scholarly journals Synchronized and asynchronous modulation of seismicity by hydrological loading: A case study in Taiwan

2021 ◽  
Vol 7 (16) ◽  
pp. eabf7282
Author(s):  
Ya-Ju Hsu ◽  
Honn Kao ◽  
Roland Bürgmann ◽  
Ya-Ting Lee ◽  
Hsin-Hua Huang ◽  
...  
Keyword(s):  
Fluid Transport ◽  
Load Cycle ◽  
Physical Factors ◽  
Driving Mechanism ◽  
Earthquake Triggering ◽  
Seismicity Rate ◽  
Level Data ◽  
Shallow Earthquakes ◽  
Annual Water ◽  
Pressure Changes

Delineation of physical factors that contribute to earthquake triggering is a challenging issue in seismology. We analyze hydrological modulation of seismicity in Taiwan using groundwater level data and GNSS time series. In western Taiwan, the seismicity rate reaches peak levels in February to April and drops to its lowest values in July to September, exhibiting a direct correlation with annual water unloading. The elastic hydrological load cycle may be the primary driving mechanism for the observed synchronized modulation of earthquakes, as also evidenced by deep earthquakes in eastern Taiwan. However, shallow earthquakes in eastern Taiwan (<18 km) are anticorrelated with water unloading, which is not well explained by either hydrological loading, fluid transport, or pore pressure changes and suggests other time-dependent processes. The moderate correlation between stacked monthly trends of large historic earthquakes and present-day seismicity implies a modestly higher seismic hazard during the time of low annual hydrological loading.

A Discussion on the measurement and interpretation of changes of strain in the Earth - Role of pore fluids in faulting

1973 ◽  
Vol 274 (1239) ◽  
pp. 297-304 ◽  
Keyword(s):  
Pore Pressure ◽  
San Andreas Fault ◽  
Fault Creep ◽  
Time Constants ◽  
San Andreas ◽  
The Earth ◽  
Shallow Earthquakes ◽  
Pressure Changes

We consider three in situ processes which involve fluid flow in the crust: fault creep, aftershocks and dilatancy. Measurements of water level in wells suggest that creep events on the San Andreas fault are coupled with pore pressure changes. Readjustment of transient pore pressure, induced by large shallow earthquakes, possess the correct time constants and magnitudes to explain the occurrence of aftershocks. And finally, temporal changes of travel times in the Gram district (U.S.S.R.) imply that dilatancy may occur in situ.

Time-lapse tomographic images of the Irpinia Fault System (Southern Italy) reveal Vp/Vs ratio changes that correlate with micro-seismicity production and evolution

2020 ◽  
Author(s):  
Grazia De Landro ◽  
Raffaella Esposito ◽  
Amoroso Ortensia ◽  
Aldo Zollo
Keyword(s):  
Pore Pressure ◽  
Seismic Velocity ◽  
Physical Modelling ◽  
Seismic Attenuation ◽  
Fault System ◽  
Earthquake Activity ◽  
Earthquake Triggering ◽  
Seismicity Rate ◽  
Velocity Models ◽  
Velocity Changes

&lt;p&gt;This study focuses on the the active fault system that caused the 1980 M_S 6.9 Irpinia earthquake (Irpinia fault zone (IFZ)) that is presently interested by a continuous and frequent micro-earthquake activity occurring within the volume in the volume enclosed by two antithetic faults. It is therefore important to improve the knowledge of the IFZ dynamics, with reference to potential future occurrence of moderate to large earthquakes, especially in terms of earthquake triggering mechanisms. Several previous works evaluated the spatial distribution of elastic/anelastic fault-embedded medium properties and related rock physical micro-parameters in connection with the seismicity rate. These studies showed a spatial correlation between high Vp/Vs, low seismic attenuation in rock volumes where most of seismicity occurs, suggesting that fluid-driven pore-pressure changes may plays a key role in controlling the seismicity production at the IFZ.&lt;br&gt;Here we reconstruct accurate 4D seismic velocity images of the volume embedding IFZ which allows to detect and track space-time changes of medium elastic properties possibly induced by fluid pore pressure migration and investigate the related seismicity production.&lt;br&gt;We analyzed the arrival time phase catalogue of about ten years (2005-2016) of Mw &lt; 3.1 events recorded by the ISNet (Irpinia Seismic Network) and INGV network. We divided the catalog in 5 not-overlapping epochs by selecting in each of them , approximately the same number of events and an uniform volume coverage, in order to ensure that the 3D P and S velocity models could be equally well resolved for each epoch. By comparing the Vp, Vs and Vp/Vs images at each epoch in the equally resolved volume, we are able to detect medium velocity changes. Some regions, in the first 6 km of depth of NE part, do not show velocity changes with time, which is interpreted as the main effect of unperturbed lithology mainly controlling the average seismic velocity. In other regions, in the central part of the model at about 8-10 km depth, we clearly detect velocity changes causing an up to 10% Vp/Vs variation between different epochs. Based on the rock physical modelling, we associate the time-varying Vp/Vs and the observed amplitude of variation to fluid-driven changes in rock physical properties related to their spatial migration or pore-pressure induced changes. The regions where large Vp/Vs changes occur appear correlated with the largest seismicity production volumes, suggesting a direct link between the physical processes associated with fluid mobility and/or pore pressure migration and earthquake generation at the IFZ.&lt;/p&gt;

The Value of Physical Factors in Insect Control

1964 ◽  
Vol 96 (1-2) ◽  
pp. 114-114
Author(s):  
P. Belton ◽  
M. G. Maw
Keyword(s):  
Insect Control ◽  
Physical Factors ◽  
New Methods ◽  
Naturally Occurring ◽  
Pressure Changes ◽  
Rapid Pressure ◽  
Methods Of Control

For several years we have been investigating the effects of natural and artificial acoustical and electrical phenomena on the behaviour of insects with a view to the development of new methods of control.A. Sounds can be exploited in two ways:–firstly to affect insects whose behaviour is stimulated by naturally-occurring sounds; secondly to use the very rapid pressure changes associated with sounds as a sort of “death ray.”

scholarly journals Cascading elastic perturbation in Japan due to the 2012 Mw 8.6 Indian Ocean earthquake

2015 ◽  
Vol 1 (9) ◽  
pp. e1500468 ◽  
Author(s):  
Andrew A. Delorey ◽  
Kevin Chao ◽  
Kazushige Obara ◽  
Paul A. Johnson
Keyword(s):  
Stress State ◽  
Plate Tectonics ◽  
Seismic Waves ◽  
Crustal Material ◽  
Earthquake Triggering ◽  
Landers Earthquake ◽  
Frictional Properties ◽  
Pressure Changes ◽  
Strain Transients

Since the discovery of extensive earthquake triggering occurring in response to the 1992 Mw (moment magnitude) 7.3 Landers earthquake, it is now well established that seismic waves from earthquakes can trigger other earthquakes, tremor, slow slip, and pore pressure changes. Our contention is that earthquake triggering is one manifestation of a more widespread elastic disturbance that reveals information about Earth’s stress state. Earth’s stress state is central to our understanding of both natural and anthropogenic-induced crustal processes. We show that seismic waves from distant earthquakes may perturb stresses and frictional properties on faults and elastic moduli of the crust in cascading fashion. Transient dynamic stresses place crustal material into a metastable state during which the material recovers through a process termed slow dynamics. This observation of widespread, dynamically induced elastic perturbation, including systematic migration of offshore seismicity, strain transients, and velocity transients, presents a new characterization of Earth’s elastic system that will advance our understanding of plate tectonics, seismicity, and seismic hazards.

Modeling intra-abdominal volume and respiratory driving pressure during pneumoperitoneum insufflation - a patient-level data meta-analysis

2020 ◽  
Author(s):  
Guido Mazzinari ◽  
Oscar Diaz-Cambronero ◽  
Ary Serpa Neto ◽  
Antonio Cañada Martinez ◽  
Lucas Rovira ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Postoperative Recovery ◽  
Bayesian Regression ◽  
Driving Pressure ◽  
Rate Of Change ◽  
Abdominal Pressure ◽  
Mathematical Function ◽  
Patient Level ◽  
Level Data ◽  
Pressure Changes

During pneumoperitoneum, intra-abdominal pressure (IAP) is usually kept at 12-14 mmHg. There is no clinical benefit in IAP increments if they do not increase intra-abdominal volume IAV. We aimed to estimate IAV (ΔIAV) and respiratory driving pressure changes (ΔPRS) in relation to changes in IAP (ΔIAP). We carried out a patient-level meta-analysis of 204 adult patients with available data on IAV and ΔPRS during pneumoperitoneum from three trials assessing the effect of IAP on postoperative recovery and airway pressure during laparoscopic surgery under general anesthesia. The primary endpoint was ΔIAV, and the secondary endpoint was ΔPRS. The endpoints' response to ΔIAP was modeled using mixed multivariable Bayesian regression to estimate which mathematical function best fitted it. IAP values on the pressure-volume (PV) curve where the endpoint rate of change according to IAP decreased were identified. Abdomino-thoracic transmission (ATT) rate, i.e., the rate ΔPRS change to ΔIAP, was also estimated. The best-fitting function was sigmoid logistic and linear for IAV and ΔPRS response, respectively. Increments in IAV reached a plateau at 6.0 [95%CI 5.9 to 6.2] L. ΔIAV for each ΔIAP decreased at IAP ranging from 9.8 [95%CI 9.7 to 9.9], to 12.2 [12.0 to12.3] mmHg. ATT rate was 0.65 [95%CI 0.62 to 0.68]. One mmHg of IAP raised ΔPRS 0.88 cmH2O. During pneumoperitoneum, IAP has a non-linear relationship with IAV and a linear one with ΔPRS. IAP should be set below the point where IAV gains diminish.

scholarly journals The hydraulic mechanism in the hind wing veins of Cybister japonicus Sharp (order: Coleoptera)

2016 ◽  
Vol 7 ◽  
pp. 904-913 ◽  
Author(s):  
Jiyu Sun ◽  
Wei Wu ◽  
Mingze Ling ◽  
Bharat Bhushan ◽  
Jin Tong
Keyword(s):  
Hind Wing ◽  
Micro Air Vehicles ◽  
Driving Mechanism ◽  
Hydraulic Control ◽  
Aerodynamic Forces ◽  
Water Beetles ◽  
Diving Beetles ◽  
Hydraulic Mechanism ◽  
Motion Characteristics ◽  
Pressure Changes

The diving beetles (Dytiscidae, Coleoptera) are families of water beetles. When they see light, they fly to the light source directly from the water. Their hind wings are thin and fragile under the protection of their elytra (forewings). When the beetle is at rest the hind wings are folded over the abdomen of the beetle and when in flight they unfold to provide the necessary aerodynamic forces. In this paper, the unfolding process of the hind wing of Cybister japonicus Sharp (order: Coleoptera) was investigated. The motion characteristics of the blood in the veins of the structure system show that the veins have microfluidic control over the hydraulic mechanism of the unfolding process. A model is established, and the hind wing extending process is simulated. The blood flow and pressure changes are discussed. The driving mechanism for hydraulic control of the folding and unfolding actions of beetle hind wings is put forward. This can assist the design of new deployable micro air vehicles and bioinspired deployable systems.

scholarly journals Pseudoprospective Evaluation of UCERF3-ETAS Forecasts during the 2019 Ridgecrest Sequence

2020 ◽  
Vol 110 (4) ◽  
pp. 1799-1817 ◽  
Author(s):  
William H. Savran ◽  
Maximilian J. Werner ◽  
Warner Marzocchi ◽  
David A. Rhoades ◽  
David D. Jackson ◽  
...  
Keyword(s):  
Model Parameters ◽  
Earthquake Rupture ◽  
Test Results ◽  
Earthquake Triggering ◽  
Spatiotemporal Evolution ◽  
Seismicity Rate ◽  
Earthquake Predictability ◽  
Aftershock Sequences ◽  
Fault Network ◽  
Synthetic Catalogs

ABSTRACT The 2019 Ridgecrest sequence provides the first opportunity to evaluate Uniform California Earthquake Rupture Forecast v.3 with epidemic-type aftershock sequences (UCERF3-ETAS) in a pseudoprospective sense. For comparison, we include a version of the model without explicit faults more closely mimicking traditional ETAS models (UCERF3-NoFaults). We evaluate the forecasts with new metrics developed within the Collaboratory for the Study of Earthquake Predictability (CSEP). The metrics consider synthetic catalogs simulated by the models rather than synoptic probability maps, thereby relaxing the Poisson assumption of previous CSEP tests. Our approach compares statistics from the synthetic catalogs directly against observations, providing a flexible approach that can account for dependencies and uncertainties encoded in the models. We find that, to the first order, both UCERF3-ETAS and UCERF3-NoFaults approximately capture the spatiotemporal evolution of the Ridgecrest sequence, adding to the growing body of evidence that ETAS models can be informative forecasting tools. However, we also find that both models mildly overpredict the seismicity rate, on average, aggregated over the evaluation period. More severe testing indicates the overpredictions occur too often for observations to be statistically indistinguishable from the model. Magnitude tests indicate that the models do not include enough variability in forecasted magnitude-number distributions to match the data. Spatial tests highlight discrepancies between the forecasts and observations, but the greatest differences between the two models appear when aftershocks occur on modeled UCERF3-ETAS faults. Therefore, any predictability associated with embedding earthquake triggering on the (modeled) fault network may only crystalize during the presumably rare sequences with aftershocks on these faults. Accounting for uncertainty in the model parameters could improve test results during future experiments.

Bioenergetics and mechanical actuation analysis with membrane transport experiments for use in biomimetic nastic structures

2006 ◽  
Vol 21 (8) ◽  
pp. 2058-2067 ◽  
Author(s):  
Luke Matthews ◽  
Vishnu Baba Sundaresan ◽  
Victor Giurgiutiu ◽  
Donald J. Leo
Keyword(s):  
Active Transport ◽  
Transport Process ◽  
Fluid Transport ◽  
Shape Change ◽  
Bilayer Membrane ◽  
Ion Channel Proteins ◽  
Polymeric Plate ◽  
Active Transport Process ◽  
Controllable Deformation ◽  
Pressure Changes

Nastic structures are synthetic constructs capable of controllable deformation and shape change similar to plant motility, designed to imitate the biological process of nastic movement found in plants. This paper considers the mechanics and bioenergetics of a prototype nastic structure system consisting of an array of cylindrical microhydraulic actuators embedded in a polymeric plate. Non-uniform expansion/contraction of the actuators in the array may yield an overall shape change resulting in structural morphing. Actuator expansion/contraction is achieved through pressure changes produced by active transport across a bilayer membrane. The active transport process relies on ion-channel proteins that pump sucrose and water molecules across a plasma membrane against the pressure gradient. The energy required by this process is supplied by the hydrolysis of adenosine triphosphate. After reviewing the biochemistry and bioenergetics of the active transport process, the paper presents an analysis of the microhydraulic actuator mechanics predicting the resulting displacement and output energy. Experimental demonstration of fluid transport through a protein transporter follows this discussion. The bilayer membrane is formed from 1-Palmitoyl-2-Oleoyl-sn-Glycero-3-[Phospho-L-Serine] (Sodium Salt), 1-Palmitoyl-2-Oleoyl-sn-Glycero- 3-Phosphoethanolamine lipids to support the AtSUT4 H+-sucrose cotransporter.

scholarly journals Physical and Socioeconomic Driving Forces of Land-Use and Land-Cover Changes: A Case Study of Wuhan City, China

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Xiangmei Li ◽  
Ying Wang ◽  
Jiangfeng Li ◽  
Bin Lei
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Arable Land ◽  
Driving Factors ◽  
Land Cover Changes ◽  
Physical Factors ◽  
Driving Mechanism ◽  
Urban Management ◽  
Wuhan City

To investigate precise nexus between land-use and land-cover changes (LUCC) and driving factors for rational urban management, we used remotely sensed images to map land use and land cover (LULC) from 1990 to 2010 for four time periods using Wuhan city, China, as a case study. Partial least squares (PLS) method was applied to analyze the relationships between LUCC and the driving factors, mainly focusing on three types of LULC, that is, arable land, built-up area, and water area. The results were as follows:(1)during the past two decades, the land-use pattern in Wuhan city showed dramatic change. Arable land is made up of the largest part of the total area. The increased built-up land came mainly from the conversion of arable land for the purpose of economic development.(2)Based on the Variable Importance in Projection (VIP), the joint effects of socioeconomic and physical factors on LUCC were dominant, though annual temperature, especially annual precipitation, proved to be less significant to LUCC. Population, tertiary industry proportion, and gross output value of agriculture were the most significant factors for three major types of LULC. This study could help us better understand the driving mechanism of urban LUCC and important implications for urban management.

scholarly journals Underlying mechanism of precursory activity from analysis of upward earthquake migration

2011 ◽  
Vol 11 (1) ◽  
pp. 135-143 ◽  
Author(s):  
O. A. Molchanov
Keyword(s):  
Subduction Zones ◽  
Characteristic Temperature ◽  
Underlying Mechanism ◽  
Earthquake Triggering ◽  
Seismic Precursors ◽  
Upward Migration ◽  
The Pacific ◽  
Shallow Earthquakes ◽  
Earthquake Migration ◽  
Precursory Activity

Abstract. In this paper we analyse the upward earthquake hypocentral migration in the ten known subduction zones and discuss a possible mechanism of such migration. The total time of the migration appears to range from 2.5 to 10 years. It leads to the estimation of the average velocity Vz~ 60−300 km yr−1. It probably corresponds to the movement of the forcing agent like stress or deformation wave from depths of the upper mantle (600–700 km) to the level of the lithosphere with subsequent initiation of fluid migration inside the crust to trigger shallow earthquakes. Averaged over all zones upward migration travel time is about 5 years (< Vz > ≈120 km yr−1) that coincides approximately with the period of characteristic temperature variation (El Nino) and crustal seismic periodicity in the Pacific region. These findings are helpful for the study of the seismic precursors and analysis of earthquake triggering.

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