Macroseismic investigations with data collected through online surveys has acquired relevance in recent years. Its easy access and low cost allow assessments of the severity of an earthquake from its effects as observed by the population. Furthermore, it is possible to generate attenuation curves for a particular region, visualize the condition of the buildings from a zip code-averaged distribution map, and estimate possible site effects. In regions without a good coverage of seismic networks, macroseismic intensities have proved to be a substitute for instrumental data. In this paper intensity maps for four earthquakes in different regions of Mexico are presented, based on data from the database of ¿Sintió un sismo? program, an online survey implemented in 2014. Less attenuation was found in areas considered tectonically stable than in those considered as active regions.
Research Article| July 15, 2015 Relationship between MMI Data and Ground Shaking in the State of Nuevo León, Northeastern Mexico Juan C. Montalvo‐Arrieta; Juan C. Montalvo‐Arrieta Universidad Autónoma de Nuevo León, Facultad de Ciencias de la Tierra, Ex‐Hacienda de Guadalupe km 8, Carr. Linares, Cerro Prieto, 67700 Linares, N.L., Méxicojmontalvoa87@gmail.com Search for other works by this author on: GSW Google Scholar Rocío L. Sosa‐Ramírez; Rocío L. Sosa‐Ramírez Universidad Autónoma de Nuevo León, Facultad de Ciencias de la Tierra, Ex‐Hacienda de Guadalupe km 8, Carr. Linares, Cerro Prieto, 67700 Linares, N.L., Méxicojmontalvoa87@gmail.com Search for other works by this author on: GSW Google Scholar Edgar G. Paz‐Martínez Edgar G. Paz‐Martínez Universidad Autónoma de Nuevo León, Facultad de Ciencias de la Tierra, Ex‐Hacienda de Guadalupe km 8, Carr. Linares, Cerro Prieto, 67700 Linares, N.L., Méxicojmontalvoa87@gmail.com Search for other works by this author on: GSW Google Scholar Seismological Research Letters (2015) 86 (5): 1489–1495. https://doi.org/10.1785/0220140206 Article history first online: 14 Jul 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Juan C. Montalvo‐Arrieta, Rocío L. Sosa‐Ramírez, Edgar G. Paz‐Martínez; Relationship between MMI Data and Ground Shaking in the State of Nuevo León, Northeastern Mexico. Seismological Research Letters 2015;; 86 (5): 1489–1495. doi: https://doi.org/10.1785/0220140206 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search ABSTRACT In this article, we implement a web questionnaire (available in Spanish at the www.fct.uanl.mx, last accessed March 2014, as Encuesta sismo) to gather citizens' observations on felt earthquakes in an area of northeastern Mexico. We generated a seismic intensity map due to the fact that some events from the October 2013 to March 2014 seismic sequence (1.9≤Mc≤4.5) were recorded and felt in the region. This sequence occurred in the central area of the state of Nuevo León. The data obtained from this questionnaire and by interviewing people living near the epicentral area are useful for a rapid postearthquake evaluation. This is important because the maximum intensity values were of V–VI near the epicentral area. Finally, the attenuation curves obtained from our study proved to be similar to those for central and eastern United States. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Abstract. The world experienced the beginning of the COVID-19 pandemic by the end of 2019, beginning of 2020. Governments implemented strategies to contain it, most based on lockdowns. Mexico was not the exception. The lockdown was initiated in March 2020 and with it, a reduction on the seismic noise level was witnessed by the seismic stations of the national and the Valley of Mexico networks. Stations located in municipalities with more than 50,000 people usually experience larger seismic noise levels at frequencies between 1 to 5 Hz, associated with human activity. The largest noise levels are recorded in Mexico City, with the largest population in the country. The largest drop was observed in Hermosillo, Sonora, however, it was also the city with the fastest return to activities, which seems to correlate with a quick increase in confirmed COVID-19 cases. Mexico initiated a traffic-light system to modulate the re-opening of economic activities for each state. Therefore, since 1 June, noise levels reflect, in general, the colour of the state traffic light. Furthermore, the reduction in the noise level at seismic stations has allowed identification of smaller earthquakes without signal processing. Also, people in cities have perceived smaller or distant quakes.
A key strategy to characterize subsurface materials is the integrative analysis of tomograms of several physical properties provided by different geophysical data. Among the recent strategies to produce these tomograms is the joint inversion. Unfortunately, most joint inversion techniques are based on hypothetical property relationships that hinder the site-specific property correlations that characterize individual materials. Differently, a recently developed cross-gradient joint inversion technique is underpinned by the hypothesis of structural resemblance and permits the coexistence of natural property correlations that provide the key to unravel the signatures of subsurface materials. In the present work, electromagnetic, seismic and potential field data are jointly inverted for several field sites with near surface targets. The results show not only a clearer disposition of the mapped units in structural terms, but also a sound evidence of their actual fluid-mineral characteristics. In general, the results demonstrate the power of analyzing multiple-property images when they are structurally consistent.