APPENDIX B PARAMETRIC CATALOGUE OF EARTHQUAKES B.1. Notes on Parametric Table The catalogue lists all selected earthquakes in our region from the beginning of instrumental recording in 1898 to the end of 1995. In general the focal parameters are given with a precision that reflects the quality of their determination. These notes should be read carefully before consulting the catalogue. B.1.1. Origin Following the date, the origin time of each event is given in Universal Time to an appropriate precision, in hours, minutes and seconds. For some early events, particularly those determined from felt information only, the time is given only to the nearest minute, hour or even day. For many recent earthquakes agencies report origin times to a decimal of a second. These have been rounded. An asterisk following the date signifies that the event is a foreshock or aftershock. The epicentre is given in degrees of north latitude and west longitude. Most epicentres are given with a precision of 0.1°, but for better determined events a precision of 0.01° is given. In the middle and early periods this is usually reserved for epicentres that are exceptionally well determined by closely spaced isoseismals. At the other extreme, some poorly determined epicentres are listed only to the nearest degree. No figures are given that are not considered significant. A consequence of this is that positions given in original sources as 1/4° or 3/4° are rounded to .3° or .8° respectively. Depths given as close to the standard default value of 33 km, or for which there is no specific information, are listed as n. If there is definite indication of upper crustal or shallower depth, the designation is s. Unspecified or poorly determined subcrustal and intermediate depths are given as n+ and i, respectively; s usually signifies a depth less than 16 km, n+ a depth between 45 and 60 km, and i one of more than 60 km. Standard default depths (such as .01R or 96 km used by ISS) are rounded to the nearest 5 or 10 km. Depths found by modern computer relocations to be greater than normal may be given to the nearest kilometre, as determined. B.1.2. Agency When origin determinations are available from more than one agency, the choice is generally made in the following order of preference: 1. AM. Well determined macroseismic location carried out by us 2. AR. Good instrumental relocation by us 3. Am. Less well determined macroseismic location by us 4. Ar. Relocated by us, using combined instrumental and felt data, or poor instrumental data 5. Relocations made in special studies: AC. Acharya, 1965 C. Camacho, 1991 D. Dewey and Algermissen, 1974 E. Engdahl, van der Hilst and Buland, 1998 G. Gutenberg, 1958; Gutenberg and Richter, 1956 GD. Güendel, 1986 K. Kelleher, Sykes and Oliver, 1973 M. Molnar and Sykes, 1969 MR. Martinez, 1978 S. Sykes and Ewing, 1965 W. Wysession, Okal and Miller, 1991 6. Locations made by national and international agencies: B. BCIS/Strasbourg I. BAAS/ISS/ISC J. Jesuit Seismological Association OT. Ottawa, Canada SJ. San José, Costa Rica T. Tacubaya, Mexico U. USCGS/USGS/NEIC B.1.3. Size Four columns give information relating to the earthquake's size. Ms Unbracketed values give the surface-wave magnitude determined by us, using the Prague formula as described in the text. The value is followed by the number of station readings used in the determination. Values given in brackets are determinations made by other agencies. mB/mb In the early part of the catalogue this is generally the body -wave magnitude mB, from long- or medium-period instruments, determined by us and followed by the number of stations used. When the value given is bracketed we have adopted it from another agency. For the later period most of the magnitudes from other agencies, and particularly those determined by NEIC, will be mb from short-period instruments.. M*/log Mo For the early period up to 1917, this column gives an equivalent Ms determined from Milne seismographs, followed by the number of stations used. For the period after 1976, we list the logarithm of the seismic moment in newton-metres, usually taken from publications of Harvard University or bulletins of the US Geological Survey. N This column lists the number of station observations reported to the main agency. Not all these are necessarily used in location. If no other information on size is available, this number may be used to give a rough estimate of comparative size of events in the same time period. B.1.4. Other Information In the Felt column roman numerals give the highest reported MSK intensity, where this is V or more. F denotes felt reports of unspecified intensity, or a reported intensity of IV or less. D denotes damage reported, but no specified intensity. Two-letter abbreviations in the column Reg indicate the region by giving the country closest to the epicentre. These are for a guide only, and minor inconsistencies may occur when earthquakes are in a border region or offshore. BZ Belize CR Costa Rica ES El Salvador GU Guatemala HO Honduras MX Mexico NI Nicaragua PA Panama We list other agencies whose solutions we have considered, but not necessarily all other agencies that have published solutions. Notes signifies an entry in the detailed Case Histories in Appendix 1, ts the report of a tsunami, and volc an association with volcanism. The final column gives the felt radii in kilometres where these can be determined for specific MSK intensities.