Central America is a seismically active region located in a tectonic setting dominated by the subduction zone between the Cocos and Caribbean plates, transform boundaries between the North American and Caribbean plates, and local or crustal faulting with some of the most important fault systems aligned with the volcanic arc. Combining seismic data from various Central American seismic agency catalogs covering the period from 1520 to 2020, we present an updated regional earthquake catalog for the region. Fourteen databases containing seismic events from local and regional agencies were collected for different time periods, homogenized to moment magnitude (Mw), and subsequently unified using a prioritization criteria approach. We analyzed to the data to identify and remove duplicate earthquakes, prioritizing records with the lowest RMS value, depth consistent with their location based on the region’s crustal thickness, and magnitudes in accordance with historical reports or bibliographic sources. Additionally, significant seismic events (Mw ≥ 6.0) were carefully reviewed based on their epicentral locations and magnitudes, according on reliable publications. The earthquake catalog compiled includes a total of 260 548 earthquakes, for which we conducted a descriptive, spatiotemporal statistical analysis, as well as estimations of the magnitude of completeness (Mc) and declustering. Among the most important results, we highlight recent completeness periods for magnitudes Mw < 5.0. Geographically, seismic zones with better Mc are directly related to either good seismic network coverage or high seismicity rates in the region. As regards declustering, the Reasenberg declustering method considers several main shocks with 76

We report on seismic and tsunami monitoring and early warning systems in Nicaragua and Central America, regions that are bordered by plate boundaries and subduction zones with related high seismic and tsunami risks. These systems were established in Nicaragua only after big earthquake and tsunami disasters (that took place in Managua in 1972 and the Pacific coast in 1992, respectively). The Nicaraguan seismic network is well developed, and the National Tsunami Warning System (NTWS) is a model for the Central American region. In 2015, the Central American countries and the Intergovernmental Oceanographic Commission (IOC) of the United Nations Educational, Scientific and Cultural Organization (UNESCO), along with the Tsunami Warning Systems (TWS) for the Pacific and the Caribbean, accepted Nicaragua's proposal to create a regional TWS that would improve tsunami services for Central America. In 2016, Instituto Nicaraguense de Estudios Territoriales (INETER) started to develop the Central American Tsunami Advisory Center (CATAC) and intensified cooperation and real-time data exchange with regional seismic networks and civil protection institutions. INETER initiated a project with the Japanese cooperation to reinforce CATAC until full services would be established in 2019. Since 2016, INETER has been cooperating with the Swiss Seismological Service (SED) to develop earthquake early warnings (EEW) in Nicaragua and Central America. EEW, besides being favorable for tsunami warning, could help compensate for the extreme seismic vulnerability of millions of homes in Nicaragua and Central America that are made from adobe or other bad construction materials. Alerts, received just a few seconds before the destructive shaking, could permit inhabitants of adobe houses to leave their collapsing homes, thus saving their lives.

On 10 April 2014, an M w 6.1 earthquake struck central Nicaragua. The main event and the aftershocks were clearly recorded by the Nicaraguan national seismic network and other regional seismic stations. These crustal earthquakes were strongly felt in central Nicaragua but caused relatively little damage. This is in sharp contrast to the destructive effects of the 1972 earthquake in the capital city of Managua. The differences in damage stem from the fact that the 1972 earthquake occurred on a fault beneath the city; in contrast, the 2014 event lies offshore, under Lake Managua. The distribution of aftershocks of the 2014 event shows two clusters of seismic activity. In the northwestern part of Lake Managua, an alignment of aftershocks suggests a northwest to southeast striking fault, parallel to the volcanic arc. The source mechanism agrees with this right-lateral, strike-slip motion on a plane with the same orientation as the aftershock sequence. For an earthquake of this magnitude, seismic scaling relations between fault length and magnitude predict a sub-surface fault length of approximately 16 km. This length is in good agreement with the extent of the fault defined by the aftershock sequence. A second cluster of aftershocks beneath Apoyeque volcano occurred simultaneously, but spatially separated from the first. There is no clear alignment of the epicenters in this cluster. Nevertheless, the decay of the number of earthquakes beneath Apoyeque as a function of time shows the typical behavior of an aftershock sequence and not of a volcanic swarm. The northeast–southwest striking Tiscapa/Ciudad Jardín and Estadio faults that broke during the 1972 and 1931 Managua earthquakes are orthogonal to the fault where the 10 April earthquake occurred. These orthogonal faults in close geographic proximity show that Central Nicaragua is being deformed in a complex tectonic setting. The Nicaraguan forearc sliver, between the trench and the volcanic arc, moves to the northwest relative to the Caribbean plate at a rate of 14 mm/year. Part of the deformation is apparently accommodated by strain partitioning in the form of bookshelf faulting, on a system of orthogonal faults. The sinistral faults striking northeast–southwest rotate blocks of the Caribbean plate in a clockwise manner. The recent crustal earthquakes in central Nicaragua in 1931, 1972 and 2005 earthquakes took place on these left-lateral faults. The motion of the forearc sliver is also accommodated by a second set of right-lateral, strike-slip faults oriented parallel to the volcanic arc. Faults with this orientation and direction of motion are responsible for the 2014 and possibly the 1955 earthquakes. The presence of this geometry of orthogonal crustal faults highlights the seismic hazard posed by this complex faulting system, not only in the capital city of Managua, but also to the major Nicaraguan cities, which lie close to the volcanic arc.

Research Article| May 01, 2014 RTQUAKE, A Real‐Time Earthquake Detection System Integrated with SEISAN T. Utheim; T. Utheim aUniversity of Bergen, Department of Earth Science, P.O. Box 7803, N‐5020 Bergen, Norway Search for other works by this author on: GSW Google Scholar J. Havskov; J. Havskov aUniversity of Bergen, Department of Earth Science, P.O. Box 7803, N‐5020 Bergen, Norway Search for other works by this author on: GSW Google Scholar M. Ozyazicioglu; M. Ozyazicioglu bEarthquake Research Center, Ataturk University, Erzurum, Turkey Search for other works by this author on: GSW Google Scholar J. Rodriguez; J. Rodriguez cInstituto Politecnico, C/Padre Angel Arias #1, San Cristobal, Loyola, Dominican Republic Search for other works by this author on: GSW Google Scholar E. Talavera E. Talavera dInstituto Nicaragüense de Estudios Territoriales, Apdo. Postal 2110, Managua, Nicaragua Search for other works by this author on: GSW Google Scholar Seismological Research Letters (2014) 85 (3): 735–742. https://doi.org/10.1785/0220130175 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 T. Utheim, J. Havskov, M. Ozyazicioglu, J. Rodriguez, E. Talavera; RTQUAKE, A Real‐Time Earthquake Detection System Integrated with SEISAN. Seismological Research Letters 2014;; 85 (3): 735–742. doi: https://doi.org/10.1785/0220130175 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 Seismic networks have over the last 10–15 years become nearly exclusively real‐time networks. The software used for data collection is both commercial and largely public domain. The two main public domain real‐time detection systems are Earth Worm (EW; Johnson et al., 1995; http://www.earthwormcentral.org; last accessed March 2014) and SeisComP3 (SC3; www.seiscomp3.org). Both systems receive data in real time, perform triggering, store data in a continuous manner, and automatically determine location and magnitude. For a comparison and evaluation of the two systems, see Olivieri and Clinton (2012). EW and SC3 read data sources using different communication... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

A new evaluation of seismic hazard in Central America has been carried out as part of the cooperation project named RESIS II under the auspices of the Norway Cooperation Agency (NORAD). Several seismic-hazard experts from Costa Rica, Guatemala, Honduras, Nicaragua, El Salvador, Panama, Norway, and Spain participated in the study, which was aimed at obtaining results suitable for seismic design purposes. The analysis started with a thorough revision of the national seismic catalogs from which a catalog for Central America has been compiled and homogenized to moment magnitude, M-w. Seismotectonic models proposed for the region were revised, and a new regional zonation was proposed, taking into account seismotectonic data, seismicity, focal mechanisms, and GPS observations. Besides, ground-motion prediction equations (GMPEs) for subduction, volcanic, and crustal zones were revised, and the most suitable ones were calibrated with Central American strong-motion data. Subsequently, a seismic-hazard analysis was developed in terms of peak ground acceleration (PGA) and spectral accelerations SA (T) for periods of 0.1, 0.2, 0.5, 1, and 2 s, by means of the probabilistic seismic-hazard assessment (PSHA) approach. As a result, different hazard maps were obtained for the quoted parameters, together with uniform hazard spectra (UHS) for six of the capital cities of Central America. Disaggregation was also carried out in these capitals for the target motion given by the PGA and SA (1 s) and obtained for return periods of 500 years and 2500 years. Therefore, the control earthquakes for motions of short and long periods were derived. This is the first study developed in Central America at a regional scale after 10 years.

A new evaluation of seismic hazard in the Central America region has been carried out, in the frame of the cooperation project RESIS II, financed by the Norway Cooperation Agency (NORAD). Different experts in seismic hazard from Costa Rica, Guatemala, Nicaragua , El Salvador, Norway and Spain participated in the study, which was aimed at obtaining results suitable for seismic design purposes. The analysis started with an exhaustive revision of the seismic catalogues of each country from which a global catalogue for CA has been configured and homogenised at moment magnitude, Mw. Seismotectonic models proposed for the region were revised and a regional zonation was proposed, taking into account seismotectonic data, seismicity, focal mechanisms, GPS observations and other evidences useful for defining seismic sources. In parallel, attenuation models for subduction and volcanic crustal zones were revised and the more suitable models were calibrated with strong motion data. Taking the previous inputs, the seismic hazard analysis was developed in terms of peak ground acceleration, PGA and spectral accelerations SA (T) for periods of 0.1, 0.5, 1 and 2 s, through the PSHA methodology (Probabilistic Seismic Hazard Assessment). As a result, different hazard maps were obtained for the quoted parameters, together with Uniform Hazard Spectra (UHS) in the main populations of Central America. This is the first study developed at regional scale after the last earthquakes that have occurred in the region and as a result the new generation of maps will be useful in the revision of seismic codes of the area.

Research Article| September 01, 1998 Central American Seismic Center (CASC) E. Alvarenga; E. Alvarenga Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar R. Barquero; R. Barquero Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar I. Boschini; I. Boschini Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar J. Escobar; J. Escobar Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar M. Fernández; M. Fernández Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar P. Mayol; P. Mayol Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar J. Havskov; J. Havskov Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar N. Gálvez; N. Gálvez Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar Z. Hernández; Z. Hernández Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar L. Ottemöller; L. Ottemöller Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar J. Pacheco; J. Pacheco Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar C. Redondo; C. Redondo Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar W. Rojas; W. Rojas Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar F. Vega; F. Vega Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar E. Talavera; E. Talavera Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar W. Taylor; W. Taylor Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar A. Tapia; A. Tapia Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar C. Tenorio; C. Tenorio Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar J. Toral J. Toral Institute of Solid Earth Physics University of Bergen Bergen, Norway (J.H.) Search for other works by this author on: GSW Google Scholar Seismological Research Letters (1998) 69 (5): 394–399. https://doi.org/10.1785/gssrl.69.5.394 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation E. Alvarenga, R. Barquero, I. Boschini, J. Escobar, M. Fernández, P. Mayol, J. Havskov, N. Gálvez, Z. Hernández, L. Ottemöller, J. Pacheco, C. Redondo, W. Rojas, F. Vega, E. Talavera, W. Taylor, A. Tapia, C. Tenorio, J. Toral; Central American Seismic Center (CASC). Seismological Research Letters 1998;; 69 (5): 394–399. doi: https://doi.org/10.1785/gssrl.69.5.394 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentBy SocietySeismological Research Letters Search Advanced Search This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not currently have access to this article.