readings were not all taken on the 65 same date. Thus, the sound profiles which are presented m< represent composites. Sound profiles for each of the four ~'53 sites are presented for weekdays (a summary of the Monday through Friday profiles), Saturday, and Sunday. 45 Average hourly decibel levels were calculated using the as ............... logarithmic averaging protocol. 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 1 or"1 1 AM Noon PM TIME 85 Jr. Tarapaca (business district) Re suits 75 65 Weekday Sound Profiles ,< re, '1J55 Sound levels varied considerably among the four sites on weekdays. The patterns of environmental sound were 45 most consistent in the center of the city, along the principal 35 6 8 9 1; 1'1 1'2 ; 2 3 4 5 6 7 8 9 110 1~ 12 commercial strip and in the plaza central where decibel AM Noon PM levels varied less than 10 dBA between the early morning 35 TIME hours and the evening. The highest consistent decibel Jr. Cinco Esquinas (residential) levels were recorded in the commercial core of the city at ~s the corner of Jr. Lima and Jr. Tarapacfi (Fig 2). Readings at 65 this site averaged near 70 dBA throughout most of the day, m< with a mid-morning peak around 10 am. Sound levels 953 dropped off slightly between 2 and 4 pm, and then 45 increased marginally through the late afternoon and early evening. Decibel levels dropped to about 65 dBA between 35 J i i J i t i i i / i i ~ ; 8 ;0 1., li , ~ 3 . 5 ; 7 s 8 .,o .,1 .,2 9 and 10 pm, and then fell precipitously to about 42 dBA at AM Noon PM TIME midnight. 83 Huambocancha (peripheral residential) Despite a central location and considerable vehicular and pedestrian traffic, sound levels in the central plaza 73 averaged about 10 dBA lower than those recorded in the 65 commercial area of the city on Jr. Tarapacfi. During most of < the day decibel levels recorded in the plaza varied between vss 55 and 65 dBA. Early morning decibel levels averaged around 60 dBA, climbing slowly during the course of the 43 morning to a high of about 65 dBA at 1 pro. Decibel levels 85 dropped about 5 dBA after 1 pm and then remained 8 10 11 12 1 2 4 5 6 7 8 9 10 AM Noon PM constant at about 60 dBA until 9 pm, and then declined TIME sharply to 45 dBA at midnight. Weekday sound profiles, Cajamarca, Peru A much more varied pattern of ambient sound is Fig 2 apparent in Cajamarca's residential neighborhoods.