Seismic Noise Levels in Northern Baja California, Mexico

2019 ◽  
Vol 109 (2) ◽  
pp. 610-620 ◽  
Author(s):  
Erik E. Ramírez ◽  
J. Antonio Vidal‐Villegas ◽  
M. Alejandra Nuñez‐Leal ◽  
Jorge Ramírez‐Hernández ◽  
Adán Mejía‐Trejo ◽  
...  
Keyword(s):  
Seismic Noise ◽  
Baja California ◽  
Noise Levels

scholarly journals SEARCH FOR GEOTHERMAL SEISMIC NOISE IN THE EAST MESA AREA, IMPERIAL VALLEY, CALIFORNIA

Geophysics ◽  
1975 ◽  
Vol 40 (6) ◽  
pp. 1066-1072 ◽  
Author(s):  
H. M. Iyer
Keyword(s):  
Heat Flow ◽  
Seismic Noise ◽  
Critical Evaluation ◽  
Thermal Gradients ◽  
Noise Levels ◽  
Imperial Valley ◽  
Bureau Of Reclamation ◽  
Cultural Noise ◽  
Noise Experiment ◽  
The U.S

A seismic noise experiment was conducted in the East Mesa area of Imperial Valley, California, by the U.S. Geological Survey (USGS) in May 1972. There is a pronounced heat flow anomaly over the area, and between July 1972 and the present five deep test wells have been drilled over the anomaly by the U.S. Bureau of Reclamation (U.S. Bureau of Reclamation, 1974). At the time of our survey, we were aware of results from a preliminary seismic noise survey in East Mesa by Teledyne Geotech (Douze and Sorrells, 1972). A detailed noise survey was conducted by Teledyne Geotech soon after our experiment (Geothermal Staff of Teledyne Geotech, 1972). Both the Teledyne Geotech surveys show noise levels (in the 3.0 to 5.0 hz band) 12–18 db higher over the area where the thermal gradients and heat flow reach maximum values than in the surroundings. Our results, on the other hand, show that the seismic noise field in the area is dominated by cultural noise, and it is impossible to see a noise anomaly that can be related to the geothermal phenomena in East Mesa. We think that it is important to take into account this disagreement between the two results in order to make a critical evaluation of the utility of seismic noise as a geothermal prospecting tool. The purpose of this note is to put our findings on record.

SEISMIC NOISE MEASUREMENTS IN YELLOWSTONE NATIONAL PARK

Geophysics ◽  
1974 ◽  
Vol 39 (4) ◽  
pp. 389-400 ◽  
Author(s):  
H. M. Iyer ◽  
Tim Hitchcock
Keyword(s):  
Yellowstone National Park ◽  
Seismic Noise ◽  
National Park ◽  
Hot Springs ◽  
Spectral Band ◽  
Spectral Characteristics ◽  
Frequency Noise ◽  
Noise Levels ◽  
High Noise ◽  
Geothermal Activity

In September and October, 1972 the U. S. Geological Survey made an investigation of seismic noise associated with the known geothermal phenomena in Yellowstone National Park. Eighty‐four stations, each recording for at least 48 hours, were operated. All major geyser basins were covered by the experiment. L-shaped three‐element arrays, three‐component stations, and single vertical component stations were operated. Four eight‐element mobile arrays were operated to study propagation characteristics of the noise. Preliminary analysis of data shows that high noise levels are associated with all the major thermal areas in the park. An elongated band of high noise envelops Lower and Upper Geyser Basins; noise levels are high around Norris Basin, Mammoth Hot Springs, Sulphur Mountain, and Mud Volcano; and a strong noise field exists around Lower and Upper Falls of the Yellowstone River. The seismic waves generated by the waterfalls have very different spectral characteristics from the waves associated with geothermal activity. The geothermal noise is predominantly in the spectral band of 2–8 hz, whereas the waterfall noise is predominantly around 2 hz. A mobile array operated near Norris Basin showed coherent wave trains radiating from seismic sources in the basin. Seismic noise measured around 50 m from Old Faithful Geyser showed amplitude fluctuations that followed the eruption cycles of the geyser. A few minutes after each eruption, the noise level starts rising slowly in ramplike fashion. Twenty to thirty minutes before the next eruption, sharp bursts of noise activity occur with increasing rapidity and continue for a few minutes after the eruption. The predominant energy of seismic noise generated by Old Faithful is at frequencies well above 8 hz. We postulate that only such high frequency noise is generated by the surface activity of geysers and hot springs and that the lower frequency noise found in and around the geyser basins is generated by a deeper convection system associated with the geothermal activity.

scholarly journals Temporal changes in anthropogenic seismic noise levels associated with economic and leisure activities during the COVID-19 pandemic

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiro Nimiya ◽  
Tatsunori Ikeda ◽  
Takeshi Tsuji
Keyword(s):  
Seismic Noise ◽  
Ambient Noise ◽  
Anthropogenic Activities ◽  
Leisure Activities ◽  
Time Of Day ◽  
Noise Levels ◽  
Economic Activities ◽  
State Of Emergency ◽  
Tokyo Metropolitan Area ◽  
Day Of The Week

AbstractSeismic ambient noise with frequencies > 1 Hz includes noise related to human activities. A reduction in seismic noise during the COVID-19 pandemic has been observed worldwide, as restrictions were imposed to control outbreaks of the SARS-CoV-2 virus. In this context, we studied the effect of changes in anthropogenic activities during COVID-19 on the seismic noise levels in the Tokyo metropolitan area, Japan, considering time of day, day of the week, and seasonal changes. The results showed the largest reduction in noise levels during the first state of emergency under most conditions. After the first state of emergency was lifted, the daytime noise reverted to previous levels immediately on weekdays and gradually on Sundays. This was likely because economic activities instantly resumed, while non-essential outings on Sundays were still mostly avoided. Furthermore, the daytime noise level on Sundays was strongly reduced regardless of changes on weekdays after the second state of emergency, which restricted activities mainly at night. Sunday noise levels gradually increased from the middle of the second state of emergency, suggesting a gradual reduction in public concern about COVID-19 following a decrease in the number of infections. Our findings demonstrate that seismic noise can be used to monitor social activities.

scholarly journals Temporal changes in anthropogenic seismic noise levels associated with economic and leisure activities during the COVID-19 pandemic

2021 ◽  
Author(s):  
Hiro Nimiya ◽  
Tatsunori Ikeda ◽  
Takeshi Tsuji
Keyword(s):  
Seismic Noise ◽  
Ambient Noise ◽  
Anthropogenic Activities ◽  
Leisure Activities ◽  
Time Of Day ◽  
Noise Levels ◽  
Economic Activities ◽  
State Of Emergency ◽  
Tokyo Metropolitan Area ◽  
Day Of The Week

Abstract Seismic ambient noise with frequencies > 1 Hz includes noise related to human activities. A reduction in seismic noise during the COVID-19 pandemic has been observed worldwide, as restrictions were imposed to control outbreaks of the SARS-CoV-2 virus. In this context, we studied the effect of changes in anthropogenic activities during COVID-19 on the seismic noise levels in the Tokyo metropolitan area, Japan, considering time of day, day of the week, and seasonal changes. The results showed the largest reduction in noise levels during the first state of emergency under most conditions. After the first state of emergency was lifted, the daytime noise reverted to previous levels immediately on weekdays and gradually on Sundays. This was likely because economic activities instantly resumed, while non-essential outings on Sundays were still mostly avoided. Furthermore, the daytime noise level on Sundays was strongly reduced regardless of changes on weekdays after the second state of emergency, which restricted activities mainly at night. Sunday noise levels gradually increased from the middle of the second state of emergency, suggesting a gradual reduction in public concern about COVID-19 following a decrease in the number of infections. Our findings demonstrate that seismic noise can be used to monitor social activities.

scholarly journals Temporal changes in anthropogenic seismic noise levels associated with economic and leisure activities during the COVID-19 pandemic

2020 ◽  
Author(s):  
Hiro Nimiya ◽  
Tatsunori Ikeda ◽  
Takeshi Tsuji
Keyword(s):  
Seasonal Variation ◽  
Human Activities ◽  
Seismic Noise ◽  
Anthropogenic Activities ◽  
Leisure Activities ◽  
Noise Levels ◽  
Economic Activities ◽  
State Of Emergency ◽  
Tokyo Metropolitan Area ◽  
School Activities

Abstract Seismic noise of frequencies >1 Hz includes noise that is strongly related to human activities. Reduction in seismic noise during the COVID-19 pandemic has been observed worldwide as restrictions were imposed on numerous human activities to control outbreaks of the virus. In this context, we studied the effect of reduced anthropogenic activities during COVID-19 on the noise levels in the Tokyo metropolitan area, Japan, considering seasonal variation. A significant reduction in noise was observed during the emergency, including that of frequencies >20 Hz, which was associated with school activities. After lifting the state of emergency, noise reverted to previous levels immediately for weekdays, but gradually for Sunday. This was likely because economic activities instantly resumed post-emergency on weekdays; however, most people still continued to avoid non-essential outings on Sunday. We also observed seasonal variation related to school holidays, energy consumption, and industrial activity. Noise levels in the frequency range of 1–5 Hz were found to be related to construction activity, which increased in winter and gradually decreased from 2017. Our findings demonstrate that seismic noise can be used to monitor economic activities and movement of people at a local scale.

scholarly journals COVID-19 lockdown effects on the seismic recordings in Central America

Solid Earth ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 2127-2144
Author(s):  
Mario Arroyo-Solórzano ◽  
Diego Castro-Rojas ◽  
Frédérick Massin ◽  
Lepolt Linkimer ◽  
Ivonne Arroyo ◽  
...  
Keyword(s):  
Costa Rica ◽  
El Salvador ◽  
Central America ◽  
Seismic Noise ◽  
Temporal Variations ◽  
Noise Levels ◽  
Contributing Factors ◽  
Seismic Stations ◽  
Before And After ◽  
Seismic Records

Abstract. A noticeable decrease in seismic noise was registered worldwide during the lockdown measures implemented in 2020 to prevent the spread of COVID-19. In Central America, strong lockdown measures started during March of 2020. In this study, we used seismic stations from Costa Rica, Guatemala, El Salvador, and Nicaragua to study the effects of these measures on seismic records by characterizing temporal variations in the high-frequency band (4–14 Hz) via spectral and amplitude analyses. In addition, we studied the link between the reduction in seismic noise and the number of earthquake detections and felt reports in Costa Rica and Guatemala. We found that seismic stations near the capitals of Costa Rica, Guatemala, and El Salvador presented a decrease in their typical seismic noise levels, from 200 to 140, from 100 to 80, and from 120 to 80 nm, respectively. Our results showed that the largest reduction of ∼ 50 % in seismic noise was observed at seismic stations near main airports, busy roads, and densely populated cities. In Nicaragua, the seismic noise levels remained constant (∼ 40 nm), as no lockdown measures were applied. We suggest that the decrease in seismic noise levels may have increased earthquake detections and the number of felt reports of low-magnitude earthquakes. However, the variations observed in several seismic parameters before and after the lockdown are not significant enough to easily link our observations or separate them from other contributing factors. Our results imply that the study of seismic noise levels can be useful to verify compliance with lockdown measures and to explore their effects on earthquake detection and felt reports.

Correlation between Ambient Seismic Noises and Economic Growth

2020 ◽  
Vol 91 (4) ◽  
pp. 2343-2354 ◽  
Author(s):  
Tae-Kyung Hong ◽  
Jeongin Lee ◽  
Giha Lee ◽  
Junhyung Lee ◽  
Seongjun Park
Keyword(s):  
Economic Growth ◽  
High Frequency ◽  
Noise Level ◽  
Seismic Noise ◽  
Economic Conditions ◽  
Seasonal Effects ◽  
Ambient Seismic Noise ◽  
Frequency Noise ◽  
Noise Levels ◽  
Wide Range

Abstract Human activity is a major source of high-frequency seismic noise. Long-term ambient seismic noise levels and their influencing factors are investigated. The diurnal seismic noise level in 5–15 Hz display high correlation with human activities including traffic and industrial operations that are related to economic conditions. The temporal noise-level variations are consistent among three components. Analysis with seismic noises in three consecutive months of each year enables us to estimate the noise levels without seasonal effects. The daytime seismic noise-level changes in major cities of 11 countries are assessed using the 3 month records for decades. The annual seismic noise levels present strong correlations with gross domestic product (GDP), particularly with manufacturing and industrial GDP. The seismic noise levels increase quickly with GDP in low-GDP regions but slowly in high-GDP regions. This is because high-GDP regions already have large volumes of existing noise-inducing sources and because added sources contribute weakly. The seismic noise levels increased by 14%–111% for 5–23 yr depending on the economic conditions. The correlation between ambient seismic noise level and economy growth is a global feature. The high-frequency noise level may be a proxy to present the economic condition. Economic growth affects the Earth environment in a wide range of aspects.

Using Seismic Noise Levels to Monitor Social Isolation: An Example From Rio de Janeiro, Brazil

2020 ◽  
Vol 47 (16) ◽  
Author(s):  
Fábio L. Dias ◽  
Marcelo Assumpção ◽  
Pedro S. Peixoto ◽  
Marcelo B. Bianchi ◽  
Bruno Collaço ◽  
...  
Keyword(s):  
Social Isolation ◽  
Seismic Noise ◽  
Rio De Janeiro ◽  
Noise Levels
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