Microtremor response of a mass movement in Federal District of Brazil

The present study provides a brief description of the ambient noise recorded at a slow moving mass movement in Ribeirão Contagem Basin. The area is an interesting natural laboratory as river detachment processes in a number of different stages can be identified and are easily accessible. We investigate the site dynamic characteristics of the study area by recording ambient noise time-series at nine points, using portable nine three-component short period seismometers. The time-series are processed to give both horizontal to vertical spectral ratio (HVSR) curves as well as time-frequency plots of noise power spectral density (SPD). The HVSR curves illustrate and quantify aspects of site resonance effects due to underlying geology. Probability density function (PDF) shows that noise level lies well between new high noise model (NHNM) and new lower noise model (NLNM) and their probabilities are higher above 2 Hz. HVSR curves present a uniform lithologically controlled peak at 2 Hz. Directional properties of the wavefield are determined by beamforming method. The f-k analysis results in the E-W component show that at 5 Hz phase velocities are close to 1700 m/s while at 10 Hz dropped to 250 m/s. We observed that between 5 and 16 Hz the incoming wavefield arrive from 260 degrees. Further studies will apply a detailed noise analysis for the understanding of dynamics of the mass movement, which is triggered by the river erosion

Microtremor Response of a Mass Movement in Federal District of Brazil

The present study provides a brief description of the ambient noise recorded at a slow moving mass movement in Ribeirão Contagem Basin. The area is an interesting natural laboratory as river detachment processes in a number of different stages can be identified and are easily accessible. We investigate the site dynamic characteristics of the study area by recording ambient noise time-series at nine points, using portable nine three-component short period seismometers. The time-series are processed to give both horizontal to vertical spectral ratio (HVSR) curves as well as time-frequency plots of noise power spectral density (SPD). The HVSR curves illustrate and quantify aspects of site resonance effects due to the local geological setting. Probability density function (PDF) shows that noise level lies well between new high noise model (NHNM) and new lower noise model (NLNM) and their probabilities are higher above 2 Hz. HVSR curves present a uniform lithologically controlled peak at 2 Hz. Directional properties of the wavefield are determined by beamforming method. The f-k analysis results in the E-W component show that at 5 Hz phase velocities are close to 1700 m/s while at 10 Hz dropped to 250 m/s. We observed that between 5 and 16 Hz the incoming wavefield arrive from 260 degrees. Further studies will apply a detailed noise analysis for relating the dynamics of the landslide (which can be retriggered by river erosion as well as rainfalls and seismic shaking) to possible changes in detectable physical properties

Suitability Analysis of Groundwater for Eco-friendly Agricultural Growths in Food Basket of Pakistan

Water is an important component of earth’s atmosphere and it sustains ecosystems, agriculture and human settlements on earth (Samson et al., 2010). Salinity, sodicity and toxicity generally need to be considered for the evaluation of suitable quality of groundwater for irrigation (Khan et al., 2014; Cobbina et al., 2012; Todd and Mays, 2005). In Thal Doab Aquifer (TDA) groundwater occurs as a layer of fresh water over saline water and its availability is subjected to recharging potency of the Indus and Chenab rivers (Hussain et al., 2017 a, 2016 a)

Introductory review of potential applications of nanoseismic monitoring in seismic energy characterization

Major terrestrial hazards are associated with the formation of fractures that evolve with time and lead to structural collapse. The fracture signals emitted in response to stress accumulation and its release, if properly understood, provide sound background for the development of Early Warning Systems (EWSs). Different attempts have been made in the past for their proper understanding, but in this study Nanoseismic Monitoring (NM) is being discussed, in terms of its sensor employment and signal processing modules. NM is a method dedicated to the detection, localization, and characterization of very low-energy seismic signals (ML<1) at short distances (<10 km). Data are acquired by small aperture (max 200m) seismic arrays that are easy to install and consist of one central three component (3C) sensor surrounded by three vertical one-component (1C) sensors in a tripartite layout that are suited for the beam forming processing. Detection and location of weak events are done by dedicated software: the NanoseismicSuite, which was developed at Stuttgart University, Germany. The signals are processed by sonograms (i.e., spectrograms with a frequency-dependent noise adaptation). The sonograms enhance the display of weak signal energy down to the noise threshold and allow supervised pattern recognition of weak target events in the frequency domain. Locations of weak events are supported by a graphical jackknifing approach. The case studies have shown that NM can successfully detect various weak fracture signals induced by the (stress relief mechanisms of near-surface geoprocesses) landslide dynamics, structural health, hydraulic fracturing, erosional features, pre-mature sinkholes, pending rock fall, and micro-seismicity associated with active faults