Entropy is a state function. The entropy increase principle tells us that under isolated or adiathermal conditions, the spontaneous development of a system from a state of non-equilibrium to a state of equilibrium is a process of entropy increase, in which a state of equilibrium corresponds to a state of maximum entropy. When the system is in a state of equilibrium, it is also at its most chaot...

Slow slip forms part of the spectrum of fault behaviour between stable creep and destructive earthquakes1,2. Slow slip occurs near the boundaries of large earthquake rupture zones3,4 and may sometimes trigger fast earthquakes2. It is thought to occur in faults comprised of rocks that strengthen under fast slip rates, preventing rupture as a normal earthquake, or on faults that have elevated por...

A catalog of 383 earthquakes in southeastern New York, southwestern Connecticut, northern New Jersey, and eastern Pennsylvania, including metropolitan New York City and Philadelphia, is compiled from historical and instrumental data from 1677 through 2006. A magnitude-felt area relationship is used to calculate the equivalent magnitudembLg prior to the advent of abundant instrumental data in 19...

We show using a comparison of source time function pulse widths that a group of earthquakes on the San Andreas Fault near Parkfield have a constant duration over a magnitude range of 1.4 to 3.7. Earthquakes on secondary faults have an increase in duration with magnitude, which is the expected relationship for the usual observation of constant stress drop. The constant duration suggests that fau...

We used a comparison of source time function pulse widths to show that a group of earthquakes on the San Andreas fault near Parkfield have a constant duration over a magnitude range of 1.4–3.7. Earthquakes on secondary faults have an increase in duration with magnitude, which is the expected relationship for the usual observation of constant stress drop. The constant duration suggests that faul...

The characteristics of earthquake swarms can neither be described by simple laws nor are the underlying mechanisms presently understood. Swarm activity is often assumed to be caused by an intrusion of uids into the seismogenic zone. We have studied the earthquake catalog of the large earthquake swarm which occurred in the year 2000 in Vogtland, SE-Germany and NW-Bohemia, an area well-known for ...

[1] We relate seismologically observable parameters such as radiated energy, seismic moment, rupture area, and rupture speed to the dynamics of faulting. To achieve this objective, we computed the radiated energy for 23 subduction zone earthquakes recorded between 1992 and 2001; most of these earthquakes have a magnitude Mw > 7.5, but we also included some smaller (Mw 6.7) well-studied subducti...

Induced earthquakes currently pose a significant hazard in the central United States, but there is considerable uncertainty about the severity of their ground motions. We measure stress drops of 39 moderate-magnitude induced and tectonic earthquakes in the central United States and eastern North America. Induced earthquakes, more than half of which are shallower than 5 km, show a comparable med...

Seismic hazard and risk are fundamentally different concepts. Seismic hazard describes phenomena generated by earthquakes that have potential to cause harm, but seismic risk is the likelihood (chance) of experiencing a specified level of seismic hazard in a given time exposure. Seismic hazard occurs naturally and can be evaluated from instrumental, historical, and geological observations. Seism...