Anthropogenic fluid injections are known to induce earthquakes. The mechanisms involved are poorly understood, and our ability to assess the seismic hazard associated with geothermal energy or unconventional hydrocarbon production remains limited. We directly measure fault slip and seismicity induced by fluid injection into a natural fault. We observe highly dilatant and slow [~4 micrometers pe...

Detailed studies of the seismicity of several subduction zones demonstrate that shallow-dipping thrust zones turn to steeper angles at depths of about 40 kilometers. An increased downward body force resulting from shallow phase changes in subducted oceanic crust may be the cause of this increased dip angle. In addition, the volume reduction associated with phase changes may produce sufficiently...

Earthquake aftershock identification is closely related to the question “Are aftershocks different from the rest of earthquakes?” We give a positive answer to this question and introduce a general statistical procedure for clustering analysis of seismicity that can be used, in particular, for aftershock detection. The proposed approach expands the analysis of Baiesi and Paczuski [PRE, 69, 06610...

Thermal perturbation of mantle phase relations in subduction zones gives rise to significant buoyancy anomalies. Finite element modeling of stresses arising from these anomalies reveals transition from principal tension to compression near ∼400 km depth, down-dip compression over ∼400-690 km (peaking at ∼550 km), and transition to rapidly fading tension below ∼690 km. Such features, even when c...

Seismicity induced by fluid injection and withdrawal has emerged as a central element of the scientific discussion around subsurface technologies that tap into water and energy resources. Here we present the application of coupled flow-geomechanics simulation technology to the post mortem analysis of a sequence of damaging earthquakes (Mw= 6.0 and 5.8) in May 2012 near the Cavone oil field, in ...

[1] Abstract: The subducting Nazca Plate shows a high degree of along-strike heterogeneity in terms of intermediate-depth seismicity ( 70–300 km), orientations of slab stress, and volcanism. We compile the intermediate-depth earthquakes of South America from the Harvard Centroid Moment Tensor (CMT) catalogue to determine along-strike dip variations, and we explore the variable level of correlat...

The ongoing, dramatic increase in seismicity in the central United States that began in 2009 is believed to be the result of injection-induced seismicity (Ellsworth, 2013). Although the basic mechanism for activation of slip on a fault by subsurface fluid injection is well established (Healy et al., 1968; Raleigh et al., 1976; Nicholson and Wesson, 1992; McGarr et al., 2002; Ellsworth, 2013), t...

A review of case histories of reservoir-induced seismicity (RIS) in China shows that it mainly occurs in granitic and karst terranes. Seismicity in granitic terranes is mainly associated with pore pressure diffusion whereas in karst terranes the chemical effect of water appears to play a major role in triggering RIS. In view of the characteristic features of RIS in China, we can expect moderate...

This paper proposes a new model—the Markov-modulated Hawkes process with stepwise decay (MMHPSD)—to investigate the variation in seismicity rate during a series of earthquake sequences including multiple main shocks. The MMHPSD is a self-exciting process which switches among different states, in each of which the process has distinguishable background seismicity and decay rates. Parameter estim...

The present day seismic activity from a region reflects the active tectonics and can confirm the seismic potential of the seismogenic sources as they are modelled using the historical seismicity. This paper makes a comparative analysis of the last decade seismicity recorded in the Banat Seismic Region (western part of Romania) and the historical seismicity of the region (Mw≥4.0). Four significa...