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The Municipality of Zapopan, Jalisco, is located west of the Guadalajara Metropolitan Zone at the intersection of three rift zones: Tepic-Zacoalco, Chapala-Tula, and Colima. The importance of this region lies in the recent population growth that it has experienced in a few years. This growth has been supported by the development in commercial and service activities, and mainly in industry and technology, being ranked as the second-most populous city in Mexico, behind the federal capital.The western region of the Guadalajara Metropolitan Zone (GMZ) has numerous fault systems where, historically, there have been significant earthquakes and seismic swarms such as those that occurred in 1685-1687, 1875, 1932, 1995 and 2002, showing similar characteristics. Besides, it is in this region where the Caldera de la Primavera is located, a rhyolitic volcanic caldera that continues presenting seismic and geothermal activity.Recently, in the years 2015 and 2016, new seismic swarms occurred and were recorded instrumentally for the first time by the Jalisco Seismic and Accelerometric Network (RESAJ). The two seismic sequences took place in two alignments in the same direction as the Colima rift. These epicenters suggest the existence of two almost parallel normal faults, and that would be forming the Graben of Zapopan. Due to the length of these faults, 16 km for the east fault, and 28 km for the west fault, earthquakes of magnitudes 6.2 - 6.5 could be generated.In the framework of the CeMIEGeo P-24 project (SENER-CONACyT), we continue studying the seismicity of this region with the deployment of 25 seismic stations in the vicinity of La Caldera de la Primavera. This study revealed the high seismicity that was taking place in the area of ​​Zapopan, Tesistán Valley, and La Caldera de la Primavera.Based on these new studies and the knowledge of the seismic history of the region, a collaboration agreement has been established between the Research Group UDG-CA-276 SisVOc and Civil Protection of the Municipality of Zapopan for the installation of a local seismic network that will allow to define tectonic and structurally the fault systems of the region and mitigate the possible effects of the local seismicity in the population. Since May 2019, three Obsidian 8X seismic stations with Lennartz 1Hz LE3D and Episensor sensors and two accelerometers installed in the city have been operating, constituting the Zapopan Seismic and Accelerometric Network (RESAZ). The RESAZ operates together with the nearest stations of the RESAJ. In this work, we present the first results of the seismicity analysis recorded in Zapopan.

European Geosciences Union (EGU) General Assembly 2020, 4-8 May 2020, The geodynamic complexity in the interaction between Rivera, Cocos and NOAM plates is mainly reflected in the high and not well located seismicity of the region. In the framework of TsuJal Project, a study of the passive seismic activity was carried out. A temporal seismic network with 25 Obsidian stations with sensor Le-3D MkIII were deploying from the northern part of Nayarit state to the south of Colima state, including the Marias Islands, in addition to the Jalisco telemetric Seismic Network, being a total of 50 seismic stations on land. Offshore, ten Ocean Bottom Seismographs type LCHEAPO 2000 with 4 channels (3 seismic short period and 1 pressure sensors) were deployed and recover by the BO El Puma from UNAM in an array from the Marias Islands to off coast of the border of Colima and Michoacan state, in the period from 19th April to 7th November 2016. A seismic sequence started on May 7, 2016 with an earthquake Mw = 5.6 reported by CMT-Harvard, USGS and SSN at the area north of Paleo Rivera Transform fault and west of the Middle America Trench, an area with a very complex tectonics due to the interaction of Rivera, Cocos and NOAM plates. An analysis of this earthquake sequence from May 7 to May 11 using data from OBS and adequate P-Wave velocity model for Rivera plate is presented, 87 earthquakes were located. Data from onland stations were integrated after a travel-time residual analysis. We observed that the new location is about 50 km southwest direction, from previous one, between the Paleo Rivera Transform fault and the northern tip of the East Pacific Rise – Pacific Cocos Segment. This area has a different tectonic stress regime, This Research is funded by : CONACYT – FOMIXJAL2008 –96567 (2009); CONACYT – FOMIXJAL2008 –96539 (2009); CONACYT – FOMIXJAL2010 –149245 (2011); CONACyT-FOMIXJal (2012-08-189963) [MEXICO]; CGL(2011-29474-C02-01) DGI Plan Nacional I+D+i [España]. NOC Cruise Jc098, RRS James Cook UK; COIP/COPO/UNAM J-GAP2013 Cruise (BO El Puma); Secretaria de Marina (Mexico) ARM Holzinger; Secretaria de Defensa Nacional (Mexico); Unidad de Tecnologia Marina (Spain); Unidad Municipal de Proteccion Civil y Bomberos (Puerto Vallarta, Mexico); Unidad Estatal de Proteccion Civil y Bomberos (Nayarit State, Mexico); Unidad Municipal de Proteccion Civil y Bomberos (Jalisco State, Mexico); Reserva de la Biosfera (Islas Marias) CONANP-SEMARNAT; Organo Desconcentrado de Prevencion y Readaptacion Social de la SEGOP; Secretaria de Relaciones Exteriores (Mexico)

Historically, the city of Guadalajara has been affected not only by great regional earthquakes (M > 7.0) associated with the subduction process and regional crustal structures but also by local seismic sequences, that caused moderate to severe structural damage to buildings, whose source is not clear. Between December 2015 and May 2016, two seismic sequences occurred, affecting the city of Guadalajara. Both seismic sequences were recorded by the Jalisco Seismic Accelerometric Telemetric Network. The preliminary locations for May 2016 sequence estimated by the Antelope automatic system show alignment with an NNE-SSW trend, west of the city of Guadalajara. The subsequent relocations of theses earthquakes show two N–S alignments at the west of the city of Guadalajara, which agree with December 2015 hypocenters. The focal mechanisms analysis of the earthquakes shows that most of them correspond to normal fault mechanisms that are parallel to the hypocentral alignments suggesting the existence of two active faults responsible for the seismic sequences. Furthermore, these structures might constitute a graben, which we refer to as Zapopan Graben. Additionally, we calculated that these faults are 21 and 28 km length, respectively, which indicates that could have the potential to generate shallow earthquakes that reach magnitudes of 6.2 and 6.5, and could cause significant damages in the Guadalajara Metropolitan Zone.

We present the first study of seismicity in the region of the Jalisco Block using data recorded by the Jalisco Seismic Accelerometric Telemetric Network between June and December 2015. During this period, 683 local earthquakes with magnitudes between 1.0

Nuñez-Cornu, Francisco ... et al.-- 14 pages, 9 figures, 1 table, In the spring of 2014, an onshore–offshore geophysical experiment (“Crustal Characterization of the Rivera plate–Jalisco Block Boundary and Its Implications for Seismic and Tsunami Hazard Assessment”) was carried out in the frame of the TsuJal project to define the crustal architecture of the western Mexican active margin and identify potential structural sources that can trigger earthquakes and tsunamis at the convergence between the Rivera plate (RP) and the Jalisco Block (JB) within the North American plate. In this work, we present the preliminary results about bathymetric, structural geology, and wide‐angle seismic data of the southern coast of Bahía de Banderas. These data indicate the slab thickness in this area is about 10 km and presents a dip angle of about 8°. Continental crustal thickness below Puerto Vallarta is about 20 km, but no evidences of continental Moho and clear subduction features (trench, accretionary prism) are observed. Nevertheless, this model supports the hypothesis that the region of Bahía de Banderas is under strong crustal stresses generating structural lineaments with the same trends offshore and inland due to the convergence of the RP against the JB. Most of the seismicity reported can be associated with the main structural lineaments. Moreover, the Banderas Canyon (BC) is apparently in an eastward opening process, which seems to continue through the Rio Pitillal river valley; no seismic or morphological evidences were found to suggest the BC is a continuation of the Vallarta graben. Offshore, the Sierra de Cleofas, located south of María Cleofas Island, marks the limit between the RP and the JB along 100 km. It may be the result of the RP pushing against the JB establishing the beginning of the current subduction process, with associated seismic activity. If a subduction type earthquake occurs in this area, the associated magnitude will be about 7.5 and could have a tsunamigenic effect, This Research is funded by Consejo Nacional de Ciencia y Tecnología (CONACYT) – Fondo Mixto CONACYT – Gobierno de Jalisco (FOMIXJAL) 2008-96567 (2009); CONACYT–FOMIXJAL 2008-96539 (2009); CONA-CYT–FOMIXJAL 2010-149245 (2011); CONACYT–FOMIXJAL (2012-08-189963) (MEXICO); Ciencias de la Tierra y Cambio Global (CGL; 2011-29474-C02-01) Dirección General de Investigación (DGI) Plan Nacional I+D+i (España). National Oceanography Centre (NOC) Cruise JC098, RRS James Cook (United Kingdom); Funding for the EL PUMA campaign was provided by Universidad Nacional Autónoma de México (UNAM) (Comisión Académica de los Buques Oceanográficos de la UNAM [CABO]) and Dirección General de Asuntos del Personal Académico de la UNAM (DGAPA) Grant Number IN115513-3; Secretaría de Marina (Mexico) ARM Holzinger; Secretaría de Defensa Nacional (Mexico); Unidad Municipal de Proteccion Civil y Bomberos (Puerto Vallarta, Mexico); Unidad Estatal de Proteccion Civil y Bomberos (Nayarit State, Mexico); Unidad Municipal de Proteccion Civil y Bomberos (Jalisco State, Mexico); Reserva de la Biosfera (Islas Marías) Comisión Nacional de Áreas Naturales y Protegidas (CONANP)-Secretaría de Medio Ambiente y Recursos Naturales (SEMARNAT); Órgano Desconcentrado de Prevención y Readaptacion Social de la Secretaría de Gobernación (SEGOB); Secretaría de Relaciones Exteriores (Mexico)

Ceboruco volcano is a stratovolcano located in western central Mexico within the state of Nayarit. Ceboruco volcano is one of the active volcanoes of the Trans-Mexican Volcanic Belt and lies within the Tepic-Zacoalco Rift structure. Eruptions at Ceboruco volcano have been reported over the last 1000 years with eruptions every 126 years on average, with the most recent eruption occurring in 1870. Current activity at Ceboruco volcano is primarily fumarolic emissions. Continued population and socio-economic growth around the volcano over the last 20 years, make urgent the need to study Ceboruco volcano. Previous investigations of seismicity classified the recorded earthquakes into four families using waveform and spectral features. In this paper, we present a seismicity study from March 2012 to July 2014 using four portable seismic stations within the context of the regional stress and structures near Ceboruco volcano. Of the 489 volcanic earthquakes recorded during this time period, only 33 could be located using P- and S-wave arrivals registered at least three stations. The P- and S-phase arrival times were obtained using particle motion. The epicentral distribution of these earthquakes is around the volcanic edifice along three structural lineaments with preferred ENE-WSW orientations, roughly perpendicular to Tepic-Zacoalco Rift and, following the youngest deformation pattern. Hypocentral depths locate within first 10 km, indicating the earthquakes are a result of local tectonic stresses, intrusions into the magma chamber, or both.

Colima Volcano (19.512°N, 103.617°W, 4000 m.a.s.l.), located on the border between the states of Jalisco and Colima in western Mexico, is the most active volcano in the country. Its activity has taken place through diverse styles of eruption, from very explosive to effusive. In the last decades it has presented frequent vulcanian eruptions with episodes of dome construction–destruction. Four of these cycles occurred from 1990 to 2005, the last one from July 2003 to September 2005. We focus on this last period, for which we analyzed seismic phases and coupled pressure airwaves from high dynamic range seismograms, both in the time and frequency domains, to determine characteristic features, propagation velocities, and origin times for both deep seismic sources and the associated explosions. The results show that the sources of the P-waves associated with the explosions are not located at the summit, but instead at different shallow locations for the different explosions, suggesting the presence of various magmatic pathways within the volcano.

From 1990 to 2004, four cycles of dome growth and explosive dome destruction occurred at the Colima volcano. In this paper, we describe these cycles, focusing on the seismic characteristics of the last three cycles from 1997 and 2004, for which we have the best data. Four episodes of dome building occurred: from early 1991 to late 1992, from November 1998 into January 1999, from November 2001 through February 2003, and from September 2004 into 2005. The rate of extrusion during these episodes ranged from a low-extrusion rate accompanied by seismicity and evolved with time to a high rate of aseismic extrusion for the last episode in 2004. The first of these four extrusive episodes was followed by dome-destroying explosions in July 1994. The second extrusive episode was followed by four dome-destroying explosions over six months and a fifth explosion 17 months later, while the third extrusive episode was followed by three dome-destroying explosions over two months. A fourth extrusive episode began in 2004. The nature of each explosion was somewhat different. For each of the explosions, we compare the total seismic energy released (1) during the hours prior to each explosion, (2) during each explosion, and (3) during the hours after each explosion. We also propose an additional method for classifying the explosions based on coupled acoustic waves and describe characteristics of the volcanic earthquakes recorded. We use data from the 10 May 1999 explosion to construct a new P -wave velocity model for the upper structure of the volcano.

We present a fresh look at the source region of the 22 January 2003 M w 7.4 Armeria earthquake, which occurred off the Pacific coast of the state of Colima, Mexico, near the town of Armeria. The effects of this earthquake in the neighboring states of Colima and Jalisco were different and stronger than those of previous recent major earthquakes in the region. This earthquake and its aftershocks were recorded by two local telemetered seismograph networks (RESCO and RESJAL). From 22 January to 24 January 2003, no important seismicity was located on the plates interface, or within the Rivera Plate, and most epicenters were located west of the Armeria River, which is the western border of the Colima Graben, and is located outside of the Colima Gap region. From 24 January to 31 January, the seismicity recorded by both networks showed a migration in depth, with an almost vertical offshore distribution between 4 and 24 km in depth. For this period, a seven-station portable digital seismograph network, equipped with three-component seismometers, was deployed in the epicentral area to study the aftershock sequence in detail. With this denser network more than 200 M L > 2.0 aftershocks were recorded. The aftershock foci were deeper than those recorded during the early period and most of them locate on a hypothetical 12° dipping interface between the Rivera and North American Plates. Composite focal mechanism solutions for the aftershocks located during both periods indicate a reverse fault character that changes with time. Analysis of the new dataset still indicates that the earthquake was a shallow intraplate event.

Several studies of local seismicity were carried out between 1996 and 1998 on the coast and north of the Jalisco Block (JB) using a portable seismic network consisting of five Lennartz M88 seismographs with Le 3D (1 Hz) seismometers. The data from these studies, complemented with data from RESCO (Colima Seismic Network), is used to characterize three seismogenic zones in the region. One seismicity zone, located east of the Middle America Trench (MAT), under the continental plate, is associated with the interaction of the Rivera and North America plates, and can be characterized as a Double Seismic Zone (DSZ) with geometry suggesting a bending plate and, probably, oblique subduction; this pattern is clearer south of the 20°N parallel. A second zone of continental intraplate seismicity is located between Ameca and Amatlan de Canas, in the northeastern part of the study region, where the source depths vary from very shallow to about 35 km. The third zone is Bahia de Banderas where the stress pattern seems to be very complex; here we observe different types of seismic events: the first type consists of shallow events, located in the southern part of the Bay and a under continental area, that seems to be associated with the interplate (Rivera/North America) activity. A second event type with depths between 10 and 30 km, seems to be related to features that cross the Bay in an EW direction. In this zone, there is also a high shallow continental seismicity, which agrees with continental topographic features.

The Ceboruco stratovolcano (2,280 m.a.s.l.) is located in Nayarit, Mexico, at the western end of the Mexican volcanic belt, near several population centers and by the side of a strategic highway. During the last 1,000 years it has had, on the average, one eruption every 125 years. It last eruptive activity began in 1870, and during the following 5 years it presented superficial activity including vapor emissions, ash falls, and rhyodacitic lava flows along the southeast side. A data set consisting of 139 low-frequency volcanic-type earthquakes, recorded from March 2003 to July 2008 at the CEBN triaxial short period digital station on the southwestern side of the volcano, was classified according to waveform and spectral characteristics into four families: short duration, extended coda, bobbin, and modulated amplitude. Approximate hypocentral locations indicate that there is no particular location for events of any family, but rather that all events occur at different points within the volcano. The presence of ongoing volcanic-earthquake activity together with the ongoing vapor emissions indicate that the Ceboruco volcano continues to be active, and the higher occurrence rates of short-duration events, as compared with those for the other families, could indicate an increase in the stress in the volcanic edifice. This apparent stress increase, together with the fact that the last eruption occurred 143 years ago, tell us that the Ceboruco may be approaching a critical state, and may represent a hazard to the surrounding communities and economic activities.

The coast in the state of Jalisco and south of Nayarit is located within a region of high seismic potential, increasing population, and tourism development. This motivated Civil Defense authorities of Jalisco and the Universidad de Guadalajara to launch in the year 2000 the assessment of the seismic risk of the region. This work focuses in the seismicity study of the area of Bahía de Banderas and northern coast of Jalisco, which is actually a seismic gap. We perform an analysis of available seismograms to characterize active crustal structures, their relationship to surface morphology, and possible extent of these structures into the bay shallow parts. The data consist of waveforms recorded during 2003 when the seismograph network spanned the region. Our method is based on the identification of seismic clusters or families using cross-correlation of waveforms, earthquake relocation and modeling of fault planes. From an initial data set of 404 located earthquakes, 96 earthquakes with ML < 3.6 are related to 17 potentially active continental structures. We present fault plane model for 11 structures. A subgroup of 7 structures is aligned parallel to the Middle America Trench, as a possible consequence of oblique subduction. The foci of the earthquakes were grouped into clusters corresponding to fault dimensions of hundred of meters, may be considered as asperities or barriers in tectonic structures with lengths between 10 and 30 km. These structures could generate shallow earthquakes with magnitudes between 5.0 and 6.0 and represent an additional seismic threat to the region.