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Location of the Carlsberg Fault zone from seismic controlled‐source fan recordings
Author(s) -
Nielsen Lars,
Thybo Hans
Publication year - 2004
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl019603
Subject(s) - geology , seismology , fault (geology) , shadow zone , baltic shield , seismic wave , tectonics
We locate the concealed Carlsberg Fault zone in the city of Copenhagen from seismic fan recordings. The fault is part of a fault system close to the border between the Danish Basin and the Baltic Shield. Recent earthquakes indicate that this area is tectonically active. The fault zone is a seismic low‐velocity zone. Fan shots were recorded on three receiver arrays (1.5–2.4 km long arcs) across the fault. Sources were placed inside and up to ∼500 m away from the ∼400–700 m wide fault zone at offsets of up to ∼7 km. Shots inside the fault zone show: 1) weak, delayed first arrivals inside the fault zone; 2) stronger first arrivals outside the fault zone; 3) guided waves inside the fault zone. The fault is a shadow zone for shots detonated outside the fault zone. Our approach facilitates fault mapping in densely urbanized areas where seismic profiling is not feasible.