Michael Manga - Böcker

It has been documented for many centuries that earthquakes and other tectonic processes have hydrological effects.  The magnitude and the spatial and temporal patterns of such signals recorded by scientific instruments in modern times have not always been straightforward to explain, and hence remain the subject of active research, especially those that might be precursors to earthquakes. This volume contains 9 papers that present new observations on earthquake-related hydrological, geochemical, and geophysical changes in Japan, Taiwan, Baja California in Mexico, and mostly China, one paper on laboratory rock-mechanics study, and a brief overview of Chinese research on earthquake prediction during the past 5 decades.  Some of the observed changes occurred several days before earthquakes, and are explained with the consideration of heterogeneity of the earth's crust and earthquake-related slow-slip events, with earthquake forecasting as a possible application.

Although the effects of earthquakes on streams and groundwater have been reported for thousands of years, this field has only blossomed into an active area of research in the last twenty years after quantitative and continuous documentation of field data became available.

Distantearthquakesarewellknowntoinduceawiderangeofresponsesinsurface water and groundwater. These responses are often viewed as mere curiositiesas theiroccurrenceislimitedinspaceandtime.Thefrequentemphasisonearthquake precursorsinstudiesofthesephenomenaalsotendstopushthestudyof'earthquake hydrology' away from the mainstream of geoscience. The observed phenomena, however,probetheinteractionbetweenhydrogeologicalprocessesandmechanical deformationintheshallowcrust.Hencetheyprovideinsightintotheinteraction among water cycle, tectonics, and properties of the crust. As such, the study of earthquakehydrologyalsohasthepotentialtoprovideamorequantitativeand- depthunderstandingofthenatureofearthquakeprecursorsandevaluatewhether theyareinfactprecursors. The title of this book re ects the nature of the connections we address: we focus on how earthquakes affect hydrology. Water also in uences earthquakes as it affects the strength of faults and the rheology of rocks. Our emphasis here, however, is not on the hydrology of earthquakes, but on understanding the hydrological phenomena induced or modi ed by earthquakes.The boundary betweenthe'hydrologyofearthquakes'andthe'earthquake-inducedhydrological phenomena', however, can sometimes be blurred. For example, triggered ear- quakes are sometimes explained by a re-distribution of pore pressure following the triggering earthquake. Hence, triggered seismicity may be an example of an earthquake-induced hydrological phenomenon. Thestudyofthelatter,therefore, canbeimportanttowardsabetterunderstandingofthemechanicsofatleastsome earthquakes. Therearemanystudents,postdocsandcolleagueswewishtothankforcolla- ratingonresearchprojectsrelatedtothetopicsreviewedinthisbook,orparticip- inginstimulatingdiscussionsintheclasswetaughtcalled'Earthquakehydrology'. In particular, we wish to thank Emily Brodsky, Yeeping Chia, Douglas Dreger, Shemin Ge, Fu-qiong Huang, Tom Holzer, Chris Huber, Joel Rowland, Martin Saar, Yaolin Shi, Chung-Ho Wang, Kelin Wang, Pei-ling Wang and Alex Wong forenlighteningexchanges.HunterPhilsonhelpedwith guresandtheindex.We v vi Preface alsothanktheNationalScienceFoundation,theMillerInstituteforBasicResearch inScience,andNASAforsupportingtheresearchandsynthesisinthisvolume.