Carlos Mendoza - Academia.edu (original) (raw)

Papers by Carlos Mendoza

The Holocene, 2009

The historical behaviour of Cipreses glacier from the nineteenth through the early twentieth cent... more The historical behaviour of Cipreses glacier from the nineteenth through the early twentieth century is described based on written records, cartography, iconography and photographs. These data allow us to infer that the last maximum advance of Cipreses glacier attributable to the ‘Little Ice Age’ occurred around AD 1842. The first historical retreat was recorded in 1858 and, since then, the glacier has shown a clear retreating trend with no new advances. All this information was compared with the historical data gathered for San Rafael glacier, which shows the occurrence of a cold period contemporary with the European LIA. Whereas Cipreses glacier was retreating by 1858, San Rafael glacier was advancing, reaching its last maximum between 1857 and 1875. The dates for the advances and retreats reveal a time-lag of approximately 30 years in the responses of these glaciers. The comparison of timing in glacier advances suggests that this time-lag is due to changes in precipitation and te...

Journal of Molecular Catalysis A: Chemical, 2010

The formation of organic molecules of the type XHn, where X is H, C, N and O and n=1−4, on the hy... more The formation of organic molecules of the type XHn, where X is H, C, N and O and n=1−4, on the hydrogenated surface of a polycyclic aromatic hydrocarbon flake (coronene) has been examined in detail with the CATIVIC parametric quantum chemical code. Hydrogen chemisorption on different sites, surface–adsorbate bonding properties and layer formation are studied. The interactions of H, O, N and C on one-center sites of the H-saturated monolayer give rise to the formation of free H2, OH and NH while the CH molecule remains attached to the surface. Reactions on two-center sites lead to the formation of the free triatomic molecules H2O, NH2 and CH2. One-center interactions of OH, NH, NH2, CH2 and CH3 also result in the respective formation of H2O, NH2, NH3, CH3 and CH4. We find that the reactions of atoms and small molecules with the hydrogenated coronene surface in most cases must overcome relatively high energy barriers in order to lead to reaction products.

Boletín de la Sociedad …, 2010

We analyze the Tecomán, Colima, earthquake (Mw 7.6) of January 22, 2003, one of the major seismic... more We analyze the Tecomán, Colima, earthquake (Mw 7.6) of January 22, 2003, one of the major seismic events that has occurred in the Colima-Jalisco region, México, during the last 100 years. We describe its rupture process by a classical waveform modeling of ...

Journal of Geophysical Research: Solid Earth, 1993

, Zihuatanejo earthquakes in western Mexico were inverted to derive the distributions and depths ... more , Zihuatanejo earthquakes in western Mexico were inverted to derive the distributions and depths of coseismic slip. Broadband P wave displacements and intermediate-period records were included to incorporate a wide frequency band in the analysis. For the Zihuatanejo earthquake, digital Hrecordslocatedawayfromthenodaldirectionswereusedintheinversionprocess.NonnodalH records located away from the nodal directions were used in the inversion process. Nonnodal Hrecordslocatedawayfromthenodaldirectionswereusedintheinversionprocess.NonnodalH waveforms were not available for the Playa Azul earthquake, but additional azimuthal coverage was obtained by including selected worldwide analog P wave records. The results for the Playa Azul earthquake indicate that rupture occurred in two separate zones both updip and downdip of the point of initial nucleation with the majority of the slip concentrated in a circular region (15-km radius) downdip from the hypocenter. The maximum slip in this downdip region exceeds 3.6 m and is at a depth of about 16 km. The computed seismic moment is 7.14 x 1026 dyn cm. Coseismic slip is observed to occur entirely within the area of reduced slip separating the two main shallow sources of the Michoacan earthquake that occurred almost 4 years later on September 19, 1985. For the Zihuatanejo earthquake the P and $H data suggest rupture over a larger area (30-km radius) with a lower peak slip (2 m) and encompassing depths between 12 and 26 km. Slip is concentrated in an area adjacent to one of the major sources of the Michoacan earthquake and represents the southeastern continuation of rupture along the Cocos-North America plate boundary. The corresponding seismic moment is 1.35 x 10 27 dyn cm. The zones of peak slip observed for the Playa Azul, Zihuatanejo, and Michoacan earthquakes are interpreted as asperity regions that control the cessation and generation of large earthquakes within the Michoacan segment of the plate boundary. The stress drops within each of these asperities are observed to be very similar and may reflect a characteristic asperity strength for this portion of the subduction zone.

Journal of Geophysical Research, 1996

We employ a finite fault inversion scheme to infer the distribution of coseismic slip for the Jul... more We employ a finite fault inversion scheme to infer the distribution of coseismic slip for the July 12, 1993, Hokkaido-Nansei-Oki earthquake using strong ground motions recorded by the Japan Meteorological Agency within 400 km of the epicenter and vertical P waveforms recorded by the Global Digital Seismograph Network at teleseismic distances. The assumed fault geometry is based on the location of the aftershock zone and comprises two fault segments with different orientations: a northern segment striking at N20øE with a 30 ø dip to the west and a southern segment with a N20øW strike. For the southern segment we use both westerly and easterly dip directions to test thrust orientations previously proposed for this portion of the fault. The variance reduction is greater using a shallow west dipping segment, suggesting that the direction of dip did not change as the rupture propagated south from the hypocenter. This indicates that the earthquake resulted from the shallow underthrusting of Hokkaido beneath the Sea of Japan. Static vertical movements predicted by the corresponding distribution of fault slip are consistent with the general pattern of surface deformation observed following the earthquake. Fault rupture in the northern segment accounts for about 60% of the total P wave seismic moment of 3.4 x 102o N m and includes a large circular slip zone (4-m peak) near the earthquake hypocenter at depths between 10 and 25 km. Slip in the southern segment is also predominantly shallower than 25 km, but the maximum coseismic displacements (2.0-2.5 m) are observed at a depth of about 5 km. This significant shallow slip in the southern portion of the rupture zone may have been responsible for the large tsunami that devastated the small offshore island of Okushiri. Localized shallow faulting near the island, however, may require a steep westerly dip to reconcile the measured values of ground subsidence.

Journal of Geophysical Research, 1996

A hybrid global search algorithm is used to solve the nonlinear problem of calculating slip ampli... more A hybrid global search algorithm is used to solve the nonlinear problem of calculating slip amplitude, rake, risetime, and rupture time on a finite fault. Thirty-five strong motion velocity records are inverted by this method over the frequency band from 0.1 to 1.0 Hz for the Northridge ...

Journal of Electron Spectroscopy and Related Phenomena, 2011

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright

Geophysical Journal International, 2012

The purpose of this study is to develop and test a modification to a previous method of regional ... more The purpose of this study is to develop and test a modification to a previous method of regional seismic event location based on Empirical Green's Functions (EGF) produced from ambient seismic noise (Barmin et al., 2011). Elastic EGFs between pairs of seismic stations are determined by cross-correlating long ambient noise time-series recorded at the two stations. The EGFs principally contain Rayleigh and Love wave energy on the vertical and transverse components, respectively, and we utilize these signals between about 5 and 12 sec period. The previous method, based exclusively on Rayleigh waves, may yield biased epicentral locations for certain event types with hypocentral depths between 2 and 5 km. Here we present theoretical arguments that show how Love waves can be introduced to reduce or potentially eliminate the bias. We also present applications of Rayleigh and Love wave EGFs to locate ten reference events in the western USA. The separate Rayleigh and Love epicentral locations and the joint locations using a combination of the two waves agree to within 1 km distance, on average, but confidence ellipses are smallest when both types of waves are used.

Geophysical Journal International, 1995

Vertical, teleseismic P waves recorded for the 1979 March 14 Petatlan, Mexico, earthquake were us... more Vertical, teleseismic P waves recorded for the 1979 March 14 Petatlan, Mexico, earthquake were used to derive the distribution of coseismic slip using a linear finite-fault inversion scheme that solves for the amount of slip in each of a series of consecutive time windows. Data recorded by six stations of the Global Digital Seismograph Network were inverted in addition to digitized analogue long-period recordings available from nine Worldwide Standardized Seismograph Network stations. The digital data include four broad-band and short-period velocity waveforms reconstructed from the short-and long-period components. The timewindow approach allows for a variable rise time on the fault and accounts for the source multiplicity evident in the recorded P waveforms. Synthetic tests conducted using the inversion method on the limited data set, however, reveal that the data are insufficient to identify the exact dislocation duration on the fault. The method is thus implemented by prescribing the fault rise time using five consecutive 1 s time windows. The coseismic slip inferred from the P waves shows a small 70cm peak near the earthquake hypocentre and a large zone of dislocation (1.2 m maximum) further southeast. The slip pattern covers depths from 3 to 25 km and is located southeast of other recent large interplate ruptures on the Michoacan segment of the Mexican subduction zone. This result indicates that the 1979 Petatlan earthquake broke an independent, adjacent portion of the Cocos-North America plate boundary. The seismic moment of 1.5 X lo" dyn cm inferred from the P waves is approximately one-half the long-period moment estimated by other investigators from the observed surface waves. Although the discrepancy is within the uncertainty of the seismic-moment estimates, it may suggest the presence of a component of slow interplate motion that did not radiate significant P-wave energy.

The Holocene, 2009

The historical behaviour of Cipreses glacier from the nineteenth through the early twentieth cent... more The historical behaviour of Cipreses glacier from the nineteenth through the early twentieth century is described based on written records, cartography, iconography and photographs. These data allow us to infer that the last maximum advance of Cipreses glacier attributable to the ‘Little Ice Age’ occurred around AD 1842. The first historical retreat was recorded in 1858 and, since then, the glacier has shown a clear retreating trend with no new advances. All this information was compared with the historical data gathered for San Rafael glacier, which shows the occurrence of a cold period contemporary with the European LIA. Whereas Cipreses glacier was retreating by 1858, San Rafael glacier was advancing, reaching its last maximum between 1857 and 1875. The dates for the advances and retreats reveal a time-lag of approximately 30 years in the responses of these glaciers. The comparison of timing in glacier advances suggests that this time-lag is due to changes in precipitation and te...

Journal of Molecular Catalysis A: Chemical, 2010

The formation of organic molecules of the type XHn, where X is H, C, N and O and n=1−4, on the hy... more The formation of organic molecules of the type XHn, where X is H, C, N and O and n=1−4, on the hydrogenated surface of a polycyclic aromatic hydrocarbon flake (coronene) has been examined in detail with the CATIVIC parametric quantum chemical code. Hydrogen chemisorption on different sites, surface–adsorbate bonding properties and layer formation are studied. The interactions of H, O, N and C on one-center sites of the H-saturated monolayer give rise to the formation of free H2, OH and NH while the CH molecule remains attached to the surface. Reactions on two-center sites lead to the formation of the free triatomic molecules H2O, NH2 and CH2. One-center interactions of OH, NH, NH2, CH2 and CH3 also result in the respective formation of H2O, NH2, NH3, CH3 and CH4. We find that the reactions of atoms and small molecules with the hydrogenated coronene surface in most cases must overcome relatively high energy barriers in order to lead to reaction products.

Boletín de la Sociedad …, 2010

We analyze the Tecomán, Colima, earthquake (Mw 7.6) of January 22, 2003, one of the major seismic... more We analyze the Tecomán, Colima, earthquake (Mw 7.6) of January 22, 2003, one of the major seismic events that has occurred in the Colima-Jalisco region, México, during the last 100 years. We describe its rupture process by a classical waveform modeling of ...

Journal of Geophysical Research: Solid Earth, 1993

, Zihuatanejo earthquakes in western Mexico were inverted to derive the distributions and depths ... more , Zihuatanejo earthquakes in western Mexico were inverted to derive the distributions and depths of coseismic slip. Broadband P wave displacements and intermediate-period records were included to incorporate a wide frequency band in the analysis. For the Zihuatanejo earthquake, digital Hrecordslocatedawayfromthenodaldirectionswereusedintheinversionprocess.NonnodalH records located away from the nodal directions were used in the inversion process. Nonnodal Hrecordslocatedawayfromthenodaldirectionswereusedintheinversionprocess.NonnodalH waveforms were not available for the Playa Azul earthquake, but additional azimuthal coverage was obtained by including selected worldwide analog P wave records. The results for the Playa Azul earthquake indicate that rupture occurred in two separate zones both updip and downdip of the point of initial nucleation with the majority of the slip concentrated in a circular region (15-km radius) downdip from the hypocenter. The maximum slip in this downdip region exceeds 3.6 m and is at a depth of about 16 km. The computed seismic moment is 7.14 x 1026 dyn cm. Coseismic slip is observed to occur entirely within the area of reduced slip separating the two main shallow sources of the Michoacan earthquake that occurred almost 4 years later on September 19, 1985. For the Zihuatanejo earthquake the P and $H data suggest rupture over a larger area (30-km radius) with a lower peak slip (2 m) and encompassing depths between 12 and 26 km. Slip is concentrated in an area adjacent to one of the major sources of the Michoacan earthquake and represents the southeastern continuation of rupture along the Cocos-North America plate boundary. The corresponding seismic moment is 1.35 x 10 27 dyn cm. The zones of peak slip observed for the Playa Azul, Zihuatanejo, and Michoacan earthquakes are interpreted as asperity regions that control the cessation and generation of large earthquakes within the Michoacan segment of the plate boundary. The stress drops within each of these asperities are observed to be very similar and may reflect a characteristic asperity strength for this portion of the subduction zone.

Journal of Geophysical Research, 1996

We employ a finite fault inversion scheme to infer the distribution of coseismic slip for the Jul... more We employ a finite fault inversion scheme to infer the distribution of coseismic slip for the July 12, 1993, Hokkaido-Nansei-Oki earthquake using strong ground motions recorded by the Japan Meteorological Agency within 400 km of the epicenter and vertical P waveforms recorded by the Global Digital Seismograph Network at teleseismic distances. The assumed fault geometry is based on the location of the aftershock zone and comprises two fault segments with different orientations: a northern segment striking at N20øE with a 30 ø dip to the west and a southern segment with a N20øW strike. For the southern segment we use both westerly and easterly dip directions to test thrust orientations previously proposed for this portion of the fault. The variance reduction is greater using a shallow west dipping segment, suggesting that the direction of dip did not change as the rupture propagated south from the hypocenter. This indicates that the earthquake resulted from the shallow underthrusting of Hokkaido beneath the Sea of Japan. Static vertical movements predicted by the corresponding distribution of fault slip are consistent with the general pattern of surface deformation observed following the earthquake. Fault rupture in the northern segment accounts for about 60% of the total P wave seismic moment of 3.4 x 102o N m and includes a large circular slip zone (4-m peak) near the earthquake hypocenter at depths between 10 and 25 km. Slip in the southern segment is also predominantly shallower than 25 km, but the maximum coseismic displacements (2.0-2.5 m) are observed at a depth of about 5 km. This significant shallow slip in the southern portion of the rupture zone may have been responsible for the large tsunami that devastated the small offshore island of Okushiri. Localized shallow faulting near the island, however, may require a steep westerly dip to reconcile the measured values of ground subsidence.

Journal of Geophysical Research, 1996

A hybrid global search algorithm is used to solve the nonlinear problem of calculating slip ampli... more A hybrid global search algorithm is used to solve the nonlinear problem of calculating slip amplitude, rake, risetime, and rupture time on a finite fault. Thirty-five strong motion velocity records are inverted by this method over the frequency band from 0.1 to 1.0 Hz for the Northridge ...

Journal of Electron Spectroscopy and Related Phenomena, 2011

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright

Geophysical Journal International, 2012

The purpose of this study is to develop and test a modification to a previous method of regional ... more The purpose of this study is to develop and test a modification to a previous method of regional seismic event location based on Empirical Green's Functions (EGF) produced from ambient seismic noise (Barmin et al., 2011). Elastic EGFs between pairs of seismic stations are determined by cross-correlating long ambient noise time-series recorded at the two stations. The EGFs principally contain Rayleigh and Love wave energy on the vertical and transverse components, respectively, and we utilize these signals between about 5 and 12 sec period. The previous method, based exclusively on Rayleigh waves, may yield biased epicentral locations for certain event types with hypocentral depths between 2 and 5 km. Here we present theoretical arguments that show how Love waves can be introduced to reduce or potentially eliminate the bias. We also present applications of Rayleigh and Love wave EGFs to locate ten reference events in the western USA. The separate Rayleigh and Love epicentral locations and the joint locations using a combination of the two waves agree to within 1 km distance, on average, but confidence ellipses are smallest when both types of waves are used.

Geophysical Journal International, 1995

Vertical, teleseismic P waves recorded for the 1979 March 14 Petatlan, Mexico, earthquake were us... more Vertical, teleseismic P waves recorded for the 1979 March 14 Petatlan, Mexico, earthquake were used to derive the distribution of coseismic slip using a linear finite-fault inversion scheme that solves for the amount of slip in each of a series of consecutive time windows. Data recorded by six stations of the Global Digital Seismograph Network were inverted in addition to digitized analogue long-period recordings available from nine Worldwide Standardized Seismograph Network stations. The digital data include four broad-band and short-period velocity waveforms reconstructed from the short-and long-period components. The timewindow approach allows for a variable rise time on the fault and accounts for the source multiplicity evident in the recorded P waveforms. Synthetic tests conducted using the inversion method on the limited data set, however, reveal that the data are insufficient to identify the exact dislocation duration on the fault. The method is thus implemented by prescribing the fault rise time using five consecutive 1 s time windows. The coseismic slip inferred from the P waves shows a small 70cm peak near the earthquake hypocentre and a large zone of dislocation (1.2 m maximum) further southeast. The slip pattern covers depths from 3 to 25 km and is located southeast of other recent large interplate ruptures on the Michoacan segment of the Mexican subduction zone. This result indicates that the 1979 Petatlan earthquake broke an independent, adjacent portion of the Cocos-North America plate boundary. The seismic moment of 1.5 X lo" dyn cm inferred from the P waves is approximately one-half the long-period moment estimated by other investigators from the observed surface waves. Although the discrepancy is within the uncertainty of the seismic-moment estimates, it may suggest the presence of a component of slow interplate motion that did not radiate significant P-wave energy.